WO2009099978A1 - Arrangement suitable for driving floating ccfl based backlight - Google Patents
Arrangement suitable for driving floating ccfl based backlight Download PDFInfo
- Publication number
- WO2009099978A1 WO2009099978A1 PCT/US2009/032787 US2009032787W WO2009099978A1 WO 2009099978 A1 WO2009099978 A1 WO 2009099978A1 US 2009032787 W US2009032787 W US 2009032787W WO 2009099978 A1 WO2009099978 A1 WO 2009099978A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- pair
- luminaire
- balancing transformer
- balancing
- transformer
- Prior art date
Links
- 238000007667 floating Methods 0.000 title description 24
- 238000004804 winding Methods 0.000 claims description 153
- 230000001747 exhibiting effect Effects 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 19
- 230000008878 coupling Effects 0.000 claims description 6
- 238000010168 coupling process Methods 0.000 claims description 6
- 238000005859 coupling reaction Methods 0.000 claims description 6
- 238000010586 diagram Methods 0.000 description 18
- 239000002184 metal Substances 0.000 description 12
- 239000000470 constituent Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000003071 parasitic effect Effects 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000003467 diminishing effect Effects 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000010363 phase shift Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
- H05B41/14—Circuit arrangements
- H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
- H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
- H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
- H05B41/2821—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a single-switch converter or a parallel push-pull converter in the final stage
- H05B41/2822—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a single-switch converter or a parallel push-pull converter in the final stage using specially adapted components in the load circuit, e.g. feed-back transformers, piezoelectric transformers; using specially adapted load circuit configurations
Definitions
- Backlight systems in LCD or other applications typically include one or more CCFLs and an inverter system to provide both DC to AC power conversion and control of the lamp brightness. Even brightness across the panel and clean operation of inverters with low switching stresses, low EMI, and low switching losses is desirable.
- the lamps are typically arranged with their longitudinal axis proceeding horizontally. In general, even brightness involves two dimensions: uniform brightness in the vertical dimension, i.e. among the various lamps; and uniform brightness along the longitudinal axis of each of the various lamps in the horizontal dimension. Brightness uniformity in the vertical dimension is largely dependent on matching the lamp currents which normally requires a certain type of balancing technique to maintain an even lamp current distribution.
- Patent S/N 7,242,147 issued July 10, 2007 to Jin, entitled “Current Sharing Scheme for Multiple CCFL Lamp Operation", the entire contents of which is incorporated herein by reference, is addressed to a ring balancer comprising a plurality of balancing transformers which facilitate current sharing in a multi-lamp backlight system thus providing even lamp current distribution.
- the term single ended drive architecture refers to a backlight arrangement in which the high voltage drive power is applied from only one side of the lamp, which is usually called the 'hot' end, and the other side of the lamp is normally at ground potential and referred as the 'cold' end.
- Phase Inverters for CCFL Backlight System is addressed to an inverter arrangement in which the switching elements are split into two inverter arms that are deployed at separate terminals of a floating lamp structure.
- Such a concept provides even brightness across the longitudinal dimension of the lamps with lower cost compared with the conventional approach of deploying a full bridge circuit at each end of the lamps, while maintaining the advantages of soft switching operation of the full bridge.
- separate inverter circuits are still needed to develop driving power at both ends of the lamp, and in addition, wiring of power cables and control signals could lead to potential electromagnetic interference issues, in particular as high voltage signals traversing the chassis length exhibitive capacitive coupling to the chassis.
- a reflective material is disposed behind the lamps, typically based on metal, the metal based reflective material further adding to the capacitive coupling.
- a backlighting arrangement that can provide even luminance across each lamp in the system, preferably with only one inverter circuit, and further preferably where there is no high voltage or high switching current wiring across the horizontal length of the panel.
- a backlighting arrangement in which pairs of balancing transformers are provided, each associated with a particular luminaire.
- the primary winding of each of the balancing transformers is coupled in series with a respective end of the associated luminaire.
- the secondary windings of the balancing transformers are connected in a single closed loop, and arranged to be in-phase.
- the luminaires each comprise a pair of lamps, and an additional pair of balancing transformers is provided associated with each pair of lamps.
- the primary windings of the additional pair are coupled in series and between the lamps.
- the secondary windings of the additional pair are connected in-phase within the single closed loop.
- the luminaire is connected across an AC power source, such as an inverter or a single ended AC power source, and the nexus of the pair of lamps not directly connected to the AC power source receives energy via the balancing transformers thereby providing even brightness.
- the present embodiments enable a backlighting arrangement comprising: a first lead and a second lead arranged to receive and return an alternating current; at least one luminaire; and at least one first balancing transformer pair each of the transformer pair associated with a particular one of the at least one luminaire, the primary winding of a first balancing transformer of each of the first balancing transformer pair serially coupled between the first lead and a first end of the associated at least one luminaire, and the primary winding of a second balancing transformer of each of the first balancing transformer pair serially coupled between the second lead and a second end of each of the associated at least one luminaire, wherein the secondary windings of all of the at least one first balancing transformer pair are serially connected in a closed in-phase loop.
- at least one of the at least one luminaire comprises a serially connected pair of linear lamps.
- at least one of the at least one luminaire comprises a U-shaped lamp.
- At least one of the at least one luminaire comprises a single linear lamp.
- the backlighting arrangement further comprises a differential alternating current source arranged to supply power to the at least one luminaire via the first and second leads.
- the at least one luminaire comprises a plurality of luminaires.
- the backlighting arrangement further comprises a single ended alternating current source arranged to supply power to the at least one luminaire via the first and second leads, wherein the first lead is connected to the single ended alternating current source, and the second lead is connected to a ground connection.
- the backlighting arrangement further comprises a sense resistor serially connected within the serially connected closed in- phase loop arranged to present a voltage drop representation of the current flowing through the closed in-phase loop.
- the backlighting arrangement further comprises at least one second balancing transformer pair each of the second transformer pair associated with a particular one of the at least one luminaire and wherein each of the at least one luminaire comprises a pair of linear lamps each exhibiting a far end removed from each of the first and second ends of the luminaire, the primary windings of the second balancing transformer pair being arranged in series and serially coupled between the far ends of associated pair of linear lamps, the secondary windings of the second balancing transformer pair being serially connected in-phase in the closed in-phase serial loop.
- the backlighting arrangement further comprises a differential alternating current source arranged to supply power to the at least one luminaire via the first and second leads.
- the backlighting arrangement further comprises a single ended alternating current source arranged to supply power to the at least one luminaire via the means for first and second leads, wherein the first lead is connected to the single ended alternating current source, and the second lead is connected to a ground connection.
- the backlighting arrangement further comprises a sense resistor serially connected within the serially connected closed in- phase loop arranged to present a voltage drop representation of the current flowing through the closed in-phase loop.
- each of the at least one luminaire comprises a pair of linear lamps each exhibiting a far end removed from each of the first and second ends of the luminaire, the arrangement further comprising at least one second balancing transformer each associated with a particular one of the pair of linear lamps, the primary windings of each of the second balancing transformer being coupled between the far ends of the associated pair of linear lamps, the secondary windings of the second balancing transformer being serially connected in-phase in the closed in- phase serial loop.
- the at least one pair of linear lamps are arranged substantially in parallel to backlight a display, and wherein the serially connected closed in-phase loop exhibits a single twisted wire pair connecting a portion of the closed in-phase loop associated with a first end of the display to a portion of the closed in-phase loop associated with a second end of the display opposing the first end of the display.
- the present embodiments independently provide for a method of driving at least one luminaire, comprising: receiving an alternating current; providing at least one luminaire; and providing a first balancing transformer pair associated with each of the provided at least one luminaire, the primary winding of a first transformer of the respective balancing transformer pair associated with a first end of the associated luminaire, and the primary winding of a second transformer of the particular balancing transformer pair associated with a second end of the associated luminaire; coupling the received alternating current via the primary windings of the first balancing transformer pair to each end of the provided at least one luminaire; and arranging the secondary windings of all of the provided at least one first balancing transformer pair in a serially connected closed in-phase loop.
- At least one of the provided at least one luminaire comprises a serially connected pair of linear lamps. In another embodiment, at least one of the provided at least one luminaire comprises a U-shaped lamp.
- At least one of the provided at least one luminaire comprises a single linear lamp. In another embodiment the method further comprises sensing a current flowing through the closed in-phase loop.
- each of the provided at least one luminaire comprises a pair of linear lamps each exhibiting a far end removed from each of the first and second ends of the luminaire, the method further comprising: providing at least one second balancing transformer pair, each balancing transformer of the pair associated with a particular one of the provided at least one luminaire; arranging the primary windings of the second balancing transformer pair in series and serially connecting the series arranged primary windings between the far ends of the associated pair of linear lamps; and arranging the secondary windings of the provided at least one second balancing transformer pair in the serially connected closed in- phase loop.
- the present embodiment independently provide for a backlighting arrangement comprising: a means for receiving an alternating current exhibiting a first lead and a second lead; a plurality of luminaires; and a plurality of first balancing transformer pairs each associated with a particular one of the plurality of luminaires, the primary winding of a first balancing transformer of each of the first balancing transformer pair serially coupled between the first lead of the means for receiving an alternating current and a first end of the associated luminaire, and the primary winding of a second balancing transformer of each of the first balancing transformer pair serially coupled between the second lead of the means for receiving an alternating current and a second end of the associated luminaire, wherein the secondary windings of all of the at least one first balancing transformer pair are serially connected in a closed in-phase loop.
- the backlighting arrangement further comprises a plurality of second balancing transformer pairs each associated with a particular one of the plurality of luminaires and wherein each of the plurality of luminaires comprises a pair of lamps each exhibiting a far end removed from each of the first and second ends of the luminaire, the primary windings of the associated second balancing transformer pair being arranged in series and serially connected between the far ends of the pair of linear lamps, the secondary windings of the second balancing transformer pair being serially connected in-phase in the closed in-phase serial loop.
- FIG. 2 illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement comprising a plurality of luminaires, each constituted of a serially connected linear lamp pair, and a differential AC source in which energy is supplied to the far side of each of the lamps by a balancing network;
- FIG. 3 illustrates a high level block diagram of an exemplary embodiment of a lighting arrangement comprising a plurality of luminaires, each constituted of a single linear lamp, and a single ended AC source
- Fig. 4 illustrates a high level block diagram of an exemplary embodiment of a lighting arrangement comprising a plurality of luminaires, each constituted of a U-shaped lamp, and a single ended AC source;
- FIG. 5 illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement comprising a plurality of luminaires, each constituted of a pair of serially coupled linear lamps, and a differential AC source;
- Fig. 6 illustrates a high level block diagram of an exemplary embodiment of a lighting arrangement comprising a plurality of luminaires, each constituted of a pair of serially coupled linear lamps, and a single ended AC source
- Fig. 7 illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement comprising a plurality of luminaires, each constituted of a U-shaped lamp, and a differential AC source
- Fig. 6 illustrates a high level block diagram of an exemplary embodiment of a lighting arrangement comprising a plurality of luminaires, each constituted of a U-shaped lamp, and a differential AC source
- Fig. 7 illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement comprising a plurality of luminaires, each constituted of a U-shaped lamp, and a differential AC source
- Fig. 6 illustrates a high level block diagram of an exemplary embodiment of a lighting arrangement comprising a plurality of luminaires, each constituted of a U
- FIG. 8 illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement comprising a plurality of luminaires, each constituted of a linear lamp pair, each of the linear lamp pairs sharing a single balancing transformer at the far end, and a differential AC source, in which energy is supplied to the far side of each of the lamp pairs by a balancing network.
- Certain of the present embodiments enable a backlighting arrangement in which pairs of balancing transformers are provided, each associated with a particular luminaire.
- the primary winding of each of the balancing transformers is coupled in series with a respective end of the associated luminaire.
- the secondary windings of the balancing transformers are connected in a single closed loop, and arranged to be in-phase.
- Fig. IA illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement 10 comprising a single luminaire, constituted of a lamp 20, arranged to backlight a display 30.
- Display 30 is typically constituted of a metal based chassis.
- Floating lighting arrangement 10 further comprises: a driver 40; a driving transformer 50 exhibiting a first output 60 and a second output 70; a first and a second balancing transformer 80; and a twisted wire pair 90.
- the outputs of driver 40 are connected to both ends of the primary winding of driving transformer 50.
- the first end of the secondary winding of driving transformer 50 denoted first output 60, is connected to the first end of the primary winding of first balancing transformer 80.
- the second end of the primary winding of first balancing transformer 80 is connected to the first end of lamp 20.
- the second end of lamp 20 is connected to the first end of the primary winding of second balancing transformer 80, and the second end of the primary winding of second balancing transformer 80 is connected the second end of the secondary winding of driving transformer 50, denoted second output 70.
- the secondary windings of first and second balancing transformers 80 are connected in a closed serial loop, the serial loop further comprising a sense resistor RS.
- the polarity of the secondary windings of first and second balancing transformers 80 are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop.
- the wires of the closed loop connecting the secondary windings of first and second balancing transformers 80 are arranged via a twisted wire pair 90.
- the first end of lamp 20 is in physical proximity of driving transformer 50, e.g. on the same side of display 30 typically constituted of a metal based chassis, as driving transformer 50, and in physical proximity of first balancing transformer 80, and preferably generally define a first plane.
- lamp 20, typically constituted of a linear lamp generally extends axially away from the proximity of driving transformer 50, and generally defines a second plane, further preferably orthogonal to the first plane.
- driver 40 which in one embodiment comprises a direct drive backlight driver as described in U.S. Patent S/N 5,930,121 issued July 27, 1999 to Henry, entitled “Direct Drive Backlight System", the entire contents of which is incorporated herein by reference, provides a differential AC source via driving transformer 50.
- the secondary of driving transformer 50 is allowed to float.
- first output 60 as AC+
- second output 70 as AC-, which is appropriate for 1/2 the drive cycle.
- polarity is reversed and the direction of current flow is reversed.
- a current Il is developed through the primary winding of first balancing transformer 80, responsive to AC+ at first output 60, and driven through lamp 20.
- Current Il proceeds via the primary winding of second balancing transformer 80 and is returned to AC- at second output 70.
- Current 12 is developed in the secondary of first balancing transformer 80, responsive to II, and flows via sense resistor RS and a first wire of twisted wire pair 90 to the secondary of second balancing transformer 80.
- the voltage developed across the secondary of second balancing transformer 80 is in phase in the closed loop with the voltage developed across the secondary of first balancing transformer 80, and thus current 12 continues through the secondary of second balancing transformer 80 and is returned via a second wire of twisted wire pair 90.
- the turns ratio of each of first and second balancing transformers 80 are such that twisted wire pair 90 exhibits low voltage and high current, thereby reducing any capacitive coupling to the constituent chassis of display 30.
- the use of twisted wire pair 90, exhibiting similar current and voltage with reverse polarity in each of the constituent wires further reduces any electromagnetic interference caused by twisted wire pair 90 traversing the length of display 30.
- first and second balancing transformers 80 are serially connected in a closed loop, and thus the current circulating in each of the secondary winding is substantially equal. If the magnetizing currents of the balancing transformers are neglected, the following relationship can be established for each of the balancing transformers :
- Npi -H Ns I -H
- N P2 -I1 N S2 -I2; EQ. 1
- Fig. IB illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement 100 constituted of a pair of linear lamps 20, arranged to backlight a display 30.
- Floating lighting arrangement 100 further comprises: a driver 40; a driving transformer 50 exhibiting a first output 60 and second output 70; a first and a second balancing transformer 80; a first and a second balancing transformer 85; and a twisted wire pair 90.
- Balancing transformers 80 and 85 may be of identical type without exceeding the scope of the invention.
- the outputs of driver 40 are connected to both ends of the primary winding of driving transformer 50.
- the first end of the secondary winding of driving transformer 50 denoted first output 60, is connected to the first end of the primary winding of first balancing transformer 80.
- the second end of the primary winding of first balancing transformer 80 is connected to the first end of first lamp 20.
- the second end of first lamp 20 is connected to the first end of the primary winding of first balancing transformer 85, and the second end of the primary winding of first balancing transformer 85 is connected the first end of the primary winding of second balancing transformer 85.
- the second end of the primary winding of second balancing transformer 85 is connected to the first end of second lamp 20.
- the second end of second lamp 20 is connected to the first end of the primary winding of second balancing transformer 80 and the second end of the primary winding of second balancing transformer 80 is connected to the second end of the secondary winding of driving transformer 50, denoted second output 70.
- the secondary windings of first and second balancing transformers 80 and the secondary windings of first and second balancing transformers 85 are connected in a single closed serial loop via a sense resistor RS.
- the polarity of the secondary windings of the first and second balancing transformers 80 and the secondary windings of the first and second balancing transformers 85 are arranged so that voltages induced in the secondary windings are in phase and add within the serial closed loop.
- the wires of the closed loop connecting the respective ends of the secondary windings of the first and second balancing transformers 80 to respective ends of the secondary windings of the first and second balancing transformers 85 are arranged via a twisted wire pair 90.
- first end of first lamp 20 and the second end of second lamp 20 are in physical proximity of driving transformer 50, e.g. on the same side of display 30 typically constituted of a metal based chassis, as driving transformer 50, and in physical proximity of first and second balancing transformers 80, and preferably generally define a first plane.
- first and second lamps 20, each typically constituted of a linear lamp generally extend axially away from the proximity of driving transformer 50, and generally define a second plane, further preferably orthogonal to the first plane.
- driver 40 provides a differential AC source via driving transformer 50.
- the secondary of driving transformer 50 is allowed to float.
- first output 60 as AC+
- second output 70 as AC-, which is appropriate for 1/2 the drive cycle.
- polarity is reversed and the direction of current flow is reversed.
- a current Il is developed through the primary winding of first balancing transformer 80, responsive to AC+ at first output 60, and driven through first lamp 20.
- Current Il proceeds through the primary winding of first balancing transformer 85, through the primary winding of second balancing transformer 85, through second lamp 20, through the primary winding of second balancing transformer 80 and is returned to AC- at second output 70.
- the secondary windings of first and second balancing transformers 80 and first and second balancing transformers 85 are serially connected in a closed loop, and thus current 12 circulating in each of the secondary windings is substantially equal. If the magnetizing currents of the balancing transformers are neglected, the following relationship can be established for each of the balancing transformers:
- Ipi (N S1 /N P1 )-I S1 ;
- Ip 2 (Ns 2 ZN P2 )-Is 2 ;
- I P3 (Ns 3 ZN P3 yi S3 ;
- Ip 4 (N S4 ZN P4 )-I S4 EQ. 4
- lamp current can also be detected by sense resistor RS in the secondary winding loop and measured responsive to voltage drop across sense resistor RS. Because the secondary windings of balancing transformers 80, 85 are isolated from the lamp high voltage side, the signal from sense resistor RS can be fed to a low voltage controller circuit directly for regulation and monitoring purposes. Such application is especially useful with a floating lamp configuration, such as floating lighting arrangement 100, where no ground potential node is available in the lamp circuit for direct current sensing.
- Coupling the secondary windings of the balancing transformers 80, 85 in a closed loop also couples energy between balancing transformers 80, 85 through the circulating current in the secondary winding loop.
- the energies needed to drive the far end of first and second lamps 20 are coupled by this mechanism through balancing transformers 85.
- the balancing error of the lamp current is related to the lamp operating voltage and the magnetizing inductance of the balancing transformer as described below under steady state operating condition:
- ⁇ I represents the balancing error, i.e. the difference of the lamp current from the lamp terminals
- ⁇ is the angular frequency of the AC source
- Lm is the magnetizing inductance from the primary side of the balancer
- V is the lamp operating voltage
- the two wires can be brought to one edge of display 30 and twisted together to yield minimum electro-magnetic field interference, as illustrated by twisted wire pair 90. Further, because the voltage in secondary windings of transformer balancers 20 may be set to be very low responsive to an appropriate turns ratio, the twisted wire pair does not produce any high capacitive leakage current and associated interference.
- FIG. 2 illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement 200 arranged to backlight a display 30 comprising a plurality of luminaires 205A ... 205K, each constituted of a pair of serially arranged linear lamps 20Al, 20A2 ...20Kl, 20K2, and a differential AC source in which energy is supplied to the far side of each of the lamps by a balancing network.
- Floating lighting arrangement 200 further comprises: a driver 40; a driving transformer 50 exhibiting a first output 60 and a second output 70; a plurality of balancing transformers 80; a plurality of balancing transformers 85; and a wire pair 210A, 210B.
- the first end of the secondary winding of driving transformer 50 is connected through the primary winding of a respective balancing transformer 80 to a first end of first linear lamp 20Al, ...,20Kl of each of the respective luminaires 205 A, ..., 205K.
- the nexus of the second end of first linear lamp 20Al, ..., 20Kl and the first end of second linear lamp 20A2, ..., 20K2 of each luminaire 205 A, ..., 205K is connected through the primary windings of the respective associated pair of balancing transformers 85 arranged in series.
- the second end of each second linear lamp 20A2 ...
- the secondary windings of the balancing transformers 80, 85 are connected in a closed loop, in which the polarity of the secondary windings are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop.
- a sense resistor RS is inserted within the loop to detect current flow.
- the wires of the closed loop connecting across the length of the linear lamps, denoted 210A, 210B, are arranged in a twisted wire pair.
- lighting arrangement 200 is illustrated with first output 60 exhibiting AC+ and second output 70 exhibiting AC-, which is appropriate for 1/2 the drive cycle. During the second half of the drive cycle, polarity is reversed and the direction of current flow is reversed. Current flow in the primary windings is illustrated as II, and current flow in the secondary loop is illustrated as 12.
- lighting arrangement 200 operates in all respects similar to the operation of lighting arrangement 100, with power for the side of all lamps not directly connected to driving transformer 50, i.e. the far or cold end, supplied by the closed loop of the secondary windings of balancing transformers 80, 85. Power is thus alternately driven into each end of each lamp 20.
- FIG. 3 illustrates a high level block diagram of an embodiment of a lighting arrangement 300 arranged to backlight a display 30 in accordance with a principle of the invention comprising a plurality of luminaires, each constituted of a single linear lamps 2OA, 2OB, ... 2OK, 2OL and a single ended high voltage AC source, exhibiting a common return which is typically connected to chassis ground plane, in which energy is supplied to the far end of each of the linear lamps 2OA, 2OB, ... 2OK, 2OL by a balancing network.
- Grounded lighting arrangement 300 further comprises a plurality of balancing transformers 80 each associated with one end of a particular linear lamp 2OA, 2OB,... 2OK, 2OL.
- the number of lamps is shown as being divisible by 2, however this is not meant to be limiting in any way and an odd number of lamps 20 may be supplied without exceeding the scope of the invention.
- the high voltage AC input is connected in parallel through the primary winding of a respective balancing transformer 80 to a first end of each linear lamp 2OA, 2OB,...20L, 2OK.
- the second end of each linear lamp 2OA, 2OB,...20L, 2OK is connected through the primary winding of the respective associated balancing transformer 80 to the common return.
- the secondary windings of the balancing transformers 80 are connected in a closed loop, in which the polarity of the secondary windings are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop.
- a sense resistor (not shown) is inserted within the loop to detect current flow.
- the wires of the closed loop connecting across the length of the linear lamps are arranged in a twisted wire pair.
- the direction of current flow is illustrated when a positive voltage appears at the high voltage AC input, denoted HVAC.
- Current flow in the primary windings is illustrated as II, and current flow in the secondary loop is illustrated as 12. Current flows in the opposite direction for each of Il and 12 when a negative voltage, with respect to the common return, appears at HVAC.
- each linear lamp 2OA, 2OB,...2OL, 2OK is in physical proximity of a source driving transformer providing the HVAC, e.g. on the same side of display 30 typically constituted of a metal based chassis, as the driving transformer, and in physical proximity of the associated balancing transformers 80, and preferably generally define a first plane.
- each linear lamp 2OA, 2OB,...2OL, 2OK generally extend axially away from the proximity of the source driving transformer providing the HVAC, and generally define a second plane, further preferably orthogonal to the first plane.
- lighting arrangement 300 operates in all respects similar to the operation of lighting arrangement 200, except that all the lamps are driven with the same voltage from their hot side, i.e. the side connected to HVAC. Driving energy is coupled to the far or cold side by the closed loop of the secondary winding when a negative voltage with respect to the common return appears at input HVAC. Power is thus alternately driven into each end of each lamp 20.
- the high voltage AC input is connected in parallel through the primary winding of a respective balancing transformer 80 to a first end of each U-shaped lamp 410A, ..., 410K.
- the second end of each U-shaped lamp 410A, ..., 410K is connected through the primary winding of a respective balancing transformer 80 to the common return.
- the secondary windings of the balancing transformers 80 are connected in a closed loop, in which the polarity of the secondary windings are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop.
- a sense resistor (not shown) is inserted within the loop to detect current flow.
- the direction of current flow is illustrated when a positive voltage appears at the high voltage AC input, denoted HVAC.
- Current flow in the primary windings is illustrated as II, and current flow in the secondary loop is illustrated as 12.
- each U-shaped lamp 410A, ... 410K generally extends axially away from the proximity of the source driving transformer providing the high voltage AC input, and generally define a second plane, further preferably orthogonal to the first plane.
- lighting arrangement 400 operates in all respects similar to the operation of lighting arrangement 300, with the far or cold end of the lamps 410 appearing on the same vertical plane as the hot end by the U-shape lamp arrangement.
- the drive power for the cold end is derived through the closed secondary winding loop as described above in relation to arrangement 300. Power is thus alternately driven into each end of each lamp 410.
- FIG. 5 illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement 500 arranged to backlight a display 30 comprising a plurality of luminaires 510A, ..., 510K, each constituted of a pair of serially coupled linear lamps, and a differential AC source.
- Floating lighting arrangement 500 further comprises a plurality of balancing transformers 80 each associated with one end of a particular luminaire 510A, ..., 510K.
- the number of balancing transformers is twice the number of luminaires 510.
- One end of the differential driving AC voltage, denoted AC+, is connected in parallel through the primary winding of a respective balancing transformer 80 to a first end of each of the luminaires 510A, ..., 510K.
- the second end of each luminaire 510A, ..., 510K is connected through the primary winding of the respective associated balancing transformer 80 to the second end of the differential driving AC voltage, denoted AC-.
- the secondary windings of the balancing transformers 80 are connected in a closed loop, in which the polarity of the secondary windings are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop.
- a sense resistor (not shown) is inserted within the loop to detect current flow.
- the direction of current flow is illustrated when a positive voltage appears at AC+.
- Current flow in the primary windings is illustrated as II, and current flow in the secondary loop is illustrated as 12.
- each luminaire 510A Preferably, the first end and second ends of each luminaire 510A, ...,
- each luminaire 510A, ..., 510K are in physical proximity of a source driving transformer providing the differential high voltage AC input, e.g. on the same side of display 30 typically constituted of a metal based chassis, as the driving transformer, and in physical proximity of the associated balancing transformers 80, and preferably generally define a first plane.
- each luminaire 510A, ..., 510K generally extends axially away from the proximity of the source driving transformer providing the differential high voltage AC input, and generally define a second plane, further preferably orthogonal to the first plane.
- lighting arrangement 500 operates in all respects similar to the operation of lighting arrangement 400 and is therefore not further detailed.
- FIG. 6 illustrates a high level block diagram of an embodiment of a grounded lighting arrangement 600 arranged to backlight a display 30 in accordance with a principle of the invention comprising a plurality of luminaires 51 OA, ... , 51 OK, each constituted of a pair of serially coupled linear lamps, and a single ended high voltage AC source, exhibiting a common return which is typically connected to a chassis ground plane.
- Grounded lighting arrangement 600 further comprises a plurality of balancing transformers 80 each associated with one end of a particular luminaire 510A, ..., 510K.
- the secondary windings of the balancing transformers 80 are connected in a closed loop, in which the polarity of the secondary windings are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop.
- a sense resistor (not shown) is inserted within the loop to detect current flow.
- the direction of current flow is illustrated when a positive voltage appears at the high voltage AC input, denoted HVAC.
- Current flow in the primary windings is illustrated as II, and current flow in the secondary loop is illustrated as 12.
- each luminaire 510A, ..., 510K are in physical proximity of a source driving transformer providing the single ended high voltage AC input, e.g. on the same side of display 30 typically constituted of a metal based chassis, as the driving transformer, and in physical proximity of the associated balancing transformers 80, and preferably generally define a first plane.
- each luminaire 510A, ..., 510K generally extends axially away from the proximity of the source driving transformer providing the differential high voltage AC input, and generally define a second plane, further preferably orthogonal to the first plane.
- lighting arrangement 600 operates in all respects similar to the operation of lighting arrangement 500 and is therefore not further detailed.
- the second end of each U-shaped lamp 410A, ..., 410K is connected through the primary winding of the respective associated balancing transformer 80 to the second end of the differential AC input, denoted AC-.
- the secondary windings of the balancing transformers 80 are connected in a closed loop, in which the polarity of the secondary windings are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop.
- a sense resistor (not shown) is inserted within the loop to detect current flow.
- the direction of current flow is illustrated when a positive voltage appears at first input AC+.
- Current flow in the primary windings is illustrated as II, and current flow in the secondary loop is illustrated as 12.
- the first end and second ends of each U-shaped lamp 410A are connected in a closed loop, in which the polarity of the secondary windings are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop.
- a sense resistor (not shown) is inserted within the loop to detect current flow.
- the direction of current flow is illustrated when a positive voltage appears at first input AC+.
- Current flow in the primary windings is illustrated as II, and current flow in the secondary loop
- ... 410K are in physical proximity of a source driving transformer providing the differential AC input, e.g. on the same side of display 30 typically constituted of a metal based chassis, as the driving transformer, and in physical proximity of the associated balancing transformers 80, and preferably generally define a first plane.
- each U-shaped lamp 410A, ... 410K generally extends axially away from the proximity of the source driving transformer providing the differential AC input, and generally define a second plane, further preferably orthogonal to the first plane.
- lighting arrangement 700 operates in all respects similar to the operation of lighting arrangement 400 and is therefore not further detailed.
- FIG. 8 illustrates a high level block diagram of an embodiment of a floating lighting arrangement 800 in accordance with a principle of the invention comprising a plurality of luminaries 205 A, ..., 205K, each constituted of a serially arranged linear lamp pair, 20Al, 20A2 ...20Kl, 20K2, and a differential AC source in which energy is supplied to the far end of each of the lamp pairs by a balancing network
- Floating lighting arrangement 800 comprises: a driver 40; a driving transformer 50 exhibiting a first output 60 and a second output 70; a plurality of balancing transformers 80; a plurality of balancing transformers 85; and a wire pair 210A, 210B.
- Each luminaire 205 A, ..., 205K has associated therewith a balancing transformer 80 associated with a first end thereof and a balancing transformer 80 associated with a second end thereof.
- a single balancing transformer 85 serially connects the far ends of the lamps of each linear lamp pair 20Al, 20A2 ...20Kl, 20K2.
- the outputs of driver 40 are connected to both ends of the primary winding of driving transformer 50.
- the first end of the secondary winding of driving transformer 50, denoted first output 60 is connected through the primary winding of a respective balancing transformer 80 to a first end of first lamp 20Al, ...,20Kl of each of the respective luminaires 205 A, ..., 205K.
- the secondary windings of the balancing transformers 80, 85 are connected in a closed loop, in which the polarity of the secondary windings are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop.
- a sense resistor RS is inserted within the loop to detect current flow.
- the wires of the closed loop connecting across the length of the linear lamps, denoted 210A, 210B, are arranged in a twisted wire pair.
- lighting arrangement 200 is illustrated with first output 60 exhibiting AC+ and second output 70 exhibiting AC-, which is appropriate for 1/2 the drive cycle. During the second half of the drive cycle, polarity is reversed and the direction of current flow is reversed. Current flow in the primary windings is illustrated as II, and current flow in the secondary loop is illustrated as 12.
- each first linear lamp 20Al, ..., 20Kl and the second end of each second linear lamp 20A2, ..., 20K2 are in physical proximity of driving transformer 50, e.g. on the same side of display 30 typically constituted of a metal based chassis, as driving transformer 50, and in physical proximity of first balancing transformers 80, and preferably generally define a first plane.
- first linear lamps 20Al, ..., 20Kl and second linear lamps 20A2, ..., 20K2, typically constituted of linear lamps generally extend axially away from the proximity of driving transformer 50, and generally define a second plane, further preferably orthogonal to the first plane.
- lighting arrangement 800 is in all respects similar to lighting arrangement 200, with a single balancing transformer shared between the linear lamp pairs of each luminaire 205.
- Arrangement 800 reduces the amount of balancing transformers required at the far end.
- the driving voltage developed at the far end of the lamps is half of that supplied by arrangement 200 if the same type of balancing transformer is used.
- balancing transformers 85 of arrangement 800 may be supplied with double the turns ratio to compensate for the reduced driving voltage.
- Arrangement 800 exhibits a drive at each of the lamps 20, as contrasted with arrangement 500 in which drive for the nexus of the serially connected lamps is not supplied.
- certain of the present embodiments enable a backlighting arrangement in which pairs of balancing transformers are provided, each associated with a particular luminaire.
- the primary winding of each of the balancing transformers is coupled in series with a respective end of the associated luminaire.
- the secondary windings of the balancing transformers are connected in a single closed loop, and arranged to be in-phase.
Abstract
A backlighting arrangement constituted of: a means for receiving an alternating current comprising a first lead and a second lead; at least one luminaire; and at least one first balancing transformer pair each associated with a particular one of the at least one luminaire, the primary of a first balancing transformer of the first balancing transformer pair serially coupled between the first lead of the means for receiving an alternating current and a first end of each of the at least one luminaire, and the primary of a second balancing transformer of the first balancing transformer pair serially coupled between the second lead of the means for receiving an alternating current and a second end of each of the at least one luminaire. The secondaries of all of the at least one first balancing transformer pair are serially connected in a closed in-phase loop.
Description
ARRANGEMENT SUITABLE FOR DRIVING FLOATING CCFL BASED
BACKLIGHT
BACKGROUND OF THE INVENTION
[0001] The present invention relates to the field of cold cathode fluorescent lamp based lighting and more particularly to an arrangement in which balancing transformers are supplied at each end of the lamp.
[0002] Fluorescent lamps are used in a number of applications including, without limitation, backlighting of display screens, televisions and monitors. One particular type of fluorescent lamp is a cold cathode fluorescent lamp (CCFL). Such lamps require a high starting voltage (typically on the order of 700 to 1 ,600 volts) for a short period of time to ionize a gas contained within the lamp tubes and fire or ignite the lamp. This starting voltage may be referred to herein as a strike voltage or striking voltage. After the gas in a CCFL is ionized and the lamp is fired, less voltage is needed to keep the lamp on. [0003] In liquid crystal display (LCD) applications, a backlight is needed to illuminate the screen so as to make a visible display. Backlight systems in LCD or other applications typically include one or more CCFLs and an inverter system to provide both DC to AC power conversion and control of the lamp brightness. Even brightness across the panel and clean operation of inverters with low switching stresses, low EMI, and low switching losses is desirable. [0004] The lamps are typically arranged with their longitudinal axis proceeding horizontally. In general, even brightness involves two dimensions: uniform brightness in the vertical dimension, i.e. among the various lamps; and uniform brightness along the longitudinal axis of each of the various lamps in the horizontal dimension. Brightness uniformity in the vertical dimension is largely dependent on matching the lamp currents which normally requires a certain type of balancing technique to maintain an even lamp current distribution. U.S. Patent S/N 7,242,147 issued July 10, 2007 to Jin, entitled "Current Sharing Scheme for Multiple CCFL Lamp Operation", the entire contents of which is incorporated herein by reference, is addressed to a ring balancer comprising a plurality of balancing
transformers which facilitate current sharing in a multi-lamp backlight system thus providing even lamp current distribution.
[0005] Brightness uniformity in the horizontal dimension is impacted by the existence of parasitic capacitance between the CCFLs and the chassis. As a result of the parasitic capacitance, leakage current exists along the length of the lamps and such leakage further results in diminishing brightness along the lamps' longitudinal axis towards the cold end in a single ended drive architecture. The term single ended drive architecture refers to a backlight arrangement in which the high voltage drive power is applied from only one side of the lamp, which is usually called the 'hot' end, and the other side of the lamp is normally at ground potential and referred as the 'cold' end. With the increasing size of LCD televisions and monitors, increases in lamp length, wire length and operating voltage associated with the resultant large backlighting systems make the leakage effect more significant, and consequently uniform horizontal brightness across lamps arranged in a single ended drive architecture is more difficult to achieve. In order to obtain even horizontal brightness for each of the CCF lamps, i.e. that the lamps should not exhibit a light gradient along its longitudinal axis, energy has to be alternatively driven into each end of the lamp. Thus, most large backlight inverter systems are configured to support 'floating' lamp structures, in which both lamp terminals are connected to a high voltage driving source, with a 180° phase shift to each other, and floating in relation to the chassis ground plane.
[0006] As described above, a factor in achieving even brightness over a CCFL is the ability to symmetrically power the lamp alternatively at both ends. This is more difficult to achieve as the length of the lamp increases. Among the conventional inverter topologies, a phase shifted full-bridge topology and a resonant full-bridge topology are most commonly used for CCFL inverter applications because of their ability to produce symmetric lamp current waveforms and clean switching operations. [0007] U.S. Patent S/N 7,187,139 issued March 6, 2007 to Jin, entitled "Split
Phase Inverters for CCFL Backlight System", the entire contents of which is incorporated herein by reference, is addressed to an inverter arrangement in which the switching elements are split into two inverter arms that are deployed at separate terminals of a floating lamp structure. Such a concept provides even brightness across the longitudinal dimension of the lamps with lower cost compared with the
conventional approach of deploying a full bridge circuit at each end of the lamps, while maintaining the advantages of soft switching operation of the full bridge. Unfortunately, separate inverter circuits are still needed to develop driving power at both ends of the lamp, and in addition, wiring of power cables and control signals could lead to potential electromagnetic interference issues, in particular as high voltage signals traversing the chassis length exhibitive capacitive coupling to the chassis. Often, a reflective material is disposed behind the lamps, typically based on metal, the metal based reflective material further adding to the capacitive coupling. [0008] What is further desired, and not provided by the prior art, is a backlighting arrangement that can provide even luminance across each lamp in the system, preferably with only one inverter circuit, and further preferably where there is no high voltage or high switching current wiring across the horizontal length of the panel.
SUMMARY OF THE INVENTION
[0009] Accordingly, it is a principal object of the present invention to overcome at least some of the disadvantages of the prior art. This is provided in certain embodiments by a backlighting arrangement in which pairs of balancing transformers are provided, each associated with a particular luminaire. The primary winding of each of the balancing transformers is coupled in series with a respective end of the associated luminaire. The secondary windings of the balancing transformers are connected in a single closed loop, and arranged to be in-phase. [00010] In one exemplary embodiment, the luminaires each comprise a pair of lamps, and an additional pair of balancing transformers is provided associated with each pair of lamps. The primary windings of the additional pair are coupled in series and between the lamps. The secondary windings of the additional pair are connected in-phase within the single closed loop. The luminaire is connected across an AC power source, such as an inverter or a single ended AC power source, and the nexus of the pair of lamps not directly connected to the AC power source receives energy via the balancing transformers thereby providing even brightness.
[00011] The present embodiments enable a backlighting arrangement comprising: a first lead and a second lead arranged to receive and return an alternating current; at least one luminaire; and at least one first balancing transformer
pair each of the transformer pair associated with a particular one of the at least one luminaire, the primary winding of a first balancing transformer of each of the first balancing transformer pair serially coupled between the first lead and a first end of the associated at least one luminaire, and the primary winding of a second balancing transformer of each of the first balancing transformer pair serially coupled between the second lead and a second end of each of the associated at least one luminaire, wherein the secondary windings of all of the at least one first balancing transformer pair are serially connected in a closed in-phase loop. [00012] In one embodiment at least one of the at least one luminaire comprises a serially connected pair of linear lamps. In another embodiment at least one of the at least one luminaire comprises a U-shaped lamp.
[00013] In one embodiment at least one of the at least one luminaire comprises a single linear lamp. In another embodiment, the backlighting arrangement further comprises a differential alternating current source arranged to supply power to the at least one luminaire via the first and second leads. In yet another embodiment the at least one luminaire comprises a plurality of luminaires.
[00014] In one embodiment the backlighting arrangement further comprises a single ended alternating current source arranged to supply power to the at least one luminaire via the first and second leads, wherein the first lead is connected to the single ended alternating current source, and the second lead is connected to a ground connection. In yet another embodiment, the backlighting arrangement further comprises a sense resistor serially connected within the serially connected closed in- phase loop arranged to present a voltage drop representation of the current flowing through the closed in-phase loop. [00015] In one embodiment the backlighting arrangement further comprises at least one second balancing transformer pair each of the second transformer pair associated with a particular one of the at least one luminaire and wherein each of the at least one luminaire comprises a pair of linear lamps each exhibiting a far end removed from each of the first and second ends of the luminaire, the primary windings of the second balancing transformer pair being arranged in series and serially coupled between the far ends of associated pair of linear lamps, the secondary windings of the second balancing transformer pair being serially connected in-phase in the closed in-phase serial loop. In one further embodiment the backlighting
arrangement further comprises a differential alternating current source arranged to supply power to the at least one luminaire via the first and second leads. In another further embodiment the backlighting arrangement further comprises a single ended alternating current source arranged to supply power to the at least one luminaire via the means for first and second leads, wherein the first lead is connected to the single ended alternating current source, and the second lead is connected to a ground connection. In yet another further embodiment the backlighting arrangement further comprises a sense resistor serially connected within the serially connected closed in- phase loop arranged to present a voltage drop representation of the current flowing through the closed in-phase loop.
[00016] In one embodiment each of the at least one luminaire comprises a pair of linear lamps each exhibiting a far end removed from each of the first and second ends of the luminaire, the arrangement further comprising at least one second balancing transformer each associated with a particular one of the pair of linear lamps, the primary windings of each of the second balancing transformer being coupled between the far ends of the associated pair of linear lamps, the secondary windings of the second balancing transformer being serially connected in-phase in the closed in- phase serial loop. In one further embodiment the at least one pair of linear lamps are arranged substantially in parallel to backlight a display, and wherein the serially connected closed in-phase loop exhibits a single twisted wire pair connecting a portion of the closed in-phase loop associated with a first end of the display to a portion of the closed in-phase loop associated with a second end of the display opposing the first end of the display. [00017] The present embodiments independently provide for a method of driving at least one luminaire, comprising: receiving an alternating current; providing at least one luminaire; and providing a first balancing transformer pair associated with each of the provided at least one luminaire, the primary winding of a first transformer of the respective balancing transformer pair associated with a first end of the associated luminaire, and the primary winding of a second transformer of the particular balancing transformer pair associated with a second end of the associated luminaire; coupling the received alternating current via the primary windings of the first balancing transformer pair to each end of the provided at least one luminaire; and
arranging the secondary windings of all of the provided at least one first balancing transformer pair in a serially connected closed in-phase loop.
[00018] In one embodiment at least one of the provided at least one luminaire comprises a serially connected pair of linear lamps. In another embodiment, at least one of the provided at least one luminaire comprises a U-shaped lamp.
[00019] In one embodiment at least one of the provided at least one luminaire comprises a single linear lamp. In another embodiment the method further comprises sensing a current flowing through the closed in-phase loop. [00020] In one embodiment each of the provided at least one luminaire comprises a pair of linear lamps each exhibiting a far end removed from each of the first and second ends of the luminaire, the method further comprising: providing at least one second balancing transformer pair, each balancing transformer of the pair associated with a particular one of the provided at least one luminaire; arranging the primary windings of the second balancing transformer pair in series and serially connecting the series arranged primary windings between the far ends of the associated pair of linear lamps; and arranging the secondary windings of the provided at least one second balancing transformer pair in the serially connected closed in- phase loop. In one further embodiment the method further comprises sensing a current flowing through the closed in-phase loop. [00021] In one embodiment each of the provided at least one luminaire comprises a pair of linear lamps each exhibiting a far end removed from each of the first and second ends of the luminaire, the method further comprising: providing at least one second balancing transformer; serially connecting the primary winding of one of the provided at least one second balancing transformer between the far ends of the associated pair of linear lamps; and arranging the secondary windings of the provided at least one second balancing transformer in the serially connected closed in- phase loop.
[00022] The present embodiment independently provide for a backlighting arrangement comprising: a means for receiving an alternating current exhibiting a first lead and a second lead; a plurality of luminaires; and a plurality of first balancing transformer pairs each associated with a particular one of the plurality of luminaires, the primary winding of a first balancing transformer of each of the first balancing transformer pair serially coupled between the first lead of the means for receiving an
alternating current and a first end of the associated luminaire, and the primary winding of a second balancing transformer of each of the first balancing transformer pair serially coupled between the second lead of the means for receiving an alternating current and a second end of the associated luminaire, wherein the secondary windings of all of the at least one first balancing transformer pair are serially connected in a closed in-phase loop.
[00023] In one embodiment the backlighting arrangement further comprises a plurality of second balancing transformer pairs each associated with a particular one of the plurality of luminaires and wherein each of the plurality of luminaires comprises a pair of lamps each exhibiting a far end removed from each of the first and second ends of the luminaire, the primary windings of the associated second balancing transformer pair being arranged in series and serially connected between the far ends of the pair of linear lamps, the secondary windings of the second balancing transformer pair being serially connected in-phase in the closed in-phase serial loop.
[00024] Additional features and advantages of the invention will become apparent from the following drawings and description.
BRIEF DESCRIPTION OF THE DRAWINGS [00025] For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, purely by way of example, to the accompanying drawings in which like numerals designate corresponding elements or sections throughout. [00026] With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. In the accompanying drawings:
[00027] Fig. IA illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement comprising a luminaire constituted of a single lamp;
[00028] Fig. IB illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement comprising a luminaire constituted of a pair of lamps;
[00029] Fig. 2 illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement comprising a plurality of luminaires, each constituted of a serially connected linear lamp pair, and a differential AC source in which energy is supplied to the far side of each of the lamps by a balancing network;
[00030] Fig. 3 illustrates a high level block diagram of an exemplary embodiment of a lighting arrangement comprising a plurality of luminaires, each constituted of a single linear lamp, and a single ended AC source; [00031] Fig. 4 illustrates a high level block diagram of an exemplary embodiment of a lighting arrangement comprising a plurality of luminaires, each constituted of a U-shaped lamp, and a single ended AC source;
[00032] Fig. 5 illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement comprising a plurality of luminaires, each constituted of a pair of serially coupled linear lamps, and a differential AC source;
[00033] Fig. 6 illustrates a high level block diagram of an exemplary embodiment of a lighting arrangement comprising a plurality of luminaires, each constituted of a pair of serially coupled linear lamps, and a single ended AC source; [00034] Fig. 7 illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement comprising a plurality of luminaires, each constituted of a U-shaped lamp, and a differential AC source; and [00035] Fig. 8 illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement comprising a plurality of luminaires, each constituted of a linear lamp pair, each of the linear lamp pairs sharing a single balancing transformer at the far end, and a differential AC source, in which energy is supplied to the far side of each of the lamp pairs by a balancing network.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[00036] Certain of the present embodiments enable a backlighting arrangement in which pairs of balancing transformers are provided, each associated with a particular luminaire. The primary winding of each of the balancing transformers is coupled in series with a respective end of the associated luminaire. The secondary windings of the balancing transformers are connected in a single closed loop, and arranged to be in-phase.
[00037] In one exemplary embodiment, the luminaires each comprise a pair of lamps, and an additional pair of balancing transformers is provided associated with each pair of lamps. The primary windings of the additional pair are coupled in series and between the lamps. The secondary windings of the additional pair are connected in-phase within the single closed loop. The luminaire is connected across an AC power source, such as an inverter or a single ended AC power source, and the nexus of the pair of lamps not directly connected to the AC power source receives energy via the balancing transformer thereby providing even brightness.
[00038] Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is applicable to other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.
[00039] Fig. IA illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement 10 comprising a single luminaire, constituted of a lamp 20, arranged to backlight a display 30. Display 30 is typically constituted of a metal based chassis. Floating lighting arrangement 10 further comprises: a driver 40; a driving transformer 50 exhibiting a first output 60 and a second output 70; a first and a second balancing transformer 80; and a twisted wire pair 90. The outputs of driver 40 are connected to both ends of the primary winding of driving transformer 50. The first end of the secondary winding of driving transformer 50, denoted first output 60, is connected to the first end of the primary winding of first balancing transformer 80. The second end of the primary winding of first balancing transformer 80 is connected to the first end of lamp 20. The second
end of lamp 20 is connected to the first end of the primary winding of second balancing transformer 80, and the second end of the primary winding of second balancing transformer 80 is connected the second end of the secondary winding of driving transformer 50, denoted second output 70. The secondary windings of first and second balancing transformers 80 are connected in a closed serial loop, the serial loop further comprising a sense resistor RS. The polarity of the secondary windings of first and second balancing transformers 80 are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop. Optionally, the wires of the closed loop connecting the secondary windings of first and second balancing transformers 80 are arranged via a twisted wire pair 90.
[00040] Preferably, the first end of lamp 20 is in physical proximity of driving transformer 50, e.g. on the same side of display 30 typically constituted of a metal based chassis, as driving transformer 50, and in physical proximity of first balancing transformer 80, and preferably generally define a first plane. Preferably, lamp 20, typically constituted of a linear lamp, generally extends axially away from the proximity of driving transformer 50, and generally defines a second plane, further preferably orthogonal to the first plane.
[00041] In operation, driver 40, which in one embodiment comprises a direct drive backlight driver as described in U.S. Patent S/N 5,930,121 issued July 27, 1999 to Henry, entitled "Direct Drive Backlight System", the entire contents of which is incorporated herein by reference, provides a differential AC source via driving transformer 50. In one further embodiment the secondary of driving transformer 50 is allowed to float. For simplicity, we designate first output 60 as AC+ and second output 70 as AC-, which is appropriate for 1/2 the drive cycle. During the second half of the drive cycle, polarity is reversed and the direction of current flow is reversed.
[00042] A current Il is developed through the primary winding of first balancing transformer 80, responsive to AC+ at first output 60, and driven through lamp 20. Current Il proceeds via the primary winding of second balancing transformer 80 and is returned to AC- at second output 70. Current 12 is developed in the secondary of first balancing transformer 80, responsive to II, and flows via sense resistor RS and a first wire of twisted wire pair 90 to the secondary of second balancing transformer 80. The voltage developed across the secondary of second balancing transformer 80 is in phase in the closed loop with the voltage developed
across the secondary of first balancing transformer 80, and thus current 12 continues through the secondary of second balancing transformer 80 and is returned via a second wire of twisted wire pair 90.
[00043] Advantageously, in a preferred embodiment the turns ratio of each of first and second balancing transformers 80 are such that twisted wire pair 90 exhibits low voltage and high current, thereby reducing any capacitive coupling to the constituent chassis of display 30. The use of twisted wire pair 90, exhibiting similar current and voltage with reverse polarity in each of the constituent wires further reduces any electromagnetic interference caused by twisted wire pair 90 traversing the length of display 30.
[00044] As described above, the secondary windings of first and second balancing transformers 80 are serially connected in a closed loop, and thus the current circulating in each of the secondary winding is substantially equal. If the magnetizing currents of the balancing transformers are neglected, the following relationship can be established for each of the balancing transformers :
Npi -H = NsI-H; NP2-I1 = NS2-I2; EQ. 1
[00045] Npi and Il denote the primary turns and primary current respectively of first balancing transformer 80; Ns1 and 12 denote the secondary turns and secondary current respectively of first balancing transformer 80; Np2 and Il denote the primary turns and primary current respectively of second balancing transformer 80; and Ns2 and 12 denote the secondary turns and secondary current respectively of second balancing transformer 80. Solving for Il and 12 of EQ. 1 results in:
Il = (Nsi/NP1)-I2 = (NS2/NP2)-I2 EQ. 2
Thus, in accordance with EQ. 2, the secondary current sensed by the voltage drop across sense resistor RS,is a function of the primary current and the turns ratio of the balancing transformers 80. Sense resistor RS is advantageously not connected to the high voltage associated with first and second outputs 60, 70, and thus may be connected to a low voltage controller to sense the current through lamp 20.
[00046] Current 12 connected via the closed loop of the secondary windings, ensures that the current Il entering the first end of lamp 20 is substantially equal to current Il leaving the second end of lamp 20.
[00047] Fig. IB illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement 100 constituted of a pair of linear lamps 20, arranged to backlight a display 30. Floating lighting arrangement 100 further comprises: a driver 40; a driving transformer 50 exhibiting a first output 60 and second output 70; a first and a second balancing transformer 80; a first and a second balancing transformer 85; and a twisted wire pair 90. Balancing transformers 80 and 85 may be of identical type without exceeding the scope of the invention.
[00048] The outputs of driver 40 are connected to both ends of the primary winding of driving transformer 50. The first end of the secondary winding of driving transformer 50, denoted first output 60, is connected to the first end of the primary winding of first balancing transformer 80. The second end of the primary winding of first balancing transformer 80 is connected to the first end of first lamp 20. The second end of first lamp 20 is connected to the first end of the primary winding of first balancing transformer 85, and the second end of the primary winding of first balancing transformer 85 is connected the first end of the primary winding of second balancing transformer 85. The second end of the primary winding of second balancing transformer 85 is connected to the first end of second lamp 20. The second end of second lamp 20 is connected to the first end of the primary winding of second balancing transformer 80 and the second end of the primary winding of second balancing transformer 80 is connected to the second end of the secondary winding of driving transformer 50, denoted second output 70. [00049] The secondary windings of first and second balancing transformers 80 and the secondary windings of first and second balancing transformers 85 are connected in a single closed serial loop via a sense resistor RS. The polarity of the secondary windings of the first and second balancing transformers 80 and the secondary windings of the first and second balancing transformers 85 are arranged so that voltages induced in the secondary windings are in phase and add within the serial closed loop. Optionally, the wires of the closed loop connecting the respective ends of the secondary windings of the first and second balancing transformers 80 to
respective ends of the secondary windings of the first and second balancing transformers 85 are arranged via a twisted wire pair 90.
[00050] Preferably, the first end of first lamp 20 and the second end of second lamp 20 are in physical proximity of driving transformer 50, e.g. on the same side of display 30 typically constituted of a metal based chassis, as driving transformer 50, and in physical proximity of first and second balancing transformers 80, and preferably generally define a first plane. Preferably, first and second lamps 20, each typically constituted of a linear lamp, generally extend axially away from the proximity of driving transformer 50, and generally define a second plane, further preferably orthogonal to the first plane.
[00051] In operation, driver 40 provides a differential AC source via driving transformer 50. In one further embodiment the secondary of driving transformer 50 is allowed to float. For simplicity, we designate first output 60 as AC+ and second output 70 as AC-, which is appropriate for 1/2 the drive cycle. During the second half of the drive cycle, polarity is reversed and the direction of current flow is reversed.
[00052] A current Il is developed through the primary winding of first balancing transformer 80, responsive to AC+ at first output 60, and driven through first lamp 20. Current Il proceeds through the primary winding of first balancing transformer 85, through the primary winding of second balancing transformer 85, through second lamp 20, through the primary winding of second balancing transformer 80 and is returned to AC- at second output 70. As described above, the secondary windings of first and second balancing transformers 80 and first and second balancing transformers 85 are serially connected in a closed loop, and thus current 12 circulating in each of the secondary windings is substantially equal. If the magnetizing currents of the balancing transformers are neglected, the following relationship can be established for each of the balancing transformers:
Np1-Ip1 = NS1-Isi; Np2-Ip2 = NS2-Is2; Np3-Ip3 = NS3-Is3; Np4-Ip4 = NS4-Is4; EQ. 3
Npi and Ip1 of EQ. 3 denote the primary turns and primary current respectively of first balancing transformer 80; Ns1 and Isi denote the secondary turns and secondary current respectively of first balancing transformer 80; Np2 and Ip2 denote the primary turns and primary current respectively of first balancing transformer 85; Ns2 and Is2
denote the secondary turns and secondary current respectively of first balancing transformer 85; Np3 and Ip3 denote the primary turns and primary current respectively of second balancing transformer 85; Ns3 and Is3 denote the secondary turns and secondary current respectively of second balancing transformer 85; Np4 and Ip4 denote the primary turns and primary current respectively of second balancing transformer 80; and Ns4 and Is4 denote the secondary turns and secondary current respectively of second balancing transformer 80. Solving for each of the primary currents results in:
Ipi = (NS1/NP1)-IS1; Ip2 = (Ns2ZNP2)-Is2; IP3 = (Ns3ZNP3yiS3; Ip4 = (NS4ZNP4)-IS4 EQ. 4
[00053] From EQ. 4 it is obvious that the primary current and hence the lamp current conducted by the respective lamps can be controlled proportionally with the turns ratio (Ns1ZNp1, Ns2ZNs2A NskZNpk) of the balancing transformers. Physically, if any current in a particular balancing transformer deviates from the relationships defined in EQ. 4, the resulting magnetic flux from the error ampere turns will induce a corresponding correction voltage in the primary winding to force the primary current to follow the balancing condition of EQ. 4. A balanced lamp current condition between first lamp 20 and second lamp 20 can be thus obtained by using the same primary to secondary turns ratio for all the balancing transformers 80, 85. [00054] Further, because the secondary loop current is proportional to the primary side lamp current according to EQ. 4, lamp current can also be detected by sense resistor RS in the secondary winding loop and measured responsive to voltage drop across sense resistor RS. Because the secondary windings of balancing transformers 80, 85 are isolated from the lamp high voltage side, the signal from sense resistor RS can be fed to a low voltage controller circuit directly for regulation and monitoring purposes. Such application is especially useful with a floating lamp configuration, such as floating lighting arrangement 100, where no ground potential node is available in the lamp circuit for direct current sensing. [00055] Coupling the secondary windings of the balancing transformers 80, 85 in a closed loop also couples energy between balancing transformers 80, 85 through the circulating current in the secondary winding loop. The energies needed to drive the far end of first and second lamps 20 are coupled by this mechanism through balancing transformers 85. Under such circumstances the balancing error of the lamp
current is related to the lamp operating voltage and the magnetizing inductance of the balancing transformer as described below under steady state operating condition:
ΔI = V/(ωLm) EQ. 5
Where ΔI represents the balancing error, i.e. the difference of the lamp current from the lamp terminals, ω is the angular frequency of the AC source, Lm is the magnetizing inductance from the primary side of the balancer, and V is the lamp operating voltage. [00056] With such an arrangement, there is no requirement for an inverter circuit, or inverter arms, driving the far ends of first and second lamp 20, resulting in a significant cost savings since the driving current is supplied via the secondary winding loop. Advantageously, there are only two wires extending across display 30, in line with the longitudinal axes of first and second lamps 20, to form the loop connection of the balancer secondary windings. Because current 12 flowing in the two wires has equal amplitude and opposite direction, the two wires can be brought to one edge of display 30 and twisted together to yield minimum electro-magnetic field interference, as illustrated by twisted wire pair 90. Further, because the voltage in secondary windings of transformer balancers 20 may be set to be very low responsive to an appropriate turns ratio, the twisted wire pair does not produce any high capacitive leakage current and associated interference.
[00057] Fig. 2 illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement 200 arranged to backlight a display 30 comprising a plurality of luminaires 205A ... 205K, each constituted of a pair of serially arranged linear lamps 20Al, 20A2 ...20Kl, 20K2, and a differential AC source in which energy is supplied to the far side of each of the lamps by a balancing network. Floating lighting arrangement 200 further comprises: a driver 40; a driving transformer 50 exhibiting a first output 60 and a second output 70; a plurality of balancing transformers 80; a plurality of balancing transformers 85; and a wire pair 210A, 210B. Each luminaire 205 A, ..., 205K has associated therewith a balancing transformer 80 associated with a first end thereof and a balancing transformer 80 associated with a second end thereof. Each luminaire 205 A, ..., 205K has further
associated therewith a pair of balancing transformers 85 serially connected between the far ends of the constituent linear lamps 20Al, 20A2 ...20Kl, 20K2. [00058] The outputs of driver 40 are connected to both ends of the primary winding of driving transformer 50. The first end of the secondary winding of driving transformer 50, denoted first output 60, is connected through the primary winding of a respective balancing transformer 80 to a first end of first linear lamp 20Al, ...,20Kl of each of the respective luminaires 205 A, ..., 205K. The nexus of the second end of first linear lamp 20Al, ..., 20Kl and the first end of second linear lamp 20A2, ..., 20K2 of each luminaire 205 A, ..., 205K, is connected through the primary windings of the respective associated pair of balancing transformers 85 arranged in series. The second end of each second linear lamp 20A2 ... 20K2 is connected through the primary winding of a respective associated balancing transformer 80 to the second end of the secondary winding of driving transformer 50, denoted second output 70. [00059] The secondary windings of the balancing transformers 80, 85 are connected in a closed loop, in which the polarity of the secondary windings are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop. Optionally, a sense resistor RS is inserted within the loop to detect current flow. Optionally, the wires of the closed loop connecting across the length of the linear lamps, denoted 210A, 210B, are arranged in a twisted wire pair. For clarity, and to further illustrate the phase relationship of the secondary transformers, lighting arrangement 200 is illustrated with first output 60 exhibiting AC+ and second output 70 exhibiting AC-, which is appropriate for 1/2 the drive cycle. During the second half of the drive cycle, polarity is reversed and the direction of current flow is reversed. Current flow in the primary windings is illustrated as II, and current flow in the secondary loop is illustrated as 12.
[00060] Preferably, the first end of each first linear lamp 20Al, ..., 20Kl and the second end of each second linear lamp 20A2, ..., 20K2 are in physical proximity of driving transformer 50, e.g. on the same side of display 30 typically constituted of a metal based chassis, as driving transformer 50, and in physical proximity of first balancing transformers 80, and preferably generally define a first plane. Preferably, first linear lamps 20Al, ..., 20Kl and second linear lamps 20A2, ..., 20K2 generally extend axially away from the proximity of driving transformer 50, and generally define a second plane, further preferably orthogonal to the first plane.
[00061] In operation lighting arrangement 200 operates in all respects similar to the operation of lighting arrangement 100, with power for the side of all lamps not directly connected to driving transformer 50, i.e. the far or cold end, supplied by the closed loop of the secondary windings of balancing transformers 80, 85. Power is thus alternately driven into each end of each lamp 20.
[00062] Fig. 3 illustrates a high level block diagram of an embodiment of a lighting arrangement 300 arranged to backlight a display 30 in accordance with a principle of the invention comprising a plurality of luminaires, each constituted of a single linear lamps 2OA, 2OB, ... 2OK, 2OL and a single ended high voltage AC source, exhibiting a common return which is typically connected to chassis ground plane, in which energy is supplied to the far end of each of the linear lamps 2OA, 2OB, ... 2OK, 2OL by a balancing network. Grounded lighting arrangement 300 further comprises a plurality of balancing transformers 80 each associated with one end of a particular linear lamp 2OA, 2OB,... 2OK, 2OL. The number of lamps is shown as being divisible by 2, however this is not meant to be limiting in any way and an odd number of lamps 20 may be supplied without exceeding the scope of the invention. There are twice as many balancing transformers 80 as linear lamps. [00063] The high voltage AC input is connected in parallel through the primary winding of a respective balancing transformer 80 to a first end of each linear lamp 2OA, 2OB,...20L, 2OK. The second end of each linear lamp 2OA, 2OB,...20L, 2OK is connected through the primary winding of the respective associated balancing transformer 80 to the common return.
[00064] The secondary windings of the balancing transformers 80 are connected in a closed loop, in which the polarity of the secondary windings are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop. Optionally, a sense resistor (not shown) is inserted within the loop to detect current flow. Optionally, the wires of the closed loop connecting across the length of the linear lamps are arranged in a twisted wire pair. For clarity, and to further illustrate the phase relationship of the secondary transformers, the direction of current flow is illustrated when a positive voltage appears at the high voltage AC input, denoted HVAC. Current flow in the primary windings is illustrated as II, and current flow in the secondary loop is illustrated as 12. Current flows in the opposite
direction for each of Il and 12 when a negative voltage, with respect to the common return, appears at HVAC.
[00065] Preferably, the first end of each linear lamp 2OA, 2OB,...2OL, 2OK is in physical proximity of a source driving transformer providing the HVAC, e.g. on the same side of display 30 typically constituted of a metal based chassis, as the driving transformer, and in physical proximity of the associated balancing transformers 80, and preferably generally define a first plane. Preferably, each linear lamp 2OA, 2OB,...2OL, 2OK generally extend axially away from the proximity of the source driving transformer providing the HVAC, and generally define a second plane, further preferably orthogonal to the first plane.
[00066] In operation, lighting arrangement 300 operates in all respects similar to the operation of lighting arrangement 200, except that all the lamps are driven with the same voltage from their hot side, i.e. the side connected to HVAC. Driving energy is coupled to the far or cold side by the closed loop of the secondary winding when a negative voltage with respect to the common return appears at input HVAC. Power is thus alternately driven into each end of each lamp 20.
[00067] Fig. 4 illustrates a high level block diagram of an embodiment of a exemplary lighting arrangement 400 arranged to backlight a display 30 comprising a plurality of luminaires, each constituted of a U-shaped lamp 410A, ..., 410K, and a single ended AC source, exhibiting a common return which is typically connected to chassis ground plane, in accordance with a principle of the invention, in which energy is supplied to the side of each of the lamp pairs connected to the common return by a balancing network. Grounded lighting arrangement 400 further comprises a plurality of balancing transformers 80 each associated with one end of a particular U-shaped lamp 410A, ..., 410K. There are twice as many balancing transformers 80 as U- shaped lamps 410.
[00068] The high voltage AC input is connected in parallel through the primary winding of a respective balancing transformer 80 to a first end of each U-shaped lamp 410A, ..., 410K. The second end of each U-shaped lamp 410A, ..., 410K is connected through the primary winding of a respective balancing transformer 80 to the common return.
[00069] The secondary windings of the balancing transformers 80 are connected in a closed loop, in which the polarity of the secondary windings are
arranged so that voltages induced in the secondary windings are in phase and add within the closed loop. Optionally, a sense resistor (not shown) is inserted within the loop to detect current flow. For clarity, and to further illustrate the phase relationship of the secondary transformers, the direction of current flow is illustrated when a positive voltage appears at the high voltage AC input, denoted HVAC. Current flow in the primary windings is illustrated as II, and current flow in the secondary loop is illustrated as 12.
[00070] Preferably, the first end and second ends of each U-shaped lamp 410A,
... 410K are in physical proximity of a source driving transformer providing the single ended high voltage AC input, e.g. on the same side of display 30 typically constituted of a metal based chassis, as the driving transformer, and in physical proximity of the associated balancing transformers 80, and preferably generally define a first plane. Preferably, each U-shaped lamp 410A, ... 410K generally extends axially away from the proximity of the source driving transformer providing the high voltage AC input, and generally define a second plane, further preferably orthogonal to the first plane.
[00071] In operation lighting arrangement 400 operates in all respects similar to the operation of lighting arrangement 300, with the far or cold end of the lamps 410 appearing on the same vertical plane as the hot end by the U-shape lamp arrangement. The drive power for the cold end is derived through the closed secondary winding loop as described above in relation to arrangement 300. Power is thus alternately driven into each end of each lamp 410.
[00072] Fig. 5 illustrates a high level block diagram of an exemplary embodiment of a floating lighting arrangement 500 arranged to backlight a display 30 comprising a plurality of luminaires 510A, ..., 510K, each constituted of a pair of serially coupled linear lamps, and a differential AC source. Floating lighting arrangement 500 further comprises a plurality of balancing transformers 80 each associated with one end of a particular luminaire 510A, ..., 510K. The number of balancing transformers is twice the number of luminaires 510. [00073] One end of the differential driving AC voltage, denoted AC+, is connected in parallel through the primary winding of a respective balancing transformer 80 to a first end of each of the luminaires 510A, ..., 510K. The second end of each luminaire 510A, ..., 510K is connected through the primary winding of
the respective associated balancing transformer 80 to the second end of the differential driving AC voltage, denoted AC-.
[00074] The secondary windings of the balancing transformers 80 are connected in a closed loop, in which the polarity of the secondary windings are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop. Optionally, a sense resistor (not shown) is inserted within the loop to detect current flow. For clarity, and to further illustrate the phase relationship of the secondary transformers, the direction of current flow is illustrated when a positive voltage appears at AC+. Current flow in the primary windings is illustrated as II, and current flow in the secondary loop is illustrated as 12.
[00075] Preferably, the first end and second ends of each luminaire 510A, ...,
510K are in physical proximity of a source driving transformer providing the differential high voltage AC input, e.g. on the same side of display 30 typically constituted of a metal based chassis, as the driving transformer, and in physical proximity of the associated balancing transformers 80, and preferably generally define a first plane. Preferably, each luminaire 510A, ..., 510K generally extends axially away from the proximity of the source driving transformer providing the differential high voltage AC input, and generally define a second plane, further preferably orthogonal to the first plane. [00076] In operation lighting arrangement 500 operates in all respects similar to the operation of lighting arrangement 400 and is therefore not further detailed. Disadvantageously, power is not directly driven into the far, or cold, end of each of the linear lamps of the luminaries 510A, ..., 510K. [00077] Fig. 6 illustrates a high level block diagram of an embodiment of a grounded lighting arrangement 600 arranged to backlight a display 30 in accordance with a principle of the invention comprising a plurality of luminaires 51 OA, ... , 51 OK, each constituted of a pair of serially coupled linear lamps, and a single ended high voltage AC source, exhibiting a common return which is typically connected to a chassis ground plane. Grounded lighting arrangement 600 further comprises a plurality of balancing transformers 80 each associated with one end of a particular luminaire 510A, ..., 510K. The number of balancing transformers is twice the number of luminaires 510.
[00078] The input of the single ended high voltage AC source is connected in parallel through the primary winding of a respective balancing transformer 80 to a first end of each of luminaires 510A, ..., 510K. The second end of each luminaire 510A, ..., 510K is connected through the primary winding of the respective associated balancing transformer 80 to the common return.
[00079] The secondary windings of the balancing transformers 80 are connected in a closed loop, in which the polarity of the secondary windings are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop. Optionally, a sense resistor (not shown) is inserted within the loop to detect current flow. For clarity, and to further illustrate the phase relationship of the secondary transformers, the direction of current flow is illustrated when a positive voltage appears at the high voltage AC input, denoted HVAC. Current flow in the primary windings is illustrated as II, and current flow in the secondary loop is illustrated as 12. [00080] Preferably, the first end and second ends of each luminaire 510A, ...,
510K are in physical proximity of a source driving transformer providing the single ended high voltage AC input, e.g. on the same side of display 30 typically constituted of a metal based chassis, as the driving transformer, and in physical proximity of the associated balancing transformers 80, and preferably generally define a first plane. Preferably, each luminaire 510A, ..., 510K generally extends axially away from the proximity of the source driving transformer providing the differential high voltage AC input, and generally define a second plane, further preferably orthogonal to the first plane. [00081] In operation lighting arrangement 600 operates in all respects similar to the operation of lighting arrangement 500 and is therefore not further detailed.
[00082] Fig. 7 illustrates a high level block diagram of an embodiment of a floating lighting arrangement 700 arranged to backlight a display 30 in accordance with a principle of the invention comprising a plurality of luminaires, each constituted of a U-shaped lamp 410A, ..., 410K, and a differential AC source. Lighting arrangement 700 further comprises a plurality of balancing transformers 80 each associated with one end of a particular U-shaped lamp 410A, ..., 410K. There are twice as many balancing transformers 80 as U-shaped lamps 410.
[00083] A first end of the differential AC input, denoted AC+, is connected in parallel through the primary winding of a respective balancing transformer 80 to a first end of each U-shaped lamp 410A, ..., 410K. The second end of each U-shaped lamp 410A, ..., 410K is connected through the primary winding of the respective associated balancing transformer 80 to the second end of the differential AC input, denoted AC-.
[00084] The secondary windings of the balancing transformers 80 are connected in a closed loop, in which the polarity of the secondary windings are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop. Optionally, a sense resistor (not shown) is inserted within the loop to detect current flow. For clarity, and to further illustrate the phase relationship of the secondary transformers, the direction of current flow is illustrated when a positive voltage appears at first input AC+. Current flow in the primary windings is illustrated as II, and current flow in the secondary loop is illustrated as 12. [00085] Preferably, the first end and second ends of each U-shaped lamp 410A,
... 410K are in physical proximity of a source driving transformer providing the differential AC input, e.g. on the same side of display 30 typically constituted of a metal based chassis, as the driving transformer, and in physical proximity of the associated balancing transformers 80, and preferably generally define a first plane. Preferably, each U-shaped lamp 410A, ... 410K generally extends axially away from the proximity of the source driving transformer providing the differential AC input, and generally define a second plane, further preferably orthogonal to the first plane. [00086] In operation lighting arrangement 700 operates in all respects similar to the operation of lighting arrangement 400 and is therefore not further detailed. [00087] Fig. 8 illustrates a high level block diagram of an embodiment of a floating lighting arrangement 800 in accordance with a principle of the invention comprising a plurality of luminaries 205 A, ..., 205K, each constituted of a serially arranged linear lamp pair, 20Al, 20A2 ...20Kl, 20K2, and a differential AC source in which energy is supplied to the far end of each of the lamp pairs by a balancing network Floating lighting arrangement 800 comprises: a driver 40; a driving transformer 50 exhibiting a first output 60 and a second output 70; a plurality of balancing transformers 80; a plurality of balancing transformers 85; and a wire pair 210A, 210B. Each luminaire 205 A, ..., 205K has associated therewith a balancing
transformer 80 associated with a first end thereof and a balancing transformer 80 associated with a second end thereof. A single balancing transformer 85 serially connects the far ends of the lamps of each linear lamp pair 20Al, 20A2 ...20Kl, 20K2. [00088] The outputs of driver 40 are connected to both ends of the primary winding of driving transformer 50. The first end of the secondary winding of driving transformer 50, denoted first output 60, is connected through the primary winding of a respective balancing transformer 80 to a first end of first lamp 20Al, ...,20Kl of each of the respective luminaires 205 A, ..., 205K. The nexus of the second end of the respective first lamp 20Al, ..., 20Kl and the first end of the respective second lamp 20A2, ..., 20K2 of each luminaire 205 A, ..., 205K, is connected through the primary winding of the respective associated balancing transformer 85. The second end of each second lamp 20A2 ... 20K2 is connected through the primary winding of the respective associated balancing transformer 80 to the second end of the secondary winding of driving transformer 50, denoted second output 70.
[00089] The secondary windings of the balancing transformers 80, 85 are connected in a closed loop, in which the polarity of the secondary windings are arranged so that voltages induced in the secondary windings are in phase and add within the closed loop. Optionally, a sense resistor RS is inserted within the loop to detect current flow. Optionally, the wires of the closed loop connecting across the length of the linear lamps, denoted 210A, 210B, are arranged in a twisted wire pair. For clarity, and to further illustrate the phase relationship of the secondary transformers, lighting arrangement 200 is illustrated with first output 60 exhibiting AC+ and second output 70 exhibiting AC-, which is appropriate for 1/2 the drive cycle. During the second half of the drive cycle, polarity is reversed and the direction of current flow is reversed. Current flow in the primary windings is illustrated as II, and current flow in the secondary loop is illustrated as 12.
[00090] Preferably, the first end of each first linear lamp 20Al, ..., 20Kl and the second end of each second linear lamp 20A2, ..., 20K2 are in physical proximity of driving transformer 50, e.g. on the same side of display 30 typically constituted of a metal based chassis, as driving transformer 50, and in physical proximity of first balancing transformers 80, and preferably generally define a first plane. Preferably, first linear lamps 20Al, ..., 20Kl and second linear lamps 20A2, ..., 20K2, typically
constituted of linear lamps, generally extend axially away from the proximity of driving transformer 50, and generally define a second plane, further preferably orthogonal to the first plane.
[00091] In operation lighting arrangement 800 is in all respects similar to lighting arrangement 200, with a single balancing transformer shared between the linear lamp pairs of each luminaire 205. Arrangement 800 reduces the amount of balancing transformers required at the far end. Disadvantageously, the driving voltage developed at the far end of the lamps is half of that supplied by arrangement 200 if the same type of balancing transformer is used. There is no requirement that the same balancing transformers be utilized, and balancing transformers 85 of arrangement 800 may be supplied with double the turns ratio to compensate for the reduced driving voltage.
[00092] Arrangement 800 exhibits a drive at each of the lamps 20, as contrasted with arrangement 500 in which drive for the nexus of the serially connected lamps is not supplied.
[00093] Thus certain of the present embodiments enable a backlighting arrangement in which pairs of balancing transformers are provided, each associated with a particular luminaire. The primary winding of each of the balancing transformers is coupled in series with a respective end of the associated luminaire. The secondary windings of the balancing transformers are connected in a single closed loop, and arranged to be in-phase.
[00094] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.
[00095] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as are commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods are described herein.
[00096] All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the patent specification, including definitions, will prevail. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting. [00097] It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather the scope of the present invention is defined by the appended claims and includes both combinations and subcombinations of the various features described hereinabove as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description and which are not in the prior art.
Claims
1. A backlighting arrangement comprising: a first lead and a second lead arranged to receive and return an alternating current; at least one luminaire; and at least one first balancing transformer pair each of said transformer pair associated with a particular one of said at least one luminaire, the primary winding of a first balancing transformer of each of said first balancing transformer pair serially coupled between said first lead and a first end of said associated at least one luminaire, and the primary winding of a second balancing transformer of each of said first balancing transformer pair serially coupled between said second lead and a second end of each of said associated at least one luminaire, wherein the secondary windings of all of said at least one first balancing transformer pair are serially connected in a closed in-phase loop.
2. A backlighting arrangement according to claim 1, wherein at least one of said at least one luminaire comprises a serially connected pair of linear lamps.
3. A backlighting arrangement according to claim 1, wherein at least one of said at least one luminaire comprises a U-shaped lamp.
4. A backlighting arrangement according to claim 1, wherein at least one of said at least one luminaire comprises a single linear lamp.
5. A backlighting arrangement according to any of claims 1 - 4, further comprising a differential alternating current source arranged to supply power to said at least one luminaire via said first and second leads.
6. A backlighting arrangement according to any of claims 1 - 4, further comprising a single ended alternating current source arranged to supply power to said at least one luminaire via said first and second leads, wherein said first lead is connected to said single ended alternating current source, and said second lead is connected to a ground connection.
7. A backlighting arrangement according to any of claims 1 - 4, further comprising a sense resistor serially connected within said serially connected closed in-phase loop arranged to present a voltage drop representation of the current flowing through the closed in-phase loop.
8. A backlighting arrangement according to claim 1, further comprising at least one second balancing transformer pair each of said second transformer pair associated with a particular one of said at least one luminaire and wherein each of said at least one luminaire comprises a pair of linear lamps each exhibiting a far end removed from each of said first and second ends of said luminaire, the primary windings of said second balancing transformer pair being arranged in series and serially coupled between said far ends of associated pair of linear lamps, the secondary windings of said second balancing transformer pair being serially connected in-phase in said closed in-phase serial loop.
9. A backlighting arrangement according to claim 8, further comprising a differential alternating current source arranged to supply power to said at least one luminaire via said first and second leads.
10. A backlighting arrangement according to claim 8, further comprising a single ended alternating current source arranged to supply power to said at least one luminaire via said means for first and second leads, wherein said first lead is connected to said single ended alternating current source, and said second lead is connected to a ground connection.
11. A backlighting arrangement according to claim 8, further comprising a sense resistor serially connected within said serially connected closed in-phase loop arranged to present a voltage drop representation of the current flowing through the closed in-phase loop.
12. A backlighting arrangement according to claim 1, wherein each of said at least one luminaire comprises a pair of linear lamps each exhibiting a far end removed from each of said first and second ends of said luminaire, the arrangement further comprising at least one second balancing transformer each associated with a particular one of said pair of linear lamps, the primary windings of each of said second balancing transformer being coupled between said far ends of said associated pair of linear lamps, the secondary windings of said second balancing transformer being serially connected in-phase in said closed in-phase serial loop.
13. A backlighting arrangement according to any of claims 8 - 12, wherein said at least one pair of linear lamps are arranged substantially in parallel to backlight a display, and wherein said serially connected closed in-phase loop exhibits a single twisted wire pair connecting a portion of the closed in-phase loop associated with a first end of the display to a portion of the closed in-phase loop associated with a second end of the display opposing said first end of the display.
14. A backlighting arrangement according to claim 1, wherein said at least one luminaire comprises a plurality of luminaires.
15. A method of driving at least one luminaire, comprising: receiving an alternating current; providing at least one luminaire; and providing a first balancing transformer pair associated with each of said provided at least one luminaire, the primary winding of a first transformer of the respective balancing transformer pair associated with a first end of said associated luminaire, and the primary winding of a second transformer of said particular balancing transformer pair associated with a second end of said associated luminaire; coupling said received alternating current via said primary windings of said first balancing transformer pair to each end of said provided at least one luminaire; and arranging the secondary windings of all of said provided at least one first balancing transformer pair in a serially connected closed in-phase loop.
16. A method according to claim 15, wherein at least one of said provided at least one luminaire comprises a serially connected pair of linear lamps.
17. A method according to claim 15, wherein at least one of said provided at least one luminaire comprises a U-shaped lamp.
18. A method according to claim 15, wherein at least one of said provided at least one luminaire comprises a single linear lamp.
19. A method according to any of claims 15 - 18, further comprising sensing a current flowing through the closed in-phase loop.
20. A method according to claim 15, wherein each of said provided at least one luminaire comprises a pair of linear lamps each exhibiting a far end removed from each of said first and second ends of said luminaire, the method further comprising: providing at least one second balancing transformer pair, each balancing transformer of said pair associated with a particular one of said provided at least one luminaire; arranging the primary windings of said second balancing transformer pair in series and serially connecting the series arranged primary windings between said far ends of said associated pair of linear lamps; and arranging the secondary windings of said provided at least one second balancing transformer pair in said serially connected closed in-phase loop.
21. A method according to claim 20, further comprising sensing a current flowing through the closed in-phase loop.
22. A method according to claim 15, wherein each of said provided at least one luminaire comprises a pair of linear lamps each exhibiting a far end removed from each of said first and second ends of said luminaire, the method further comprising: providing at least one second balancing transformer; serially connecting the primary winding of one of said provided at least one second balancing transformer between said far ends of said associated pair of linear lamps; and arranging the secondary windings of said provided at least one second balancing transformer in said serially connected closed in-phase loop.
23. A backlighting arrangement comprising: a means for receiving an alternating current exhibiting a first lead and a second lead; a plurality of luminaires; and a plurality of first balancing transformer pairs each associated with a particular one of said plurality of luminaires, the primary winding of a first balancing transformer of each of said first balancing transformer pair serially coupled between said first lead of said means for receiving an alternating current and a first end of the associated luminaire, and the primary winding of a second balancing transformer of each of said first balancing transformer pair serially coupled between said second lead of said means for receiving an alternating current and a second end of the associated luminaire, wherein the secondary windings of all of said at least one first balancing transformer pair are serially connected in a closed in-phase loop.
24. A backlighting arrangement according to claim 23, further comprising a plurality of second balancing transformer pairs each associated with a particular one of said plurality of luminaires and wherein each of said plurality of luminaires comprises a pair of lamps each exhibiting a far end removed from each of said first and second ends of said luminaire, the primary windings of said associated second balancing transformer pair being arranged in series and serially connected between said far ends of said pair of linear lamps, the secondary windings of said second balancing transformer pair being serially connected in-phase in said closed in-phase serial loop.
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US2622708P | 2008-02-05 | 2008-02-05 | |
US61/026,227 | 2008-02-05 | ||
US5599308P | 2008-05-25 | 2008-05-25 | |
US61/055,993 | 2008-05-25 | ||
US11412408P | 2008-11-13 | 2008-11-13 | |
US61/114,124 | 2008-11-13 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2009099978A1 true WO2009099978A1 (en) | 2009-08-13 |
Family
ID=40512190
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2009/032788 WO2009099979A1 (en) | 2008-02-05 | 2009-02-02 | Balancing arrangement with reduced amount of balancing transformers |
PCT/US2009/032787 WO2009099978A1 (en) | 2008-02-05 | 2009-02-02 | Arrangement suitable for driving floating ccfl based backlight |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2009/032788 WO2009099979A1 (en) | 2008-02-05 | 2009-02-02 | Balancing arrangement with reduced amount of balancing transformers |
Country Status (3)
Country | Link |
---|---|
US (3) | US8008867B2 (en) |
TW (2) | TW200939886A (en) |
WO (2) | WO2009099979A1 (en) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2010004795A1 (en) * | 2008-07-08 | 2010-01-14 | シャープ株式会社 | Illuminating device and display device |
KR20110028963A (en) * | 2009-09-14 | 2011-03-22 | 삼성전자주식회사 | Backlight assembly and display apparatus having the same |
TWI404457B (en) * | 2009-09-18 | 2013-08-01 | Innolux Corp | Lamp driving circuit |
JP5063659B2 (en) * | 2009-10-20 | 2012-10-31 | 日本航空電子工業株式会社 | connector |
US8278829B1 (en) * | 2010-02-11 | 2012-10-02 | Miami Green Licensing, Llc | Method and apparatus for reducing radiation from a light fixture |
US9614452B2 (en) | 2010-10-24 | 2017-04-04 | Microsemi Corporation | LED driving arrangement with reduced current spike |
WO2012061052A1 (en) | 2010-10-24 | 2012-05-10 | Microsemi Corporation | Synchronous regulation for led string driver |
DE102016120108A1 (en) * | 2016-10-21 | 2018-04-26 | Endress+Hauser Process Solutions Ag | Method, communication module and system for transmitting diagnostic data of a field device in a process automation system |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20030015974A1 (en) * | 2001-07-23 | 2003-01-23 | Patent-Treuhand-Gesellschaft Fur Elektrische Gluhl | Ballast for operating at least one low-pressure discharge lamp |
US20050093471A1 (en) * | 2003-10-06 | 2005-05-05 | Xiaoping Jin | Current sharing scheme for multiple CCF lamp operation |
US20060119293A1 (en) * | 2004-12-03 | 2006-06-08 | Chun-Kong Chan | Lamp load-sharing circuit |
DE102005001326A1 (en) * | 2005-01-11 | 2006-07-20 | Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH | Electronic Ballast (ECG) |
Family Cites Families (183)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2429162A (en) | 1943-01-18 | 1947-10-14 | Boucher And Keiser Company | Starting and operating of fluorescent lamps |
US2440984A (en) | 1945-06-18 | 1948-05-04 | Gen Electric | Magnetic testing apparatus and method |
US2572258A (en) | 1946-07-20 | 1951-10-23 | Picker X Ray Corp Waite Mfg | X-ray tube safety device |
US2968028A (en) | 1956-06-21 | 1961-01-10 | Fuje Tsushinki Seizo Kabushiki | Multi-signals controlled selecting systems |
US2965799A (en) | 1957-09-26 | 1960-12-20 | Gen Electric | Fluorescent lamp ballast |
US3141112A (en) | 1962-08-20 | 1964-07-14 | Gen Electric | Ballast apparatus for starting and operating electric discharge lamps |
DE1671007B2 (en) | 1965-11-23 | 1971-04-08 | MANGAN ZINC FERRITE CORE WITH HIGH INITIAL PERMEABILITY | |
US3597656A (en) | 1970-03-16 | 1971-08-03 | Rucker Co | Modulating ground fault detector and interrupter |
US3611021A (en) | 1970-04-06 | 1971-10-05 | North Electric Co | Control circuit for providing regulated current to lamp load |
US3683923A (en) | 1970-09-25 | 1972-08-15 | Valleylab Inc | Electrosurgery safety circuit |
US3742330A (en) | 1971-09-07 | 1973-06-26 | Delta Electronic Control Corp | Current mode d c to a c converters |
US3737755A (en) | 1972-03-22 | 1973-06-05 | Bell Telephone Labor Inc | Regulated dc to dc converter with regulated current source driving a nonregulated inverter |
US3936696A (en) | 1973-08-27 | 1976-02-03 | Lutron Electronics Co., Inc. | Dimming circuit with saturated semiconductor device |
US3944888A (en) | 1974-10-04 | 1976-03-16 | I-T-E Imperial Corporation | Selective tripping of two-pole ground fault interrupter |
US4060751A (en) | 1976-03-01 | 1977-11-29 | General Electric Company | Dual mode solid state inverter circuit for starting and ballasting gas discharge lamps |
US6002210A (en) | 1978-03-20 | 1999-12-14 | Nilssen; Ole K. | Electronic ballast with controlled-magnitude output voltage |
US4388562A (en) | 1980-11-06 | 1983-06-14 | Astec Components, Ltd. | Electronic ballast circuit |
US4353009A (en) | 1980-12-19 | 1982-10-05 | Gte Products Corporation | Dimming circuit for an electronic ballast |
US4523130A (en) | 1981-10-07 | 1985-06-11 | Cornell Dubilier Electronics Inc. | Four lamp modular lighting control |
US4463287A (en) | 1981-10-07 | 1984-07-31 | Cornell-Dubilier Corp. | Four lamp modular lighting control |
US4700113A (en) | 1981-12-28 | 1987-10-13 | North American Philips Corporation | Variable high frequency ballast circuit |
US4441054A (en) | 1982-04-12 | 1984-04-03 | Gte Products Corporation | Stabilized dimming circuit for lamp ballasts |
US4630005A (en) | 1982-05-03 | 1986-12-16 | Brigham Young University | Electronic inverter, particularly for use as ballast |
US4698554A (en) | 1983-01-03 | 1987-10-06 | North American Philips Corporation | Variable frequency current control device for discharge lamps |
JPS60518A (en) | 1983-06-16 | 1985-01-05 | Hayashibara Takeshi | Device for responding dropped voltage at nonlinear section of diode |
US4562338A (en) | 1983-07-15 | 1985-12-31 | Osaka Titanium Co., Ltd. | Heating power supply apparatus for polycrystalline semiconductor rods |
US4574222A (en) | 1983-12-27 | 1986-03-04 | General Electric Company | Ballast circuit for multiple parallel negative impedance loads |
JPS60163397A (en) | 1984-02-03 | 1985-08-26 | シャープ株式会社 | Device for firing fluorescent lamp |
US4567379A (en) | 1984-05-23 | 1986-01-28 | Burroughs Corporation | Parallel current sharing system |
US4663570A (en) | 1984-08-17 | 1987-05-05 | Lutron Electronics Co., Inc. | High frequency gas discharge lamp dimming ballast |
US6472827B1 (en) | 1984-10-05 | 2002-10-29 | Ole K. Nilssen | Parallel-resonant inverter-type fluorescent lamp ballast |
US4672300A (en) | 1985-03-29 | 1987-06-09 | Braydon Corporation | Direct current power supply using current amplitude modulation |
BE902709A (en) | 1985-06-20 | 1985-12-20 | Backer Adrien Sa | METHOD AND DEVICE FOR MONITORING LIGHT BEACONS. |
US4780696A (en) | 1985-08-08 | 1988-10-25 | American Telephone And Telegraph Company, At&T Bell Laboratories | Multifilar transformer apparatus and winding method |
GB2179477B (en) | 1985-08-23 | 1989-03-30 | Ferranti Plc | Power supply circuit |
US4622496A (en) | 1985-12-13 | 1986-11-11 | Energy Technologies Corp. | Energy efficient reactance ballast with electronic start circuit for the operation of fluorescent lamps of various wattages at standard levels of light output as well as at increased levels of light output |
DK339586D0 (en) | 1986-07-16 | 1986-07-16 | Silver Gruppen Prod As | ELECTRONIC BALLAST |
EP0264135B1 (en) | 1986-10-17 | 1993-01-13 | Kabushiki Kaisha Toshiba | Power supply system for discharge load |
US4766353A (en) | 1987-04-03 | 1988-08-23 | Sunlass U.S.A., Inc. | Lamp switching circuit and method |
US4761722A (en) | 1987-04-09 | 1988-08-02 | Rca Corporation | Switching regulator with rapid transient response |
JPH061413B2 (en) | 1987-07-16 | 1994-01-05 | ニシム電子工業株式会社 | Ferro-resonant transformer for three-phase constant voltage |
JPH01189897A (en) | 1988-01-26 | 1989-07-31 | Tokyo Electric Co Ltd | Discharge lamp lighting device |
US4902942A (en) | 1988-06-02 | 1990-02-20 | General Electric Company | Controlled leakage transformer for fluorescent lamp ballast including integral ballasting inductor |
JPH0722055B2 (en) | 1988-06-29 | 1995-03-08 | ニシム電子工業株式会社 | Ferro-resonant three-phase constant voltage transformer device |
US4847745A (en) | 1988-11-16 | 1989-07-11 | Sundstrand Corp. | Three phase inverter power supply with balancing transformer |
US5057808A (en) | 1989-12-27 | 1991-10-15 | Sundstrand Corporation | Transformer with voltage balancing tertiary winding |
US5030887A (en) | 1990-01-29 | 1991-07-09 | Guisinger John E | High frequency fluorescent lamp exciter |
US5036255A (en) | 1990-04-11 | 1991-07-30 | Mcknight William E | Balancing and shunt magnetics for gaseous discharge lamps |
US5173643A (en) | 1990-06-25 | 1992-12-22 | Lutron Electronics Co., Inc. | Circuit for dimming compact fluorescent lamps |
US6121733A (en) | 1991-06-10 | 2000-09-19 | Nilssen; Ole K. | Controlled inverter-type fluorescent lamp ballast |
US6127785A (en) | 1992-03-26 | 2000-10-03 | Linear Technology Corporation | Fluorescent lamp power supply and control circuit for wide range operation |
US5563473A (en) | 1992-08-20 | 1996-10-08 | Philips Electronics North America Corp. | Electronic ballast for operating lamps in parallel |
EP0587923A1 (en) | 1992-09-14 | 1994-03-23 | U.R.D. Co. Ltd. | High-frequency constant-current feeding system |
US5394065A (en) | 1992-11-09 | 1995-02-28 | Tunewell Technology Limited | Circuit for supplying current to a discharge tube |
US5349272A (en) | 1993-01-22 | 1994-09-20 | Gulton Industries, Inc. | Multiple output ballast circuit |
US5434477A (en) | 1993-03-22 | 1995-07-18 | Motorola Lighting, Inc. | Circuit for powering a fluorescent lamp having a transistor common to both inverter and the boost converter and method for operating such a circuit |
US5485057A (en) | 1993-09-02 | 1996-01-16 | Smallwood; Robert C. | Gas discharge lamp and power distribution system therefor |
DE4333253A1 (en) | 1993-09-30 | 1995-04-06 | Deutsche Aerospace | Circuit arrangement for adapting an unbalanced line system to a balanced line system |
US5475284A (en) | 1994-05-03 | 1995-12-12 | Osram Sylvania Inc. | Ballast containing circuit for measuring increase in DC voltage component |
US5539281A (en) | 1994-06-28 | 1996-07-23 | Energy Savings, Inc. | Externally dimmable electronic ballast |
US5574356A (en) | 1994-07-08 | 1996-11-12 | Northrop Grumman Corporation | Active neutral current compensator |
US5574335A (en) | 1994-08-02 | 1996-11-12 | Osram Sylvania Inc. | Ballast containing protection circuit for detecting rectification of arc discharge lamp |
JP2891449B2 (en) | 1994-08-03 | 1999-05-17 | 株式会社日立製作所 | Discharge lamp lighting device |
US5615093A (en) | 1994-08-05 | 1997-03-25 | Linfinity Microelectronics | Current synchronous zero voltage switching resonant topology |
US5557249A (en) | 1994-08-16 | 1996-09-17 | Reynal; Thomas J. | Load balancing transformer |
KR0137917B1 (en) | 1994-10-28 | 1998-05-15 | 김광호 | Back-light driving circuit of liquid crystal display element |
US5519289A (en) | 1994-11-07 | 1996-05-21 | Jrs Technology Associates, Inc. | Electronic ballast with lamp current correction circuit |
US5652479A (en) | 1995-01-25 | 1997-07-29 | Micro Linear Corporation | Lamp out detection for miniature cold cathode fluorescent lamp system |
US5754012A (en) | 1995-01-25 | 1998-05-19 | Micro Linear Corporation | Primary side lamp current sensing for minature cold cathode fluorescent lamp system |
JP3543236B2 (en) | 1995-03-06 | 2004-07-14 | 株式会社キジマ | Push-pull inverter |
KR0148053B1 (en) | 1995-05-12 | 1998-09-15 | 김광호 | Backlight driving control device and its driving control method of liquid crystal display elements |
EP0757511B1 (en) | 1995-07-31 | 2003-03-26 | STMicroelectronics S.r.l. | Starting circuit, MOS transistor using the same and corresponding applications |
EP0766500B1 (en) | 1995-09-27 | 2001-12-12 | Koninklijke Philips Electronics N.V. | Ballast with balancer transformer for fluorescent lamps |
TW381409B (en) | 1996-03-14 | 2000-02-01 | Mitsubishi Electric Corp | Discharging lamp lighting device |
US5636111A (en) | 1996-03-26 | 1997-06-03 | The Genlyte Group Incorporated | Ballast shut-down circuit responsive to an unbalanced load condition in a single lamp ballast or in either lamp of a two-lamp ballast |
US5619402A (en) | 1996-04-16 | 1997-04-08 | O2 Micro, Inc. | Higher-efficiency cold-cathode fluorescent lamp power supply |
US5825133A (en) | 1996-09-25 | 1998-10-20 | Rockwell International | Resonant inverter for hot cathode fluorescent lamps |
US5828156A (en) | 1996-10-23 | 1998-10-27 | Branson Ultrasonics Corporation | Ultrasonic apparatus |
US5912812A (en) | 1996-12-19 | 1999-06-15 | Lucent Technologies Inc. | Boost power converter for powering a load from an AC source |
TW408558B (en) | 1996-12-25 | 2000-10-11 | Tec Corp | Power supply device and discharge lamp lighting apparatusv |
JPH10199687A (en) | 1997-01-08 | 1998-07-31 | Canon Inc | Fluorescent lamp inverter device |
GB9701687D0 (en) | 1997-01-28 | 1997-03-19 | Tunewell Technology Ltd | Improvements in or relating to an a.c. current distribution system |
US5923129A (en) | 1997-03-14 | 1999-07-13 | Linfinity Microelectronics | Apparatus and method for starting a fluorescent lamp |
US5930121A (en) | 1997-03-14 | 1999-07-27 | Linfinity Microelectronics | Direct drive backlight system |
US6441943B1 (en) | 1997-04-02 | 2002-08-27 | Gentex Corporation | Indicators and illuminators using a semiconductor radiation emitter package |
EP0928061A4 (en) | 1997-04-22 | 2004-05-12 | Nippon Electric Co | Neutral-point inverter |
US5914842A (en) | 1997-09-26 | 1999-06-22 | Snc Manufacturing Co., Inc. | Electromagnetic coupling device |
US6188553B1 (en) | 1997-10-10 | 2001-02-13 | Electro-Mag International | Ground fault protection circuit |
US6020688A (en) | 1997-10-10 | 2000-02-01 | Electro-Mag International, Inc. | Converter/inverter full bridge ballast circuit |
US6072282A (en) | 1997-12-02 | 2000-06-06 | Power Circuit Innovations, Inc. | Frequency controlled quick and soft start gas discharge lamp ballast and method therefor |
US6181066B1 (en) | 1997-12-02 | 2001-01-30 | Power Circuit Innovations, Inc. | Frequency modulated ballast with loosely coupled transformer for parallel gas discharge lamp control |
JPH11233285A (en) | 1998-02-18 | 1999-08-27 | Aibis:Kk | Light modulation control device |
JP3832074B2 (en) | 1998-02-24 | 2006-10-11 | 松下電工株式会社 | Discharge lamp lighting device |
JP3559162B2 (en) | 1998-04-21 | 2004-08-25 | アルパイン株式会社 | Driving method of backlight lamp |
US6043609A (en) | 1998-05-06 | 2000-03-28 | E-Lite Technologies, Inc. | Control circuit and method for illuminating an electroluminescent panel |
US5892336A (en) | 1998-05-26 | 1999-04-06 | O2Micro Int Ltd | Circuit for energizing cold-cathode fluorescent lamps |
US6445141B1 (en) | 1998-07-01 | 2002-09-03 | Everbrite, Inc. | Power supply for gas discharge lamp |
JP4153592B2 (en) | 1998-07-09 | 2008-09-24 | 松下電工株式会社 | Discharge lamp lighting device |
US6181084B1 (en) | 1998-09-14 | 2001-01-30 | Eg&G, Inc. | Ballast circuit for high intensity discharge lamps |
US6169375B1 (en) | 1998-10-16 | 2001-01-02 | Electro-Mag International, Inc. | Lamp adaptable ballast circuit |
US6127786A (en) | 1998-10-16 | 2000-10-03 | Electro-Mag International, Inc. | Ballast having a lamp end of life circuit |
US6181083B1 (en) | 1998-10-16 | 2001-01-30 | Electro-Mag, International, Inc. | Ballast circuit with controlled strike/restart |
US6037720A (en) | 1998-10-23 | 2000-03-14 | Philips Electronics North America Corporation | Level shifter |
US6150772A (en) | 1998-11-25 | 2000-11-21 | Pacific Aerospace & Electronics, Inc. | Gas discharge lamp controller |
US6114814A (en) | 1998-12-11 | 2000-09-05 | Monolithic Power Systems, Inc. | Apparatus for controlling a discharge lamp in a backlighted display |
US6900600B2 (en) | 1998-12-11 | 2005-05-31 | Monolithic Power Systems, Inc. | Method for starting a discharge lamp using high energy initial pulse |
US6137240A (en) | 1998-12-31 | 2000-10-24 | Lumion Corporation | Universal ballast control circuit |
US6108215A (en) | 1999-01-22 | 2000-08-22 | Dell Computer Corporation | Voltage regulator with double synchronous bridge CCFL inverter |
US6104146A (en) | 1999-02-12 | 2000-08-15 | Micro International Limited | Balanced power supply circuit for multiple cold-cathode fluorescent lamps |
US6049177A (en) | 1999-03-01 | 2000-04-11 | Fulham Co. Inc. | Single fluorescent lamp ballast for simultaneous operation of different lamps in series or parallel |
EP1077018A1 (en) | 1999-03-09 | 2001-02-21 | Koninklijke Philips Electronics N.V. | Inductive component, and circuit arrangement comprising such an inductive component |
US6198234B1 (en) | 1999-06-09 | 2001-03-06 | Linfinity Microelectronics | Dimmable backlight system |
JP2001006888A (en) | 1999-06-21 | 2001-01-12 | Koito Mfg Co Ltd | Discharge lamp lighting circuit |
US6804129B2 (en) | 1999-07-22 | 2004-10-12 | 02 Micro International Limited | High-efficiency adaptive DC/AC converter |
US6259615B1 (en) | 1999-07-22 | 2001-07-10 | O2 Micro International Limited | High-efficiency adaptive DC/AC converter |
US6198236B1 (en) | 1999-07-23 | 2001-03-06 | Linear Technology Corporation | Methods and apparatus for controlling the intensity of a fluorescent lamp |
US6320329B1 (en) | 1999-07-30 | 2001-11-20 | Philips Electronics North America Corporation | Modular high frequency ballast architecture |
US6218788B1 (en) | 1999-08-20 | 2001-04-17 | General Electric Company | Floating IC driven dimming ballast |
US20020030451A1 (en) | 2000-02-25 | 2002-03-14 | Moisin Mihail S. | Ballast circuit having voltage clamping circuit |
US6472876B1 (en) | 2000-05-05 | 2002-10-29 | Tridonic-Usa, Inc. | Sensing and balancing currents in a ballast dimming circuit |
AU2001251230A1 (en) | 2000-05-12 | 2001-11-26 | John Chou | Integrated circuit for lamp heating and dimming control |
US6522558B2 (en) | 2000-06-13 | 2003-02-18 | Linfinity Microelectronics | Single mode buck/boost regulating charge pump |
US6307765B1 (en) | 2000-06-22 | 2001-10-23 | Linfinity Microelectronics | Method and apparatus for controlling minimum brightness of a fluorescent lamp |
US6215256B1 (en) | 2000-07-07 | 2001-04-10 | Ambit Microsystems Corporation | High-efficient electronic stabilizer with single stage conversion |
US6310444B1 (en) | 2000-08-10 | 2001-10-30 | Philips Electronics North America Corporation | Multiple lamp LCD backlight driver with coupled magnetic components |
US6459215B1 (en) | 2000-08-11 | 2002-10-01 | General Electric Company | Integral lamp |
US6494587B1 (en) | 2000-08-24 | 2002-12-17 | Rockwell Collins, Inc. | Cold cathode backlight for avionics applications with strobe expanded dimming range |
EP1324357A4 (en) | 2000-09-14 | 2008-10-22 | Matsushita Electric Works Ltd | Electromagnetic device and high-voltage generating device and method of producing electromagnetic device |
US6433492B1 (en) | 2000-09-18 | 2002-08-13 | Northrop Grumman Corporation | Magnetically shielded electrodeless light source |
US6680834B2 (en) | 2000-10-04 | 2004-01-20 | Honeywell International Inc. | Apparatus and method for controlling LED arrays |
DE10049842A1 (en) | 2000-10-09 | 2002-04-11 | Tridonic Bauelemente | Operating circuit for gas discharge lamps, has additional DC supply line for each gas discharge lamp for preventing unwanted lamp extinction |
JP2002175891A (en) | 2000-12-08 | 2002-06-21 | Advanced Display Inc | Multi-lamp type inverter for backlight |
US6501234B2 (en) | 2001-01-09 | 2002-12-31 | 02 Micro International Limited | Sequential burst mode activation circuit |
KR100759362B1 (en) * | 2001-01-18 | 2007-09-19 | 삼성전자주식회사 | A backlight assembly and a liquid crystal display device having the same |
US6420839B1 (en) | 2001-01-19 | 2002-07-16 | Ambit Microsystems Corp. | Power supply system for multiple loads and driving system for multiple lamps |
US6417631B1 (en) | 2001-02-07 | 2002-07-09 | General Electric Company | Integrated bridge inverter circuit for discharge lighting |
TW478292B (en) | 2001-03-07 | 2002-03-01 | Ambit Microsystems Corp | Multi-lamp driving system |
US6459216B1 (en) | 2001-03-07 | 2002-10-01 | Monolithic Power Systems, Inc. | Multiple CCFL current balancing scheme for single controller topologies |
US6509696B2 (en) | 2001-03-22 | 2003-01-21 | Koninklijke Philips Electronics N.V. | Method and system for driving a capacitively coupled fluorescent lamp |
DE10115388A1 (en) | 2001-03-28 | 2002-10-10 | Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh | Control circuit for an LED array |
KR100815890B1 (en) | 2001-03-31 | 2008-03-24 | 엘지.필립스 엘시디 주식회사 | Method Of Winding Coil and Transformer and Invertor for Liquid Crystal Display Using The Same |
US6628093B2 (en) | 2001-04-06 | 2003-09-30 | Carlile R. Stevens | Power inverter for driving alternating current loads |
US6570344B2 (en) | 2001-05-07 | 2003-05-27 | O2Micro International Limited | Lamp grounding and leakage current detection system |
US6515881B2 (en) | 2001-06-04 | 2003-02-04 | O2Micro International Limited | Inverter operably controlled to reduce electromagnetic interference |
JP2002367835A (en) | 2001-06-04 | 2002-12-20 | Toko Inc | Inverter transformer |
US6630797B2 (en) | 2001-06-18 | 2003-10-07 | Koninklijke Philips Electronics N.V. | High efficiency driver apparatus for driving a cold cathode fluorescent lamp |
TWI256860B (en) | 2001-06-29 | 2006-06-11 | Hon Hai Prec Ind Co Ltd | Multi-tube driving system |
US6486618B1 (en) | 2001-09-28 | 2002-11-26 | Koninklijke Philips Electronics N.V. | Adaptable inverter |
US6559606B1 (en) | 2001-10-23 | 2003-05-06 | O2Micro International Limited | Lamp driving topology |
JP2003133095A (en) | 2001-10-30 | 2003-05-09 | Mitsubishi Electric Corp | Discharge lamp lighting device |
US6703796B2 (en) | 2001-11-09 | 2004-03-09 | Ambit Microsystems Corp. | Power supply and inverter used therefor |
TW556860U (en) | 2001-12-14 | 2003-10-01 | Taiwan Power Conversion Inc | Current equalizer back light plate |
US6781326B2 (en) | 2001-12-17 | 2004-08-24 | Q Technology Incorporated | Ballast with lamp sensor and method therefor |
US20030141829A1 (en) | 2002-01-31 | 2003-07-31 | Shan-Ho Yu | Current equalizer assembly for LCD backlight panel |
US6930893B2 (en) | 2002-01-31 | 2005-08-16 | Vlt, Inc. | Factorized power architecture with point of load sine amplitude converters |
TW595263B (en) | 2002-04-12 | 2004-06-21 | O2Micro Inc | A circuit structure for driving cold cathode fluorescent lamp |
US6969958B2 (en) | 2002-06-18 | 2005-11-29 | Microsemi Corporation | Square wave drive system |
TWI277371B (en) | 2002-06-26 | 2007-03-21 | Darfon Electronics Corp | Inverter for driving multiple discharge lamps |
US7777431B2 (en) | 2002-08-06 | 2010-08-17 | Sharp Kabushiki Kaisha | Inverter circuit, fluorescent bulb operating device, backlight device, and liquid crystal display device |
JP3951176B2 (en) | 2002-09-06 | 2007-08-01 | ミネベア株式会社 | Discharge lamp lighting device |
JP2004335443A (en) | 2003-02-10 | 2004-11-25 | Masakazu Ushijima | Inverter circuit for discharge tube for multiple lamp lighting, and surface light source system |
US6870330B2 (en) | 2003-03-26 | 2005-03-22 | Microsemi Corporation | Shorted lamp detection in backlight system |
US6936975B2 (en) | 2003-04-15 | 2005-08-30 | 02Micro International Limited | Power supply for an LCD panel |
TW200501829A (en) | 2003-06-23 | 2005-01-01 | Benq Corp | Multi-lamp driving system |
US7187139B2 (en) | 2003-09-09 | 2007-03-06 | Microsemi Corporation | Split phase inverters for CCFL backlight system |
US7250726B2 (en) | 2003-10-21 | 2007-07-31 | Microsemi Corporation | Systems and methods for a transformer configuration with a tree topology for current balancing in gas discharge lamps |
TW200517014A (en) | 2003-11-10 | 2005-05-16 | Kazuo Kohno | Drive circuit for lighting fixture |
US7265499B2 (en) | 2003-12-16 | 2007-09-04 | Microsemi Corporation | Current-mode direct-drive inverter |
US7250731B2 (en) * | 2004-04-07 | 2007-07-31 | Microsemi Corporation | Primary side current balancing scheme for multiple CCF lamp operation |
KR100616613B1 (en) * | 2004-08-27 | 2006-08-28 | 삼성전기주식회사 | Black-light inverter for u-shaped lamp |
KR101072376B1 (en) * | 2004-09-23 | 2011-10-11 | 엘지디스플레이 주식회사 | Backlight Assembly of Liquid Crystal Display Device |
JP2006156338A (en) * | 2004-11-05 | 2006-06-15 | Taiyo Yuden Co Ltd | Lamp lighting device |
WO2006107305A1 (en) * | 2005-03-31 | 2006-10-12 | Microsemi Corporation | Zigzag topology for balancing current among multiple lamps |
US7439685B2 (en) * | 2005-07-06 | 2008-10-21 | Monolithic Power Systems, Inc. | Current balancing technique with magnetic integration for fluorescent lamps |
TWI350128B (en) * | 2005-08-10 | 2011-10-01 | Au Optronics Corp | Lamp drive circuit |
US7446485B2 (en) * | 2005-08-24 | 2008-11-04 | Beyond Innovation Technology Co., Ltd. | Multi-lamp driving system |
KR20070059721A (en) * | 2005-12-07 | 2007-06-12 | 삼성전자주식회사 | Inverter circuit, back light assembly and liquid crystal display device having the same |
KR20070109223A (en) * | 2006-05-10 | 2007-11-15 | 엘지이노텍 주식회사 | Apparatus for driving lamps of liquid crystal display device |
US7777425B2 (en) * | 2006-09-19 | 2010-08-17 | O2Micro International Limited | Backlight circuit for LCD panel |
KR101213772B1 (en) * | 2006-09-28 | 2012-12-17 | 삼성디스플레이 주식회사 | Inverter circuit and backlight assembly having the same |
US7821208B2 (en) * | 2007-01-08 | 2010-10-26 | Access Business Group International Llc | Inductively-powered gas discharge lamp circuit |
TWI334123B (en) * | 2007-02-26 | 2010-12-01 | Au Optronics Corp | Lightting apparatus with current feedback |
CN101409972B (en) * | 2007-10-12 | 2016-10-05 | 昂宝电子(上海)有限公司 | For multiple cold cathode fluorescence lamps and/or the drive system of external-electrode fluorescent lamp and method |
-
2009
- 2009-01-20 TW TW098102000A patent/TW200939886A/en unknown
- 2009-01-20 TW TW098101999A patent/TW200948201A/en unknown
- 2009-02-02 WO PCT/US2009/032788 patent/WO2009099979A1/en active Application Filing
- 2009-02-02 US US12/363,805 patent/US8008867B2/en not_active Expired - Fee Related
- 2009-02-02 US US12/363,807 patent/US7990072B2/en not_active Expired - Fee Related
- 2009-02-02 US US12/363,806 patent/US7977888B2/en not_active Expired - Fee Related
- 2009-02-02 WO PCT/US2009/032787 patent/WO2009099978A1/en active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20030015974A1 (en) * | 2001-07-23 | 2003-01-23 | Patent-Treuhand-Gesellschaft Fur Elektrische Gluhl | Ballast for operating at least one low-pressure discharge lamp |
US20050093471A1 (en) * | 2003-10-06 | 2005-05-05 | Xiaoping Jin | Current sharing scheme for multiple CCF lamp operation |
US20060119293A1 (en) * | 2004-12-03 | 2006-06-08 | Chun-Kong Chan | Lamp load-sharing circuit |
DE102005001326A1 (en) * | 2005-01-11 | 2006-07-20 | Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH | Electronic Ballast (ECG) |
Also Published As
Publication number | Publication date |
---|---|
US20090195178A1 (en) | 2009-08-06 |
TW200948201A (en) | 2009-11-16 |
US8008867B2 (en) | 2011-08-30 |
WO2009099979A1 (en) | 2009-08-13 |
TW200939886A (en) | 2009-09-16 |
US20090195174A1 (en) | 2009-08-06 |
US7977888B2 (en) | 2011-07-12 |
US7990072B2 (en) | 2011-08-02 |
US20090195175A1 (en) | 2009-08-06 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8008867B2 (en) | Arrangement suitable for driving floating CCFL based backlight | |
JP4101228B2 (en) | Discharge tube parallel lighting system for surface light source | |
US7242147B2 (en) | Current sharing scheme for multiple CCF lamp operation | |
CN100452940C (en) | Multiple lamp LCD backlight driver with coupled magnetic components | |
US7173382B2 (en) | Nested balancing topology for balancing current among multiple lamps | |
CN1682428B (en) | Inverter circuit, fluorescent bulb lighting device, backlight device, and liquid crystal display device | |
JP2003031383A (en) | Multi-lamp driving system | |
US7777425B2 (en) | Backlight circuit for LCD panel | |
US7619371B2 (en) | Inverter for driving backlight devices in a large LCD panel | |
US7205726B2 (en) | Discharge lamp drive apparatus and liquid crystal display apparatus | |
US7764024B2 (en) | Piezoelectric transformer module for generating balance resonance driving current and related light module | |
CN201369867Y (en) | Multi lamp-tube driving system | |
JP4658110B2 (en) | Discharge tube parallel lighting system for surface light source | |
KR100689989B1 (en) | Apparatus for parallel driving ccfl | |
US7825608B2 (en) | Multi-discharge tube lighting apparatus | |
CN101730352A (en) | Backlight source for driving image display device and driving system for driving multi-tube lamp | |
JP2008146961A (en) | Inverter circuit for lighting multiple lamps |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 09707984 Country of ref document: EP Kind code of ref document: A1 |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 09707984 Country of ref document: EP Kind code of ref document: A1 |