WO2001043266A1

WO2001043266A1 - Electrical power strip with ac to dc power supply

Info

Publication number: WO2001043266A1
Application number: PCT/US1999/029434
Authority: WO
Inventors: Phillip Lam
Original assignee: Am Group Corp.
Priority date: 1999-12-10
Filing date: 1999-12-10
Publication date: 2001-06-14
Also published as: AU2175300A

Abstract

The familiar power strip (200) or uninterruptable power supply (UPS) commonly used with personal computer systems (216) are supplied with an internal AC to DC power supply and a plurality of DC sockets (202, 205, 208, 211) at its face. The DC sockets (202, 205, 208, 211) are connected to the (DC) output of the power supply, via a resistor network, for supplying different DC levels at the sockets and the sockets are configured differently to mate with plugs of specified configuration keyed to the proper DC voltage level. The power supply has an input cable with a plug for connection to an in-the-wall socket and includes AC sockets (220, 221) electrically connected to that cable electrically in parallel to the resistor network for providing AC power at (AC) sockets (220, 221) at the face of the strip. According to another aspect, the UPS is equipped with circuitry which connects between the DC side of the AC/DC converter therein and a plurality of sockets on the face (202, 205, 208, 211) of the UPS for supplying DC voltage there. The UPS also is equipped with two batteries. One battery is connected between the DC side of the AC/DC converter and the DC side of a DC/AC converter both standard in prior art UPS devices. The other battery is connected between the DC side of the AC/DC converter and the DC voltage determining circuitry. The first battery provides back up for AC sockets (220, 211) in the UPS face; the second, back up for the DC sockets (202, 205, 208, 211) should an AC power failure occur. A single battery embodiment is also disclosed.

Description

TITLE: ELECTRICAL POWER STRIP WITH AC TO DC POWER SUPPLY FIELD OF THE INVENTION

This invention relates to power strips and more particularly to power strips such as are in common use for connection to a host (personal computer) PC, a monitor, a printer, a key board and speakers typical of a PC system. BACKGROUND OF THE INVENTION

Personal computers (PC's) and the equipment which constitute a PC system are in widespread use. Typically, such equipment is connected into sockets, provided for such equipment at the rear of the computer. The equipment also obtains AC power from an in-the-wall socket or more frequently, via a power strip connected to an in- the-wall socket. The power strip provides a plurality of sockets, configured like the wall socket, for connection to each piece of equipment. In this manner, AC power is supplied conveniently to each piece of equipment, each including an internal AC to DC power supply for utilizing the AC power.

But there are peripherals also operative with host equipment (such as a PC) which do not come equipped with internal AC to DC power supplies. Such equipment might be, for example, a CD-ROM, amplifier, FAX machine - etc. Each piece of such equipment is sold with an adapter which plugs into the wall and provides the requisite DC voltage in each instance.

U.S. Patent No. 5,563,782 issued October 8, 1996, describes a multi-socket, in-the-wall outlet which includes an AC to DC convertor and provides sockets for both AC and for DC voltage. The outlet has to be installed in the wall and wired into the house wiring. Further, U.S. Patent No. 5,321,349 describes a battery-powered, portable power supply with a single (switchable) socket for supplying DC power. But neither the in-the-wall outlet nor the portable battery-powered equipment provides a portable, multisocket arrangement which allows the flexibility and ease of use of the familiar power strip.

But the familiar power strip merely provides multiple sockets for supplying like AC voltages. Peripheral equipment requiring different DC voltages still requires an in- the-wall outlet and an adapter. BRIEF DESCRIPTION OF THE INVENTION

In accordance with the principles of this invention, the familiar power strip for simultaneous activation of a PC and associated monitor, keyboard, printer — etc, includes an internal (AC to DC) power supply and sockets to which the power supply provides different DC voltages. Consequently, host equipment, such as a PC, can have peripherals, which do not have internal (AC to DC) power supplies, connected to DC sockets in the power strip in the same manner as the presently associated equipment is now connected to a power strip for receiving AC power.

By providing a plug and cable instead of requiring wall installation, a portable universal power strip is provided for convenient use where one need only plug into a matching (mating) socket for setting up, say, a computer system or a high fidelity sound system.

In accordance with further principles of this invention, the above mentioned power strip also includes at least one battery for supplying temporary power to the DC sockets for permitting safe shut off procedures to occur in case of a power failure.

Presently available uninterruptible power sources (UPS) do include a battery. But the battery output is connected between an AC/DC converter and a DC/AC converter so that AC power (only) is supplied at the sockets.

In accordance with one embodiment of this invention, an additional battery is connected between the AC/DC converter and the resistor networks which deliver DC voltages to the various (DC) sockets.

In accordance with another embodiment only a single battery need be used. BRIEF DESCRIPTION OF THE DRAWING

Fig. 1 is a schematic view of a prior art power strip;

Fig's. 2a and 2b are schematic top and side views of a power strip in accordance with the principles of this invention;

Fig. 3 is a block diagram of the circuit of the power strip of figure 2;

Fig. 4 is a circuit diagram of the power strip of figures 2 and 3 showing a resistor network for supplying DC voltage to the sockets therein; and

Fig. 5 is a resistor network for the power strip of fig's. 2 and 3.

Fig. 6 is a schematic view of a prior art uninterruptable power source (UPS).

Fig's. 7 and 8 are circuit diagrams for first and second embodiments of a UPS in accordance with the principles of this invention; Fig. 9 is a schematic view of a UPS in accordance with the principles of this invention; and

Fig. 10 is a schematic view of an illustrative system employing the UPS of fig. 9.

DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENTS OF THIS INVENTION

Fig. 1 shows a familiar prior art power strip 10. The power strip includes a plurality of sockets 11, 12, 13, 14, 15, 16 and 17, each of which is a standard wall receptacle for receiving a plug which mates with a wall outlet. The power strip includes a cable 20 and a plug 21 configured to plug into a wall socket. The power strip also includes a switch 22 operative to supply power to each of the sockets.

Fig's. 2a and 2b are top and side views of an illustrative power strip 30 in accordance with the principles of this invention. The power strip includes an elevated portion 31 which houses a plurality (illustratively two) AC (voltage) sockets 32 and 33 and an on-off switch 35. The AC sockets are connected to a wall socket (not shown) via a cable 36.

The power strip of fig. 2 also includes a lower portion 40 which includes a plurality of DC voltage sockets in a familiar configuration. The DC sockets illustratively are 3V, 5V, 6V, 7.5V, 6V, 12V, 15V, 17V, and 24V. Two sockets (42 and 43) are illustratively of undesignated voltages and two sockets (45 and 46) are switchable to one of several voltages 9V, 12V, 15V and 24V for socket 45 and 3 V, 5V, 6V, 7.5V, 9V, 12V, and 15V for socket 46. Fig's. 3 and 4 are a block diagram and a circuit diagram for the power strip of fig. 2 respectively. The circuit of fig. 4 is most easily understood with reference to the block diagram of fig. 3. Specifically, block 42 represents the AC supply from an in- the-wall outlet. The house voltage is filtered as indicated by block 42. The AC voltage is supplied to a control circuit represented by block 43 in fig. 4. The control circuit may be any microprocessor capable of controlling the required performance herein and conveniently includes protection and reset functions as well. The protection and reset functions are represented by block 44 and is well understood in the art.

The circuit (43) also controls an AC-DC converter represented by block 45. A second control circuit 46, also a microprocessor, controls a DC-DC converter 47 and includes feedback and protection function represented by block 48. Converter 47 is connected to a resistor network for supplying the proper voltage levels at the respective sockets of lower portion 40 of fig. 2b. The resistor network is represented by block 49 in fig. 3. The AC connection to sockets 32 and 33 of fig. 2a is represented by block 51.

Fig. 4 shows an illustrative circuit diagram corresponding to the block diagram of fig. 3. The correspondence between the two figures is indicated by the broken lines in fig. 4 designated to correspond to the blocks of fig. 3.

The circuit is configured to couple to a wall outlet represented by a vertical broken line (42) to the left as viewed in the figure. The EMI filter (42) comprises a standard arrangement of inductors in fig. 4 encompassed by broken lines designated 42. The control and protection and reset functions (43 and 44 in fig. 3) are implemented by a microprocessor similarly designated in fig. 4. The AC-DC converter (45) is implemented by a standard arrangement of transforms, diodes and capacitors as is well understood. The DC-DC converter similarly is a standard component. The control, feedback and protection functions (46 and 48) are implemented by a microprocessor.

The DC out block 49 of fig. 3 is implemented by a resistor network shown in fig. 5. Specifically, fig. 5 shows lines 55 and 56 connected to switchable sockets 45 and 46, of fig. 2A, respectively. The figure also shows lines 60, 61, and 62 connected to sockets (non switchable) 65, 66, and 67 of fig. 2A. Broken lines 70 and 71 indicate connections to the remaining sockets (non switchable) of fig. 2 A. Ground connections for the resistor network are shown at 75, 76, and 77.

The voltage output from EMI filter 42 is rectified by diode bridge 52 with the voltage level determined by capacitor 53 of fig. 4. Control circuit 43 (with protection and reset 44) operates as a voltage regulator and regulates AC-DC converter 45 to generate the specified voltage for the DC-DC converter 47 (along with control circuit 46 with feedback and protection circuit 48).

A set of blocks 46, 47, 48 is necessary for each socket on lower portion 40 of fig. 2a and is shown in fig. 4 illustratively only for a single socket. Specifically, fig. 5 shows two switchable sockets 45 and 46 along with at least three fixed voltage sockets 60, 61, and 62. The circuitry represented by blocks 46, 47, and 48 in fig. 3 is required for each of these sockets. Fig. 6 shows a familiar prior art UPS 110. The UPS includes a plurality of sockets 111, 112, 113, 114, 115, 116, 117 and 118, each of which is a standard wall receptacle for receiving a plug which mates with a wall outlet. The UPS includes a cable 120 and a plug 121 configured to plug into a wall socket. The UPS also includes a switch 122 operative to supply power to each of the sockets.

Fig. 7 is a block diagram of an illustrative UPS in accordance with the principles of this invention. Block 125 represents a line transformer to which switch 126 is connected. An output of the transformer is connected to the input of line voltage control 131. Control 131 has the familiar auto boost and auto buck outputs 133 and 134. The output of control 131 is connected to AC sockets 127, 128, and 129.

An output 135 of transformer 125 is connected to the input of recharge AC/DC converter 136. The output of converter 136 is connected to battery 137. The output of battery 137 is connected to DC/AC inverter 139. The output of inverter 139 is connected to sockets 127, 128 and 129 as shown.

The output of converter 136 also is connected to a second battery 140 as well as directly to control and over voltage protection circuits 141, 142 and 143. The output of battery 140 is connected to the inputs to control circuits 141, 142, and 143 also. The outputs of circuits 141, 142, and 143 are connected to inputs of current and over voltage protection circuits 146, 147 and 148 respectively. The outputs of circuits 146, 147, and 148 are connected to different DC sockets which are DIN sockets in the illustrative embodiment designated DIN-1, DIN-2, and DIN-3 in fig. 2. The outputs of circuits 146, 147, and 148 are also connected to inputs to circuits 141, 142 and 143 as shown.

Dashed line 150 encompasses the components found in prior art UPS devices. The dashed line is shown encompassing the familiar EMI filter 151 as well as plug 152 as shown. The components outside the dashed lines are provided in accordance with the principles of this invention to provide uninterruptible power to DC sockets in the event of a power failure at plug 152.

Fig. 8 shows an alternative embodiment of this invention using only a single battery 160. All the components encompassed by dashed line 170 in fig. 8 can be seen to correspond with like components encompassed by dashed line 150 of fig. 7 and, accordingly, are not further designated or discussed herein.

But in the embodiment of fig. 8, the output of battery 160 is connected to a DC DC converter 161. The output of converter 61 is connected to voltage control circuits 164, 165, and 166. The output of circuits 164, 165 and 166 are connected to current and over voltage protection circuits 168, 169 and 170. The outputs of circuits 168, 169 and 170 are connected to inputs of circuits 164, 165 and 166 respectively.

The outputs of circuits 168, 169 and 170 also are connected to DC sockets 172, 173 and 174, respectively as shown.

The various components herein may be any such components capable of operating as required and are standard, commercially available items.

Fig. 9 is a schematic view of an operating model 190 of the embodiment of fig. 7 with an extra (a fourth) socket 191. In addition the model included a plurality of switches 194, 195, 196 and 197 for sockets 146, 147, 148 and 191 respectively. Each switch is operable to select a voltage from one of a set of voltages available at the associated socket. For example, switch 194 is operable to select one of 5.5, 6, 7.5, and 8 volts all available at socket 194. A cable arrangement disclosed in copending application Serial No. 09/059,979 filed April 14, 1998 and assigned to the assignee of the present application is available to ensure the availability of a correct voltage for the connected peripheral.

U.S. Patent Serial No. 5,777,397 issued July 7, 1998 to the inventor of the present application disclosed the switch arrangement and operation thereof.

The invention has been described with a plurality of AC and DC sockets. It is to be understood that the number of sockets was chosen as illustrative and a best estimate of what a commercial em would require. The number may be varied within the spirit and scope of the invention.

Each of the control circuits 41, 42 and 43 of fig. 2 or 164, 165 and 166 of fig. 8 may include a resistor network for determining the voltages available at the associated DC socket. Such a resistor network in this context is disclosed in U.S. Patent Serial No. 5,753,978 issued May 19, 1998 as well as in the above-identified U.S. Patent. Other equivalent techniques, including solid state designs and software- controlled vo age selection circuitry also may be used.

Fig. 10 illustrates how an AC & DC power station or power pier 200 may be used to supply AC and DC voltages, as required, to a variety of components which comprise a system. In the system of fig.lO, a speaker and sub woofer 201 is connected to socket 205, zip drive 207 is connected to socket 208; and external CD drive 210 is connected to socket 111 - all DC sockets. Monitor 215 and computer 216 are connected to AC sockets 220 and 221 respectively. The power pier is capable of supplying to many other components such as an external FAX/modem, floppy drive, photo scanners, video camera, wireless phones, label printers, point of sale devices, bar code scanners and credit card readers.

Claims

WHAT IS CLAIM IS:

1. A power strip for providing both AC and DC voltages for different pieces of equipment, said power strip including an AC to DC converter and a plurality of sockets on a face of the power strip, said power strip including a cable having at the distal end thereof a plug for connection to an in-the-wall outlet, said power strip having internal thereto an output connected to said sockets via a resistor network for providing different DC vo ages at said sockets, said power source also having at said face at least one socket for supplying AC power, said one socket being connected electrically directly to the proximal end of said cable.

2. A power strip as in claim 1 having a plurality of like-configured sockets for providing AC power, each of said like-configured sockets being connected electrically to said proximal end of said cable.

3. A power strip as in claim 1 including means for varying the vo age at at least one of said sockets connected to said resistor network.

4. A power strip as in claim 2 including means for varying the voltage at at least one of said DC sockets.

5. A power strip, said power strip having a first face and including an AC to DC converter therein, said converter having an input and an output, means for connecting said input to a wall outlet, said power strip including a plurality of sockets at said face, said output being connected to said plurality of sockets via a resistor network for providing a DC voltage at each of said sockets, said power strip also including at said face at least one AC socket connected to said input for providing AC voltage there.

6. A power strip as in claim 5 wherein said plurality of sockets are of like configuration.

7. A power strip as in claim 6 also including a second AC socket connected to said input.

8. A power strip as in claim 5 including means for varying the voltage at at least one of said DC sockets.

9. A power strip as in claim 7 including means for varying the voltage at at least one of said DC sockets.

10. A power strip as in claim 8 including means for varying the voltages at a plurality of said DC sockets.

11. A power strip as in claim 5 wherein said resistor network provides a different voltage at each of said sockets.

12. An uninterruptable power supply, said supply including a connector for connection to a source of AC power and a plurality of first sockets, said supply also including first means for supplying AC voltage at each of said sockets, said means comprising an AC/DC converter and a DC/AC converter and having a first battery connected between the DC sides of said converters, said connector being connected to the AC side of said AC/DC converter and said sockets being connected to the AC side of said DC/AC converter, said supply also including a plurality of second sockets and second means for supplying DC voltages to each of said second sockets.

13. A supply as in claim 12 wherein said second means comprises a DC/DC converter, said DC/DC converter being connected between said first battery and said plurality of second sockets.

14. A supply as in claim 13 also including a voltage control circuit and a current and over voltage protection circuit between said DC/DC converter and each of said plurality of second sockets.

15. A supply as in claim 12 including a second battery, said second battery being connected between the DC side of said AC/DC converter and said plurality of second sockets, said supply also including a direct electrical connection between said second sockets and the DC side of said AC/DC converter.

16. A supply as in claim 15 also including a voltage control circuit and a current and over voltage protection circuit between said second battery and said plurality of second sockets.

17. A supply as in claim 12 also including a switch for each of said plurality of second sockets for selecting the DC voltage supplied at the associated socket.

18. A supply as in claim 13 also including a switch for each of said plurality of second sockets for selecting the voltage supplied at the associated socket.

19. A supply as in claim 15 also including a switch for each of said plurality of second sockets for selecting the voltage supplied at the associated socket.

20. An uninterruptible power source (UPS) said UPS comprising a housing and a plurality of sockets in said housing, said UPS including connector means for connecting to a source of AC power, said UPS including a first battery and both an AC/DC and a DC to AC converter, said battery being connected between the DC sides of said converters, the AC side of said DC to AC converter being connected to ones of said sockets, said UPS also including a second battery, said second battery being connected between the DC sides of said AC/DC converter and, in parallel to each of a plurality of resistor networks, each of said resistor networks being connected to one of said sockets for providing DC voltage there, each of said resistor networks also being connected to the DC side of said AC/DC converter.