CN100426662C - Power amplifier - Google Patents

Abstract

The present invention discloses a Doherty power amplifier which comprises a carrier power amplifier, a peak value power amplifier, a lambda/4 transmission line of the carrier power amplifier (lambda/4 means one fourth of the wave length of the carrier power amplifier) and a lambda/4 transmission line of the peak value power amplifier, wherein the carrier power amplifier and the peak value power amplifier are respectively connected in parallel at the input end and the output end; the lambda/4 transmission line of the carrier power amplifier is connected between the carrier power amplifier and the output end; the lambda/4 transmission line of the peak value power amplifier is connected between the input end and the peak value power amplifier. The Doherty power amplifier further comprises a first lambda/4 impedance transformation device, a second lambda/4 impedance transformation device, a third lambda/4 impedance transformation device and a fourth lambda/4 impedance transformation device, wherein the first lambda/4 impedance transformation device and the second lambda/4 impedance transformation device are in cascade connection between the carrier power amplifier and the lambda/4 transmission line of the carrier power amplifier; the third lambda/4 impedance transformation device and the fourth lambda/4 impedance transformation device are in cascade connection between the peak value power amplifier and the output end. The present invention ensures that the load impedance of the carrier power amplifier and the peak value power amplifier is kept optimal within a great power grade range so as to ensure that the Doherty power keeps high efficiency within the great power grade range.

Description

A kind of power amplifier

Technical field

The present invention relates to the power amplifier technical field, particularly a kind of Du He carries (Doherty) power amplifier.

Background technology

Power amplifier (abbreviation power amplifier) is a vitals in the modern wireless communication systems, and high power amplification efficiency not only can reduce the operation cost of radio communication, can also improve the reliability of power amplifier.In numerous high efficiency power amplifiers, the Doherty power amplifier improves the favor that obviously and more and more is subjected to industry owing to its simplicity of design, to power amplification efficiency.The Doherty power amplifier is considered to the mainstream technology of power amplifier in a period of time from now on.

Fig. 1 is the basic principle figure of Doherty power amplifier.The Doherty power amplifier is parallel with carrier power amplifier and peak value power amplifier between its input and output, wherein carrier power amplifier also is known as main power amplifier, and the peak value power amplifier also is known as auxiliary power amplifier.Also be connected with λ/4 transmission lines between carrier power amplifier and the output and between peak value power amplifier and the input respectively, its characteristic impedance Zm and Za are respectively 50 Ω, wherein the main effect of the λ of main power amplifier/4 transmission lines is to carry out impedance conversion, and the main effect of the λ of auxiliary power amplifier/4 transmission lines is the time-delays that remedy the auxiliary power amplifier branch road, thereby makes the time delay unanimity of two branch roads.

The basic design philosophy of Doherty power amplifier is to bear different input signal powers respectively with two dissimilar power amplifiers, guarantee that as far as possible two power amplifiers all are operated in separately the saturation region, thereby guarantee that whole power amplifier all maintains higher signal power in the input signal power scope of trying one's best big.The used core design thought of Doherty power amplifier is active load migration (Active-Load-Pulling), promptly change the load impedance of carrier power amplifier by the power output (electric current) of peak value power amplifier, make carrier power amplifier be operated in one efficiently between the amplification region in.

In the Doherty power amplifier, common main power amplifier is operated in B or AB class, and auxiliary power amplifier then is operated in the C class.Main power amplifier is worked always in the power bracket of whole input signal, and auxiliary power amplifier is only just started working when main power amplifier reaches capacity.The electric current that it was exported when auxiliary power amplifier was started working can change the output impedance of main power amplifier, the active load migration promptly takes place, this load migration feature can make main power amplifier keep can exporting more electric current to load under the saturated situation, thereby the whole efficiency that makes the Doherty power amplifier keeps higher, the linearity can not worsen, and reaches capacity up to auxiliary power amplifier.The place that needs in the design of main power amplifier and auxiliary power amplifier to pay close attention to is to its 1dB compression point (P _1dBThe size of selection point) and they output effective impedance separately, these factor affecting the whole efficiency of Doherty power amplifier.The design core of Doherty power amplifier match circuit is that the output current that will guarantee the peak value power amplifier can carry out correct effectively traction to the load impedance of carrier power amplifier, and this just means that this correct impedance draw could take place must to keep correct amplitude, phase place and time delay to concern between the output signal of peak value power amplifier and carrier power amplifier.

Prior art is directly to adopt classical Doherty structure mostly, and Fig. 2 has provided the project organization figure of common Doherty power amplifier in the prior art.Because the design of the input matching circuit of Doherty power amplifier is little to the overall linear and the effectiveness affects of power amplifier, as long as they can make the phase place of peak value power amplifier and carrier power amplifier consistent with time delay, therefore in Fig. 2, do not provide the input matching circuit of peak value power amplifier and carrier power amplifier.

In the prior art, common biasing (offset) line by peak value power amplifier and carrier power amplifier input and output among debugging Fig. 2 makes the phase place of two paths of signals and time-delay be consistent.In debug process, offset line by carrier power amplifier and the input and output of peak value power amplifier among adjustment Fig. 2 can make the phase place of two paths of signals and time delay be consistent on certain power grade, the load impedance of peak value power amplifier and carrier power amplifier is reached near the theoretical needed value of Doherty power amplifier substantially, promptly will make when the peak value power amplifier is not worked under small-signal and to close the impedance of the place of road joint having seen to the peak value power amplifier in output is high resistant, the twice when making the load impedance of carrier power amplifier be its operate as normal in addition under the small-signal situation.Theory analysis and result of the test show that the Doherty power amplifier that designs with this method can improve power amplification efficiency significantly.Fig. 3 and Fig. 4 describe be before its peak work is decontroled beginning work with reach capacity after the situation of change of R1 and R2.Wherein, Fig. 3 has provided the value of former R1 of its peak work relieving beginning work and R2; And Fig. 4 has provided the unconventional and unrestrained value to saturated R1 later on and R2 of its peak work.From Fig. 3 and Fig. 4 as can be seen before its peak work is decontroled beginning work with reach capacity after R1 become 50 Ω by 100 Ω, and R2 becomes 50 Ω by high resistant.

As everyone knows, the design of the output matching circuit of power amplifier is carried out according to power match, according to the load line theory, the linearity of power amplifier and efficient just can reach best when the load impedance of power tube was some particular values under specific power output situation, and the load impedance that the load line theory is emphasized generally refers to the B-B1 output of chip-scale triode at the interface among Fig. 5, but generally refers to the output of power tube after the A-A1 place Chip Packaging among Fig. 5 in actual applications.Know by Fig. 5, requirement for the tool practical significance of Doherty power amplifier design should be: before its peak work is decontroled beginning work with reach capacity after, it is original 1/2nd that the real part R1c of the load impedance of carrier power amplifier pipe becomes, and the real part R2p of the load impedance of peak value power tube becomes its optimum load impedance when saturated by high resistant.And according to traditional design, the R1 at A-A1 interface and R2 are difficult to be transformed into by the coupling microwave network R1c and the R2p at the B-B1 interface of satisfying top condition.That is to say, when the match circuit that under a certain power grade, has designed the Doherty power amplifier, make the load impedance of carrier power amplifier under this power grade, be the best, but, under other power grade, because the R1 at A-A1 interface and the R1c and the R2p at R2 and B-B1 interface are inconsistent, so this moment, the load impedance of carrier power amplifier and peak value power amplifier was not to be in the best, make that this moment, the Doherty power amplifier did not have good signal power, thereby reduced the efficient of Doherty power amplifier, that is this Doherty power amplifier only has higher efficient near certain power grade, and not high in the efficient of other power grade.

In addition, the core concept of Doherty power amplifier is the active load migration, this load migration feature can make under the saturated situation of main power amplifier maintenance can export more electric current to load, thereby the whole efficiency that makes power amplifier keeps higher, the linearity can not worsen, unconventional and unrestrained up to its peak work to saturated, the be rivals in a contest load traction of carrier power amplifier of its peak work will guarantee that exactly the load impedance of carrier power amplifier all will guarantee to be the best on each power grade, because the impedance variation at A-A1 interface and the impedance variation at B-B 1 interface can not be synchronous, therefore traditional design is difficult to accomplish this point.

Summary of the invention

In view of this, the present invention proposes a kind of Doherty power amplifier, in bigger power grade scope, remain the best in order to the load impedance that guarantees carrier power amplifier and peak value power amplifier, thereby guarantee that the Doherty power amplifier keeps high efficient in bigger power grade scope.

According to above-mentioned purpose, the invention provides a kind of Doherty power amplifier, comprise carrier power amplifier and peak value power amplifier, λ/4 transmission lines that are connected the carrier power amplifier between carrier power amplifier and the output that are connected in parallel on input and output and be connected input and the peak value power amplifier between λ/4 transmission lines of peak value power amplifier, described Doherty power amplifier further comprises: level is associated in a λ/4 impedance conversion devices and the 2nd λ/4 impedance conversion devices between λ/4 transmission lines of carrier power amplifier and carrier power amplifier; The resistance value of a described λ/4 impedance conversion devices square with the square of the resistance value of described the 2nd λ/4 impedance conversion devices; Level be associated in that its peak work is put and output between the 3rd λ/4 impedance conversion devices and the 4th λ/4 impedance conversion devices.

Described λ/4 impedance conversion devices are λ/8 impedance conversion lines that λ/4 impedance conversion lines or two ends have the electric capacity that is parallel to ground.

Preferably, described the 3rd λ/4 impedance conversion devices are identical with a λ/4 impedance conversion devices; Described the 4th resistance λ/4 impedance conversion devices are identical with the 2nd λ/4 impedance conversion devices.

In technique scheme, the resistance value of a described λ/4 impedance conversion devices and the 2nd λ/4 impedance conversion devices satisfies under the different capacity grade ${\mathrm{RL}}_{\mathrm{opt}}=\left(\frac{{Z_{m1}}^2}{{{\mathrm{<figure-callout\; id="2"\; label="Z\; m"\; filenames="C20061005858600152.png"\; state="\{\{state\}\}">Z</figure-callout>}}_m}^2}\right)R_{\mathrm{opt}};$ RL wherein _OptBe the optimum load impedance value at the carrier power amplifier output, R _OptBe the optimum load impedance value in the 2nd λ/4 impedance conversion devices and carrier power amplifier λ/4 transmission line junctions, Z _M1Be the resistance value of a λ/4 impedance conversion devices, Z _M2It is the resistance value of the 2nd λ/4 impedance conversion devices.

In technique scheme, the resistance value of a described λ/4 impedance conversion devices and the 2nd λ/4 impedance conversion devices satisfies under the different capacity grade ${\mathrm{RL}}_{\mathrm{opt}}=\left(\frac{{Z_{m1}}^2}{{{\mathrm{<figure-callout\; id="2"\; label="Z\; m"\; filenames="C20061005858600152.png"\; state="\{\{state\}\}">Z</figure-callout>}}_m}^2}\right)R_{\mathrm{opt}};$ RL wherein _OptBe the optimum load impedance value at the carrier power amplifier output, R _OptBe the optimum load impedance value in the 2nd λ/4 impedance conversion devices and carrier power amplifier λ/4 transmission line junctions, Z _M1Be the resistance value of a λ/4 impedance conversion devices, Z _M2It is the resistance value of the 2nd λ/4 impedance conversion devices.And the resistance value of described the 3rd λ/4 impedance conversion devices and the 4th λ/4 impedance conversion devices satisfies under the different capacity grade $R{L}_{\mathrm{opt}}=\left(\frac{{Z_{m3}}^2}{{{\mathrm{<figure-callout\; id="4"\; label="Z\; m"\; filenames="C20061005858600182.png"\; state="\{\{state\}\}">Z</figure-callout>}}_m}^2}\right)R_{\mathrm{opt}};$ RL wherein _OptBe the optimum load impedance value at peak value power amplifier output, R _OptBe the optimum load impedance value in the 4th λ/4 impedance conversion devices and peak value power amplifier λ/4 transmission line junctions, Z _M3Be the resistance value of the 3rd λ/4 impedance conversion devices, Z _M4It is the resistance value of the 4th λ/4 impedance conversion devices.

Further, between a λ/4 impedance conversion devices and the 2nd λ/4 impedance conversion devices, be connected with odd harmonic component open-circuit impedance device and between λ/4 transmission lines of the 2nd λ/4 impedance conversion devices and carrier power amplifier, be connected with even-order harmonic component open-circuit impedance device; Or between a λ/4 impedance conversion devices and the 2nd λ/4 impedance conversion devices, be connected with even-order harmonic component short-circuit impedance device and between λ/4 transmission lines of the 2nd λ/4 impedance conversion devices and carrier power amplifier, be connected with odd harmonic component short-circuit impedance device; Or between a λ/4 impedance conversion devices and the 2nd λ/4 impedance conversion devices, be connected with even-order harmonic component open-circuit impedance device and between λ/4 transmission lines of the 2nd λ/4 impedance conversion devices and carrier power amplifier, be connected with odd harmonic component open-circuit impedance device; Or between a λ/4 impedance conversion devices and the 2nd λ/4 impedance conversion devices, be connected with odd harmonic component short-circuit impedance device and between λ/4 transmission lines of the 2nd λ/4 impedance conversion devices and carrier power amplifier, be connected with even-order harmonic component short-circuit impedance device.

Further, between the 3rd λ/4 impedance conversion devices and the 4th λ/4 impedance conversion devices, be connected with odd harmonic component open-circuit impedance device and between the 4th λ/4 impedance conversion devices and output, be connected with even-order harmonic component open-circuit impedance device; Or between the 3rd λ/4 impedance conversion devices and the 4th λ/4 impedance conversion devices, be connected with even-order harmonic component short-circuit impedance device and between the 4th λ/4 impedance conversion devices and output, be connected with odd harmonic component short-circuit impedance device; Or between the 3rd λ/4 impedance conversion devices and the 4th λ/4 impedance conversion devices, be connected with even-order harmonic component open-circuit impedance device and between the 4th λ/4 impedance conversion devices and output, be connected with odd harmonic component open-circuit impedance device; Or between the 3rd λ/4 impedance conversion devices and the 4th λ/4 impedance conversion devices, be connected with odd harmonic component short-circuit impedance device and between the 4th λ/4 impedance conversion devices and output, be connected with even-order harmonic component short-circuit impedance device.

Preferably, the λ/4 open circuit LC resonant networks of described odd harmonic component open-circuit impedance device λ/4 open-circuit impedance transformation line that are triple-frequency harmonics or triple-frequency harmonics; And/or the λ/8 open circuit LC resonant networks of described even-order harmonic component open-circuit impedance device λ/8 open-circuit impedance transformation line that are fundamental frequency or fundamental frequency; And/or the described odd harmonic component short-circuit impedance device λ/4 short-circuit impedance transformation line that are triple-frequency harmonics or the λ/4 short circuit LC resonant networks of triple-frequency harmonics; And/or the described even-order harmonic component short-circuit impedance device λ/8 short-circuit impedance transformation line that are fundamental frequency or the λ/8 short circuit LC resonant networks of fundamental frequency.

From such scheme as can be seen, because the present invention is between 4 transmission of carrier power amplifier and carrier power amplifier and increased the λ/4 impedance conversion lines of two cascades between peak value power amplifier and the output respectively, make that the load impedance of carrier power amplifier and output place of peak value power amplifier is synchronous with the load impedance variation of encapsulation back power amplifier output place, thereby the load impedance that guarantees carrier power amplifier and peak value power amplifier remains the best in bigger power grade scope, guarantees that the Doherty power amplifier keeps high efficient in bigger power grade scope.The present invention further is designed to F class power amplifier or anti-F class power amplifier with carrier power amplifier and/or peak value power amplifier, thereby has further improved the efficient of Doherty power amplifier, and has also simplified the design of Doherty power amplifier match circuit.

Description of drawings

Fig. 1 is the basic principle figure of Doherty power amplifier;

Fig. 2 is the project organization figure of Doherty power amplifier common in the prior art;

Fig. 3 is the value of R1 and R2 before its peak work relieving beginning work;

Fig. 4 decontrols the reach capacity value of later R1 and R2 of beginning for its peak work;

Fig. 5 is the plane of reference A-A1 and the B-B1 of load impedance in the Doherty power amplifier design;

Fig. 6 is the structural representation according to the Doherty power amplifier of first embodiment of the invention;

Fig. 7 is the design principle figure of F class power amplifier;

Fig. 8 is the structural representation of the Doherty power amplifier of F class power amplifier for carrier power amplifier;

Fig. 9 is the structural representation of the Doherty power amplifier of anti-F class power amplifier for carrier power amplifier;

Figure 10 is the another kind of structural representation of the Doherty power amplifier of F class power amplifier for carrier power amplifier;

Figure 11 is the another kind of structural representation of the Doherty power amplifier of anti-F class power amplifier for carrier power amplifier.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, the present invention is described in more detail by the following examples.

According to the Doherty power amplifier of first embodiment of the invention as shown in Figure 6.With reference to Fig. 6, compare with general Doherty power amplifier, Doherty power amplifier in the first embodiment of the invention has comprised that further level is associated in a λ/4 impedance conversion devices and the 2nd λ/4 impedance conversion devices between λ/4 transmission lines of carrier power amplifier and carrier power amplifier in the carrier power amplifier signal path, and level is associated in the 3rd λ/4 impedance conversion devices and the 4th λ/4 impedance conversion devices between the peak value power amplifier and output in its peak work discharge signal path, and their resistance value is respectively Zm1, Zm2, Zm3 and Zm4.These λ/4 impedance conversion devices can be λ/4 impedance conversion lines, also can be that two ends have the λ/8 impedance conversion lines of electric capacity that are parallel to ground, are example with λ/4 impedance conversion lines in the following narration.It should be noted that in order to make schematic diagram simpler and clearer, in the figure of Fig. 6 and back, all do not draw input offset line and output offset line and other parts, this does not represent not comprise these parts in these Doherty power amplifiers.

Compare with Fig. 5, Ropt is the real part of carrier power amplifier at the load impedance at A-A1 place, and RLopt is the real part of carrier power amplifier at the load impedance at B-B1 place.Structure according to Fig. 6 can obtain ${\mathrm{RL}}_{\mathrm{opt}}=\left(\frac{{Z_{m1}}^2}{{{\mathrm{<figure-callout\; id="2"\; label="Z\; m"\; filenames="C20061005858600152.png"\; state="\{\{state\}\}">Z</figure-callout>}}_m}^2}\right)R_{\mathrm{opt}},$ Because Zm1 and Zm2 are constants, so the variation of Ropt and RLopt is synchronous, that is A-A1 load impedance variation and B-B1 load impedance at the interface at the interface become synchronously among Fig. 5.Pass through Zm1, Zm2 and the distinctive active load draw of Doherty power amplifier like this, just can be so that the Doherty power amplifier has higher efficient in bigger power grade.

Zm1 and Zm2 are provided with arbitrarily.Preferably, can obtain by following method: the optimum load impedance Ropt and the RLopt substitution of carrier power amplifier under the different capacity grade ${\mathrm{RL}}_{\mathrm{opt}}=\left(\frac{{Z_{m1}}^2}{{{\mathrm{<figure-callout\; id="2"\; label="Z\; m"\; filenames="C20061005858600152.png"\; state="\{\{state\}\}">Z</figure-callout>}}_m}^2}\right)R_{\mathrm{opt}},$ According to these equations simultaneousness equation group, group obtains Zm1 and Zm2 by solving an equation.Wherein the optimum load impedance of carrier power amplifier under the different capacity grade can obtain with the emulation design method of the load impedance traction (LOAD_PULL) that provides in electric design automation (EDA) simulation software, also can obtain with the LOAD_PULL tester.

Zm3 in its peak work discharge signal path and the setting of Zm4 are similar with Zm2 to the Zm1 in the carrier power amplifier signal path.Zm3 and Zm4 are provided with arbitrarily.Preferably, can obtain by following method: its peak work is placed on optimum load impedance Ropt and RLopt substitution under the different capacity grade ${\mathrm{RL}}_{\mathrm{opt}}=\left(\frac{{Z_{m3}}^2}{{{\mathrm{<figure-callout\; id="4"\; label="Z\; m"\; filenames="C20061005858600182.png"\; state="\{\{state\}\}">Z</figure-callout>}}_m}^2}\right)R_{\mathrm{opt}},$ According to these equations simultaneousness equation group, group obtains Zm3 and Zm4 by solving an equation.Equally, the optimum load impedance that its peak work is placed under the different capacity grade can obtain with the emulation design method of the load impedance traction (LOAD_PULL) that provides in electric design automation (EDA) simulation software, also can obtain with the LOAD_PULL tester.

In addition, for design processes simplified, it is identical with a λ/4 impedance conversion devices generally to get the 3rd λ/4 impedance conversion devices, and the 4th resistance λ/4 impedance conversion devices are identical with the 2nd λ/4 impedance conversion devices.

Further,, thereby carrier power amplifier and peak value power amplifier can be designed to F class (Class F) power amplifier or anti-F class power amplifier, further improve the efficient of Doherty power amplifier because carrier power amplifier and peak value power amplifier back among Fig. 6 have λ/4 impedance conversion lines.

Fig. 7 is the schematic diagram of F class power amplifier.The basic principle of F class power amplifier is LC low pass filter and load impedance R _LIn parallel to all odd harmonic component of carrier signal at R _LThe place presents low-resistance, present high resistant through drain electrode place at power tube behind λ/4 impedance conversion lines, and present low-resistance in drain electrode place for all even-order harmonic Xiang Ze, know by Fourier transform, additional odd harmonic item makes the voltage waveform of output drain electrode place of triode present square wave, triode turn-offs the transition that produces a steeper from being conducting to, and has reduced the overlay region of drain electrode place voltage and current, thereby has reduced the efficient of the power consumption raising device of device.λ among Fig. 6/4 impedance conversion lines have played important effect in the realization of whole C lass F, make the power amplifier match circuit simplicity of design a lot, and lack λ/4 impedance conversion lines in the general common Doherty match circuit design, therefore carrier power amplifier or peak value power amplifier can not be designed to F class power amplifier.

Shown in Fig. 8 is the situation that the carrier power amplifier in the first embodiment of the invention is designed to F class power amplifier.As shown in Figure 8, between a λ/4 impedance conversion lines and the 2nd λ/4 impedance conversion lines, be connected with odd harmonic component open-circuit impedance device, and between λ/4 transmission lines of the 2nd λ/4 impedance conversion lines and carrier power amplifier, be connected with even-order harmonic component open-circuit impedance device.The odd harmonic component open-circuit impedance device here can be triple-frequency harmonics (3f ₀) λ/4 open-circuit impedance transformation line, also can be 3f ₀λ/4 open circuit LC resonant networks, below with 3f ₀λ/4 open-circuit impedance transformation line be the example explanation.The described even-order harmonic component open-circuit impedance device here can be to be fundamental frequency (f ₀) λ/8 open-circuit impedance transformation line, also can be f ₀λ/8 open circuit LC resonant networks, below with f ₀λ/8 open-circuit impedance transformation line be the example explanation.

Referring to Fig. 8,3f ₀λ/4 open-circuit impedance transformation line make output drain electrode place of carrier power pipe present high resistant to the odd harmonic component, f ₀λ/8 open-circuit impedance transformation line make the output drain electrode place antithesis order harmonic components of carrier power pipe present low-resistance, the voltage waveform of carrier power amplifier pipe output drain electrode place presents square wave like this, carrier power amplifier shows as a F class power amplifier efficiently.

Fig. 9 shown in being is the situation that the carrier power amplifier in the first embodiment of the invention is designed to anti-F class power amplifier.As shown in Figure 9, between a λ/4 impedance conversion lines and the 2nd λ/4 impedance conversion lines, be connected with f ₀λ/8 open-circuit impedance transformation line, and between λ/4 transmission lines of the 2nd λ/4 impedance conversion lines and carrier power amplifier, be connected with 3f ₀λ/4 open-circuit impedance transformation line.

Referring to Fig. 9,3f ₀λ/4 open-circuit impedance transformation line make output drain electrode place of carrier power pipe present low-resistance to the odd harmonic component, f ₀λ/8 open-circuit impedance transformation line make the output drain electrode place antithesis order harmonic components of carrier power pipe present high resistant, the current waveform of carrier power amplifier pipe output drain electrode place presents square wave like this, carrier power amplifier shows as an anti-efficiently F class power amplifier.

Shown in Figure 10 is the another kind of situation that the carrier power amplifier in the first embodiment of the invention is designed to F class power amplifier.As shown in figure 10, between a λ/4 impedance conversion lines and the 2nd λ/4 impedance conversion lines, be connected with even-order harmonic component short-circuit impedance device, and between λ/4 transmission lines of the 2nd λ/4 impedance conversion devices and carrier power amplifier, be connected with odd harmonic component short-circuit impedance device.The described even-order harmonic component short-circuit impedance device here can be to be f ₀λ/8 short-circuit impedance transformation line, also can be f ₀λ/8 short circuit LC resonant networks, below with f ₀λ/8 short-circuit impedance transformation line be the example explanation.The odd harmonic component short-circuit impedance device here can be 3f ₀λ/4 short-circuit impedance transformation line, also can be 3f ₀λ/4 short circuit LC resonant networks, below with 3f ₀λ/4 short-circuit impedance transformation line be the example explanation.

Referring to Figure 10, f ₀λ/8 short-circuit impedance transformation line make output drain electrode place of carrier power pipe present high resistant to the odd harmonic component, and 3f ₀λ/4 short-circuit impedance transformation line make the output drain electrode place antithesis order harmonic components of carrier power pipe present low-resistance, the voltage waveform of carrier power amplifier pipe output drain electrode place presents square wave like this, carrier power amplifier shows as a F class power amplifier efficiently.

Figure 11 shown in being is the another kind of situation that the carrier power amplifier in the first embodiment of the invention is designed to anti-F class power amplifier.As shown in figure 11, between a λ/4 impedance conversion lines and the 2nd λ/4 impedance conversion lines, be connected with 3f ₀λ/4 short-circuit impedance transformation line, and between λ/4 transmission lines of the 2nd λ/4 impedance conversion devices and carrier power amplifier, be connected with f ₀λ/8 short-circuit impedance transformation line.

Referring to Figure 11, f ₀λ/8 short-circuit impedance transformation line make output drain electrode place of carrier power pipe present low-resistance to the odd harmonic component, 3f ₀λ/4 short-circuit impedance transformation line make the output drain electrode place antithesis order harmonic components of carrier power pipe present high resistant, the current waveform of carrier power amplifier pipe output drain electrode place presents square wave like this, carrier power amplifier shows as an anti-efficiently F class power amplifier.

Above Fig. 8 to Figure 11 has described the situation that carrier power amplifier is designed to F class or anti-F class, and the peak value power amplifier similarly.With Fig. 8 is example, only need be connected with 3f between the 3rd λ/4 impedance conversion lines and the 4th λ/4 impedance conversion lines ₀The open-circuit impedance line, and between the 4th λ/4 impedance conversion lines and output, be connected with f ₀λ/8 open-circuit impedance lines, just the peak value power amplifier can be designed to F class power amplifier.Other situation similarly repeats no more here.

In an embodiment of the present invention, can only carrier power amplifier be designed to F class power amplifier or anti-F class power amplifier, also can only the peak value power amplifier be designed to F class power amplifier or anti-F class power amplifier, carrier power amplifier and peak value power amplifier F class power amplifier or anti-F class power amplifier be can also be designed to simultaneously, perhaps carrier power amplifier and peak value power amplifier F class power amplifier or anti-F class power amplifier be designed to respectively.

The above only is preferred embodiment of the present invention, and is in order to restriction the present invention, within the spirit and principles in the present invention not all, any modification of being done, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (9)

1, a kind of Du He carries the Doherty power amplifier, comprise carrier power amplifier and peak value power amplifier, quarter-wave λ/4 transmission lines that are connected the carrier power amplifier between carrier power amplifier and the output that are connected in parallel on input and output and be connected input and the peak value power amplifier between λ/4 transmission lines of peak value power amplifier, it is characterized in that described Doherty power amplifier further comprises:

Level is associated in a λ/4 impedance conversion devices and the 2nd λ/4 impedance conversion devices between λ/4 transmission lines of carrier power amplifier and carrier power amplifier; The resistance value of a described λ/4 impedance conversion devices square with the square of the resistance value of described the 2nd λ/4 impedance conversion devices;

Level be associated in that its peak work is put and output between the 3rd λ/4 impedance conversion devices and the 4th λ/4 impedance conversion devices.

2, Doherty power amplifier according to claim 1 is characterized in that, described λ/4 impedance conversion devices are λ/8 impedance conversion lines that λ/4 impedance conversion lines or two ends have the electric capacity that is parallel to ground.

3, Doherty power amplifier according to claim 1 is characterized in that, described the 3rd λ/4 impedance conversion devices are identical with a λ/4 impedance conversion devices; Described the 4th resistance λ/4 impedance conversion devices are identical with the 2nd λ/4 impedance conversion devices.

According to claim 1 or 3 described Doherty power amplifiers, it is characterized in that 4, the resistance value of a described λ/4 impedance conversion devices and the 2nd λ/4 impedance conversion devices satisfies under the different capacity grade ${\mathrm{RL}}_{\mathrm{opt}}=\left(\frac{{Z_{m1}}^2}{{Z_{m2}}^2}\right)R_{\mathrm{opt}};$ RL wherein _OptBe the optimum load impedance value at the carrier power amplifier output, R _OptBe the optimum load impedance value in the 2nd λ/4 impedance conversion devices and carrier power amplifier λ/4 transmission line junctions, Z _M1Be the resistance value of a λ/4 impedance conversion devices, Z _M2It is the resistance value of the 2nd λ/4 impedance conversion devices.

5, Doherty power amplifier according to claim 1 is characterized in that,

The resistance value of a described λ/4 impedance conversion devices and the 2nd λ/4 impedance conversion devices satisfies under the different capacity grade ${\mathrm{RL}}_{\mathrm{opt}}=\left(\frac{{Z_{m1}}^2}{{Z_{m2}}^2}\right)R_{\mathrm{opt}};$ RL wherein _OptBe the optimum load impedance value at the carrier power amplifier output, R _OptBe the optimum load impedance value in the 2nd λ/4 impedance conversion devices and carrier power amplifier λ/4 transmission line junctions, Z _M1Be the resistance value of a λ/4 impedance conversion devices, Z _M2It is the resistance value of the 2nd λ/4 impedance conversion devices;

The resistance value of described the 3rd λ/4 impedance conversion devices and the 4th λ/4 impedance conversion devices satisfies under the different capacity grade ${\mathrm{RL}}_{\mathrm{opt}}=\left(\frac{{Z_{m3}}^2}{{Z_{m4}}^2}\right)R_{\mathrm{opt}};$ RL wherein _OptBe the optimum load impedance value at peak value power amplifier output, R _OptBe the optimum load impedance value in the 4th λ/4 impedance conversion devices and peak value power amplifier λ/4 transmission line junctions, Z _M3Be the resistance value of the 3rd λ/4 impedance conversion devices, Z _M4It is the resistance value of the 4th λ/4 impedance conversion devices.

6, Doherty power amplifier according to claim 1 is characterized in that,

Between a λ/4 impedance conversion devices and the 2nd λ/4 impedance conversion devices, be connected with odd harmonic component open-circuit impedance device and between λ/4 transmission lines of the 2nd λ/4 impedance conversion devices and carrier power amplifier, be connected with even-order harmonic component open-circuit impedance device; Or

Between a λ/4 impedance conversion devices and the 2nd λ/4 impedance conversion devices, be connected with even-order harmonic component short-circuit impedance device and between λ/4 transmission lines of the 2nd λ/4 impedance conversion devices and carrier power amplifier, be connected with odd harmonic component short-circuit impedance device; Or

Between a λ/4 impedance conversion devices and the 2nd λ/4 impedance conversion devices, be connected with even-order harmonic component open-circuit impedance device and between λ/4 transmission lines of the 2nd λ/4 impedance conversion devices and carrier power amplifier, be connected with odd harmonic component open-circuit impedance device; Or

Between a λ/4 impedance conversion devices and the 2nd λ/4 impedance conversion devices, be connected with odd harmonic component short-circuit impedance device and between λ/4 transmission lines of the 2nd λ/4 impedance conversion devices and carrier power amplifier, be connected with even-order harmonic component short-circuit impedance device.

7, according to claim 1 or 6 described Doherty power amplifiers, it is characterized in that,

Between the 3rd λ/4 impedance conversion devices and the 4th λ/4 impedance conversion devices, be connected with odd harmonic component open-circuit impedance device and between the 4th λ/4 impedance conversion devices and output, be connected with even-order harmonic component open-circuit impedance device; Or

Between the 3rd λ/4 impedance conversion devices and the 4th λ/4 impedance conversion devices, be connected with even-order harmonic component short-circuit impedance device and between the 4th λ/4 impedance conversion devices and output, be connected with odd harmonic component short-circuit impedance device; Or

Between the 3rd λ/4 impedance conversion devices and the 4th λ/4 impedance conversion devices, be connected with even-order harmonic component open-circuit impedance device and between the 4th λ/4 impedance conversion devices and output, be connected with odd harmonic component open-circuit impedance device; Or

Between the 3rd λ/4 impedance conversion devices and the 4th λ/4 impedance conversion devices, be connected with odd harmonic component short-circuit impedance device and between the 4th λ/4 impedance conversion devices and output, be connected with even-order harmonic component short-circuit impedance device.

8, Doherty power amplifier according to claim 6 is characterized in that,

λ/4 open-circuit impedance the transformation line that described odd harmonic component open-circuit impedance device is a triple-frequency harmonics or the λ of triple-frequency harmonics/4 open circuit LC resonant networks; And/or

λ/8 open-circuit impedance the transformation line that described even-order harmonic component open-circuit impedance device is a fundamental frequency or the λ of fundamental frequency/8 open circuit LC resonant networks; And/or

λ/4 short-circuit impedance transformation line that described odd harmonic component short-circuit impedance device is a triple-frequency harmonics or the λ of triple-frequency harmonics/4 short circuit LC resonant networks; And/or

λ/8 short-circuit impedance transformation line that described even-order harmonic component short-circuit impedance device is a fundamental frequency or the λ of fundamental frequency/8 short circuit LC resonant networks.

9, Doherty power amplifier according to claim 7 is characterized in that,

λ/4 open-circuit impedance the transformation line that described odd harmonic component open-circuit impedance device is a triple-frequency harmonics or the λ of triple-frequency harmonics/4 open circuit LC resonant networks; And/or

λ/8 open-circuit impedance the transformation line that described even-order harmonic component open-circuit impedance device is a fundamental frequency or the λ of fundamental frequency/8 open circuit LC resonant networks; And/or

λ/4 short-circuit impedance transformation line that described odd harmonic component short-circuit impedance device is a triple-frequency harmonics or the λ of triple-frequency harmonics/4 short circuit LC resonant networks; And/or

λ/8 short-circuit impedance transformation line that described even-order harmonic component short-circuit impedance device is a fundamental frequency or the λ of fundamental frequency/8 short circuit LC resonant networks.

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