WO2017028563A1

WO2017028563A1 - Symmetry doherty power amplification circuit apparatus and power amplifier

Info

Publication number: WO2017028563A1
Application number: PCT/CN2016/082085
Authority: WO
Inventors: 余敏德; 舒峰; 段斌
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-08-20
Filing date: 2016-05-13
Publication date: 2017-02-23
Also published as: CN106470015A

Abstract

Disclosed are a symmetry Doherty power amplification circuit apparatus and a power amplifier. The symmetry Doherty power amplifier comprises a main power amplification channel and one or more auxiliary power amplification channel. The Doherty power amplifier further comprises: a network with reactance varying with power that is disposed on the auxiliary power amplification channel; and an additional phase-shifting network that is disposed on the main power amplification channel, a first phase being a phase difference between an input signal received by an input end of the main power amplification channel and an input signal received by an input end of the auxiliary power amplification channel, and a second phase being a phase difference between an output signal outputted by an output end of the main power amplification channel and an output signal outputted by an output end of the auxiliary power amplification channel. In this way, the problem that a symmetry Doherty power amplification circuit cannot meet a relatively high peak-to-average ratio requirement is resolved.

Description

Symmetric Doherty Doherty Power Amplifier Circuit and Power Amplifier

Technical field

The present application relates to, but is not limited to, the field of communications, and in particular to a symmetric Doherty power amplifier circuit device and power amplifier.

Background technique

At present, with the increasingly fierce competition in the wireless communication market, the performance of base station products has become the main focus of competition in the industry. The power amplifier (referred to as power amplifier) as an important part of the base station directly relates to the quality and communication effect of the signal transmitted by the base station. In order to improve the transmission rate and utilize spectrum resources more effectively, the base station widely adopts Orthogonal Frequency Division Multiplexing (OFDM) and Quadrature Phase Shift Keyin (QPSK) peaks. The ratio is more than the modulation mode. Therefore, it is required to work normally under the condition of peak-to-average ratio. Not only must the linear index be met, but also the high working efficiency needs to be reached. At this stage, the DOHERTY amplifier is equipped with digital pre-distortion (DPD). ) can better meet the above requirements, therefore, Doherty power amplifier has become a research hotspot of current base station applications.

FIG. 1 is a schematic circuit diagram of a Doherty power amplifier in the related art. As shown in FIG. 1 , it is composed of 2 to a plurality of power amplifier tubes, and is divided into a main power amplifier PA1 and an auxiliary power amplifier PA2. The input signal is separated into the main power amplifier PA1 and the auxiliary power amplifier PA2 through the bridge, and is amplified by two channels and then combined into one way. In order to compensate for the 90° phase difference caused by the bridge, the output of the main power amplifier PA1 needs to be phase aligned through the 1/4 wavelength microstrip line. The symmetric DOHERTY power amplifier adopts the same power tube and the same structure as the auxiliary power amplifier PA1 and the auxiliary power amplifier PA2, and has the characteristics of relatively easy design and good production consistency in the case of the Peak-to-Average Ratio (PAR). It has been widely used. In this case, when the output power of the main power amplifier PA1 is small, the auxiliary power amplifier PA2 is in the off state. In order to reduce the influence of the auxiliary power amplifier PA2 on the main power amplifier PA1, the auxiliary power amplifier PA2 power needs to be adopted by the OFFSET impedance line of the appropriate electrical length. The cut-off impedance of the tube is impedance-transformed so that it has a high-resistance open state for the main power amplifier PA1 at the junction of the power synthesis unit, and when the output power of the main power amplifier PA1 is gradually increased, the auxiliary power amplifier PA2 starts to work, and at the same time, the main work The load modulation of PA1 makes the output impedance of the main power amplifier PA1 power tube continuously shift from the highest efficiency point to the maximum power point, and finally the auxiliary power amplifier PA2 The power tube together achieves the maximum power point output impedance. In this case, the symmetric Doherty power tube saturation power and the maximum efficiency point impedance need to satisfy the 2:1 VSWR impedance relationship, and the main power amplifier power tube is required in the peak-to-average ratio application. The corresponding VSWR impedance relationship is greater than 2:1, but since the symmetrical Doherty main power amplifier PA1 power tube output impedance cannot meet the load modulation when the auxiliary amplifier is working, it is greater than the standing wave 2:1 impedance requirement, and the symmetric DOHERTY amplifier will be used. The efficiency or output power has an impact.

At the same time, in some practical applications, the saturation power maximum point and the efficiency maximum point impedance relationship of the power tube are greater than the 2:1 standing wave ratio. In this case, if the power tube is used to form a symmetric DOHERTY circuit, the maximum power point and maximum efficiency are required. Select a suitable impedance in the vicinity of the point to compromise the performance so that the two meet the 2:1 standing wave ratio relationship, which will also have a loss in output power and work efficiency.

In view of the related art, the symmetric DOHERTY power amplifier circuit cannot adapt to the problem of high peak-to-average ratio requirement, and an effective solution has not been proposed.

Summary of the invention

The following is an overview of the topics detailed in this document. This summary is not intended to limit the scope of the claims.

According to an aspect of an embodiment of the present invention, a symmetric Doherty power amplifier circuit device is provided, comprising: a power distribution unit configured to allocate an input signal to a plurality of signals of a predetermined phase difference, and output to the main amplification channel respectively And an auxiliary amplification channel; the main amplification channel includes: an additional phase shifting network, a main amplification channel microstrip line connected to the additional phase shifting network, and a main amplifier connected to the main amplification channel microstrip line, configured to pass through The additional phase shifting network and the main amplification channel microstrip line perform phase alignment of the main amplification channel signal and the auxiliary amplification channel signal, and power amplification of the main amplification channel signal by the main amplifier; at least one auxiliary amplification channel, including: auxiliary An amplifying channel microstrip line, an auxiliary amplifier connected to the auxiliary amplifying channel microstrip line, a reactance with the auxiliary amplifier connected to the output power change network, and configured to perform an auxiliary amplifying channel signal through the auxiliary amplifying channel microstrip line Align with the phase of the main amplification channel signal, assisted amplification by the auxiliary amplifier The channel signal is subjected to power amplification, and in the high-efficiency operation state of the main amplifier small signal, the shutdown impedance of the auxiliary amplifier at the closing point is reduced to a predetermined value by the reactance with the output power variation network; the power synthesis unit is set The signal input to the main amplification channel and the auxiliary amplification channel is combined into one signal at a combining point, and then output.

The phase characteristic of the additional phase shifting network is the same as the phase characteristic of the reactance with the output power variation network.

Wherein, the additional phase shifting network is configured to cancel the phase difference caused by the reactance changing network with the output power.

Wherein the main amplification channel microstrip line is set to cancel the predetermined phase difference and a phase difference caused by the auxiliary amplification channel microstrip line and the auxiliary amplifier.

Wherein the auxiliary amplification channel microstrip line is arranged to cancel the phase difference caused by the main amplification channel microstrip line and the main amplifier.

Wherein, the reactance varies with the output power of the network to set: in the high-efficiency operation state of the main amplifier small signal, by controlling the value of the inductive impedance or the capacitive impedance at the junction point caused by the control, the shutdown impedance is reduced to Predetermined value.

The additional phase shifting network is: an offset microstrip line, an inductor-capacitor LC phase shifting network, or a resistor-capacitor RC phase shifting network.

The network whose reactance varies with the output power is: an offset microstrip line, a varactor diode, or a variable reactance circuit.

The primary amplification channel microstrip line includes: a first biased microstrip line connected to the additional phase shifting network, a second biased microstrip line connected to the main amplifier output, and The second biased microstrip line is connected to a 1/4 wavelength microstrip line.

The auxiliary amplification channel microstrip line includes: a third offset microstrip line connected to the power distribution unit, and a fourth offset microstrip line connected to the reactance with the output power change network.

According to another aspect of the present invention, a symmetric Doherty DOHERTY power amplifier is further provided, comprising: a main power amplification channel and one or more auxiliary power amplification channels, wherein the main power amplification channel comprises: a first compensation microstrip line, a main power amplifier, and a second compensation microstrip line connected in series; each of the auxiliary power amplification channels includes: a third compensation microstrip line sequentially connected in series, an auxiliary power amplifier, and a fourth compensation micro a strip line, wherein the DOHERTY power amplifier further includes: a reactance with power variation network disposed on the auxiliary power amplification channel, wherein the reactance with the power variation network is set to turn off the auxiliary power amplifier Set to a first predetermined threshold; an additional phase shifting network, disposed on the main power amplifying channel, wherein The additional phase shifting network is configured such that the first phase difference is the same as the second phase difference, wherein the first phase is an input signal received by an input end of the main power amplifying channel and the auxiliary power amplifying channel The input end receives a phase difference between the input signals, and the second phase is a phase difference between an output signal outputted by the output end of the main power amplification channel and an output signal outputted by the output end of the auxiliary power amplification channel .

Wherein the reactance is connected between the auxiliary power amplifier and the fourth compensated microstrip line with a power change network, or the reactance is connected to the fourth compensated microstrip line and the Between the outputs of the auxiliary power amplifier channels.

Wherein the additional phase shifting network is connected between the input end of the main power amplifying channel and the first compensating microstrip line, or the additional phase shifting network is connected to the first compensating microstrip line and Between the main power amplifiers.

Wherein the phase and frequency characteristics of the additional phase shifting network are the same as the phase and frequency characteristics of the reactance with the power varying network.

The reactance with power variation network, the additional phase shifting network, the first compensated microstrip line, the second compensated microstrip line, the third compensated microstrip line, and the fourth compensation micro The strip lines are commonly arranged such that the first phase difference is the same as the second phase difference.

Wherein the fourth compensation microstrip line is set such that an impedance of the auxiliary power amplification channel is a second predetermined threshold and a turn-off impedance of the auxiliary power amplifier is adjusted to a third predetermined threshold, wherein the third The predetermined threshold is greater than the first predetermined threshold.

Wherein, the DOHERTY power amplifier further includes: a power distribution unit configured to allocate power, wherein an input end of the power distribution unit is configured to receive an input signal, and a first output end of the power distribution unit is connected to the additional An input end of the phase shifting network, the second output end of the power distribution unit is connected to the third compensation microstrip line; a power combining unit configured to synthesize power, wherein the first input end of the power combining unit passes a microstrip impedance conversion line connected to the second compensation microstrip line, a second input end of the power synthesis unit being connected to the fourth compensation microstrip line, or a second input end of the power synthesis unit The reactance varies with the power change network connection.

Wherein the power distribution unit allocates the input signal as a multiplex signal having a phase difference of 90°, and inputs the multiplex signal to the main power amplification channel and the one or more Auxiliary power amplification channel.

The power of each signal of the multiple signals is 1/N of the input signal power, where N is the number of the multiple signals.

Wherein the power distribution unit comprises a bridge.

The additional phase shifting network includes at least one of the following: a microstrip line; an LC phase shifting network composed of an inductor and a capacitor; and an RC phase shifting network composed of a capacitor and a resistor.

The reactance with power variation network includes at least one of the following: a microstrip line; a varactor diode; and a reactance circuit.

According to an embodiment of the invention, a symmetric Doherty DOHERTY power amplifier is used, comprising: a main power amplification channel and one or more auxiliary power amplification channels, wherein the main power amplification channel comprises: a first compensation microstrip connected in series in series a line, a main power amplifier and a second compensating microstrip line; each auxiliary power amplifying channel comprises: a third compensating microstrip line connected in series, an auxiliary power amplifier and a fourth compensating microstrip line, wherein the DOHERTY power amplifier further comprises The reactance with power variation network is disposed on the auxiliary power amplification channel, wherein the reactance with the power variation network is set to set the shutdown impedance of the auxiliary power amplifier to a first predetermined threshold; the additional phase shift network is set in the main power amplification channel And wherein the additional phase shifting network is set such that the first phase difference is the same as the second phase difference, wherein the first phase is received by the input end of the main power amplifying channel and the input end of the auxiliary power amplifying channel is received The phase difference between the input signals, the second phase is the output of the main power amplification channel Phase difference between the output signal of the output signal to the output terminal of the auxiliary power amplification channel. The problem that the symmetric DOHERTY power amplifier circuit can not adapt to the high peak-to-average ratio requirement is solved, thereby achieving the standing wave ratio relationship of the main power amplifier saturation power and the maximum efficiency point impedance, and the application range of the symmetric DOHERTY power amplifier circuit is expanded. Improve the efficiency of the symmetrical DOHERTY power amplifier circuit in the peak-to-average ratio application, so that the symmetrical DOHERTY power amplifier circuit can adapt to the higher peak-to-average ratio requirements, and at the same time, it can also improve the linearity of the power amplifier.

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF abstract

In the drawing:

1 is a circuit diagram of a Doherty power amplifier in the related art;

2 is a schematic structural diagram of a DOHERTY power amplifier according to an embodiment of the present invention;

3 is a schematic diagram (1) of a power amplifier DOHERTY power amplifier circuit according to an embodiment of the invention;

4 is a schematic diagram (II) of a power amplifier DOHERTY power amplifier circuit according to an embodiment of the present invention;

5 is a schematic diagram of a shutdown impedance when an auxiliary amplifier is turned off in the related art;

6 is a schematic diagram of an auxiliary amplifier turn-off impedance according to an embodiment of the present invention;

7 is a schematic diagram of a junction point impedance when an auxiliary amplifier transitions from an off-operation state to a high-power output state, in accordance with an embodiment of the present invention;

8 is a characteristic diagram of output power and additional phase shift introduced by a reactance with power variation network according to an embodiment of the present invention;

9 is a characteristic diagram of a DOHERTY power amplifier output power and an additional phase shift in the related art;

Figure 10 is a graph showing the output power and additional phase shift of a DOHERTY power amplifier in accordance with an embodiment of the present invention.

Embodiments of the invention

It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

It should be noted that the terms "first", "second" and the like in the specification and claims of the embodiments of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. order.

In this embodiment, a symmetric Doherty DOHERTY power amplifier is provided. FIG. 2 is a schematic structural diagram of a DOHERTY power amplifier according to an embodiment of the present invention. As shown in FIG. 2, the method includes: a main power amplification channel 22 and one or more The auxiliary power amplifying channel 24, wherein the main power amplifying channel 22 comprises: a first compensating microstrip line connected in series, a main power amplifier and a second compensating microstrip line; each auxiliary power amplifying channel 24 comprises: serially connected in series a third compensation microstrip line, an auxiliary power amplifier, and a fourth compensation microstrip line, wherein the DOHERTY power amplifier further includes: a reactance with power variation network 242 disposed on the auxiliary power amplification channel 24, wherein the reactance varies with the power 242 is configured to set the turn-off impedance of the auxiliary power amplifier to a first predetermined threshold; an additional phase shifting network 222 disposed on the main power amplifying channel 22, wherein the additional phase shifting network 222 So that the first phase difference is the same as the second phase difference, wherein the first phase is between the input signal received by the input end of the main power amplification channel and the input signal received by the input end of the auxiliary power amplification channel a phase difference, the second phase being a phase difference between an output signal outputted by the output of the main power amplifying channel and an output signal outputted by the output of the auxiliary power amplifying channel.

The additional phase shifting network and the auxiliary power amplifying channel added by the main power amplifying channel in the above DOHERTY power amplifier increase the reactance with the power variation network, and the symmetric DOHERTY power amplifier circuit is solved by adjusting the additional phase shifting network and the auxiliary power amplifying channel. It can adapt to the problem of higher peak-to-average ratio requirement, and then improve the standing wave ratio relationship between the main power amplifier saturation power and the maximum efficiency point impedance, expand the application range of the symmetric DOHERTY power amplifier circuit, and improve the peak-to-average ratio application of the symmetric DOHERTY power amplifier circuit. The efficiency makes the symmetrical DOHERTY power amplifier circuit adapt to the higher peak-to-average ratio requirements, and at the same time has a certain effect of improving the linearity of the power amplifier.

The reactance with power variation network 242 is disposed on the auxiliary power amplification channel 24, wherein the reactance is connected between the auxiliary power amplifier and the fourth compensated microstrip line with the power variation network 242, or the reactance is connected to the power variation network 242 at the fourth Compensating between the microstrip line and the output of the auxiliary power amplification channel.

The additional phase shifting network 222 is disposed in the main power amplifying channel 22, wherein the additional phase shifting network 222 can also be connected between the input of the main power amplifying channel 22 and the first compensating microstrip line, or the additional phase shifting network 222 is connected. Between the first compensated microstrip line and the main power amplifier.

The phase and frequency characteristics of the additional phase shifting network 222 are the same as the phase and frequency characteristics of the reactance with the power varying network 242.

The reactance with power variation network 242, the additional phase shifting network 222, the first compensation microstrip line, the second compensation microstrip line, the third compensation microstrip line, and the fourth compensation microstrip line are collectively set such that the first phase difference is Same as the second phase difference.

Wherein the fourth compensation microstrip line is set such that the impedance of the auxiliary power amplification channel is a second predetermined threshold and the off impedance of the auxiliary power amplifier is adjusted to a third predetermined threshold, wherein the third predetermined threshold is greater than the first predetermined Threshold.

The DOHERTY power amplifier also includes other parts to better accommodate the symmetrical DOHERTY power amplifier circuit to accommodate higher peak-to-average ratio requirements. Among them, the DOHERTY power amplifier can also include a power distribution unit configured to distribute power, wherein an input of the power distribution unit is configured to receive an input signal, a first output of the power distribution unit is coupled to an input of the additional phase shifting network, and a second output of the power distribution unit Connected to the third compensation microstrip line; a power synthesis unit configured to synthesize power, wherein the first input end of the power synthesis unit is connected to the second compensation microstrip line through a microstrip impedance conversion line, the power synthesis unit The second input is coupled to the fourth compensated microstrip line, or the second input of the power combining unit is coupled to the reactance with the power change network.

The power distribution unit may allocate the input signal as a multiplex signal with a phase difference of 90°, and input the multiplex signal to the main power amplification channel and the one or more auxiliary power amplification channels, respectively.

The power of each signal of the multiplex signal is 1/N of the power of the input signal, where N is the number of the multiplex signals.

Wherein, the power distribution unit comprises a bridge.

The additional phase shifting network 222 described above can be configured in a variety of ways, as exemplified below. The additional phase shifting network 222 may include at least one of the following: a microstrip line; an LC phase shifting network composed of an inductor and a capacitor; and an RC phase shifting network composed of a capacitor and a resistor.

The above-mentioned reactance with power change network 224 can also have various forms of composition, which will be exemplified below. The reactance with power variation network 224 may include at least one of the following: a microstrip line; a varactor diode; and a reactance circuit.

In this embodiment, a symmetric Doherty power amplifier circuit device is also provided, which is configured to implement the above-described embodiments and preferred embodiments, and has not been described again. As used below, the term "module" may implement a combination of software and/or hardware of a predetermined function. Although the apparatus described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware, is also possible and contemplated.

In the embodiment, a symmetric Doherty power amplifier circuit device is further provided, comprising: a power distribution unit configured to distribute the input signal into a plurality of signals of a predetermined phase difference, and output to the main amplification channel and the auxiliary amplification respectively. a main amplification channel, comprising: an additional phase shifting network, a main amplifying channel microstrip line connected to the additional phase shifting network, and a main amplifier connected to the main amplifying channel microstrip line, configured to pass the additional phase shifting network, And the main amplification channel microstrip line for the main amplification channel The signal is aligned with the phase of the auxiliary amplification channel signal, and the main amplification channel signal is amplified by the main amplifier; at least one auxiliary amplification channel includes: an auxiliary amplification channel microstrip line, and an auxiliary amplifier connected to the auxiliary amplification channel microstrip line a reactance reacting with the auxiliary amplifier with the output power variation network, configured to perform phase alignment of the auxiliary amplification channel signal and the main amplification channel signal through the auxiliary amplification channel microstrip line, and power amplification of the auxiliary amplification channel signal by the auxiliary amplifier In the high-efficiency operation state of the main amplifier small signal, the shutdown impedance of the auxiliary amplifier at the closing point is reduced to a predetermined value by the reactance with the output power variation network; the power combining unit is set to be at the junction point The main amplification channel and the signal input from the auxiliary amplification channel are combined to generate a signal and then output.

The symmetrical DOHERTY power amplifier circuit is solved by adjusting the additional phase shifting network and the auxiliary power amplifying channel by the additional phase shifting network added by the main power amplifying channel and the auxiliary power amplifying channel added by the above-mentioned DOHERTY power amplifier circuit device. It is unable to adapt to the problem of higher peak-to-average ratio requirements, thereby improving the standing wave ratio relationship between the main power amplifier saturation power and the maximum efficiency point impedance, extending the application range of the symmetric DOHERTY power amplifier circuit, and improving the peak-to-average ratio of the symmetric DOHERTY power amplifier circuit. The efficiency of the application makes the symmetrical DOHERTY power amplifier circuit adapt to the higher peak-to-average ratio requirements, and at the same time has a certain effect of improving the linearity of the power amplifier.

Wherein, the phase characteristic of the additional phase shifting network is the same as the phase characteristic of the reactance with the output power changing network.

Wherein, the additional phase shifting network is set to: cancel out the phase difference caused by the reactance changing network with the output power.

Wherein, the main amplification channel microstrip line is set to cancel the predetermined phase difference and the phase difference caused by the auxiliary amplification channel microstrip line and the auxiliary amplifier.

Wherein, the auxiliary amplification channel microstrip line is set to cancel the phase difference caused by the main amplification channel microstrip line and the main amplifier.

The reactance varies with the output power of the network to set the impedance to a predetermined value by controlling the value of the inductive impedance or the capacitive impedance at the combining point caused by the main amplifier small signal high efficiency operating state.

Wherein, the additional phase shifting network is: an offset microstrip line, an inductor-capacitor LC phase shifting network, or a resistor Capacitor RC phase shifting network.

Among them, the reactance varies with the output power of the network: biased microstrip line, varactor diode, or variable reactance circuit.

The main amplification channel microstrip line includes: a first biased microstrip line connected to the additional phase shifting network, a second biased microstrip line connected to the main amplifier output, and the second offset micro 1/4 wavelength microstrip line with line connection.

The main purpose of the optional embodiment of the present invention is to provide a symmetric DOHERTY power amplifier circuit, which aims to improve the efficiency of the symmetric DOHERTY power amplifier circuit in peak-to-average ratio application, and at the same time has a certain effect of improving the linearity of the power amplifier.

The embodiment of the present invention provides a DOHERTY power amplifier circuit, and FIG. 3 is a schematic diagram of a power amplifier DOHERTY power amplifier circuit according to an embodiment of the present invention. The principle block diagram is as shown in FIG. 3, and the circuit includes a power distribution unit 1, a main amplification unit 2, a power synthesis unit 4, and At least one auxiliary amplifying unit 3 and an additional phase shifting network 8 connected in series with said main amplifying unit 2 and a reactance dependent output power varying network 9 connected in series with the auxiliary amplifier output, and associated OFFSET connecting

lines

6, 7, 10, 11 and 1/4 wavelength impedance conversion line 5. The additional phase shifting network 8 and the reactance are identical in phase characteristics with the output power varying network 9, and are arranged to cancel the phase difference introduced by the network 9 due to the increase of the reactance with the output power.

The power distribution unit 1 comprises a bridge, the input of which is connected to the input signal, and the two outputs are respectively connected to the additional phase shifting network 8 of the main amplifying unit and the input OFFSET line 6 of the auxiliary amplifying unit.

The main amplifying unit 2 comprises a main amplifier, the auxiliary amplifying unit 3 comprises an auxiliary amplifier, the additional phase shifting network 8 is connected to the output of the bridge, the input of the main amplifier is connected to the additional phase shifting network 8 via the OFFSET line 7, the main amplifier PA3 A 1/4 wavelength microstrip impedance conversion line 5 is connected between the output terminal and the power combining unit 4.

4 is further refined with the specific example of the block diagram of FIG. 3, the power distribution unit distributes the input signal into a plurality of road signals with a phase difference of 90°, and then outputs the signals to the main amplification unit and the auxiliary amplification unit for amplification;

By the additional phase shifting network 8, the input OFFSET line 7, the main amplifier PA3, the output OFFSET line 10, the 1/4 wavelength microstrip impedance conversion line 5, together the main amplification channel, the input offset line 6, the auxiliary amplifier PA4, and The reactance varies with the output power variation network 9, and the auxiliary amplification line composed of the output offset line 11, the input terminal of the auxiliary amplifier PA4 and the output terminal of the bridge, and the output terminal of the auxiliary amplifier PA4 and the reactance with the output power varying unit 9, And the reactance with the OFFSET compensation microstrip line connected between the output power varying unit 9 and the power combining unit 4. The OFFSET line 6 mainly plays a phase alignment with the main path phase, and the OFFSET line 11 mainly performs impedance matching and improves the impedance of the PA4 turn-off impedance.

By reasonably selecting the OFFSET

line

6, 7, 10, 11 line length and the additional phase shifting network 8 and the phase characteristics of the reactance with the output power varying network 9, the phase alignment of the main amplification path and the auxiliary amplification path can be achieved, and the phase difference is cancelled. The main path and the auxiliary path signal are combined into one signal and then output by the combining unit 4.

In the usual design, the auxiliary power amplifier PA4 needs to make its turn-off impedance close to the open state at the junction point through the appropriate OFFSET 11 impedance line, as shown in Figure 5, so that the impedance of the main amplification path and the auxiliary amplification path at the junction point is output in the power amplifier. The condition of the large and small signals is basically the same, that is, the standing wave ratio is 1:1. The symmetric Doherty power tube saturation power and the maximum efficiency point impedance need to satisfy the 2:1 standing wave ratio impedance relationship.

A power amplifier circuit, a power amplifying device and a matching method thereof are provided by the embodiment of the present invention, by adding a reactance with the output power change network 9 behind the auxiliary power amplifier PA4, so that the turn-off point of the combined point is appropriately deviated from the open state, so that when the main power amplifier PA3 When working in a small signal high efficiency state, the auxiliary power amplifier PA4 and the reactance with the output power change network 9 will introduce a certain inductive or capacitive impedance at the combining point as shown in Fig. 6. Controlling the reactance value at this place can reduce the main power amplifier small The impedance of the junction when the signal is operating at high efficiency.

When the main power amplifier PA3 is working at a high power, the auxiliary amplifier PA4 is switched between the off-state impedance value and the high-power state impedance value due to the load pull effect of the auxiliary power amplifier PA4 and the reactance with the output power variation network 9 . The result is shown in Fig. 7. Here, the load value of the capacitive load cut-off state is exemplified. At this time, the combined point is changed by the auxiliary power amplifier PA4 and the reactance with the output power under the impedance value and the low power condition corresponding to the maximum output power. The standing wave ratio of the impedance value of the combined point caused by the decrease of the impedance of the combined point of the network 9 will increase, and the corresponding Doherty can be improved. The ratio of the standing wave ratio corresponding to the maximum output power of the main amplifier power tube and the maximum output efficiency impedance, so that the range of the main power amplifier standing wave ratio caused by the auxiliary power amplifier load modulation can satisfy the requirement that the non-pair impedance standing wave ratio relationship is greater than 2:1, therefore While ensuring the saturation power and efficiency, the range of adaptation of the peak-to-average ratio of the symmetric DOHERTY power amplifier circuit is extended, and since the reactance of the network 9 can be changed by adjusting the reactance with the output power, the inductive or capacitive reactance can be flexibly introduced, so that the small signal is The equivalent is equivalent to grounding the inductor or capacitor in parallel with the output combining unit, which can cause the initial phase of the small signal output to be advanced or lag by a certain angle. When the power amplifier outputs a large signal, the parallel reactance is due to the auxiliary power amplifier PA4 and The effect of the load pull of the reactance with the output power variation network 9 disappears, and the previously added phase shift angle is also eliminated as shown in Fig. 8. The reactance with the output power change network 9 can be made by the reasonable design and auxiliary power amplifier PA4 connection. The phase angle is opposite to the AM-PM characteristics of the usual DOHERTY amplifier (as shown in Figure 9), both to some extent. The mutual cancellation can improve the AM-PM distortion of the whole power amplifier, thereby improving the linearity index of the power amplifier. The schematic diagram of the effect of the specific AM-PM improvement is shown in FIG. 10. It can be seen from FIG. 10 that after the embodiment of the present invention, the power amplifier AM-PM The range of characteristics with power amplifier power can be reduced from 0.2 to 0.3 (radian) to 0.22 to 0.35. The reduction of the AM-PM range indicates that the AM-PM characteristics are improved.

4 is a schematic diagram (2) of a power amplifier DOHERTY power amplifier circuit according to an embodiment of the present invention, as shown in FIG. 4:

Power distribution unit 1, additional phase shifting network 8, 50 ohm microstrip line OFFSET 7, main amplifier PA3, 50 ohm microstrip line OFFSET 10, 50 ohm 1/4 wavelength microstrip line 5 constitutes the main amplification path.

50 ohm microstrip line OFFSET 6, auxiliary amplifier PA4, reactance with output power change network 9, 50 ohm microstrip line OFFSET 11 constitutes an auxiliary amplification path. The main amplification path and the auxiliary amplification path are respectively connected to the power distribution unit 1 and the power synthesis unit 4 to form a 50 ohm 2-way symmetric Doherty circuit.

The power distribution unit 1 is composed of a bridge and its peripheral circuits. It should be noted that the bridge in this example may be a bridge of 3dB, 5dB or other specifications, which is not limited herein. For the convenience of description, only the The bridge is a 3dB bridge as an example. The input terminal of the 3dB bridge is connected to the input signal, and the two output terminals of the 3dB bridge are respectively connected to the additional phase shifting network 8 and the OFFSET line 6 of the auxiliary amplifying unit 3.

The additional phase shifting network 8 in this example is composed of a microstrip line, and it should be noted that the network is also It can be composed of an LC phase shifting network composed of an inductor and a capacitor or an RC phase shifting network composed of a capacitor and a resistor. The phase shifting characteristic of the network needs to be the same as the phase shifting characteristic of the reactance with the output power variation network 9, and the specific form is not limited herein. The network is connected to the main amplifier PA3 through the OFFSET 7, the input end of the auxiliary amplifier PA4 is connected to the output end of the 3dB bridge through the OFFSET 6, and the output end of the auxiliary amplifier main unit PA4 is passed through the reactance with the output power change network 9 And the output OFFSET 11 is connected to the combined output unit 4, and when the DOHERTY circuit operates, the reactance changes with the output power change network 9 and the auxiliary power amplifier unit 4 together with the auxiliary power amplifier PA4 operating state change and output power change The impedance of the waypoint (point P in Figure 4 of the specification). In this example, the reactance varies with the output power. The network 9 is composed of a microstrip line of suitable electrical length. In other cases, it can be controlled by a voltage-controlled varactor or other. Control the composition of the variable reactance circuit.

Adjusting the 50 ohm microstrip line length of the power variation network 9 connected to the auxiliary amplifier PA4 in this example can make the auxiliary amplifier PA4 power tube turn-off impedance exhibit capacitive reactance at the junction, and an initial -12° is added. Phase shift, at this time, the main power amplifier PA3 power tube saturation power point and the maximum efficiency point impedance relationship satisfy the 2.5:1 asymmetry ratio relationship, which can better meet the peak-to-average ratio requirement of about 8 dB. Since the main power amplifier PA3 and the auxiliary power amplifier PA4 both use the same power tube and the circuit structure is the same, the circuit expands the application range of the symmetric DOHERTY in the peak-to-average ratio (PAR>6dB), and the corresponding initial phase shift can compensate the circuit AM to a certain extent. -PM distortion, which in turn improves the linearity of the circuit.

A power amplifying device is provided in the embodiment of the present invention. The circuit structure and principle of the power amplifier circuit can be referred to the foregoing, and details are not described herein again. Due to the adoption of the above power amplifier circuit, the output power and efficiency are improved, the adaptability of the power amplifier circuit to the peak-to-average ratio signal is expanded, and the AM-PM characteristic is improved to improve the linearity index of the Doherty power amplifier.

The power amplifier circuit, the power amplifying device and the design method thereof, by adding an additional phase shifting network and a reactance with the output power change network in the main power amplifier unit and the auxiliary power amplifier unit, respectively, controlling the impedance characteristics when the power point of the auxiliary point auxiliary amplifier is turned off. Increasing the standing wave ratio relationship between the main power amplifier saturation power and the maximum efficiency point impedance extends the application range of the symmetric DOHERTY power amplifier circuit, so that the symmetric DOHERTY power amplifier circuit can adapt to higher peak-to-average ratio requirements.

It will be apparent to those skilled in the art that the various modules or steps of the present invention described above can be implemented by a general-purpose computing device that can be centralized on a single computing device or distributed. Alternatively, on a network of computing devices, they may be implemented by program code executable by the computing device such that they may be stored in the storage device by the computing device and, in some cases, The steps shown or described may be performed in an order different than that herein, or they may be separately fabricated into individual integrated circuit modules, or a plurality of the modules or steps may be implemented as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Industrial applicability

An embodiment of the present invention provides a symmetric Doherty power amplifier circuit device, including: a power distribution unit configured to allocate an input signal to a plurality of signals of a predetermined phase difference, and output to the main amplification channel and the auxiliary amplification channel, respectively; a main amplification channel, comprising: an additional phase shifting network, a main amplification channel microstrip line connected to the additional phase shifting network, and a main amplifier connected to the main amplification channel microstrip line, configured to pass the additional phase shifting network And a main amplification channel microstrip line for phase alignment of the main amplification channel signal and the auxiliary amplification channel signal, wherein the main amplification channel signal is power amplified by the main amplifier; at least one auxiliary amplification channel, including: an auxiliary amplification channel microstrip line And an auxiliary amplifier connected to the auxiliary amplification channel microstrip line, a reactance connected to the auxiliary amplifier, and an output power variation network, configured to perform an auxiliary amplification channel signal and a main amplification channel signal through the auxiliary amplification channel microstrip line Phase alignment, powering the auxiliary amplification channel signal through the auxiliary amplifier Amplifying, in the high-efficiency operation state of the main amplifier small signal, reducing the turn-off impedance at the combining point to a predetermined value when the auxiliary amplifier is turned off by the reactance with the output power change network; the power combining unit is set to be combined The signal is synthesized by combining the signals input by the main amplification channel and the auxiliary amplification channel into a signal.

The embodiment of the invention further provides a symmetric Doherty DOHERTY power amplifier, comprising: a main power amplification channel and one or more auxiliary power amplification channels, wherein the main power amplification channel comprises: a first compensation connected in series in series a microstrip line, a main power amplifier and a second compensating microstrip line; each of the auxiliary power amplifying channels comprises: a third compensating microstrip line connected in series in series, and a secondary a power amplifier and a fourth compensation microstrip line, wherein the DOHERTY power amplifier further includes: a reactance with power variation network, disposed on the auxiliary power amplification channel, wherein the reactance is set with a power change network The turn-off impedance of the auxiliary power amplifier is set to a first predetermined threshold; an additional phase shifting network is disposed on the main power amplifying channel, wherein the additional phase shifting network is set such that the first phase difference and the second phase difference are The same, wherein the first phase is a phase difference between an input signal received by an input end of the main power amplification channel and an input signal received by an input end of the auxiliary power amplification channel, where the second phase is a phase difference between an output signal outputted by the output of the main power amplifying channel and an output signal outputted by the output of the auxiliary power amplifying channel.

Claims

A symmetric Doherty power amplifier circuit device comprising:

a power distribution unit configured to allocate an input signal to a plurality of signals of a predetermined phase difference, and output to the main amplification channel and the auxiliary amplification channel, respectively;

a main amplification channel, comprising: an additional phase shifting network, a main amplification channel microstrip line connected to the additional phase shifting network, and a main amplifier connected to the main amplification channel microstrip line, configured to pass the additional phase shifting network And a main amplification channel microstrip line for phase alignment of the main amplification channel signal and the auxiliary amplification channel signal, and power amplification of the main amplification channel signal by the main amplifier;

At least one auxiliary amplification channel, comprising: an auxiliary amplification channel microstrip line, an auxiliary amplifier connected to the auxiliary amplification channel microstrip line, a reactance output power variation network connected to the auxiliary amplifier, configured to be amplified by the auxiliary The channel microstrip line performs phase alignment of the auxiliary amplification channel signal and the main amplification channel signal, and the auxiliary amplification amplifier performs power amplification on the auxiliary amplification channel signal, and the main amplifier with the small signal high efficiency working state passes the reactance with the output power The varying network reduces the turn-off impedance at the combining point when the auxiliary amplifier is turned off to a predetermined value;

The power synthesizing unit is configured to synthesize a signal input by the main amplifying channel and the auxiliary amplifying channel into a signal at a combining point, and then output the signal.
The apparatus of claim 1 wherein the phase characteristic of the additional phase shifting network is the same as the phase characteristic of the reactance with the output power varying network.
The apparatus of claim 1 wherein said additional phase shifting network is arranged to cancel out a phase difference caused by a reactance varying network with output power.
The apparatus according to claim 1, wherein said main amplification channel microstrip line is set to cancel said predetermined phase difference, and a phase difference caused by said auxiliary amplification channel microstrip line and an auxiliary amplifier.
The apparatus of claim 1, wherein the auxiliary amplification channel microstrip line is arranged to cancel a phase difference caused by the main amplification channel microstrip line and the main amplifier.
The apparatus according to claim 1, wherein said reactance with output power variation network is set to: inductive impedance or capacitive impedance at the junction point caused by controlling the main amplifier small signal high efficiency operating state a value that reduces the shutdown impedance to a predetermined value.
The apparatus of claim 1, wherein the additional phase shifting network is: an offset microstrip line, an inductor-capacitor LC phase shifting network, or a resistor-capacitor RC phase shifting network.
The apparatus of claim 1, wherein the reactance varies with the output power network: an offset microstrip line, a varactor diode, or a variable reactance circuit.
The apparatus of claim 1 wherein said primary amplification channel microstrip line comprises: a first biased microstrip line coupled to said additional phase shifting network, and a second bias coupled to said main amplifier output A microstrip line and a 1/4 wavelength microstrip line connected to the second biased microstrip line are disposed.
The apparatus of claim 1, wherein the auxiliary amplification channel microstrip line comprises: a third offset microstrip line connected to the power distribution unit, and a first connection to the reactance with an output power change network Four offset microstrip lines.
A symmetric Doherty DOHERTY power amplifier comprising: a main power amplification channel and one or more auxiliary power amplification channels, wherein the main power amplification channel comprises: a first compensation microstrip line connected in series in series, a main power amplifier And the second compensating microstrip line; each of the auxiliary power amplifying channels includes: a third compensating microstrip line sequentially connected in series, an auxiliary power amplifier, and a fourth compensating microstrip line, wherein the DOHERTY power amplifier further includes:

a reactance with power variation network, disposed on the auxiliary power amplification channel, wherein the reactance with power variation network is set to set a shutdown impedance of the auxiliary power amplifier to a first predetermined threshold;

An additional phase shifting network disposed on the main power amplifying channel, wherein the additional phase shifting network is set such that the first phase difference is the same as the second phase difference, wherein the first phase is the main power amplification a phase difference between an input signal received at an input end of the channel and an input signal received at an input end of the auxiliary power amplification channel, the second phase being an output signal outputted by an output end of the main power amplification channel The phase difference between the output signals output from the output of the auxiliary power amplification channel.
The DOHERTY power amplifier according to claim 11, wherein said reactance is connected between said auxiliary power amplifier and said fourth compensating microstrip line with a power varying network, or said reactance is connected with a power varying network Between the fourth compensated microstrip line and the output of the auxiliary power amplification channel.
A DOHERTY power amplifier according to claim 11, wherein said additional phase shifting network is connected between an input of said main power amplifying channel and said first compensating microstrip line, or said additional phase shifting network Connected between the first compensation microstrip line and the main power amplifier.
The DOHERTY power amplifier of claim 11 wherein the phase and frequency characteristics of said additional phase shifting network are the same as the phase and frequency characteristics of said reactance with power varying network.
The DOHERTY power amplifier according to claim 11, wherein said reactance with power variation network, said additional phase shifting network, said first compensation microstrip line, said second compensation microstrip line, said third The compensated microstrip line and the fourth compensated microstrip line are collectively arranged such that the first phase difference is the same as the second phase difference.
The DOHERTY power amplifier according to claim 11, wherein said fourth compensation microstrip line is set such that an impedance of said auxiliary power amplifying channel is a second predetermined threshold and an off impedance of said auxiliary power amplifier is adjusted to a third predetermined threshold, wherein the third predetermined threshold is greater than the first predetermined threshold.
The DOHERTY power amplifier of claim 11 wherein said DOHERTY power amplifier further comprises:

a power distribution unit configured to distribute power, wherein an input of the power distribution unit is configured to receive an input signal, a first output of the power distribution unit being coupled to an input of the additional phase shifting network, the power a second output end of the distribution unit is coupled to the third compensation microstrip line;

a power combining unit configured to synthesize power, wherein a first input end of the power combining unit is connected to the second compensation microstrip line through a microstrip impedance conversion line, and a second input end of the power combining unit The fourth compensated microstrip line connection, or the second input of the power combining unit is coupled to the reactance with the power change network.
The DOHERTY power amplifier according to claim 17, wherein said power distribution unit distributes said input signal as a multiplex signal having a phase difference of 90°, and inputs said multiplex signal to said main power amplification, respectively A channel and the one or more auxiliary power amplification channels.
A DOHERTY power amplifier according to claim 18, said multi-channel signal The power of each signal is 1/N of the input signal power, where N is the number of the multiplexed signals.
The DOHERTY power amplifier of claim 17 wherein said power distribution unit comprises a bridge.
The DOHERTY power amplifier of claim 11 wherein said additional phase shifting network comprises at least one of:

microstrip line;

LC phase shifting network composed of inductors and capacitors;

An RC phase shifting network consisting of a capacitor and a resistor.
The DOHERTY power amplifier of claim 11 wherein said reactance versus power variation network comprises at least one of:

microstrip line;

Varactor diode

Reactance circuit.