Load modulation power amplifier and corresponding electronic device

Abstract

Disclosed in the present invention are a load modulation power amplifier and a corresponding electronic device. The load modulation power amplifier comprises a driving-stage power amplifier and a bias circuit thereof, an input power divider, a harmonic impedance controller, a main-circuit power amplifier and a bias circuit thereof, an auxiliary-circuit power amplifier and a bias circuit thereof, and a load modulation power combiner, wherein the driving-stage power amplifier is provided with a transconductance-enhanced bias circuit, the main-circuit power amplifier is provided with a phase-adjustable bias circuit, and the auxiliary-circuit power amplifier is provided with a bias circuit with a controllable enabling power point. In cooperation with a harmonic impedance matching circuit and a load modulation power combiner that has less insertion loss, units collaboratively operate to realize linearization and high efficiency of a load modulation power amplifier, which can well meet the requirements of actual applications.

Description

A load modulation power amplifier and corresponding electronic equipment Technical Field

[0001] The present invention relates to a load modulation power amplifier and also to an electronic device comprising the load modulation power amplifier, belonging to the technical field of radio frequency integrated circuits. Background Art

[0002] In certain RF power amplifier applications, such as satellite communications and walkie-talkies, it's crucial to improve the output power and efficiency of power amplifiers in mobile devices. Because modulated signals need to be transmitted, the power amplifiers must maintain output signal linearity within their rated power range. At the same time, they also aim to maximize the reliability and lifespan of mobile devices while minimizing power consumption and device temperature.

[0003] In the prior art, the design of RF power amplifiers is based on Class A or Class AB power amplifiers, which achieve better linearity through power back-off. However, the efficiency of Class A or Class AB power amplifiers at the back-off power is low, resulting in higher power consumption and device temperature of the power amplifier. The main advantage of a load-modulated power amplifier is to improve the efficiency value at the back-off power, but its linearity is limited by the changes in the load line of the main power amplifier and the switching of the working state of the auxiliary power amplifier, resulting in poor linearity of the load-modulated power amplifier at the output power back-off point. It is necessary to cooperate with the digital pre-distortion algorithm of the transceiver to obtain better linearity. However, due to the limitations of process technology and power consumption, the transceivers on mobile devices generally do not provide digital pre-distortion algorithms, or the digital pre-distortion algorithms provided are limited in capability, which makes the application of this load-modulated power amplifier subject to linearity limitations.

[0004] Therefore, how to overcome the above-mentioned problems and provide a load-modulated power amplifier with high working efficiency and good linearity remains one of the very important research topics in this field.

[0005] Summary of the Invention

[0006] The primary technical problem to be solved by the present invention is to provide a load modulation power amplifier.

[0007] Another technical problem to be solved by the present invention is to provide an electronic device including the load modulation power amplifier.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] According to a first aspect of an embodiment of the present invention, a load modulation power amplifier is provided, comprising a driver stage power amplifier and a bias circuit thereof, an input power divider, a harmonic impedance controller, a main path power amplifier and a bias circuit thereof, an auxiliary path power amplifier and a bias circuit thereof, and a load modulation combiner; wherein,

[0010] The input end of the driving stage power amplifier and its bias circuit is connected to the radio frequency signal input end, and is used to drive and amplify the input radio frequency signal, and the amplified radio frequency signal is output to the input power distributor;

[0011] The input power splitter is used to split an input radio frequency signal into two radio frequency signals with a phase difference of 90 degrees; wherein the radio frequency signal with a phase of +45 degrees enters the main power amplifier after passing through the harmonic impedance controller; the radio frequency signal with a phase of -45 degrees enters the auxiliary power amplifier after passing through the harmonic impedance controller;

[0012] The main power amplifier and its bias circuit and the auxiliary power amplifier and its bias circuit are both used to amplify the input radio frequency signal, and the amplified radio frequency signals are output to the load modulation combiner respectively;

[0013] The load modulation combiner is used to combine the power of the two input radio frequency signals into one radio frequency signal, and its output end is connected to the radio frequency signal output end;

[0014] Among them, the driving stage power amplifier is provided with a bias circuit with enhanced transconductance, the main power amplifier is provided with a bias circuit with adjustable phase, and the auxiliary power amplifier is provided with a bias circuit with controllable start-up power point and the harmonic impedance controller.

[0015] Preferably, the output end of the driving stage power amplifier is connected to the input end of the input power divider, the first output end of the input power divider is connected to the first input end of the harmonic impedance controller, and the second output end of the input power divider is connected to the second input end of the harmonic impedance controller; the first output end of the harmonic impedance controller is connected to the input end of the main power amplifier and its bias circuit, and the second output end of the harmonic impedance controller is connected to the input end of the auxiliary power amplifier and its bias circuit; the output end of the main power amplifier and its bias circuit is connected to the first input end of the load modulation combiner, and the output end of the auxiliary power amplifier and its bias circuit is connected to the second input end of the load modulation combiner.

[0016] Preferably, the driver-stage power amplifier and its bias circuit include a driver amplifier power tube, a first bias tube and a second bias tube, a first voltage-stabilizing diode, a second voltage-stabilizing diode and a third voltage-stabilizing diode, a first filter capacitor, a second filter capacitor and a first feedback capacitor, a first bias resistor, a second bias resistor and a first voltage-stabilizing resistor; wherein,

[0017] The base of the driving amplifier power tube is connected to the radio frequency signal input terminal, the emitter is connected to the ground terminal, and the collector is connected to the input terminal of the input power distributor unit;

[0018] The first bias resistor, the first voltage stabilizing diode, the second voltage stabilizing diode, the first filter capacitor and the first bias transistor constitute a main bias circuit for providing a first bias current;

[0019] The second bias resistor, the first stabilizing resistor, the third stabilizing diode, the second filter capacitor, the first feedback capacitor and the second bias transistor constitute a transconductance enhancement bias circuit for providing a second bias current.

[0020] Preferably, in the main bias circuit, the emitter of the first bias tube is connected to the base of the driving amplifier power tube, and the collector of the first bias tube and the first bias resistor are both connected to the first bias voltage terminal; the other end of the first bias resistor is connected to the base of the first bias tube, the first filter capacitor and the positive electrode of the first Zener diode, the cathode of the first Zener diode is connected to the positive electrode of the second Zener diode, and the cathode of the second Zener diode and the other end of the first filter capacitor are both connected to the ground terminal.

[0021] Preferably, in the transconductance enhancement bias circuit, the emitter of the second bias tube is connected to the base of the driving amplifier power tube and the first feedback capacitor, and the other end of the first feedback capacitor is connected to the collector of the driving amplifier power tube; the collector of the second bias tube and the second bias resistor are both connected to the first bias voltage terminal; the other end of the second bias resistor is connected to the base of the second bias tube, the first zener resistor and the second filter capacitor, the other end of the first zener resistor is connected to the anode of the third zener diode, and the cathode of the third zener diode and the other end of the second filter capacitor are both connected to the ground terminal.

[0022] Preferably, when the driving stage power amplifier outputs low power, the transconductance enhancement bias circuit is in a closed state and does not provide the second bias current; when the output power of the driving stage power amplifier increases and exceeds a set threshold, the transconductance enhancement bias circuit is turned on and provides the second bias current to increase the transconductance of the driving amplifier power tube.

[0023] Preferably, the input power divider includes a first inductor, a second inductor, a first capacitor, and a second capacitor; wherein one end of the first inductor, the second inductor, the first capacitor, and the second capacitor are connected to each other and then connected as an input end to the output end of the driver stage power amplifier and its bias circuit;

[0024] A first inductor connected in parallel and a first capacitor connected in series form a high-pass network, so that the phase of the radio frequency signal in this path leads by 45 degrees, and the other end of the first capacitor is a first output end connected to the first input end of the harmonic impedance controller;

[0025] The second inductor connected in series and the second capacitor connected in parallel form a low-pass network, so that the phase of the RF signal in this path is delayed by 45 degrees. The other end of the second inductor is connected to the second input end of the harmonic impedance controller as a second output end.

[0026] Preferably, the harmonic impedance controller includes a third inductor, a fourth inductor, a fifth inductor, and a sixth inductor, and a third capacitor, a fourth capacitor, a fifth capacitor, and a sixth capacitor; wherein the third inductor, the fifth inductor, the third capacitor, and the fifth capacitor constitute a harmonic impedance matching circuit of the main power amplifier; and the fourth inductor, the sixth inductor, the fourth capacitor, and the sixth capacitor constitute a harmonic impedance matching circuit of the auxiliary power amplifier;

[0027] Preferably, in the harmonic impedance matching circuit of the main power amplifier, one end of the third inductor and the third capacitor are connected to each other and then connected to the first output end of the input power distributor as the first input end of the harmonic impedance controller; the other ends of the third inductor and the third capacitor are connected to each other and then connected to the fifth capacitor on the one hand, and on the other hand, connected to the input end of the main power amplifier and its bias circuit as the first output end of the harmonic impedance controller; the other end of the fifth capacitor is connected to the fifth inductor, and the other end of the fifth inductor is connected to the ground end.

[0028] Preferably, the main power amplifier and its bias circuit include a main amplifying power tube, a third biasing tube, a first transistor, a second transistor, a fourth zener diode, a fifth zener diode, a third filter capacitor, a first coupling capacitor, a third biasing resistor, and a fourth biasing resistor; wherein all components except the main amplifying power tube constitute the bias circuit;

[0029] In the bias circuit, the third bias tube is an emitter follower, which is used to provide a bias current for the main amplifier power tube, and the fourth bias resistor is used to control the magnitude of the bias current;

[0030] The third bias resistor, the first coupling capacitor, the first transistor and the second transistor form a phase modulation circuit for improving phase characteristics.

[0031] Preferably, in the main power amplifier and its bias circuit, the base of the main power amplifier tube and the emitter of the third bias tube are connected and then connected to the first output terminal of the harmonic impedance controller; the emitter of the main power amplifier tube is connected to the ground terminal, and the collector of the main power amplifier tube is connected as the output terminal to the first input terminal of the load modulation combiner; the collector of the third bias tube is connected to the third bias resistor and the fourth bias resistor and then connected to the second bias voltage terminal; the other end of the third bias resistor is connected to the collector of the first transistor and the collector of the second transistor; the base of the first transistor is connected to the emitter of the third bias tube through a third filter capacitor; the base and emitter of the second transistor are connected in parallel and then connected to the ground terminal, and the emitter of the first transistor is connected to the ground terminal; the base of the third bias tube is connected to the third filter capacitor, the positive electrode of the fourth voltage regulator diode, and the other end of the fourth bias resistor; the other end of the third filter capacitor is connected to the ground terminal, the cathode of the fourth voltage regulator diode is connected to the positive electrode of the fifth voltage regulator diode, and the cathode of the fifth voltage regulator diode is connected to the ground terminal.

[0032] Preferably, the auxiliary power amplifier and its bias circuit include an auxiliary power amplifier tube, a fourth bias tube, a sixth voltage-stabilizing diode, a fourth filter capacitor, a fifth bias resistor, and a second voltage-stabilizing resistor; wherein all components except the auxiliary power amplifier tube constitute the bias circuit;

[0033] In the bias circuit, the fifth bias resistor is used to control the start-up power point of the auxiliary power amplifier; the fourth bias tube is an emitter follower, which is used to provide bias current for the auxiliary amplifier power tube;

[0034] When the input RF signal is in a small signal state, the fourth bias tube is in a semi-cutoff state and does not provide a bias current; when the input RF signal is in a large signal state, the fourth bias tube starts to provide a bias current, so that the auxiliary amplifier power tube is turned on, the output power increases rapidly, and a load modulation effect is achieved.

[0035] Preferably, in the auxiliary power amplifier and its bias circuit, the base of the auxiliary power amplifier tube and the emitter of the fourth bias tube are connected and then connected to the second output end of the harmonic impedance controller; the emitter of the auxiliary power amplifier tube is connected to the ground end, and the collector of the auxiliary power amplifier tube is connected to the second input end of the load modulation combiner as the output end; the collector of the fourth bias tube and the fifth bias resistor are connected and then connected to the third bias voltage end; the other end of the fifth bias resistor is connected to the base of the fourth bias tube, the second zener resistor and the fourth filter capacitor, the other end of the second zener resistor is connected to the positive electrode of the sixth zener diode, and the negative electrode of the sixth zener diode and the other end of the fourth filter capacitor are both connected to the ground end.

[0036] Preferably, the load modulation combiner includes a seventh inductor, an eighth inductor, a ninth inductor, a tenth inductor and an eleventh inductor, and a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor and an eleventh capacitor; wherein,

[0037] The seventh inductor, the seventh capacitor and the eighth capacitor form a CLC type main matching network;

[0038] The eighth inductor, the ninth inductor, the tenth inductor and the ninth capacitor and the tenth capacitor form a CL+CLL type auxiliary matching network;

[0039] The eleventh inductor and the eleventh capacitor form an LC type combined matching network.

[0040] Preferably, in the load modulation combiner, one end of the seventh capacitor is connected to the output end of the main power amplifier and its bias circuit as a first input end, the other end of the seventh capacitor is connected to the seventh inductor, the other end of the seventh inductor is connected to the eighth capacitor and the eleventh inductor, and the other end of the eighth capacitor is connected to the ground end; one end of the ninth capacitor and the tenth capacitor are connected and then connected to the output end of the auxiliary power amplifier and its bias circuit as a second input end, the other end of the tenth capacitor is connected to the tenth inductor, and the other end of the tenth inductor is connected to the ground end; the other end of the ninth capacitor is connected to the eighth inductor and the ninth inductor, the other end of the eighth inductor is connected to the ground end, and the other end of the ninth inductor is connected to the eighth capacitor and the eleventh inductor; the other end of the eleventh inductor is connected to the eleventh capacitor and the RF signal output end of the load modulation power amplifier, and the other end of the eleventh capacitor is connected to the ground end.

[0041] According to a second aspect of the embodiments of the present invention, an electronic device is provided, comprising the above-mentioned load modulation power amplifier.

[0042] Compared with the prior art, the load-modulated power amplifier provided by the present invention utilizes a technical solution comprising a driver-stage power amplifier with a transconductance booster bias circuit, a main and auxiliary circuit with a harmonic impedance matching circuit, a main circuit power amplifier with a phase-modulation circuit bias circuit, and an auxiliary circuit power amplifier with a bias circuit with a controllable power point, while also providing a load-modulated combiner with low insertion loss at the output end. These units work together to achieve linearization and high efficiency of the load-modulated power amplifier, effectively meeting the requirements of practical applications. Therefore, the load-modulated power amplifier provided by the present invention has the advantages of a clever and reasonable structural design, low design cost, high operating efficiency, and excellent circuit performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG1 is a schematic diagram of the structure of a typical load modulation power amplifier in the prior art;

[0044] FIG2 is a schematic structural diagram of a load modulation power amplifier provided in an embodiment of the present invention;

[0045] FIG3 is a schematic diagram of a circuit principle of a load-modulated power amplifier according to an embodiment of the present invention;

[0046] FIG4 is a circuit diagram of a driver-stage power amplifier and its bias circuit in an embodiment of the present invention;

[0047] FIG5 is a simulation test diagram showing how the second bias current provided by the transconductance booster bias circuit varies with output power in an embodiment of the present invention;

[0048] FIG6 is a comparative simulation test diagram showing the gain variation with output power when the transconductance booster bias circuit is working and not working in an embodiment of the present invention;

[0049] FIG7 is a schematic circuit diagram of a main power amplifier and its bias circuit in an embodiment of the present invention;

[0050] FIG8 is a comparative simulation test diagram of phase variation with output power when a phase modulation circuit is provided and not provided in an embodiment of the present invention;

[0051] FIG9 is a schematic circuit diagram of an auxiliary power amplifier and its bias circuit in an embodiment of the present invention;

[0052] FIG10 is a simulation test diagram showing how the gain of the load-modulated power amplifier varies with output power at different start-up power points of the auxiliary amplifier power tube (Class C) in an embodiment of the present invention;

[0053] FIG11 is a load line transformation principle diagram of a load modulation power amplifier according to an embodiment of the present invention;

[0054] FIG12 is a circuit diagram of a load modulation combiner according to an embodiment of the present invention;

[0055] FIG13 is a schematic diagram of an equivalent circuit of a load modulation combiner when a small signal is input in an embodiment of the present invention;

[0056] FIG14 is a simulation test diagram of the linearity of a load-modulated power amplifier according to an embodiment of the present invention;

[0057] FIG15 is a simulation test diagram of the efficiency of a load-modulated power amplifier according to an embodiment of the present invention;

[0058] FIG16 is a schematic diagram of an electronic device using a load modulation power amplifier provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0059] The technical content of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0060] As shown in FIG1 , a typical load-modulated power amplifier in the prior art includes a main power amplifier 101 , an auxiliary power amplifier 102 , a quarter-wavelength input transmission line 103 , a quarter-wavelength output transmission line 104 and an output matching network 105 .

[0061] Ideally, when an RF signal is input to the RF signal input port, a portion of the RF signal is input to the main power amplifier branch, amplified by main power amplifier 101, and transmitted to output matching network 105 via quarter-wavelength output transmission line 104. Another portion of the RF signal is input to the auxiliary power amplifier branch, amplified by auxiliary power amplifier 102 via quarter-wavelength input transmission line 103, and then output to output matching network 105. Output matching network 105 combines the two signals and outputs the RF signal. Main power amplifier 101 is in Class AB bias and is turned on when the signal is small; auxiliary power amplifier 102 is in Class C bias and is turned off when the signal is small. When the input signal is large enough, auxiliary power amplifier 102 is turned on to amplify the signal.

[0062] When the load modulation power amplifier is started after the auxiliary power amplifier 102 is turned on, the load impedance of the main power amplifier 101 will decrease, and the output power of the auxiliary power amplifier 102 will increase nonlinearly. If the gain curve and phase curve are not optimized, the linearity will be poor.

[0063] In the prior art, the quarter-wavelength output transmission line 104 and the output matching network 105 in the load-modulated power amplifier are circuit power loss points. Since the quarter-wavelength output transmission line 104 needs to present a higher load line to the main power amplifier 101 at low power, and needs to present a lower load line to the main power amplifier 101 at high power, the switching of the impedance conversion ratio of the quarter-wavelength output transmission line 104 at different powers results in a large power consumption loss in the circuit.

[0064] In order to solve the problems existing in the above-mentioned prior art, as shown in Figure 2, an embodiment of the present invention provides a load-modulated power amplifier with high working efficiency and good linearity, including a driving stage power amplifier and its bias circuit 111, an input power divider 112, a harmonic impedance controller 113, a main power amplifier and its bias circuit 114, an auxiliary power amplifier and its bias circuit 115 and a load-modulated power combiner 116. Among them, the RF signal input end of the load modulation power amplifier is connected to the input end of the driving stage power amplifier and its bias circuit 111, the output end of the driving stage power amplifier and its bias circuit 111 is connected to the input end of the input power divider 112, the first output end of the input power divider 112 is connected to the first input end of the harmonic impedance controller 113, and the second output end of the input power divider 112 is connected to the second input end of the harmonic impedance controller 113; the first output end of the harmonic impedance controller 113 is connected to the input end of the main power amplifier and its bias circuit 114, and the second output end of the harmonic impedance controller 113 is connected to the input end of the auxiliary power amplifier and its bias circuit 115; the output end of the main power amplifier and its bias circuit 114 is connected to the first input end of the load modulation combiner 116, and the output end of the auxiliary power amplifier and its bias circuit 115 is connected to the second input end of the load modulation combiner 116; the output end of the load modulation combiner 116 is connected to the RF signal output end of the load modulation power amplifier.

[0065] In this load-modulated power amplifier, when its RF signal input terminal receives an RF signal input, the driver-stage power amplifier first drives and amplifies the RF signal, and then outputs the amplified RF signal to the input power splitter. The input power splitter splits the input RF signal into two RF signals with a 90-degree phase difference. The RF signal with a +45-degree phase passes through a harmonic impedance controller and enters the main power amplifier; the RF signal with a -45-degree phase passes through a harmonic impedance controller and enters the auxiliary power amplifier. The main power amplifier and the auxiliary power amplifier each amplify the RF signals with a 90-degree phase difference and output them to the load-modulated combiner 116. The load-modulated combiner 116 combines the power of the two RF signals and outputs one RF signal at the RF signal output terminal.

[0066] When the input RF signal is in a small signal state, the auxiliary power amplifier is not turned on, and the main power amplifier branch presents a higher load line impedance; when the input RF signal is in a large signal state, the auxiliary power amplifier is turned on, and both the main power amplifier branch and the auxiliary power amplifier branch present a lower load line impedance.

[0067] Among them, the bias circuit of the main power amplifier, the bias circuit of the auxiliary power amplifier and the harmonic impedance matching circuit (i.e., the harmonic impedance controller unit) are all used to optimize the gain curve and phase curve of the power amplifier; the bias circuit of the driver-stage power amplifier is used to optimize the P1dB (1 decibel compressed output power) of the power amplifier; these four circuits work together to improve the linearity of the load-modulated power amplifier.

[0068] The load modulator combiner 116 is composed of lumped components, including a primary matching network, an auxiliary matching network, and a combined matching network. Its insertion loss is lower than that of the load-line structure of a load modulator power amplifier in the prior art, significantly improving the efficiency of the load modulator power amplifier at back-off power.

[0069] In one embodiment of the present invention, a schematic diagram of the load-modulated power amplifier circuit is shown in FIG3 . The components and structures of the driver-stage power amplifier and its bias circuit 111, input power divider 112, harmonic impedance controller 113, main power amplifier and its bias circuit 114, auxiliary power amplifier and its bias circuit 115, and load-modulated combiner 116 are described in detail below.

[0070] The driver-stage power amplifier and its bias circuit 111 include a driver amplifier power transistor T3, a first bias transistor T1, a second bias transistor T2, a first Zener diode D1, a second Zener diode D2, and a third Zener diode D3, a first filter capacitor Cp1, a second filter capacitor Cp2, and a first feedback capacitor Cp3, as well as a first bias resistor R1, a second bias resistor R2, and a first Zener resistor R3. The first bias resistor R1, the first Zener diode D1, the second Zener diode D2, the first filter capacitor Cp1, and the first bias transistor T1 constitute a main bias circuit; the second bias resistor R2, the first Zener resistor R3, the third Zener diode D3, the second filter capacitor Cp2, the first feedback capacitor Cp3, and the second bias transistor T2 constitute a transconductance booster (Gm-booster) bias circuit.

[0071] In the driver-stage power amplifier and its bias circuit, the RF signal input terminal of the load-modulated power amplifier is connected to the base of the driver-stage power amplifier T3, the emitter of the first bias tube T1, and the emitter of the second bias tube T2; the emitter of the driver-stage power amplifier T3 is connected to the ground terminal, and the collector of the driver-stage power amplifier T3 is connected to the input terminal of the input power distributor unit as the output terminal of the driver-stage power amplifier and its bias circuit, and is also connected to the first feedback capacitor Cp3; the other end of the first feedback capacitor Cp3 is connected to the emitter of the second bias tube T2; the collector of the second bias tube T2, the collector of the first bias tube T1, the first bias resistor R1, and the second bias resistor R2 are all connected to the The first bias voltage terminal Vreg1 is connected; the other end of the second bias resistor R2 is connected to the base of the second bias tube T2, the first voltage-stabilizing resistor R3 and the second filter capacitor Cp2, the other end of the first voltage-stabilizing resistor R3 is connected to the anode of the third voltage-stabilizing diode D3, the cathode of the third voltage-stabilizing diode D3 and the other end of the second filter capacitor Cp2 are both connected to the ground terminal; the other end of the first bias resistor R1 is connected to the base of the first bias tube T1, the first filter capacitor Cp1 and the anode of the first voltage-stabilizing diode D1, the cathode of the first voltage-stabilizing diode D1 is connected to the anode of the second voltage-stabilizing diode D2, the cathode of the second voltage-stabilizing diode D2 and the other end of the first filter capacitor Cp1 are both connected to the ground terminal.

[0072] The operating principle of the driver-stage power amplifier and its bias circuit is shown in Figure 4. When the driver-stage power amplifier outputs low power, the main bias circuit provides a first bias current Ic1, turning on the driver amplifier power transistor T3. The transconductance booster bias circuit is not turned on and provides no bias current. When the driver-stage power amplifier outputs high power, the bias current Ic1 provided by the main bias circuit remains unchanged. As the output power gradually increases, the first feedback capacitor Cp3 feeds the driver-stage output power back to the emitter of the second bias transistor T2 in the transconductance booster bias circuit, turning on the second bias transistor T2 and providing a second bias current Ic2. At this point, the bias current of the driver amplifier power transistor T3 increases, increasing its transconductance (Gm) and improving the power amplifier's P1dB. Specifically, the transconductance booster bias circuit only turns on when the input power of the driver amplifier power transistor T3 exceeds a preset threshold. The detailed operating process is shown in Figures 5 and 6.

[0073] Figure 5 shows how the second bias current Ic2 provided by the transconductance booster bias circuit changes as the output power increases. As can be seen from Figure 5, when the output power is low, the second bias current Ic2 is zero, meaning the transconductance booster bias circuit provides no bias current. However, when the output power exceeds a certain value and continues to increase, the second bias current Ic2 increases rapidly.

[0074] Figure 6 compares the gain versus output power when the transconductance booster bias circuit is operating (Ic2 > 0) and when it is not operating (Ic2 = 0). As can be seen from Figure 6, the transconductance booster bias circuit can effectively increase the power amplifier's P1 dB, thereby improving linearity.

[0075] The input power divider 112 includes a first inductor L1, a second inductor L2, a first capacitor C1, and a second capacitor C2. One end of the first inductor L1, the second inductor L2, the first capacitor C1, and the second capacitor C2 are interconnected and serve as the input end of the input power divider, connected to the output end of the driver-stage power amplifier and its bias circuit; the other end of the first inductor L1 and the other end of the second capacitor C2 are respectively connected to the ground; the other end of the first capacitor C1 serves as the first output end of the input power divider, connected to the first input end of the harmonic impedance controller unit; and the other end of the second inductor L2 serves as the second output end of the input power divider, connected to the second input end of the harmonic impedance controller unit.

[0076] The RF signal is amplified by the driver-stage power amplifier and then output to the input power splitter unit. The input power splitter splits the input RF signal into two RF signals with the same amplitude and a 90-degree phase difference, which are then output to the harmonic impedance controller unit. The RF signal phase difference is generated through the matching circuit structure. The first inductor L1 connected in parallel and the first capacitor C1 connected in series form a high-pass network, which makes the RF signal in this path phase advance. The second inductor L2 connected in series and the second capacitor C2 connected in parallel form a low-pass network, which makes the RF signal in this path phase delay, thereby obtaining two RF signals with a 90-degree phase difference.

[0077] The harmonic impedance controller 113 includes a third inductor L3, a fourth inductor L4, a fifth inductor L5, and a sixth inductor L6, as well as a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a sixth capacitor C6. The third inductor L3, the fifth inductor L5, the third capacitor C3, and the fifth capacitor C5 constitute the harmonic impedance matching circuit of the main power amplifier; the fourth inductor L4, the sixth inductor L6, the fourth capacitor C4, and the sixth capacitor C6 constitute the harmonic impedance matching circuit of the auxiliary power amplifier; and the circuit structures of the two are identical.

[0078] In the harmonic impedance control matching circuit of the main power amplifier, one end of the third inductor L3 and the third capacitor C3 are connected to each other and then connected to the first output end of the input power distributor unit as the first input end of the harmonic impedance controller unit; the other ends of the third inductor L3 and the third capacitor C3 are connected to each other and then connected to the fifth capacitor C5 on the one hand, and on the other hand, connected to the input end of the main power amplifier and its bias circuit as the first output end of the harmonic impedance controller unit; the other end of the fifth capacitor C5 is connected to the fifth inductor L5, and the other end of the fifth inductor L5 is connected to the ground end.

[0079] In the harmonic impedance matching circuit of the auxiliary power amplifier, one end of the fourth inductor L4 and the fourth capacitor C4 are connected to each other and then connected to the second output end of the input power divider unit as the second input end of the harmonic impedance controller unit; the other ends of the fourth inductor L4 and the fourth capacitor C4 are connected to each other and then connected to the sixth capacitor C6 on the one hand, and on the other hand, connected to the input end of the auxiliary power amplifier and its bias circuit as the second output end of the harmonic impedance controller unit; the other end of the sixth capacitor C6 is connected to the sixth inductor L6, and the other end of the sixth inductor L6 is connected to the ground end.

[0080] The harmonic impedance controller unit includes a harmonic impedance matching circuit for the main power amplifier and a harmonic impedance matching circuit for the auxiliary power amplifier, both of which have identical structures. The optimal efficiency impedance points of the main and auxiliary power amplifiers can be determined through source pull simulation design. The harmonic impedance controller matches the main and auxiliary amplifier power tubes to near the optimal fundamental impedance and optimal harmonic impedance points. Each matching circuit consists of a parallel resonant circuit and a series resonant circuit; the parallel resonant circuit has a third-order resonant frequency, while the series resonant circuit has a second-order resonant frequency. The second-order impedance of the source impedance of the main and auxiliary amplifier power tubes is low, while the third-order impedance is high. This shapes the input waveform to a near-square wave shape, improving circuit efficiency.

[0081] The main power amplifier and its bias circuit 114 include a main power amplifier transistor T7, a third bias transistor T4, a first transistor T5, a second transistor T6, a fourth voltage-stabilizing diode D4, a fifth voltage-stabilizing diode D5, a third filter capacitor Cp4, a first coupling capacitor Cp5, and third and fourth bias resistors R4 and R5. All components except the main power amplifier transistor T7 constitute the bias circuit.

[0082] In the main power amplifier and its bias circuit, the base of the main power amplifier tube T7 and the emitter of the third bias tube T4 are connected and then connected to the first output terminal of the harmonic impedance controller unit; the emitter of the main power amplifier tube T7 is connected to the ground terminal, and the collector of the main power amplifier tube T7 serves as the output terminal of the main power amplifier and its bias circuit and is connected to the first input terminal of the load modulation combiner unit. The collector of the third bias transistor T4 is connected to the third bias resistor R4 and the fourth bias resistor R5, and then connected to the second bias voltage terminal Vreg2. The other end of the third bias resistor R4 is connected to the collector of the first transistor T5 and the collector of the second transistor T6. The base of the first transistor T5 is connected to the emitter of the third bias transistor T4 through the third filter capacitor Cp4. The base and emitter of the second transistor T6 are connected in parallel to ground, and the emitter of the first transistor T5 is connected to ground. The base of the third bias transistor T4 is connected to the third filter capacitor Cp4, the anode of the fourth Zener diode D4, and the other end of the fourth bias resistor R5. The other end of the third filter capacitor Cp4 is connected to ground, the cathode of the fourth Zener diode D4 is connected to the anode of the fifth Zener diode D5, and the cathode of the fifth Zener diode D5 is connected to ground.

[0083] As shown in Figure 7 (similar to unit 114 in Figure 2 ), in the bias circuit of the main power amplifier transistor T7, the fourth bias resistor R5 is used to control the magnitude of the bias current provided, and the third bias transistor T4 is an emitter follower, used to provide bias current to the main power amplifier transistor T7. The third bias resistor R4, the first coupling capacitor Cp5, the first transistor T5, and the second transistor T6 form a phase modulation circuit. The third bias resistor R4 is used to control the bias point of the first transistor T5 and the second transistor T6, and the first coupling capacitor Cp5 is used to control the phase modulation amplitude. It couples the power input to the main power amplifier to the first transistor T5 and the second transistor T6, and improves the phase characteristics of the circuit by changing the junction capacitance of the first transistor T5 and the second transistor T6 by a large signal.

[0084] The effect of the phase modulation circuit is detailed in Figure 8, which shows how the phase changes with increasing output power. Curve 1 shows the phase change without the phase modulation circuit, and Curve 2 shows the phase change with the phase modulation circuit. As can be seen from Figure 8, the phase modulation circuit effectively controls the phase curve within approximately 2°, improving the circuit's linearity.

[0085] The auxiliary power amplifier and its bias circuit 115 include an auxiliary power amplifier transistor T8, a fourth bias transistor T9, a sixth voltage stabilizing diode D6, a fourth filter capacitor Cp6, a fifth bias resistor R7, and a second voltage stabilizing resistor R6. All components except the auxiliary power amplifier transistor T8 constitute its bias circuit.

[0086] In the auxiliary power amplifier and its bias circuit, the base of the auxiliary power amplifier tube T8 is connected to the emitter of the fourth bias tube T9, and then connected to the second output terminal of the harmonic impedance controller unit. The emitter of the auxiliary power amplifier tube T8 is connected to the ground terminal, and the collector of the auxiliary power amplifier tube T8, as the output terminal of the auxiliary power amplifier and its bias circuit, is connected to the second input terminal of the load modulation combiner unit. The collector of the fourth bias tube T9 is connected to the fifth bias resistor R7, and then connected to the third bias voltage terminal Vreg3. The other end of the fifth bias resistor R7 is connected to the base of the fourth bias tube T9, the second zener resistor R6, and the fourth filter capacitor Cp6. The other end of the second zener resistor R6 is connected to the anode of the sixth zener diode D6. The cathode of the sixth zener diode D6 and the other end of the fourth filter capacitor Cp6 are both connected to the ground terminal.

[0087] The bias circuit of the auxiliary power amplifier is shown in Figure 9 (same as unit 115 in Figure 2 ). The fifth bias resistor R7 is used to control the auxiliary power amplifier's turn-on power point. The second voltage-stabilizing resistor R6 and the sixth voltage-stabilizing diode D6 form a voltage-stabilizing circuit. The fourth bias transistor T9 is an emitter follower circuit that provides bias current for the auxiliary power amplifier T8. In the small-signal state, the fourth bias transistor T9 is in a semi-cutoff state and does not provide bias current, placing the auxiliary power amplifier T8 in Class C operation. As the input power increases, the input swing of the auxiliary power amplifier T8 increases, and the fourth bias transistor T9 begins to provide bias current, causing the auxiliary power amplifier T8 to enter an amplification mode and rapidly increase its output power.

[0088] The gain curve of a load-modulated power amplifier is directly related to the turn-on power point of the auxiliary amplifier power tube T8 (i.e., the Class C power amplifier). Figure 10 shows the curves of the gain of the load-modulated power amplifier as the output power increases at different turn-on power points. Curve 1 shows the Class C power amplifier turned on at a higher power point, which is close to the saturation power, resulting in premature gain curve rolloff and poor P1dB. Curve 2 shows the Class C power amplifier turned on at a lower power point, which is close to the lower power point, resulting in an upward gain curve and poor fall-back linearity. Curve 3 shows the Class C power amplifier turned on at a more appropriate power point, achieving a sufficiently high P1dB for the load-modulated power amplifier, thereby achieving optimal linearity.

[0089] The load modulator combiner 116 is composed of lumped components, as shown in FIG12 (same as unit 116 in FIG2 ), including a seventh inductor L7, an eighth inductor L8, a ninth inductor L9, a tenth inductor L10, and an eleventh inductor L11, as well as a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, a tenth capacitor C10, and an eleventh capacitor C11. The seventh inductor L7, the seventh capacitor C7, and the eighth capacitor C8 form a CLC-type main matching network; the eighth inductor L8, the ninth inductor L9, the tenth inductor L10, the ninth capacitor C9, and the tenth capacitor C10 form a CL+CLL-type auxiliary matching network; and the eleventh inductor L11 and the eleventh capacitor C11 form an LC-type combined matching network.

[0090] In the load modulation combiner, one end of the seventh capacitor C7 is connected to the output end of the main power amplifier and its bias circuit as the first input end of the load modulation combiner, the other end of the seventh capacitor C7 is connected to the seventh inductor L7, the other end of the seventh inductor L7 is connected to the eighth capacitor C8 and the eleventh inductor L11 (P node), and the other end of the eighth capacitor C8 is connected to the ground end; one end of the ninth capacitor C9 and the tenth capacitor C10 are connected as the second input end of the load modulation combiner and are connected to the output end of the auxiliary power amplifier and its bias circuit. The other end of the tenth capacitor C10 is connected to the tenth inductor L10, and the other end of the tenth inductor L10 is connected to the ground terminal; the other end of the ninth capacitor C9 is connected to the eighth inductor L8 and the ninth inductor L9, the other end of the eighth inductor L8 is connected to the ground terminal, and the other end of the ninth inductor L9 is connected to the eighth capacitor C8 and the eleventh inductor L11 (node ​​P); the other end of the eleventh inductor L11 is connected to the eleventh capacitor C11 and the RF signal output terminal of the load modulation power amplifier, and the other end of the eleventh capacitor C11 is connected to the ground terminal.

[0091] The load line transformation of the load-modulated power amplifier is shown in Figure 11. By analyzing the load line transformation principle using Kirchhoff's theorem, the relationship between the main circuit operating voltage and operating current and the auxiliary circuit operating voltage and operating current can be derived as follows:

[0092] Among them, V m The main circuit operating voltage, I m is the main circuit working current, V p is the auxiliary circuit working voltage, I p is the auxiliary circuit working current, I o The output current of the main path after passing through the transmission line, Z0 is the characteristic impedance value of the main path λ / 4 transmission line (λ is the transmission line wavelength at the operating frequency), and R is the impedance of the power combining point (point P).

[0093] The main load line Z can be obtained by calculation m and auxiliary load line Zp for:

[0094] It can be seen from formula 3 and formula 4 that when the input RF signal is a small signal, the auxiliary power amplifier has not yet turned on, that is, the auxiliary working current I p = 0, assuming R = (1 / 2) Z0, then the main power amplifier load line The load line of the auxiliary power amplifier is infinite; when the input RF signal gradually increases, the main power amplifier enters the saturation state, that is, the main working current I m When the auxiliary power amplifier is turned on, the auxiliary working current I p When the load line Z of the main power amplifier increases m Gradually decreases, the auxiliary power amplifier load line Z p Also gradually decreases, assuming I p =I m , R=(1 / 2)Z0, then the load line of the main power amplifier Auxiliary power amplifier load line Z p =Z0;

[0095] From the above analysis, it can be seen that when the input signal changes from small to large, the load line of the main power amplifier also decreases from 2Z0 to Z0, achieving the load line modulation effect and improving the efficiency at the back-off power; the load line of the auxiliary power amplifier also changes from infinity to Z0, improving the output power of the load modulation power amplifier.

[0096] When the input RF signal is a small signal, the load modulation combiner shown in Figure 12 can be equivalent to the equivalent circuit shown in Figure 13. Among them, because the auxiliary power amplifier has no output current, the device involved in the auxiliary matching network can be equivalent to the inductor L8', which forms a π-type network with the combining matching network, converting the impedance at point P into 4R opt The function of the main matching network is to convert Z P Converted to a lower impedance, if the impedance conversion ratio is 2, the load line of the main RF power amplifier is 2R opt Among them, R opt Reference impedance for matching network design.

[0097] When the input RF signal is a large signal, the auxiliary power amplifier injects working current into point P, converting the impedance of point P into 2R opt , so that the main power amplifier load line is composed of 2R opt Reduced to R opt , at this time the auxiliary power amplifier load line is R opt ;

[0098] Q of the main matching networkm The values ​​are:

[0099] Q of the combining and matching network L The value is, assuming R L 50Ohm, R opt is 6.25Ohm, then we can calculate:

[0100] Assuming that the device Q in the matching network u The value is 10. According to the insertion loss formula, the insertion loss of the load modulated power amplifier can be calculated as:

[0101] The load modulation combiner provided in the embodiment of the present invention can realize the conversion of low power and high load, and high power and small load, while maintaining low insertion loss, which is conducive to improving work efficiency.

[0102] In order to verify the excellent performance of the load-modulated power amplifier provided by the embodiment of the present invention, the inventors conducted simulation comparative tests on the technical solution and the existing technical solution, and the test results are shown in Figures 14 and 15.

[0103] Figure 14 shows the linearity simulation test results of the load-modulated power amplifier. It can be seen from Figure 14 that as the output power increases, the ACLR (adjacent channel leakage ratio) value of the load-modulated power amplifier technical solution provided by the embodiment of the present invention is lower than the ACLR value of the existing technical solution. In other words, the linearity of the load-modulated power amplifier provided by the embodiment of the present invention is significantly better than that of the existing technical solution.

[0104] FIG15 is a simulation test result of the working efficiency of the load-modulated power amplifier. It can be seen from FIG15 that as the output power increases, the working efficiency of the load-modulated power amplifier technical solution provided by the embodiment of the present invention is significantly higher than the working efficiency of the existing technical solution.

[0105] In addition, an embodiment of the present invention further provides an electronic device, which includes the above-mentioned load-modulated power amplifier, which can be used as an important component of a communication component. The electronic device referred to here refers to a computer device that can be used in a mobile environment and supports multiple communication standards such as GSM, EDGE, CDMA, TD-SCDMA, WCDMA, TDD-LTE, FDD-LTE, and NR, including mobile phones, laptops, tablet computers, and car computers. In addition, the technical solution provided by the present invention is also applicable to other applications of radio frequency integrated circuits, such as communication base stations and intelligent connected vehicles.

[0106] As shown in Figure 16, the electronic device includes at least a processor, a memory and a communication component, and may further include a sensor component, a power component, a multimedia component and an input / output interface according to actual needs. Among them, the memory, communication component, sensor component, power component, multimedia component and input / output interface are all connected to the processor. The memory can be a static random access memory (SRAM), an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), a programmable read-only memory (PROM), a read-only memory (ROM), a magnetic memory, a flash memory, etc., and the processor can be a central processing unit (CPU), a graphics processing unit (GPU), a field programmable gate array (FPGA), an application-specific integrated circuit (ASIC), a digital signal processing (DSP) chip, etc. Other communication components, sensor components, power components, multimedia components, etc. can all be implemented using general components and are not specifically described here.

[0107] In summary, the load-modulated power amplifier provided by the present invention adopts a technical solution of a driver-stage power amplifier with a transconductance booster bias circuit, a main and auxiliary harmonic impedance matching circuit, a main power amplifier with a phase-modulation circuit bias circuit, and an auxiliary power amplifier with a bias circuit with a controllable start-up power point, and is combined with a load-modulated combiner with low insertion loss at the output end. The coordinated operation of these units achieves linearization and high efficiency of the load-modulated power amplifier, which can well meet the requirements of practical applications. Therefore, the load-modulated power amplifier provided by the present invention has the beneficial effects of ingenious and reasonable structural design, low design cost, high working efficiency, and excellent circuit performance.

[0108] It should be noted that the above embodiments are only examples, and the technical solutions of the various embodiments can be combined and are all within the protection scope of the present invention.

[0109] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0110] The load-modulated power amplifier and corresponding electronic device provided by the present invention are described in detail above. For those skilled in the art, any obvious modification made thereto without departing from the essence of the present invention will constitute an infringement of the patent rights of the present invention and will result in corresponding legal liability.

Claims

1. A load modulated power amplifier, characterized in that It includes a driving-stage power amplifier and its bias circuit, an input power divider, a harmonic impedance controller, a main power amplifier and its bias circuit, an auxiliary power amplifier and its bias circuit, and a load modulation combiner; wherein, The input end of the driving stage power amplifier and its bias circuit is connected to the RF signal input end, and is used to drive and amplify the input RF signal, and the amplified RF signal is output to the input power distributor; The input power divider is used to divide an input RF signal into two RF signals with a phase difference of 90 degrees; wherein the RF signal with a phase of +45 degrees enters the main power amplifier after passing through the harmonic impedance controller; the RF signal with a phase of -45 degrees enters the auxiliary power amplifier after passing through the harmonic impedance controller; The main power amplifier and its bias circuit and the auxiliary power amplifier and its bias circuit are used to amplify the input radio frequency signal, and the amplified radio frequency signals are output to the load modulation combiner respectively; The load modulation combiner is used to combine the power of the two input RF signals into one RF signal, and its output end is connected to the RF signal output end; Among them, the driving stage power amplifier is provided with a bias circuit with transconductance enhancement, the main path power amplifier is provided with a phase-adjustable bias circuit, and the auxiliary path power amplifier is provided with a bias circuit with controllable start-up power point and the harmonic impedance controller.

2. The load modulated power amplifier according to claim 1, wherein: The output end of the driving stage power amplifier is connected to the input end of the input power distributor, the first output end of the input power distributor is connected to the first input end of the harmonic impedance controller, and the second output end of the input power distributor is connected to the second input end of the harmonic impedance controller; the first output end of the harmonic impedance controller is connected to the input end of the main power amplifier and its bias circuit, and the second output end of the harmonic impedance controller is connected to the input end of the auxiliary power amplifier and its bias circuit; the output end of the main power amplifier and its bias circuit is connected to the first input end of the load modulation combiner, and the output end of the auxiliary power amplifier and its bias circuit is connected to the second input end of the load modulation combiner.

3. The load modulated power amplifier according to claim 1, wherein: The driving stage power amplifier and its bias circuit include a driving amplifying power tube, a first bias tube and a second bias tube, and a first voltage stabilizing diode, a second voltage stabilizing diode and a third voltage stabilizing diode, and a first filter capacitor, a second filter capacitor and a first feedback capacitor, and a first bias resistor, a second bias resistor and a first voltage stabilizing resistor; wherein, The base of the driving amplifier power tube is connected to the radio frequency signal input terminal, the emitter is connected to the ground terminal, and the collector is connected to the input terminal of the input power distributor unit; The first bias resistor, the first voltage zener diode, the second voltage zener diode, the first filter capacitor and the first bias tube constitute a main bias circuit for providing a first bias current; The second bias resistor, the first voltage-stabilizing resistor, the third voltage-stabilizing diode, the second filter capacitor, the first feedback capacitor and the second bias tube constitute a transconductance enhancement bias circuit for providing a second bias current.

4. The load modulated power amplifier according to claim 3, wherein: In the main bias circuit, the emitter of the first bias tube is connected to the base of the driving amplifier power tube, and the collector of the first bias tube and the first bias resistor are both connected to the first bias voltage end; the other end of the first bias resistor is connected to the base of the first bias tube, the first filter capacitor and the positive electrode of the first voltage regulator diode, the cathode of the first voltage regulator diode is connected to the positive electrode of the second voltage regulator diode, and the cathode of the second voltage regulator diode and the other end of the first filter capacitor are both connected to the ground end.

5. The load modulated power amplifier according to claim 3, wherein: In the transconductance enhancement bias circuit, the emitter of the second bias tube is connected to the base of the driving amplifier power tube and the first feedback capacitor, and the other end of the first feedback capacitor is connected to the collector of the driving amplifier power tube; the collector of the second bias tube and the second bias resistor are both connected to the first bias voltage terminal; the other end of the second bias resistor is connected to the base of the second bias tube, the first zener resistor and the second filter capacitor, the other end of the first zener resistor is connected to the positive electrode of the third zener diode, and the negative electrode of the third zener diode and the other end of the second filter capacitor are both connected to the ground terminal.

6. The load modulated power amplifier according to claim 3, wherein: When the driver stage power amplifier outputs low power, the transconductance enhancement bias circuit is in In the off state, the second bias current is not provided; When the output power of the driving stage power amplifier increases and exceeds a set threshold, the transconductance enhancement bias circuit is turned on to provide a second bias current to increase the transconductance of the driving amplifier power tube.

7. The load modulated power amplifier according to claim 1, wherein: The input power distributor comprises a first inductor, a second inductor, a first capacitor and a second capacitor; wherein one end of the first inductor, the second inductor, the first capacitor and the second capacitor are connected to each other and then connected as an input end to the output end of the driver stage power amplifier and its bias circuit; The first inductor connected in parallel and the first capacitor connected in series form a high-pass network, so that the phase of the RF signal in this path leads by 45 degrees, and the other end of the first capacitor is a first output end connected to the first input end of the harmonic impedance controller; The second inductor connected in series and the second capacitor connected in parallel form a low-pass network, so that the phase of the RF signal in this path is delayed by 45 degrees. The other end of the second inductor is connected to the second input end of the harmonic impedance controller as a second output end.

8. The load modulated power amplifier according to claim 1, wherein: The harmonic impedance controller includes a third inductor, a fourth inductor, a fifth inductor and a sixth inductor, and a third capacitor, a fourth capacitor, a fifth capacitor and a sixth capacitor; wherein, The third inductor, the fifth inductor, the third capacitor and the fifth capacitor constitute a harmonic impedance matching circuit of the main power amplifier; The fourth inductor, the sixth inductor, the fourth capacitor and the sixth capacitor constitute a harmonic impedance matching circuit of the auxiliary power amplifier; The harmonic impedance matching circuit of the main power amplifier and the harmonic impedance matching circuit of the auxiliary power amplifier have the same structure, and are both used for matching the optimal fundamental impedance point and the optimal harmonic impedance point.

9. The load modulated power amplifier according to claim 8, wherein: In the harmonic impedance matching circuit of the main power amplifier, one end of the third inductor and the third capacitor are connected to each other and then connected to the first output end of the input power divider as the first input end of the harmonic impedance controller; the other end of the third inductor and the third capacitor are connected to each other and then connected to the fifth capacitor on the one hand, and connected to the input end of the main power amplifier and its bias circuit as the first output end of the harmonic impedance controller on the other hand; the other end of the fifth capacitor is connected to the fifth inductor, The other end of the fifth inductor is connected to the ground.

10. The load modulated power amplifier according to claim 1, wherein: The main power amplifier and its bias circuit include a main amplifying power tube, a third biasing tube, a first transistor and a second transistor, a fourth voltage stabilizing diode, a fifth voltage stabilizing diode, a third filtering capacitor, a first coupling capacitor, a third biasing resistor and a fourth biasing resistor; wherein all components except the main amplifying power tube constitute a biasing circuit; In the bias circuit, the third bias tube is an emitter follower, which is used to provide a bias current for the main amplifier power tube, and the fourth bias resistor is used to control the magnitude of the bias current; The third bias resistor, the first coupling capacitor, the first transistor and the second transistor form a phase modulation circuit for improving phase characteristics.

11. The load modulated power amplifier according to claim 10, wherein: In the main power amplifier and its bias circuit, the base of the main power amplifier tube and the emitter of the third bias tube are connected and then connected to the first output end of the harmonic impedance controller; the emitter of the main power amplifier tube is connected to the ground end, and the collector of the main power amplifier tube is connected to the first input end of the load modulation combiner as the output end; The collector of the third bias tube is connected to the third bias resistor and the fourth bias resistor and then connected to the second bias voltage terminal; the other end of the third bias resistor is connected to the collector of the first transistor and the collector of the second transistor; the base of the first transistor is connected to the emitter of the third bias tube through the third filter capacitor; the base and emitter of the second transistor are connected in parallel to the ground terminal, and the emitter of the first transistor is connected to the ground terminal; the base of the third bias tube is connected to the third filter capacitor, the positive electrode of the fourth zener diode and the other end of the fourth bias resistor; the other end of the third filter capacitor is connected to the ground terminal, the negative electrode of the fourth zener diode is connected to the positive electrode of the fifth zener diode, and the negative electrode of the fifth zener diode is connected to the ground terminal.

12. The load modulated power amplifier according to claim 1, wherein: The auxiliary power amplifier and its bias circuit include an auxiliary power amplifier tube, a fourth bias tube, a sixth voltage stabilizing diode, a fourth filter capacitor, a fifth bias resistor and a second voltage stabilizing resistor; wherein all components except the auxiliary power amplifier tube constitute a bias circuit; In the bias circuit, the fifth bias resistor is used to control the start-up power point of the auxiliary power amplifier; the fourth bias tube is an emitter follower, which is used to amplify the power of the auxiliary power amplifier. The tube provides bias current; When the input RF signal is in a small signal state, the fourth bias tube is in a semi-cutoff state and does not provide a bias current; when the input RF signal is in a large signal state, the fourth bias tube starts to provide a bias current, so that the auxiliary amplifier power tube is turned on to achieve a load modulation effect.

13. The load modulated power amplifier according to claim 12, wherein: In the auxiliary power amplifier and its bias circuit, the base of the auxiliary power amplifier tube and the emitter of the fourth bias tube are connected and then connected to the second output end of the harmonic impedance controller; the emitter of the auxiliary power amplifier tube is connected to the ground end, and the collector of the auxiliary power amplifier tube is connected to the second input end of the load modulation combiner as the output end; The collector of the fourth bias tube and the fifth bias resistor are connected to the third bias voltage terminal; the other end of the fifth bias resistor is connected to the base of the fourth bias tube, the second zener resistor and the fourth filter capacitor, the other end of the second zener resistor is connected to the positive electrode of the sixth zener diode, and the negative electrode of the sixth zener diode and the other end of the fourth filter capacitor are both connected to the ground terminal.

14. The load modulated power amplifier according to claim 1, wherein: The load modulation power combiner includes a seventh inductor, an eighth inductor, a ninth inductor, a tenth inductor and an eleventh inductor, and a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor and an eleventh capacitor; wherein, The seventh inductor, the seventh capacitor and the eighth capacitor form a CLC type main matching network; The eighth inductor, the ninth inductor, the tenth inductor and the ninth capacitor and the tenth capacitor form a CL+CLL type auxiliary circuit matching network; The eleventh inductor and the eleventh capacitor form an LC type combined matching network.

15. The load modulated power amplifier according to claim 14, wherein: In the load modulation power combiner, one end of the seventh capacitor is connected to the output end of the main power amplifier and its bias circuit as a first input end, the other end of the seventh capacitor is connected to the seventh inductor, the other end of the seventh inductor is connected to the eighth capacitor and the eleventh inductor, and the other end of the eighth capacitor is connected to the ground end; one end of the ninth capacitor and the tenth capacitor are connected and then connected to the output end of the auxiliary power amplifier and its bias circuit as a second input end, the other end of the tenth capacitor is connected to the tenth inductor, and the other end of the tenth inductor is connected to the ground end; the other end of the ninth capacitor is connected to the eighth inductor and the ninth inductor, the other end of the eighth inductor is connected to the ground end, and the other end of the ninth inductor is connected to the eighth capacitor and the eleventh inductor; The other end of the inductor is connected to the eleventh capacitor and the radio frequency signal output end of the load modulation power amplifier, and the other end of the eleventh capacitor is connected to the ground end.

16. An electronic device, characterized in that A load modulated power amplifier comprising any one of claims 1 to 15.

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