Power amplifier circuit, communication module and communication equipment

Abstract

The embodiments of the present application provide a power amplifier circuit, a communication module and a communication device, and relate to the field of terminal technology. In the power amplifier circuit, a coupling unit can decompose a radio frequency signal into a first signal and a second signal, and the first signal is transmitted to a combining point via an isolation port of the coupling unit and a first power amplifier unit. The second signal is transmitted to a combining point via a second port of the coupling unit, a second power amplifier unit and an impedance transformation unit. Among them, the impedance transformation unit is used to perform impedance transformation, so that the load impedance of the second power amplifier unit is negatively correlated with the input power of the radio frequency signal under the control of the first signal when the power is backed off. The phase shift of the first signal in the coupling unit is related to the reactance at the first port of the coupling unit. The first reactance unit is used to adjust the reactance at the first port. In this way, the phase adjustment and amplitude adjustment of the first signal are decoupled by the coupling unit and the reactance unit, thereby reducing the design difficulty and debugging difficulty of the power amplifier circuit.

Description

Technical Field

[0001] The present application relates to the field of terminal technology, and in particular to a power amplifier circuit, a communication module and a communication device. Background Art

[0002] To improve spectrum utilization and communication reliability, the modulation methods of RF signals are becoming more and more complex, and the peak-to-average power ratio (PAPR) of RF signals is getting higher and higher. To meet the linearity requirements of RF signal power amplification, the power amplifier in the power amplifier circuit usually works in a back-off state.

[0003] Compared to a conventional power amplifier circuit consisting of a power amplifier of a single structure (for example, only including a class AB power amplifier), a power amplifier circuit of a Doherty structure has a higher efficiency in a back-off state.

[0004] However, the debugging of the power amplifier circuit of the Doherty structure is difficult. Summary of the invention

[0005] The embodiment of the present application provides a power amplifier circuit, a communication module and a communication device, which are applied to the field of terminal technology. A coupler is applied to a power amplifier circuit with a Doherty structure to reduce the difficulty of debugging the power amplifier circuit.

[0006] In the first aspect, an embodiment of the present application proposes a power amplifier circuit. The power amplifier circuit includes: a first coupling unit, a first reactance unit, a first power amplification unit, a second power amplification unit and an impedance transformation unit; the first coupling unit includes: a first input port, a first isolation port, a first port and a second port, the first input port is used to input a radio frequency signal, the first isolation port is connected to the input end of the first power amplification unit, and the output end of the first power amplification unit is connected to one end of the impedance transformation unit; the output end of the first power amplification unit is used to output an amplified radio frequency signal; the first port is connected to one end of the first reactance unit, and the other end of the first reactance unit is grounded; the second port is connected to the input end of the second power amplification unit, and the output end of the second power amplification unit is connected to the other end of the impedance transformation unit;

[0007] A first coupling unit is used to decompose the radio frequency signal into a first signal and a second signal at a first input port, the first isolation port is used to output the first signal, and the second port is used to output the second signal; the first coupling unit is also used to adjust the phase of the first signal; wherein the phase shift of the first signal at the first coupling unit is related to the reactance at the first port; a first reactance unit is used to adjust the reactance at the first port; a first power amplification unit is used to amplify the first signal; a second power amplification unit is used to amplify the second signal; an impedance transformation unit is used to perform impedance transformation so that the load impedance of the second power amplification unit is negatively correlated with the input power of the radio frequency signal when the power is backed off under the control of the first signal.

[0008] The first signal may correspond to signal B hereinafter, and the second signal may correspond to signal A hereinafter. The coupling unit may correspond to coupler hereinafter.

[0009] The phase of the first signal is adjusted by the first coupling unit and the first reactance unit, thereby realizing load modulation of the junction. In the process of adjusting the phase shift of the first signal in the first coupling unit by the first reactance unit, the amplitude of the first signal changes slightly. In this way, the phase shift change and loss change of the signal in the first coupling unit are decoupled, the influence of the phase modulation of the signal on the amplitude modulation of the signal is reduced, the difficulty of predicting the impedance change of the impedance conversion unit by the first signal is reduced, and the difficulty of designing the power amplifier circuit of the load modulation structure and the difficulty of debugging are reduced.

[0010] In a possible implementation manner, the first reactance unit includes: a first capacitor.

[0011] In this way, the reactance adjustment of the first reactance unit can be achieved by replacing the capacitor. The capacitor element is easy to disassemble and convenient for debugging.

[0012] In a possible implementation, the impedance transformation unit includes: a second coupling unit; the second coupling unit includes: a second input port, a second isolation port, a third port and a fourth port; the second input port is connected to the output end of the second power amplification unit, the second isolation port is connected to the output end of the first power amplification unit, and the third port and the fourth port are both open-circuited.

[0013] In this way, impedance transformation can be achieved through the coupling unit. In addition, the phase difference between the first signal and the second signal output by the first coupling unit at the center frequency is a fixed value, and the phase shift angle changes linearly at other frequencies; the phase shift of the second signal at the second coupling unit when it is the center frequency is a fixed value, and the phase shift angle changes linearly at other frequencies. The slopes of the two linear changes are similar, and broadband phase shifting of the power amplifier circuit can be achieved.

[0014] In the second aspect, an embodiment of the present application proposes a power amplifier circuit. The power amplifier circuit includes: a power divider, a first coupling unit, a first reactance unit, a first power amplification unit, a second power amplification unit and an impedance transformation unit; the power divider includes: a first port, a second port and a third port; the first coupling unit includes: a first input port, a first isolation port, a fourth port and a fifth port; the first port is used to input a radio frequency signal, and the second port is connected to the first input port; the first isolation port is connected to the input end of the first power amplification unit, and the output end of the first power amplification unit is connected to one end of the impedance transformation unit; the output end of the first power amplification unit is used to output the amplified radio frequency signal; the fourth port is connected to one end of the first reactance unit, and the other end of the first reactance unit is grounded; the fifth port is grounded; the third port is connected to the input end of the second power amplification unit, and the output end of the second power amplification unit is connected to the other end of the impedance transformation unit;

[0015] A power divider for dividing a radio frequency signal into a first signal and a second signal, wherein the second port is used to output the first signal and the third port is used to output the second signal; a first coupling unit for adjusting the phase of the first signal; wherein the phase shift of the first signal at the first coupling unit is related to the reactance at the first port; a first reactance unit for adjusting the reactance at the fourth port; a first power amplification unit for amplifying the first signal; a second power amplification unit for amplifying the second signal; an impedance transformation unit for performing impedance transformation so that the load impedance of the first power amplification unit is negatively correlated with the input power of the radio frequency signal under the control of the first signal when the power is backed off.

[0016] The phase of the first signal is adjusted by the first coupling unit and the first reactance unit, thereby realizing load modulation of the junction. In the process of adjusting the phase shift of the first signal in the first coupling unit by the first reactance unit, the amplitude of the first signal changes slightly. In this way, the phase shift change and loss change of the signal in the first coupling unit are decoupled, the influence of the phase modulation of the signal on the amplitude modulation of the signal is reduced, the difficulty of predicting the impedance change of the impedance conversion unit by the first signal is reduced, and the difficulty of designing the power amplifier circuit of the load modulation structure and the difficulty of debugging are reduced.

[0017] In a possible implementation manner, the first reactance unit includes: a first capacitor.

[0018] In this way, the reactance adjustment of the first reactance unit can be achieved by replacing the capacitor. The capacitor element is easy to disassemble and convenient for debugging.

[0019] In a possible implementation, the power amplifier circuit also includes: a second reactance unit, the fifth port is connected to one end of the second reactance unit, and the other end of the second reactance unit is grounded; the second reactance unit is used to adjust the impedance of the fifth port to reduce the insertion loss of the first coupling unit.

[0020] In this way, the first signal may also include a signal reflected by the fifth port, which may reduce the insertion loss of the first coupling unit.

[0021] In a possible implementation manner, a difference between a reactance value of the first reactance unit and a reactance value of the second reactance unit is smaller than a preset threshold.

[0022] In this way, the reactance of the first reactance unit is close to or even the same as the reactance of the second reactance unit, which can reduce the phase difference between the signal reflected from the coupling port to the isolation port and the phase difference between the signal reflected from the through port to the isolation port, thereby reducing the insertion loss of the first coupling unit.

[0023] In a possible implementation, the second reactance unit includes: a second capacitor, and a difference between a capacitance value of the first capacitor and a capacitance value of the second capacitor is smaller than a preset threshold.

[0024] In this way, the reactance adjustment of the first reactance unit and the reactance adjustment of the second reactance unit can be achieved by replacing the capacitor. The capacitor element is easy to disassemble and convenient for debugging.

[0025] In a possible implementation, the impedance transformation unit includes: a second coupling unit; the second coupling unit includes: a second input port, a second isolation port, a sixth port and a seventh port; the second input port is connected to the output end of the second power amplification unit, the second isolation port is connected to the output end of the first power amplification unit, and the sixth port and the seventh port are both open-circuited.

[0026] In this way, impedance transformation can be achieved through the coupling unit.

[0027] In a third aspect, an embodiment of the present application provides a communication module. The communication module includes: a radio frequency integrated circuit, and a power amplifier circuit in the first aspect, any possible implementation of the first aspect, the second aspect, or any possible implementation of the second aspect; the radio frequency integrated circuit is used to output a radio frequency signal; and the power amplifier circuit is used to amplify the radio frequency signal.

[0028] In a fourth aspect, an embodiment of the present application provides a communication device. The communication device includes: an antenna and a communication module in the third aspect or any possible implementation of the third aspect;

[0029] The communication module is used to output the amplified radio frequency signal to the antenna; the antenna is used to transmit the amplified radio frequency signal.

[0030] It should be understood that the third aspect and the fourth aspect of the present application correspond to the technical solution of the first aspect or the technical solution of the second aspect of the present application, and the beneficial effects achieved by each aspect and the corresponding feasible implementation methods are similar and will not be repeated. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of the relationship between power back-off and efficiency provided in an embodiment of the present application;

[0032] Figure 2 A schematic diagram of a load impedance change of a power amplifier provided in an embodiment of the present application;

[0033] Figure 3 A schematic diagram of a Doherty structure power amplifier circuit in a possible design;

[0034] Figure 4 is a schematic diagram of a phase shift of a signal A in a power amplifier and a phase shift of a signal B in a power amplifier in a possible design;

[0035] Figure 5 A schematic diagram of the structure of a power amplifier circuit provided in an embodiment of the present application;

[0036] Figure 6 The phase difference between the signal A and the signal B provided in the embodiment of the present application when they are transmitted in the branch;

[0037] Figure 7 A schematic diagram of the insertion loss of the transmission of signal A and signal B provided in an embodiment of the present application;

[0038] Figure 8 A schematic diagram of the structure of another power amplifier circuit provided in an embodiment of the present application;

[0039] Fig. 9 A schematic diagram of the structure of an impedance conversion unit provided in an embodiment of the present application;

[0040] Fig.10 A schematic diagram of the structure of a power amplifier circuit provided in an embodiment of the present application;

[0041] Fig.11 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application;

[0042] Fig.12 A schematic diagram of the structure of a communication module provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] In order to clearly describe the technical solutions of the embodiments of the present application, some terms and technologies involved in the embodiments of the present application are briefly introduced below:

[0044] Power amplifier (PA)

[0045] By amplifying the voltage and current of the input signal, the power output of the signal is increased. Or it can be understood as power amplification of the RF signal.

[0046] It should be noted that the working state of the power amplifier can be divided into a linear region and a nonlinear region. In the linear region, the output power of the power amplifier increases linearly with the increase of the input power; when the input power of the power amplifier further increases, the power amplifier enters the nonlinear region, the output power of the power amplifier no longer increases with the increase of the input power, and the output power of the power amplifier reaches saturation, at which time, the efficiency of the power amplifier is the highest.

[0047] According to the type of power amplifier, PA can be divided into: Class A power amplifier, Class B power amplifier, Class AB power amplifier or Class C power amplifier, etc.

[0048] Among them, the Class A power amplifier is in the on state during the entire input signal cycle. When there is no input signal (it can also be understood that the power of the input signal is zero), the Class A amplifier will also consume DC power. It can also be understood that the conduction angle of the Class A power amplifier is 360 degrees.

[0049] The Class B power amplifier uses two amplifier elements in the positive half cycle and negative half cycle of the input signal, one for the positive half cycle and the other for the negative half cycle. When there is no input signal (it can also be understood that the power of the input signal is zero), the two elements are in the cut-off state. It can also be understood that the conduction angle of the Class B power amplifier is 180 degrees.

[0050] Class C power amplifiers are turned on for a small portion of the input signal cycle, usually less than 50% of the time. The operating point of a Class C amplifier is usually set near the cutoff region. It can also be understood that the conduction angle of a Class C power amplifier is less than 180 degrees.

[0051] The class AB power amplifier combines the characteristics of class A and class B amplifiers. The two amplifier elements are turned on in the positive and negative half cycles of the input signal, but there is a certain overlap of conduction time near the zero crossing point. It can also be understood that the conduction angle of the class AB power amplifier is between 180 degrees and 360 degrees.

[0052] It can be understood that the Class A power amplifier is suitable for the scenario where the RF signal is a small signal, the Class B power amplifier and the Class C power amplifier are suitable for the scenario where the RF signal is a large signal, and the Class AB power amplifier is equivalent to the Class A power amplifier when the RF signal is a small signal, and is equivalent to the Class B power amplifier when the RF signal is a large signal. Among them, the small signal refers to the RF signal input to the power amplifier with a small power, and the large signal refers to the RF signal input to the power amplifier with a large power.

[0053] 3. Power amplifier efficiency

[0054] The efficiency of a power amplifier is used to indicate the ability of the power amplifier to convert input power into output power. For example, the efficiency of a power amplifier may be a ratio of the output power of the power amplifier to the input power.

[0055] 4. Power backoff

[0056] Power back-off can be to reduce the output power of the power amplifier to below its maximum output power, or it can be understood as reducing the critical point between the linear region and the nonlinear region of the power amplifier (for example, the 1dB compression point of the power amplifier) ​​by a certain amplitude (for example, 6dB, 10dB, etc.).

[0057] In some embodiments, the power backoff is quantified in decibels (dB) to indicate the magnitude of the output power reduction. For example, taking a power amplifier with a maximum output power of decibel milliwatts (dBm) and a power backoff of 3 dB as an example, the output power is reduced to 27 dBm.

[0058] 5. Nonlinear distortion

[0059] Nonlinear distortion can be understood as the nonlinear relationship between the signal output by the nonlinear device and the signal input to the nonlinear device when the signal passes through the nonlinear device (for example, a power amplifier), resulting in signal distortion.

[0060] 6. Other terms

[0061] In the embodiments of the present application, words such as "first" and "second" are used to distinguish the same or similar items with substantially the same functions and effects. For example, the first chip and the second chip are only used to distinguish different chips, and their order is not limited. Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit them to be different.

[0062] It should be noted that in the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0063] In the embodiments of the present application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, a--c, bc, or abc, where a, b, and c can be single or multiple.

[0064] 7. Electronic devices

[0065] The electronic device of the embodiment of the present application may include a handheld device, a vehicle-mounted device, etc. with a signal amplification function. For example, some electronic devices are: mobile phones, tablet computers, PDAs, laptop computers, mobile internet devices (MIDs), wearable devices (e.g., smart watches, smart glasses, smart bracelets, or smart jewelry, etc.), virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to wireless modems, vehicle-mounted devices, Internet of Things (IoT), and the like. The present invention relates to terminal devices in an Internet of Things (IoT) system, terminal devices in a 5G network, or terminal devices in a future evolved public land mobile network (PLMN), etc., and the embodiments of the present application are not limited to this.

[0066] The electronic device in the embodiments of the present application may also be referred to as: terminal equipment, user equipment (UE), mobile station (MS), mobile terminal (MT), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent or user device, etc.

[0067] In order to improve the utilization of spectrum and the reliability of communication, the modulation method of RF signals in communication systems is becoming more and more complex, which increases the peak-to-average ratio of RF signals. The increase in the peak-to-average ratio may cause the power amplifier in the power amplifier circuit to operate in a nonlinear region, which in turn causes nonlinear distortion of the power amplifier circuit.

[0068] The power back-off method is adopted to reduce the power amplifier in the power amplifier circuit from entering the nonlinear region and reduce the nonlinear distortion.

[0069] However, in the power back-off state, the efficiency of the conventional power amplifier circuit is low. The conventional power amplifier circuit is composed of a power amplifier of a single structure, for example, the conventional power amplifier circuit only includes a class AB power amplifier.

[0070] For example, Figure 1 A schematic diagram of the relationship between power back-off and efficiency provided in an embodiment of the present application. Taking a conventional power amplifier circuit including a class B power amplifier or a class AB power amplifier as an example, the efficiency change of the class B power amplifier under different power back-off values ​​can be as follows: Figure 1 As shown in the curve 101 in FIG. 1 , the efficiency change of the class AB power amplifier at different power back-off values ​​can be shown as follows: Figure 1 As shown by curve 102 in FIG.

[0071] from Figure 1 It can be seen that the efficiency of a conventional power amplifier is negatively correlated with the power back-off value. The higher the power back-off value, the lower the efficiency of the power amplifier.

[0072] It is understandable that in the power fallback state, the efficiency of the conventional power amplifier circuit is low and the power consumption of the power amplifier circuit is high. In addition, the power amplifier circuit may emit a large amount of heat in the low efficiency state, and the heat dissipation pressure of the electronic equipment is high. In addition, when the power amplifier circuit works at low efficiency for a long time, it may be damaged by overheating due to untimely heat dissipation, thereby reducing the life of the power amplifier circuit.

[0073] In some embodiments, the electronic device uses a power amplifier circuit with a Doherty structure to amplify the radio frequency signal. Specifically, the power amplifier circuit with a Doherty structure includes: a carrier branch and a peak branch. The carrier branch is provided with an impedance conversion unit and a power amplifier, and the peak branch is provided with a power amplifier. The peak branch can perform active load modulation on the carrier branch.

[0074] Specifically, the impedance of the junction point of the carrier branch and the peak branch is maintained at 0.5Ropt. Ropt is the equivalent resistance (load impedance) of the power amplifier in the carrier branch when saturated. The impedance transformation unit can perform impedance transformation so that the load impedance of the power amplifier in the carrier branch decreases as the power of the RF signal increases under the control of the signal transmitted by the peak branch, thereby improving the efficiency of the power amplifier circuit.

[0075] Exemplarily, when the power of the radio frequency signal is low, the power amplifier of the carrier branch works, and the power amplifier of the peak branch is in a cut-off state; since the power amplifier of the peak branch does not work, the load impedance corresponding to the power amplifier of the carrier branch is relatively high;

[0076] When the power of the RF signal is power A, the power amplifier of the carrier branch works and the power amplifier of the peak branch starts to conduct. Due to the conduction of the power amplifier of the peak branch, the load impedance corresponding to the power amplifier of the carrier branch begins to decrease, thereby improving the efficiency of the power amplifier of the carrier branch.

[0077] It should be noted that the load impedance (equivalent resistance) of the power amplifier is equal to the ratio of the output voltage to the output current. Figure 2 As shown in a, when the load impedance of the power amplifier remains unchanged (that is, the slope of the output voltage / output current remains unchanged), when the output current of the power amplifier is small, the output voltage is also small. At this time, the efficiency of the power amplifier is low. Figure 2 As shown in b, when the output current of the power amplifier is small, the load impedance of the power amplifier is increased, thereby increasing the output voltage of the power amplifier, making it easier for the power amplifier to enter the saturation region in advance, thereby improving the efficiency of the power amplifier.

[0078] It is understandable that, compared with conventional power amplifier circuits, the efficiency of the power amplifier circuit of the Doherty structure is higher in the back-off state. Exemplarily, the efficiency change of the power amplifier circuit of the Doherty structure under different power back-off conditions can be as follows: Figure 1As shown in the curve 103 in , when the power back-off is less than -6dB, the efficiency of the power amplifier circuit of the Doherty structure gradually increases as the power back-off decreases; when the power back-off is 6dB, the efficiency of the power amplifier circuit of the Doherty structure reaches the highest; when the power back-off is greater than -6dB and less than 0dB, the efficiency of the power amplifier circuit of the Doherty structure first decreases and then increases as the power back-off decreases.

[0079] from Figure 1 It can be seen that compared with the conventional power amplifier circuit, the Doherty structure power amplifier circuit has higher efficiency in the power back-off state.

[0080] However, it is difficult to debug the power amplifier circuit of the Doherty structure in the possible design.

[0081] For example, Figure 3 FIG. 1 is a schematic diagram of a Doherty structure power amplifier circuit in a possible design. Figure 3 As shown, the power amplifier circuit of the Doherty structure includes: a power divider 201 , a power amplifier 202 , an impedance transformation unit 203 , a phase shift unit 204 , a power amplifier 205 and a matching network 206 .

[0082] The power divider 201 includes: port 1a, port 1b and port 1c. Port 1a is used to input RF signals, port 1b is connected to the input end of the power amplifier 202, and the output end of the power amplifier 202 is connected to one end of the impedance transformation unit 203; port 1c is connected to one end of the phase shift unit 204, and the other end of the phase shift unit 204 is connected to the input end of the power amplifier 205. The output end of the power amplifier 205, the other end of the impedance transformation unit 203 and one end of the matching network 206 are electrically connected to the junction point A. The other end of the matching network 206 is used to output the amplified RF signal.

[0083] In the embodiment of the present application, the carrier branch may include: a power amplifier 202 and an impedance transformation unit 203; the peak branch may include: a phase shift unit 204 and a power amplifier 205. The power amplifier 202 may also be called a carrier power amplifier, and the power amplifier 205 may also be called a peak power amplifier.

[0084] The power divider 201 is used to divide the radio frequency signal into two paths, namely signal A and signal B. The power of signal A and signal B are the same, and the phase of signal A and signal B are the same.

[0085] The power amplifier 202 is used to amplify the signal A. The power amplifier 202 is a class AB power amplifier, that is, the power amplifier 202 is equivalent to a class A power amplifier when the signal A is a small signal, and is equivalent to a class B power amplifier when the signal A is a large signal.

[0086] The impedance transformation unit 203 is used to perform impedance transformation so that the load impedance of the power amplifier 202 decreases as the power of the RF signal increases under the control of the signal A. The impedance transformation unit 203 is a frequency element, which can also be understood as an element whose load impedance and phase shift angle change with the frequency of the RF signal.

[0087] When performing impedance transformation, the impedance transformation unit 203 also performs phase shifting on the signal A. The phase shift angle is related to the frequency of the radio frequency signal.

[0088] In a possible design, at the center frequency of the RF signal, the impedance transformation unit 203 can produce a 90-degree phase shift on the signal A, and the characteristic impedance of the impedance transformation unit 203 is equal to the load impedance of the power amplifier 202 when saturated, thereby achieving impedance matching with a reflection coefficient of 0.

[0089] The phase shift unit 204 is the same as the impedance transformation unit 203. The phase shift unit 204 is used to shift the phase of the signal B. In a possible design, the phase shift (phase shift angle) of the signal B by the phase shift unit 204 is the same as the phase shift of the signal A by the impedance transformation unit 203, so that the signal A and the signal B are combined in phase at the junction A.

[0090] The power amplifier 205 is used to amplify the signal B. The power amplifier 205 is a class B power amplifier or a class C power amplifier, that is, the power amplifier 205 starts to work when the signal B is a large signal.

[0091] In a possible design, the load impedances of the power amplifier 202 and the power amplifier 205 when saturated are the same, for example, both are Ropt. The load impedance of the power amplifier can be understood as: the ratio of the output voltage of the power amplifier to the output current of the power amplifier.

[0092] Figure 3 The working principle of the power amplifier circuit of the Doherty structure shown is as follows:

[0093] When the power of the RF signal is low, the signal B is insufficient to trigger the power amplifier 205 to work, and the power amplifier 205 is cut off and presents an open circuit state. The load impedance of the power amplifier 205 is infinite (∞). After the impedance transformation unit 203 transforms the impedance 0.5Ropt of the junction point B, an output impedance of 2Ropt is formed at the output end of the power amplifier 202 (that is, the load impedance of the power amplifier 202 is 2Ropt).

[0094] The power amplifier 202 is a class AB power amplifier. When the power amplifier 202 starts working, the impedance transformation unit 203 transforms the load impedance of the power amplifier 205 to increase the load impedance of the power amplifier 202. The load voltage of the power amplifier 202 increases, so that the power amplifier 202 enters the saturation state in advance, that is, the power amplifier 202 is more likely to enter the saturation zone in advance as the input power increases, thereby improving the efficiency of the power amplifier 202 in signal amplification, and further improving the efficiency of the power amplifier circuit with the Doherty structure in power amplification.

[0095] The output voltage of the power amplifier 202 increases as the power of the input radio frequency signal increases, and the output power of the power amplifier 202 also increases as the power of the input radio frequency signal increases.

[0096] When the power of the radio frequency signal increases to power A, the power amplifier 205 is triggered to start working, and the load impedance of the power amplifier 205 starts to decrease.

[0097] As the power of the input RF signal continues to increase, the load impedance of the power amplifier 202 decreases from 2Ropt to Ropt, and the load impedance of the power amplifier 205 decreases from infinity (∞) to Ropt.

[0098] The power amplifier 202 remains in a pre-saturation state due to the high load voltage, the output voltage remains substantially constant, and the output current increases with the increase of the power of the input RF signal. Therefore, the output power of the power amplifier 202 increases with the increase of the power of the input RF signal.

[0099] The output voltage of the power amplifier 205 increases with the increase of the power of the input RF signal, so the output power of the power amplifier 202 increases with the increase of the power of the input RF signal. The overall power amplification efficiency of the power amplifier circuit 33 can still be maintained at a high level.

[0100] When the power of the RF signal increases to power B, when both the power amplifier 202 and the power amplifier 205 reach saturation, the load impedance of the power amplifier 202 and the load impedance of the power amplifier 205 are both Ropt, and the load impedance of the junction point A is 0.5Ropt. The power amplification efficiency of the Doherty structure power amplifier circuit reaches the highest.

[0101] It can be understood that the phases of signal A and signal B output by the power divider are the same, the phase shift of signal A in the impedance transformation unit 203 is 90 degrees, and when the phase shift of signal B in the LC phase shift unit 204 is 90 degrees, the phases of signal A and signal B at the combining point A are the same.

[0102] However, due to various reasons, when the phase shift of signal B in the LC phase shift unit 204 is 90 degrees, the phases of signal A and signal B at the junction A may be different. Therefore, it is necessary to debug the phase shift of signal B in the LC phase shift unit 204 so that the phases of signal A and signal B at the junction A are the same.

[0103] The various reasons may include: phase deviation caused by different bias states of power amplifier 202 and power amplifier 205, phase deviation caused by the length and material of each branch transmission line, etc., which are not specifically limited here.

[0104] For example, Figure 4 A schematic diagram of the phase shift of signal A in the power amplifier 202 and the phase shift of signal B in the power amplifier 205 provided in an embodiment of the present application.

[0105] like Figure 4 As shown, taking the RF signal as an N77 signal with a frequency range of 3.3 GHz to 4.2 GHz as an example, if the bias voltage of the power amplifier 202 is around 3.0 V (for example, 3.0 V, 3.1 V, 3.2 V or 3.3 V, etc.), and the bias voltage of the power amplifier 205 is around 1.0 V (for example, 1.0 V, 1.1 V, 1.2 V or 1.3 V, etc.), the phase shift of the signal A in the power amplifier 202 ranges from 74 degrees to 80 degrees; the phase shift of the signal B in the power amplifier 205 ranges from 64 degrees to 74 degrees.

[0106] In this way, there will be a certain phase deviation between the signal A and the signal B at the combining point A, resulting in a reduction in the output power and efficiency of the Doherty structure power amplifier circuit.

[0107] However, when adjusting the phase shift of the LC phase shift unit 204 to the signal B, the insertion loss of the LC phase shift unit 204 will also change, and then the power and phase of the signal B input to the power amplifier 205 will change, the amplitude and phase of the signal B output by the power amplifier 205 will change, and the phase and amplitude of the signal B at the junction A will change. Since the phase and amplitude of the signal B at the junction A change, the load impedance at the junction A changes. It is difficult to predict the load impedance at the junction A, and the design and debugging of the power amplifier circuit of the Doherty structure are difficult.

[0108] It is understandable that the size of the power divider is inversely proportional to the characteristic impedance of the power divider. When the size of the power divider is small, the characteristic impedance of the power divider is large, which makes it mismatched with the input impedance of the power amplifier 202 and the power amplifier 205, thereby reducing the performance of the power amplifier 202 and the power amplifier 205 (for example, efficiency, distortion, etc.).

[0109] When the size of the power divider is large, the characteristic impedance of the power divider is small, and it can achieve input impedance matching with the power amplifier 202 and the power amplifier 205. However, the size of the power divider is large, which is not conducive to the miniaturization of the device.

[0110] In view of this, the embodiments of the present application provide a power amplifier circuit, a communication module and a communication device. The phase adjustment of the signal transmitted in the peak branch is achieved through a coupler. Specifically, the isolation port of the coupler is connected to the power amplifier unit in the peak branch, and the reactance unit is set at the through port or the coupled port of the coupler to achieve the phase adjustment of the signal output by the isolation port.

[0111] It should be noted that in the process of adjusting the phase of the signal output from the isolation port through the reactance module, the insertion loss of the coupler changes slightly, so that the amplitude of the signal output from the isolation port changes slightly. In this way, the phase shift change and insertion loss change of the signal in the peak branch are decoupled, the influence of the phase modulation of the signal on the amplitude modulation of the signal is reduced, the difficulty of predicting the load impedance of the carrier branch is reduced, and the difficulty of designing the power amplifier circuit of the Doherty structure is reduced.

[0112] For example, Figure 5 This is a schematic diagram of the structure of a power amplifier circuit provided in an embodiment of the present application. Figure 5 As shown, the power amplifier circuit includes: a coupling unit 401 , a power amplifying unit 402 , a coupling unit 403 , a reactance unit 404 , a power amplifying unit 405 and a matching network 406 .

[0113] The coupling unit 401 includes: an input port 2a, a coupling port 2b, a through port 2c and an isolation port 2d. The coupling unit 403 includes: an input port 3a, a coupling port 3b, a through port 3c and an isolation port 3d.

[0114] The input port 2a of the coupling unit 401 is used to input the RF signal; the coupling port 2b of the coupling unit 401 is connected to the input end of the power amplification unit 402, the output end of the power amplification unit 402 is connected to the input port 3a of the coupling unit 403, and the coupling port 3b and the through port 3c of the coupling unit 403 are both open circuited.

[0115] The through port 2c of the coupling unit 401 is connected to one end of the reactance unit 404, and the other end of the reactance unit 404 is grounded;

[0116] The isolation port 2d of the coupling unit 401 is connected to the input end of the power amplifier unit 405, and the output end of the power amplifier unit 405, the isolation port 3d of the coupling unit 403 and one end of the matching network 406 are electrically connected to the junction point B. The other end of the matching network 406 is used to output the amplified RF signal.

[0117] In the embodiment of the present application, the carrier branch may include: the coupling port 2b of the coupling unit 401, the power amplifier unit 402 and the output 403; the peak branch may include: the isolation port 2d of the coupling unit 401 and the power amplifier unit 405. The power amplifier unit 402 may also be called a carrier power amplifier, and the power amplifier unit 405 may also be called a peak power amplifier.

[0118] The coupling unit 401 is used to divide the radio frequency signal into two paths, namely signal A and signal B. The power of signal A and signal B can be the same or different. The phases of signal A and signal B are different.

[0119] The phase of signal B is related to the reactance unit 404 .

[0120] The coupling unit 401 can adjust the phase of the signal B under the control of the reactance unit 404, so that the phase difference between the signal A and the signal B at the junction B is less than or equal to the threshold A. The threshold A can be 1 degree, 5 degrees or any value, which is not specifically limited here. In this way, the phase difference between the signal A and the signal B at the junction B can be within a certain range, reducing the situation where the efficiency of the power amplifier circuit is reduced due to the misalignment of the signal A and the signal B.

[0121] It should be noted that, based on the coupling effect of the electromagnetic field, the coupling line in the coupler can couple the signal transmitted by the transmission line in the coupler, and output the coupled signal from the coupling port; output the uncoupled signal from the through port, and output the reflected signal (for example, signal B) from the isolation port. The reflected signal may include: the signal reflected from the coupling port and the signal reflected from the through port.

[0122] It is understandable that, when a reactance unit is provided at the coupled port, the reactance unit can reflect part or all of the coupled signal to the isolated port. When a reactance unit is provided at the through port, the reactance unit can reflect part or all of the uncoupled signal to the isolated port.

[0123] Therefore, the phase of the reflected signal output at the isolated port is related to both the reactance at the coupled port and the reactance at the through port. Specifically, when the reactance at the coupled port changes, the phase of the reflected signal output at the isolated port changes; or, when the reactance at the through port changes, the phase of the reflected signal output at the isolated port changes.

[0124] Figure 5 In the illustrated embodiment, the phase change of the signal B output from the isolation port in the coupling unit 401 can be achieved by changing the reactance at the through port 2 c.

[0125] It is understandable that by changing the reactance at the coupling port 2b, the phase change of the signal B output from the isolation port in the coupling unit 401 can also be achieved. In some embodiments, the through port 2c is connected to the input end of the power amplification unit 402, and the coupling port 2b is connected to one end of the reactance unit 404. The embodiment of the present application does not specifically limit the connection method of the ports in the coupling unit 401.

[0126] In the embodiment of the present application, the power of the signal output by the through port and the coupled port of the coupling unit 401 may be the same or different. The coupling unit 401 may be a coupler or any other device with the same function, which is not specifically limited here.

[0127] Exemplarily, the coupling unit 401 may be a 3dB coupler. The power of the signal outputted by the through port and the coupled port of the 3dB coupler is the same.

[0128] The power amplification unit 402 is used to amplify the signal A. In the embodiment of the present application, the power amplification unit 402 may include one or more power amplifiers, and the specific number and connection method of the power amplifiers are not specifically limited herein.

[0129] In some embodiments, the power amplification unit 402 operates in a class AB mode, the transistors in the power amplification unit 402 are in an on state, and the power amplification unit 402 amplifies the signal A.

[0130] The coupling unit 403 is used to perform impedance transformation so that the load impedance of the power amplifying unit 402 changes. The coupling unit 403 is used to increase the load impedance of the power amplifying unit 402 when the power is backed off.

[0131] In some embodiments, the coupling unit 403 may convert 0.5Ropt at the combining point B into 2Ropt at the output end of the power amplifying unit 402 during power backoff.

[0132] When performing impedance transformation, the coupling unit 403 also performs phase shifting on the signal A. The phase shift angle is related to the frequency of the radio frequency signal.

[0133] The coupling unit 403 is a frequency element, which can also be understood as an element whose load impedance and phase shift angle vary with the frequency of the radio frequency signal.

[0134] In the embodiment of the present application, at the center frequency of the RF signal, the coupling unit 403 can produce a 90-degree phase shift on the signal A, and the characteristic impedance of the coupling unit 403 is equal to the load impedance of the power amplification unit 402 when saturated, thereby achieving impedance matching with a reflection coefficient of 0.

[0135] In the embodiment of the present application, the coupling unit 403 may be a coupler, or any other device having the same function, which is not specifically limited here.

[0136] The reactance unit 404 is used to adjust the phase shift of the coupling unit 401 on the signal B so that the phase of the signal B and the signal A at the junction A is less than or equal to the threshold A. The threshold A can be 1 degree, 3 degrees or any value, which is not specifically limited here.

[0137] The power amplification unit 405 is used to amplify the signal B.

[0138] In the embodiment of the present application, the power amplification unit 405 may include one or more power amplifiers, and the specific number and connection method of the power amplifiers are not specifically limited here.

[0139] In some embodiments, the power amplifier unit 405 operates in a class B mode or a class C mode.

[0140] When the power of signal B is relatively small, the power amplification unit 405 is not turned on; when the power of signal B is relatively large, the transistor in the power amplification unit 405 is turned on, and the power amplification unit 405 amplifies signal B.

[0141] In the embodiment of the present application, the load impedances of the power amplifier unit 402 and the power amplifier unit 405 when saturated are the same, for example, both are Ropt. The load impedance of the power amplifier can be understood as: the ratio of the output voltage of the power amplifier to the output current of the power amplifier.

[0142] The matching network 406 is used to perform impedance transformation on the impedance of the junction point B (eg, 10 ohms) to obtain the impedance RL (eg, 50 ohms), thereby achieving impedance matching.

[0143] Figure 5 The working principle of the power amplifier circuit of the Doherty structure shown in the figure to achieve power back-off is as follows:

[0144] When the power of the RF signal is low, the signal B is insufficient to trigger the power amplifier unit 405 to work, and the power amplifier unit 405 is cut off and presents an open circuit state. The load impedance of the power amplifier unit 405 is infinite (∞). After the coupling unit 403 transforms the impedance 0.5Ropt of the junction point C, an output impedance of 2Ropt is formed at the output end of the power amplifier unit 402 (that is, the load impedance of the power amplifier unit 402 is 2Ropt).

[0145] The power amplifier unit 402 is a class AB power amplifier. When the power amplifier unit 402 starts working, the coupling unit 403 performs impedance transformation on the load impedance of the power amplifier unit 405 to increase the load impedance of the power amplifier unit 402. The load voltage of the power amplifier unit 402 increases, so that the power amplifier unit 402 enters the saturation state in advance, that is, the power amplifier unit 402 is more likely to enter the saturation zone in advance as the input power increases, thereby improving the efficiency of the power amplifier unit 402 in signal amplification, and further improving the efficiency of the power amplifier circuit with the Doherty structure in power amplification.

[0146] The output voltage of the power amplifying unit 402 increases as the power of the input radio frequency signal increases, and the output power of the power amplifying unit 402 also increases as the power of the input radio frequency signal increases.

[0147] When the power of the radio frequency signal increases to power A, the power amplifying unit 405 is triggered to start working, and the load impedance of the power amplifying unit 405 starts to decrease.

[0148] As the power of the input RF signal continues to increase, the load impedance of the power amplifying unit 402 decreases from 2Ropt to Ropt, and the load impedance of the power amplifying unit 405 decreases from infinity (∞) to Ropt.

[0149] The power amplifier unit 402 remains in a pre-saturation state due to the high load voltage, the output voltage remains basically constant, and the output current increases with the increase of the power of the input RF signal. Therefore, the output power of the power amplifier unit 402 increases with the increase of the power of the input RF signal.

[0150] The output voltage of the power amplifier unit 405 increases with the increase of the power of the input RF signal, so the output power of the power amplifier unit 402 increases with the increase of the power of the input RF signal. The efficiency of the power amplifier circuit for power amplification as a whole can still be maintained at a high level.

[0151] When the power of the RF signal increases to power B, when the power amplifier unit 402 and the power amplifier unit 405 are both saturated, the load impedance of the power amplifier unit 402 and the load impedance of the power amplifier unit 405 are both Ropt, and the load impedance of the junction point A is 0.5Ropt, and the efficiency of power amplification of the Doherty structure power amplifier circuit reaches the highest.

[0152] Combine the following Figure 6 and Figure 7 right Figure 5 The phase changes and amplitude changes of each signal in the power amplifier circuit shown are explained.

[0153] It can be understood that signal A has phase shift in coupling unit 401, power amplifying unit 402 and coupling unit 403; signal B has phase shift in coupling unit 401 and power amplifying unit 405. If signal A and signal B have the same phase at junction B, the sum of the phase shifts of signal A in coupling unit 401, power amplifying unit 402 and coupling unit 403 is the same as the sum of the phase shifts of signal B in coupling unit 401 and power amplifying unit 405.

[0154] In some embodiments, the phase difference between the signal B output by the coupling unit 401 and the signal A is the same as the phase shift of the signal A in the coupling unit 403 .

[0155] In some other embodiments, the phase difference between the signal B and the signal A output by the coupling unit 401 is the same as the phase shift A. The phase shift A is the sum of the phase shift of the signal A in the coupling unit 403 and the difference A. The difference A is the difference between the phase shift of the signal A in the power amplification unit 402 and the phase shift of the signal B in the power amplification unit 405.

[0156] For example, taking the RF signal as an N77 signal with a frequency range of 3.3 GHz to 4.2 GHz, and the capacitance value of the capacitor C1 as 20 femtofarads (fF) and 80 fF, Figure 6 The phase difference between signal A and signal B provided in the embodiment of the present application when they are transmitted in the branch. Figure 6 As shown in a in FIG. 4 , the phase shift of the signal A in the coupling unit 403 is between 75 degrees and 110 degrees. The phase shift increases with increasing frequency and is not affected by the reactance value of the reactance unit 404 .

[0157] When the capacitance C1 is 20 fF, the phase difference between the signal B output by the coupling unit 401 and the signal A is between 75 degrees and 110 degrees, and the phase shift increases with increasing frequency.

[0158] When the capacitance C1 is 80 fF, the phase difference between the signal B output by the coupling unit 401 and the signal A is between 80 degrees and 115 degrees, and the phase shift increases with increasing frequency.

[0159] In this way, the coupling unit 403 and the coupling unit 401 can achieve phase alignment of the signal A and the signal B at the junction B. In addition, by adjusting the capacitance value of the capacitor C1, the phase of the signal B can be adjusted, thereby achieving fine phase adjustment of the signal B.

[0160] It can be understood that the amplitude of signal A is affected by the insertion losses of coupling unit 401 , power amplifying unit 402 and coupling unit 403 ; the amplitude of signal A is affected by the insertion losses of coupling unit 401 and power amplifying unit 405 .

[0161] For example, taking the RF signal as an N77 signal with a frequency range of 3.3 GHz to 4.2 GHz, and the capacitance value of the capacitor C1 as 20 fF and 80 fF, Figure 7 This is a schematic diagram of the insertion loss of signal A and signal B transmission provided in the embodiment of the present application. Figure 7 As shown in a in FIG. 1 , the insertion loss of signal A in coupling unit 403 is between 0.003 dB and 0.009 dB, and the insertion loss is relatively small. Figure 7 As shown in b, when the capacitor C1 is 20fF, the insertion loss of the signal A in the coupling unit 401 is between 7.0dB and 7.6dB. When the capacitor C1 is 80fF, the insertion loss of the signal A in the coupling unit 401 is between 7.2dB and 7.6dB. When the capacitance value of the capacitor C1 changes, the insertion loss of the signal A in the coupling unit 401 does not change much.

[0162] like Figure 7 As shown in c, when the capacitor C1 has a capacitance value of A, the insertion loss of the signal B in the coupling unit 401 is between 4.6dB and 4.77dB. When the capacitor C1 has a capacitance value of B, the insertion loss of the signal B in the coupling unit 401 is between 4.62dB and 4.77dB. When the capacitance value of the capacitor C1 changes, the insertion loss of the signal B in the coupling unit 401 does not change much, and the amplitude change of the signal B is decoupled from the phase change of the signal B.

[0163] In summary, Figure 5 In the process of adjusting the phase of signal A, the insertion loss of each branch of the Doherty structure power amplifier circuit shown in the figure changes little, so that the amplitude of each signal changes little, and thus the change of the load impedance of the signal amplification branch is easy to predict, and the design difficulty of the Doherty structure power amplifier circuit is small.

[0164] In addition, by adjusting the reactance value of the reactance unit, the phase difference between the signal B and the signal A output from the coupling unit 401 can be adjusted by translation, so as to compensate for the phase difference between the carrier power amplifier and the peak power amplifier due to different bias states. At the same time, the insertion loss changes from the through port and the isolation port through the coupling unit 401 are small. This shows that when the coupling unit 401 is used to phase-adjust the carrier branch and the peak branch, it will not affect the input power of the two branches, and the amplitude and phase are mutually decoupled in the design.

[0165] also, Figure 5 In the power amplifier circuit of the Doherty structure shown, a coupler is used to divide the radio frequency signal into two signals without a power divider. The power amplifier circuit of the Doherty structure has a smaller size, which is conducive to the miniaturization of the device.

[0166] It should be noted that the size of the coupling unit is inversely proportional to the characteristic impedance of the coupling unit. In the case of the same characteristic impedance, since the coupling unit can be a multi-layer structure, the projection area of ​​the coupling unit on the circuit is smaller than that of the power divider, and thus the power divider circuit occupies a smaller area on the printed circuit board, which is conducive to the miniaturization of electronic equipment.

[0167] Above Figure 5 The coupling unit shown may be a type of impedance transformation unit, and may also be replaced by any other form of impedance transformation unit, which is not specifically limited here.

[0168] For example, Figure 8 This is a schematic diagram of the structure of another power amplifier circuit provided in an embodiment of the present application. Figure 8 As shown, the power amplifier includes: a coupling unit 701 , a power amplifying unit 702 , an impedance transformation unit 703 , a reactance unit 704 , a power amplifying unit 705 and a matching network 706 .

[0169] The coupling unit 701 includes: an input port 4a, a coupling port 4b, a through port 4c and an isolation port 4d.

[0170] The input port 4a of the coupling unit 701 is used to input a radio frequency signal; the coupling port 4b of the coupling unit 701 is connected to the input end of the power amplification unit 702 , and the output end of the power amplification unit 702 is connected to one end of the impedance transformation unit 703 .

[0171] The through port 2c of the coupling unit 701 is connected to one end of the reactance unit 704, and the other end of the reactance unit 704 is grounded;

[0172] The isolation port 2d of the coupling unit 701 is connected to the input end of the power amplifier unit 705, and the output end of the power amplifier unit 705, the other end of the impedance transformation unit 703 and one end of the matching network 706 are electrically connected to the junction point C. The other end of the matching network 706 is used to output the amplified RF signal.

[0173] In the embodiment of the present application, the carrier branch may include: the coupling port 2b of the coupling unit 701, the power amplifier unit 702 and the output 703; the peak branch may include: the isolation port 2d of the coupling unit 701 and the power amplifier unit 705. The power amplifier unit 702 may also be called a carrier power amplifier, and the power amplifier unit 705 may also be called a peak power amplifier.

[0174] The structures and functions of the coupling unit 701, the power amplifying unit 702, the reactance unit 704, the power amplifying unit 705, and the matching network 706 can refer to the above Figure 5 The description of the corresponding components in the circuit shown will not be repeated here.

[0175] The impedance transformation unit 703 is used to perform impedance transformation, so that the load impedance of the power amplification unit 702 changes. The impedance transformation unit 703 is used to increase the load impedance of the power amplification unit 702 when the power is backed off.

[0176] When performing impedance transformation, the impedance transformation unit 703 also performs phase shifting on the signal A. The phase shift angle is related to the frequency of the radio frequency signal.

[0177] The impedance transformation unit 703 is a frequency element, and can also be understood as an element whose load impedance and phase shift angle vary with the frequency of the radio frequency signal.

[0178] In some embodiments, the impedance transformation unit 703 can achieve a 90-degree phase shift on the radio frequency signal at the center frequency, and the phase shift angle will change linearly at other frequencies.

[0179] It should be understood that the 90-degree phase shift in the embodiment of the present application may have a certain deviation, for example, 89-degree phase shift, 85-degree phase shift, etc., which is not specifically limited here.

[0180] In the embodiment of the present application, the impedance transformation unit 703 may be a microstrip line (eg Fig. 9 (as shown in a in the figure).

[0181] The impedance transformation unit 703 may also be a phase shift unit of a series inductor π-type network structure. Fig. 9 As shown in b, the phase shift unit of the series inductor π-type network structure includes: a capacitor C11, a capacitor C12, and an inductor L11. The first end of the inductor L11 is electrically connected to the first end of the capacitor C11 and serves as the input end of the series inductor π-type network, the second end of the capacitor C11 is grounded, the second end of the inductor L11 is electrically connected to the first end of the capacitor C12 and serves as the output end of the series inductor π-type network, and the second end of the capacitor C12 is grounded.

[0182] The impedance transformation unit 703 can also be a phase shift unit with a series capacitor π-type network structure. Fig. 9 For example, Fig. 9 As shown in c, the phase shift unit of the series capacitor π-type network structure includes: capacitor C11, inductor L11, and inductor L12. The first end of the capacitor C11 is electrically connected to the first end of the inductor L11 and serves as the input end of the series capacitor π-type network, the second end of the inductor L11 is grounded, the second end of the capacitor C11 is electrically connected to the first end of the inductor L12 and serves as the output end of the series capacitor π-type network, and the second end of the inductor L12 is grounded.

[0183] The impedance transformation unit 703 may also be a phase shift unit of a T-type network structure with series inductance. Fig. 9As shown in d, the phase shift unit of the series inductor T-type network structure includes: a capacitor C11, an inductor L11, and an inductor L12. The first end of the inductor L11 serves as an input end of the series inductor T-type network, the second end of the inductor L11, the first end of the inductor L12, and the first end of the capacitor C11 are electrically connected, the second end of the capacitor C11 is grounded, and the second end of the inductor L12 serves as an output end of the series inductor T-type network.

[0184] The impedance transformation unit 703 may also be a phase shift unit of a T-type network structure with series capacitors. Fig. 9 As shown in FIG. 5 , the phase shift unit of the series capacitor T-type network structure includes: a capacitor C11, a capacitor C12, and an inductor L11. The first end of the capacitor C11 serves as the input end of the series capacitor T-type network, the second end of the capacitor C11, the first end of the capacitor C12, and the first end of the inductor L11 are electrically connected, the second end of the inductor L11 is grounded, and the second end of the capacitor C12 serves as the output end of the series capacitor T-type network.

[0185] The above structures are only examples, and the impedance transformation unit 703 may also be any type of structure with a phase adjustment function (phase shifting unit), which is not specifically limited here.

[0186] Fig. 9 These inductors all satisfy L=Ropt / (2πf), and these capacitors all satisfy C=1 / (2πfRopt), where f is the center frequency of the RF signal, and Ropt is the load impedance (load impedance) of the power amplifier unit 702.

[0187] Understandably, Figure 7 In the process of adjusting the phase of signal A, the insertion loss of each branch of the Doherty structure power amplifier circuit shown in the figure changes little, so that the amplitude of each signal changes little, and thus the change of the load impedance of the signal amplification branch is easy to predict, and the design difficulty of the Doherty structure power amplifier circuit is small.

[0188] In addition, by adjusting the reactance value of the reactance unit, the phase difference between the signal B and the signal A output from the coupling unit 701 can be adjusted by translation, so as to compensate for the phase difference between the carrier power amplifier and the peak power amplifier due to different bias states. At the same time, the insertion loss changes from the through port and the isolation port through the coupling unit 701 are small. This shows that when the coupling unit 701 is used to phase-adjust the carrier branch and the peak branch, it will not affect the input power of the two branches, and the amplitude and phase are mutually decoupled in the design.

[0189] For example, Fig.10 This is a schematic diagram of the structure of another power amplifier provided in an embodiment of the present application. Fig.10As shown, the power amplifier includes: a power divider 901, a power amplifying unit 902, an impedance transformation unit 903, a coupling unit 904, a reactance unit 905, a reactance unit 906, a power amplifying unit 907 and a matching network 908.

[0190] The power divider 901 includes: port 5a, port 5b and port 5c. The coupling unit 904 includes: input port 6a, coupling port 6b, through port 6c and isolation port 6d.

[0191] Port 5a is used to input RF signals, port 5b is connected to the input end of the power amplifier 202 , the output end of the power amplifier 203 is connected to one end of the impedance transformation unit 203 ; port 1c is connected to the input port 6a of the coupling unit 904 .

[0192] The through port 6c of the coupling unit 904 is connected to one end of the reactance unit 905, and the other end of the reactance unit 905 is grounded; the coupling port 6b of the coupling unit 904 is connected to one end of the reactance unit 906, and the other end of the reactance unit 906 is grounded.

[0193] The coupling unit 904 includes: an input port 6a, a coupling port 6b, a through port 6c and an isolation port 6d.

[0194] The input port 6a of the coupling unit 904 is used to input a radio frequency signal.

[0195] The through port 6c of the coupling unit 904 is connected to one end of the reactance unit 905, and the other end of the reactance unit 905 is grounded; the coupling port 6b of the coupling unit 904 is connected to one end of the reactance unit 906, and the other end of the reactance unit 906 is grounded.

[0196] The isolation port 6d of the coupling unit 904 is connected to the input end of the power amplifier unit 907, and the output end of the power amplifier unit 907, the other end of the impedance transformation unit 903 and one end of the matching network 908 are electrically connected to the junction point D. The other end of the matching network 908 is used to output the amplified RF signal.

[0197] In the embodiment of the present application, the carrier branch may include: a power amplifier unit 902 and an impedance transformation unit 903; the peak branch may include: a coupling unit 904, a reactance unit 905, a reactance unit 906 and a power amplifier unit 907. The power amplifier unit 902 may also be referred to as a carrier power amplifier, and the power amplifier unit 907 may also be referred to as a peak power amplifier.

[0198] The power divider 901 is used to divide the radio frequency signal into two paths, namely signal A and signal B. The power of signal A and signal B may be the same or different, which is not specifically limited here.

[0199] The structures and functions of the power amplification unit 902, the impedance transformation unit 903, the power amplification unit 907 and the matching network 908 can refer to the above Figure 5 or Figure 8 The description of the corresponding components in the circuit shown will not be repeated here.

[0200] The coupling unit 904 is used to adjust the phase of the signal B. The phase shift of the signal B in the coupling unit 904 is related to the reactance of the reactance unit 905 and the reactance of the reactance unit 906. Specifically, when the reactance of the reactance unit 905 or the reactance of the reactance unit 906 changes, the phase shift of the signal B in the coupling unit 904 also changes.

[0201] In the embodiment of the present application, by changing the reactance at the through port 6 c and / or the reactance at the coupling port 6 b , the phase of the signal A output from the isolation port in the coupling unit 904 can be changed.

[0202] In the embodiment of the present application, the coupling unit 904 may be a 3dB coupler or may not be a 3dB coupler, which is not specifically limited here. A 3dB coupler can be understood as the power of the signal output by the through port and the coupled port being the same.

[0203] The reactance unit 905 is used to adjust the reactance of the through port 6 c so that the phase shift of the signal B transmitted through the coupling unit 904 is changed, and thus the phase of the signal B is changed.

[0204] The reactance unit 905 may include one or more reactance elements, such as capacitors, inductors, or magnetic beads, etc. No specific limitation is given here. In some embodiments, the reactance unit 905 includes: a capacitor. The capacitor is easy to disassemble and replace, which is convenient for debugging the power amplifier circuit.

[0205] The reactance unit 906 is used to adjust the reactance of the coupling port 6b, so that the phase shift of the signal B transmitted through the coupling unit 904 is changed, and then the phase of the signal B is changed. The reactance unit 906 may include one or more reactance elements, such as capacitors, inductors or magnetic beads, etc., which are not specifically limited here.

[0206] In some embodiments, the reactance of the reactance unit 906 and the reactance of the reactance unit 905 are less than or equal to the threshold value A. The threshold value A can be 0.1, 0.5 or any value, which is not specifically limited here. In this way, the difference between the phase of the signal reflected from the coupling port to the isolation port and the phase of the signal reflected from the through port to the isolation port can be reduced, and the insertion loss of the signal B in the coupling unit 904 can be reduced.

[0207] Exemplarily, the reactance unit 906 includes: a capacitor C4, and the difference between the capacitance value of the capacitor C4 and the capacitance value of the capacitor C3 is less than the threshold value A. The threshold value A may be 0.1fF, 0.fFf or any value, which is not specifically limited here.

[0208] In some embodiments, the coupling unit 904 is a 3dB coupler, so that the insertion loss of the coupling unit 904 can be reduced.

[0209] In this way, the capacitance value of capacitor C4 is close to or even the same as the capacitance value of capacitor C3 , so that the reactance of reactance unit 906 is close to or even the same as the reactance of reactance unit 905 , thereby reducing the insertion loss of signal B in coupling unit 904 .

[0210] It is understandable that both the reactance unit 905 and the reactance unit 906 can adjust the phase of the signal B, so the power amplifier circuit may include any one of the reactance unit 905 and the reactance unit 906, or may include the reactance unit 905 and the reactance unit 906. No specific limitation is made here.

[0211] Fig.10 The working principle of the power amplifier circuit of the Doherty structure shown in the figure to achieve power back-off is as follows:

[0212] When the power of the RF signal is low, the signal B is insufficient to trigger the power amplifier unit 907 to work, and the power amplifier unit 907 is cut off and presents an open circuit state. The load impedance of the power amplifier unit 907 is infinite (∞). After the impedance transformation unit 903 transforms the impedance 0.5Ropt of the junction point D, an output impedance of 2Ropt is formed at the output end of the power amplifier unit 902 (that is, the load impedance of the power amplifier unit 902 is 2Ropt).

[0213] The power amplifier unit 902 is a class AB power amplifier. When the power amplifier unit 902 starts working, the impedance transformation unit 903 transforms the load impedance of the power amplifier unit 907 to increase the load impedance of the power amplifier unit 902. The load voltage of the power amplifier unit 902 increases, so that the power amplifier unit 902 enters the saturation state in advance, that is, the power amplifier unit 902 is more likely to enter the saturation zone in advance as the input power increases, thereby improving the efficiency of the power amplifier unit 902 in signal amplification, and further improving the efficiency of the power amplifier circuit with the Doherty structure in power amplification.

[0214] The output voltage of the power amplifying unit 902 increases as the power of the input radio frequency signal increases, and the output power of the power amplifying unit 902 also increases as the power of the input radio frequency signal increases.

[0215] When the power of the radio frequency signal increases to power A, the power amplifying unit 907 is triggered to start working, and the load impedance of the power amplifying unit 907 starts to decrease.

[0216] As the power of the input RF signal continues to increase, the load impedance of the power amplifying unit 902 decreases from 2Ropt to Ropt, and the load impedance of the power amplifying unit 907 decreases from infinity (∞) to Ropt.

[0217] The power amplifier unit 902 remains in a pre-saturation state due to the high load voltage, the output voltage remains basically constant, and the output current increases with the increase of the power of the input RF signal. Therefore, the output power of the power amplifier unit 902 increases with the increase of the power of the input RF signal.

[0218] The output voltage of the power amplifier unit 907 increases with the increase of the power of the input RF signal, so the output power of the power amplifier unit 902 increases with the increase of the power of the input RF signal. The overall power amplification efficiency of the power amplifier circuit 33 can still be maintained at a high level.

[0219] When the power of the RF signal increases to power B, when the power amplifier unit 902 and the power amplifier unit 907 are both saturated, the load impedance of the power amplifier unit 902 and the load impedance of the power amplifier unit 907 are both Ropt, and the load impedance of the junction point A is 0.5Ropt, and the efficiency of power amplification of the Doherty structure power amplifier circuit reaches the highest.

[0220] Understandably, Fig.10 In the process of adjusting the phase of signal A, the insertion loss of each branch of the Doherty structure power amplifier circuit shown in the figure changes little, so that the amplitude of each signal changes little, and thus the change of the load impedance of the signal amplification branch is easy to predict, and the design difficulty of the Doherty structure power amplifier circuit is small.

[0221] In addition, by adjusting the reactance value of the reactance unit, the phase difference between the signal B and the signal A output from the coupling unit 904 can be adjusted by translation, so as to compensate for the phase difference between the carrier power amplifier and the peak power amplifier due to different bias states. At the same time, the insertion loss changes from the isolation port through the coupling unit 904 are small. This shows that when the coupling unit 904 is used to phase-adjust the carrier branch and the peak branch, it will not affect the input power of the branch, and the amplitude and phase are decoupled from each other in the design.

[0222] In the embodiments of the present application, the communication device can be understood as a device with a communication function. The device includes: a power amplifier circuit provided in the embodiments of the present application to realize a signal amplification function. The communication device can include the above-mentioned electronic equipment, base stations, radars, etc. No specific limitation is made here.

[0223] For example, Fig.11 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Fig.11 As shown, the electronic device includes: a processor 110, an external memory interface 120, an internal memory 121, a universal serial bus (USB) interface 130, a charging management module 140, a power management module 141, a battery 142, an antenna 1, an antenna 2, a mobile communication module 150, a wireless communication module 160, an audio module 170, a speaker 170A, a receiver 170B, a microphone 170C, an earphone interface 170D, a sensor module 180, a button 190, a motor 191, an indicator 192, a camera 193, a display screen 194, and a subscriber identification module (SIM) card interface 195, etc. Among them, the sensor module 180 may include a pressure sensor 180A, a gyroscope sensor 180B, an air pressure sensor 180C, a magnetic sensor 180D, an acceleration sensor 180E, a distance sensor 180F, a proximity light sensor 180G, a fingerprint sensor 180H, a temperature sensor 180J, a touch sensor 180K, an ambient light sensor 180L, a bone conduction sensor 180M, etc.

[0224] It is to be understood that the structure illustrated in the embodiments of the present application does not constitute a specific limitation on the electronic device. In other embodiments of the present application, the electronic device may include more or fewer components than shown in the figure, or combine certain components, or split certain components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0225] The wireless communication function of the electronic device can be implemented through the antenna 1, the antenna 2, the mobile communication module 250, the wireless communication module 260, the modulation and demodulation processor, etc.

[0226] Antenna 1 and antenna 2 are used to transmit and receive electromagnetic wave signals. Each antenna in the electronic device can be used to cover a single or multiple communication frequency bands. Different antennas can also be reused to improve the utilization of the antennas. For example, antenna 1 can be reused as a diversity antenna for a wireless local area network. In some other embodiments, the antenna can be used in combination with a tuning switch.

[0227] The mobile communication module 150 can provide solutions for wireless communications including 2G / 3G / 4G / 5G, etc., applied in electronic devices. The wireless communication module 160 can provide solutions for wireless communications including wireless local area networks (WLAN) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), infrared (IR), etc., applied in electronic devices. In some embodiments, the antenna 1 of the electronic device is coupled to the mobile communication module 150, and the antenna 2 is coupled to the wireless communication module 160, so that the electronic device can communicate with the network and other devices through wireless communication technology.

[0228] For example, Fig.12 As shown in a in FIG. 1 , the mobile communication module 150 may include: a baseband chip 31 , a radio frequency integrated circuit (RFIC) 32 and a power amplifier circuit 33 .

[0229] The baseband chip 31 is used to convert the data from the processor 110 into a baseband signal, including modulation and demodulation, digital filtering, equalization processing, etc. of the baseband signal. The RFIC 32 is used to convert the baseband signal from the baseband chip 31 into a radio frequency signal, which is transmitted through the power amplifier circuit 33 and the antenna 34. It should be noted that the baseband chip 31 and the RFIC 32 can also be integrated with the processor 110 in the SoC.

[0230] The power amplifier circuit 33 provided in the embodiment of the present application can improve the efficiency of power amplification during power fallback. Figures 5 to 10 shown.

[0231] For example, Fig.12 As shown in b, the wireless communication module 160 may include: a baseband chip 41, a radio frequency integrated circuit (RFIC) 42 and a power amplifier circuit 43.

[0232] The baseband chip 41 is used to convert the data from the processor 110 into a baseband signal, including modulation and demodulation, digital filtering, equalization processing, etc. of the baseband signal. The RFIC 42 is used to convert the baseband signal from the baseband chip 41 into a radio frequency signal, which is transmitted through the power amplifier circuit 43 and the antenna 44. It should be noted that the baseband chip 41 and the RFIC 42 can also be integrated with the processor 110 in the SoC.

[0233] The power amplifier circuit 43 provided in the embodiment of the present application can improve the efficiency of power amplification during power fallback. Figures 5 to 10 shown.

[0234] It should be noted that the module names involved in the embodiments of the present application can be defined as other names as long as the functions of each module can be achieved, and there is no specific restriction on the names of the modules.

[0235] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in the embodiments of the present application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0236] The embodiments of the present application are described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processing unit of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable device to generate a machine, so that the instructions executed by the processing unit of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0237] The above specific implementation methods further illustrate the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made on the basis of the technical solutions of the present invention should be included in the scope of protection of the present invention.

Claims

1. A power amplifier circuit, characterized in that: include: A first coupling unit, a first reactance unit, a first power amplification unit, a second power amplification unit and an impedance transformation unit; The first coupling unit includes: a first input port, a first isolation port, a first port, and a second port; The first input port is used to input a radio frequency signal, the first isolation port is connected to the input end of the first power amplification unit, the output end of the first power amplification unit is connected to one end of the impedance transformation unit; the output end of the first power amplification unit is used to output the amplified radio frequency signal; The first port is connected to one end of the first reactance unit, and the other end of the first reactance unit is grounded; The second port is connected to the input end of the second power amplification unit, and the output end of the second power amplification unit is connected to the other end of the impedance transformation unit; The first coupling unit is used to decompose the radio frequency signal into a first signal and a second signal at the first input port, the first isolation port is used to output the first signal, and the second port is used to output the second signal; The first coupling unit is further used to adjust the phase of the first signal; wherein the phase shift of the first signal in the first coupling unit is related to the reactance at the first port; The first reactance unit is used to adjust the reactance at the first port; The first power amplification unit is used to amplify the first signal; The second power amplifying unit is used to amplify the second signal; The impedance transformation unit is used to perform impedance transformation so that the load impedance of the second power amplification unit is negatively correlated with the input power of the radio frequency signal during power backoff under the control of the first signal.

2. The power amplifier circuit according to claim 1, characterized in that: The first reactance unit includes: a first capacitor.

3. The power amplifier circuit according to claim 1 or 2, characterized in that: The impedance transformation unit includes: a second coupling unit; the second coupling unit includes: a second input port, a second isolation port, a third port and a fourth port; The second input port is connected to the output end of the second power amplification unit, the second isolation port is connected to the output end of the first power amplification unit, and the third port and the fourth port are both open circuited.

4. A power amplifier circuit, characterized in that: include: A power divider, a first coupling unit, a first reactance unit, a first power amplification unit, a second power amplification unit and an impedance transformation unit; The power divider includes: a first port, a second port and a third port; the first coupling unit includes: a first input port, a first isolation port, a fourth port and a fifth port; The first port is used to input a radio frequency signal, and the second port is connected to the first input port; the first isolation port is connected to the input end of the first power amplification unit, and the output end of the first power amplification unit is connected to one end of the impedance transformation unit; the output end of the first power amplification unit is used to output the amplified radio frequency signal; The fourth port is connected to one end of the first reactance unit, and the other end of the first reactance unit is grounded; the fifth port is grounded; The third port is connected to the input end of the second power amplifying unit, and the output end of the second power amplifying unit is connected to the other end of the impedance transformation unit; The power divider is used to divide the radio frequency signal into a first signal and a second signal, wherein the second port is used to output the first signal, and the third port is used to output the second signal; The first coupling unit is used to adjust the phase of the first signal; wherein the phase shift of the first signal in the first coupling unit is related to the reactance at the first port; The first reactance unit is used to adjust the reactance at the fourth port; The first power amplification unit is used to amplify the first signal; The second power amplifying unit is used to amplify the second signal; The impedance transformation unit is used to perform impedance transformation so that the load impedance of the first power amplification unit is negatively correlated with the input power of the radio frequency signal during power backoff under the control of the first signal.

5. The power amplifier circuit according to claim 4, characterized in that: The first reactance unit includes a first capacitor.

6. The power amplifier circuit according to claim 4 or 5, characterized in that: The power amplifier circuit further includes: a second reactance unit, the fifth port is connected to one end of the second reactance unit, and the other end of the second reactance unit is grounded; The second reactance unit is used to adjust the impedance of the fifth port to reduce the insertion loss of the first coupling unit.

7. The power amplifier circuit according to claim 6, characterized in that: A difference between a reactance value of the first reactance unit and a reactance value of the second reactance unit is smaller than a preset threshold.

8. The power amplifier circuit according to claim 7, characterized in that: The second reactance unit includes: a second capacitor, and a difference between a capacitance value of the first capacitor and a capacitance value of the second capacitor is smaller than the preset threshold.

9. The power amplifier circuit according to claim 4 or 5, characterized in that: The impedance transformation unit includes: a second coupling unit; The second coupling unit includes: a second input port, a second isolation port, a sixth port and a seventh port; The second input port is connected to the output end of the second power amplification unit, the second isolation port is connected to the output end of the first power amplification unit, and the sixth port and the seventh port are both open circuited.

10. A communication module, characterized in that: include: A radio frequency integrated circuit and a power amplifier circuit as claimed in any one of claims 1 to 9; The radio frequency integrated circuit is used to output a radio frequency signal, and the power amplifier circuit is used to amplify the radio frequency signal.

11. A communication device, characterized in that: include: An antenna and a communication module as claimed in claim 10; The communication module is used to output the amplified radio frequency signal to the antenna; The antenna is used to transmit the amplified radio frequency signal.

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