Auxiliary circuit applied to power amplifier, compensation method, and related device

Abstract

An auxiliary circuit applied to a power amplifier, a compensation method, and a related device. The auxiliary circuit comprises a self-bias circuit, and the self-bias circuit comprises a constant voltage source (100), a first amplifier transistor (HBT1), a second amplifier transistor (HBT2), and a first capacitor (C1). The backoff efficiency can be improved without affecting the saturation power of a power amplifier.

Description

Auxiliary circuit, compensation method and related equipment applied to power amplifier

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on September 18, 2023, with application number 202311204275.2 and invention name “Auxiliary circuit, compensation method and related equipment applied to power amplifier”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the technical field of electronic circuits, and in particular to an auxiliary circuit, a compensation method and related equipment applied to a power amplifier. Background Art

[0003] With the advancement of wireless communication technology and the gradual integration of RF-related communication products into everyday life, current RF device design has significantly changed. As a key component in RF modules, power amplifiers (PAs) increase the power amplitude of a given input signal to drive the load level of output devices such as transmitters.

[0004] With the advent of 4G LTE and 5G communication standards, signal modulation methods have undergone significant changes compared to previous generations, shifting from constant envelope modulation to envelope shift modulation. This achieves a higher average-to-peak ratio of transmission power, maximizing system capacity and ensuring that power amplifiers maintain linearity within a certain power back-off range. However, because traditional power amplifiers have very low efficiency within the power back-off range, improving PA efficiency within this range becomes particularly important.

[0005] As a mature application method for balancing linearity and improving PAE (Power-added Efficiency), Doherty power amplifier technology features a simple structure and high cost-effectiveness. A Doherty power amplifier consists of two power amplifiers: a main amplifier (also known as a CA-Carrier Amplifier or CA) and a peak amplifier (PK). The main amplifier operates in Class AB, while the peak amplifier operates in Class B and Class C. The two amplifiers do not operate simultaneously; instead, the main amplifier operates continuously, while the peak amplifier only activates at a set peak value. A 1 / 4λ transmission line is also provided for impedance transformation, ensuring that the apparent impedance of the main amplifier and the active load impedance are reduced when the peak amplifier is operating. A 1 / 4λ transmission line is also required at the front end to balance the phase of the two paths. A typical Doherty power amplifier structure is shown in Figure 1.

[0006] Generally speaking, the operating state of a Doherty power amplifier can be divided into three stages according to the signal size: in the first stage, the auxiliary power amplifier is not working and the main power amplifier is working; in the second stage, the main power amplifier is saturated and the auxiliary power amplifier is turned on, and the Doherty power amplifier transitions from a maximum efficiency state to a maximum output state; in the third stage, when the auxiliary power amplifier is saturated, the output power of the Doherty power amplifier reaches its maximum, and high efficiency can be maintained under ideal conditions, as roughly shown in Figure 2.

[0007] The applicant has discovered through research that the 2Vbe bias architecture commonly used in Doherty power amplifiers PAs will compensate for excessive current when the Doherty power amplifier is at medium and low power, thereby reducing the fallback efficiency of the power amplifier circuit.

[0008] Summary of the Invention

[0009] In view of this, embodiments of the present invention provide an auxiliary circuit, a compensation method, and related devices applied to a power amplifier to improve the back-off efficiency of the power amplifier.

[0010] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0011] An auxiliary circuit for a power amplifier includes: a self-bias circuit connected to a main power amplifier of the power amplifier;

[0012] The self-bias circuit comprises:

[0013] A constant voltage source, a first amplifier tube, a second amplifier tube and a first capacitor;

[0014] The control end of the first amplifier tube is connected to the output end of the constant voltage source, the control end of the first amplifier tube is also used to obtain a reference current, and the input end of the first amplifier tube is connected to the first power supply;

[0015] The control end of the second amplifier tube is connected to the output end of the first amplifier tube, and the control end of the second amplifier tube is also connected to the second end of the first capacitor. The input end of the second amplifier tube is connected to the second power supply, and the output end of the second amplifier tube serves as the output end of the self-bias circuit.

[0016] The first end of the first capacitor serves as an input end of the self-bias circuit.

[0017] Optionally, in the auxiliary circuit applied to the power amplifier, the constant voltage source includes:

[0018] Low voltage drop linear regulator power supply and unidirectional tube;

[0019] The output end of the low voltage difference linear regulator power supply is connected to the input end of the unidirectional tube, and the output end of the unidirectional tube serves as the output end of the constant voltage source.

[0020] Optionally, in the auxiliary circuit applied to the power amplifier, the constant voltage source includes:

[0021] The low voltage drop linear regulator power supply is a fixed voltage source or an adjustable voltage source;

[0022] The one-way tube is a diode or a triode. When the one-way tube is a diode, the anode of the diode is the input end of the one-way tube, and the cathode of the diode is the output end of the one-way tube.

[0023] When the unidirectional tube is a triode, the base of the triode serves as the input end of the unidirectional tube, and the transmitter of the triode serves as the output end of the unidirectional tube.

[0024] Optionally, the auxiliary circuit applied to the power amplifier further includes a fixed power supply bias circuit, which is used to configure the bias current source of the auxiliary power amplifier in the power amplifier as the low voltage difference linear regulator power supply.

[0025] Optionally, the auxiliary circuit applied to the power amplifier further includes: the fixed power supply bias circuit includes:

[0026] a current mirror, a third amplifier tube, and a fourth amplifier tube;

[0027] The input end of the current mirror is connected to the output end of the low voltage drop linear regulator power supply;

[0028] The control end of the third amplifier tube is connected to the output end of the current mirror, and the input end of the third amplifier tube is connected to the first power supply;

[0029] The control end of the fourth amplifier tube is connected to the output end of the third amplifier tube, the input end of the fourth amplifier tube is connected to the second power supply, and the output end of the fourth amplifier tube is connected to the output end of the fixed power supply bias circuit.

[0030] A compensation method for a power amplifier, comprising:

[0031] Determining whether the power amplifier enters a saturation state;

[0032] When the power amplifier enters a saturation state, a preset constant current source is controlled to output a compensation current to a main power amplifier in the power amplifier.

[0033] Optionally, in the above power amplifier compensation method, after controlling a preset constant current source to output a compensation current to a main power amplifier in the power amplifier, the method further includes:

[0034] Obtaining a mirror current of the constant current source output current;

[0035] The mirror current is used as a compensation current of an auxiliary power amplifier in the power amplifier.

[0036] A power amplifier comprises any one of the above auxiliary circuits for use in a power amplifier.

[0037] Optionally, in the above power amplifier, the power amplifier further includes:

[0038] a 90° directional coupler, wherein the input end of the 90° directional coupler serves as the input end of the power amplifier, the first output end of the 90° directional coupler is used to be connected to the main power amplifier branch, and the second output end of the 90° directional coupler is used to be connected to the auxiliary power amplifier branch;

[0039] The main power amplifier branch comprises at least a first matching network and the self-bias circuit in sequence from the input end to the output end;

[0040] The auxiliary power amplifier branch comprises at least a second matching network, the fixed power supply bias circuit and a 90° phase shift circuit in sequence from the input end to the output end;

[0041] An isolation circuit, wherein the input end of the isolation circuit is connected to the output ends of the main power amplifier branch and the auxiliary power amplifier branch, and the output end of the isolation circuit serves as the output end of the power amplifier.

[0042] An electronic device, comprising a power amplifier as described in any one of the above items. Based on the above technical solution, the above solution provided by the embodiment of the present invention provides an auxiliary circuit, a power amplifier and an electronic device applied to a power amplifier, wherein the auxiliary circuit comprises a self-bias circuit, and the self-bias circuit is composed of a constant voltage source, a first amplifier tube, a second amplifier tube and a first capacitor. When it is detected that the power amplifier enters a saturation state, the first amplifier tube is turned on, and current compensation is provided to the main power amplifier in the power amplifier through the first amplifier tube. Through this design method, when the power amplifier enters a saturation state, it automatically turns on and provides current compensation to the main power amplifier, which can improve the fallback efficiency without affecting the saturation power of the power amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0044] FIG1 is a schematic diagram of the structure of a typical Doherty power amplifier;

[0045] FIG2 is a schematic diagram of the working state of a typical Doherty power amplifier;

[0046] Figure 3 is a schematic diagram of the structure of 2Vbe bias;

[0047] FIG4 is a schematic structural diagram of a self-bias circuit in an auxiliary circuit provided in an embodiment of the present application;

[0048] 5 and 6 are schematic diagrams showing simulation results of a power amplifier using the self-bias circuit shown in FIG5 ;

[0049] FIG7 is a schematic structural diagram of a self-bias circuit and a fixed power supply bias circuit in an auxiliary circuit disclosed in an embodiment of the present application;

[0050] 8, 9 and 10 are schematic diagrams showing simulation results of a power amplifier using the fixed power supply bias circuit;

[0051] FIG11 is a flow chart of a compensation method for a power amplifier disclosed in an embodiment of the present application;

[0052] FIG12 is a flow chart of a compensation method for a power amplifier disclosed in another embodiment of the present application;

[0053] FIG13 is a schematic diagram of a power amplifier circuit disclosed in an embodiment of the present application;

[0054] FIG14 is a schematic structural diagram of parts A and B in FIG13 ;

[0055] FIG15 is a schematic diagram of the structure of a 90° directional coupler;

[0056] FIG16 is a schematic diagram of a power amplifier circuit disclosed in another embodiment of the present application;

[0057] FIG17 is a schematic structural diagram of a power divider;

[0058] FIG18 is a schematic diagram of the structure of the 90° phase shift circuit disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0059] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0060] In existing technology, power amplifiers often use a 2Vbe bias (corresponding to the CA portion of the Doherty architecture). This circuit structure, shown in Figure 3, consists of two diodes, two capacitors, two amplifiers, and a voltage-drop resistor. The specific connection structure and inter-component relationships can be seen in Figure 3. This structure compensates for excessive current at low and medium power levels, thereby reducing the amplifier circuit's back-off efficiency. Specifically, because capacitor C1 in Figure 3 provides a low RF impedance at the base point of amplifier HBT1, similar to ground, some of the power that leaks from the input signal RFin is fully loaded onto the BE junction of amplifier HBT1. Due to the rectifying properties of the amplifier's PN junction, an equivalent DC voltage drop is generated across HBT1's Vbe. This voltage drop suppresses the decreasing Vbe of amplifier HBT2, allowing HBT2 to draw current from the bias circuit to stabilize its own nonlinearity. Therefore, the greater the input power, the greater I1. This bias circuit is called a self-bias circuit. Based on this, the present application has designed an auxiliary circuit that can be applied to a power amplifier. The auxiliary circuit may include a self-bias circuit. The self-bias circuit may be included in the main power amplifier of the power amplifier and is part of the main power amplifier. The self-bias circuit is used to provide current compensation to the main power amplifier in the power amplifier when it detects that the power amplifier has entered a saturated state. Through this design, when the power amplifier enters a saturated state (at this time, the power amplifier enters a medium-to-high power state), the circuit automatically turns on and provides current compensation to the main power amplifier, which can improve the fallback efficiency without affecting the saturation power of the power amplifier.

[0061] Specifically, referring to FIG4 , the self-bias circuit disclosed in the embodiment of the present application may include: a constant voltage source 100 , a first amplifier tube HBT1 , a second amplifier tube HBT2 , and a first capacitor C1 ;

[0062] The connection relationship between the above components is as follows:

[0063] The control end of the first amplifier tube HBT1 is connected to the output end of the constant voltage source 100, and the control end of the first amplifier tube HBT1 is also used to obtain the reference current I ref The input terminal of the first amplifier tube HBT1 is connected to the first power supply V batt connected;

[0064] The control end of the second amplifier tube HBT2 is connected to the output end of the first amplifier tube HBT1, the control end of the second amplifier tube HBT2 is also connected to the second end of the first capacitor C1, and the input end of the second amplifier tube HBT2 is connected to the second power supply V CCconnected, the output end of the second amplifier tube HBT2 serves as the output end of the self-bias circuit, and the output end of the self-bias circuit is located on the loop of the main power amplifier;

[0065] The first end of the first capacitor C1 serves as the input end of the self-bias circuit. The input end of the self-bias circuit is also located on the loop of the main power amplifier and is located above the output end of the self-bias circuit. The input end of the self-bias circuit is used to obtain the signal RF in , the RF in It is the electrical signal in the current loop of the main power amplifier in the power amplifier tube, or the input signal of the main power amplifier.

[0066] Furthermore, in order to ensure the safety of electronic components in the circuit and prevent the amplifier tube in the circuit from being broken down by high voltage, referring to FIG. 4 , in this solution, a first voltage-dropping resistor R1 may be further provided between the first switching tube HBT1 and the second amplifier tube HBT2. The output current of the first amplifier tube HBT1 is reduced in voltage by the first voltage-dropping resistor R1 to ensure the safety of subsequent electronic components.

[0067] In the embodiment provided in FIG4 , when the power amplifier PA enters a saturation state, the node voltage drops, and a constant voltage source 100 is used to provide bias current to the first and second amplifier tubes for current compensation, thereby improving the response speed of the amplifier tubes, thereby improving the efficiency of the power amplifier PA at the back-off power, and at the same time reducing the redundant current power consumption of the amplifier tubes; in order to verify the effect, the present application also simulates and compares the present solution with the existing solution, and the simulation results are shown in FIG5 and FIG6 . Curve L1 in FIG5 and FIG6 is the simulation curve of the power amplifier disclosed in the prior art, and curve L2 is the simulation curve of the power amplifier applying the technical solution disclosed in the present application. The horizontal axis in the simulation result diagrams in FIG5 and FIG6 is the output power of the power amplifier, the vertical axis in FIG5 is the output efficiency of the power amplifier, and the vertical axis in FIG6 is the output current of the power amplifier. Further analysis of the simulation results shown in FIG5 and FIG6 shows that the technical solution disclosed in the present application reduces the redundant current power consumption of the power amplifier and improves the back-off efficiency of the power amplifier.

[0068] Furthermore, in the bias circuit disclosed in the above embodiment, the constant voltage source 100 can be a constant voltage source of any structural type in the prior art, as long as it can output a constant target voltage. For example, referring to Figure 4, in this embodiment, the constant voltage source 100 in the bias circuit can include: a low dropout linear regulator power supply (Low Dropout Regulator, referred to as LDO) and a unidirectional tube, wherein the unidirectional tube is used to prevent current backflow, wherein the output end of the low dropout linear regulator power supply is connected to the input end of the unidirectional tube, and the output end of the unidirectional tube serves as the output end of the constant voltage source 100. Furthermore, the low-voltage-dropout linear regulator power supply can be a fixed voltage source or an adjustable voltage source. When it is an adjustable voltage source, the user can adjust the output voltage of the low-voltage-dropout linear regulator power supply according to design requirements. The unidirectional transistor can be a diode or a triode. Referring to FIG4 , when the unidirectional transistor is a diode D, the anode of the diode D serves as the input terminal of the unidirectional transistor, and the cathode of the diode D serves as the output terminal of the unidirectional transistor. When the unidirectional transistor is a triode, the base of the triode serves as the input terminal of the unidirectional transistor, and the emitter of the triode serves as the output terminal of the unidirectional transistor. When the power amplifier enters saturation, the node voltage of the power amplifier will drop. At this time, the base and emitter of the diode or triode in the constant voltage source 100 will enter a conductive state, and the low-voltage-dropout linear regulator power supply provides bias current for the main power amplifier for compensation.

[0069] After further research, the applicant found that the existing Doherty power amplifier architecture still has the problem that the auxiliary power amplifier PK tube is difficult to turn on at the same time as the main power amplifier CA tube reaches the critical saturation, thereby affecting the efficiency of the power amplifier.

[0070] In this solution, the bias current source of the auxiliary power amplifier in the power amplifier can be configured as the low-voltage dropout linear regulator power supply through a fixed power supply bias circuit, and the low-voltage dropout linear regulator power supply is used to provide bias current for the auxiliary power amplifier. In this way, after the main power amplifier CA tube is saturated, current will appear in the fixed power supply bias circuit (the fixed power supply bias circuit is used to provide compensation current to the auxiliary power amplifier), and the auxiliary power amplifier PK tube will also be turned on. Specifically, in this solution, a current mirror CM (Current Mirror) can be used to introduce the current in the bias branch of the constant voltage source 100 into the auxiliary power amplifier PK tube.

[0071] Specifically, referring to FIG7 , the auxiliary circuit may further include a fixed power bias circuit, and the fixed power bias circuit may include:

[0072] Current mirror CM, third amplifier tube HBT3 and fourth amplifier tube HBT4;

[0073] The input end of the current mirror CM is connected to the output end of the low-voltage difference linear regulator power supply, and is used to perform a mirror operation on the current output by the low-voltage difference linear regulator power supply to obtain a mirror current, and introduce the mirror current into the control end of the third amplifier tube HBT3;

[0074] The control end of the third amplifier tube HBT3 is connected to the output end of the current mirror CM, and the input end of the third amplifier tube HBT3 is connected to the first power supply V batt connected;

[0075] The control end of the fourth amplifier tube HBT4 is connected to the output end of the third amplifier tube HBT3, the input end of the fourth amplifier tube HBT4 is connected to the second power supply VCC, and the output end of the fourth amplifier tube HBT4 is connected to the output end of the fixed power supply bias circuit, and the output end of the fixed power supply bias circuit is located in the loop of the auxiliary power amplifier.

[0076] In the above solution, when the mirror circuit mirrors the output current CM of the constant voltage source 100 to the control terminal of the third amplifier tube HBT3, the third amplifier tube HBT3 is turned on, and the output current of the first power supply Vbatt is applied to the control terminal of the fourth amplifier tube HBT4. After the fourth amplifier tube HBT4 is turned on, the second power supply V CC The output current is output through the output end of the fourth amplifier tube HBT4.

[0077] Furthermore, to ensure the safety of electronic components in the fixed power bias circuit, referring to FIG7 , the design of the fixed power bias circuit may further include a second voltage-dropping resistor R2, which is disposed between the third amplifier tube HBT3 and the fourth amplifier tube HBT4 and is configured to reduce the voltage of the output current of the third amplifier tube HBT3.

[0078] Furthermore, in the fixed power supply bias circuit, to prevent interference signals in the current output by the current mirror from affecting the normal on / off operation of the third amplifier tube HBT3, referring to FIG7 , in this embodiment, a second capacitor C2 may be connected to the control terminal of the third amplifier tube HBT3. One end of the second capacitor C2 is connected to the control terminal of the third amplifier tube HBT3, and the other end of the second capacitor C2 is grounded. The second capacitor C2 is used to stabilize the input current to the control terminal of the third amplifier tube HBT3, so that the third amplifier tube HBT3 can operate reliably.

[0079] After adopting the fixed power supply bias circuit, the auxiliary power amplifier PK tube can be accurately turned on at the saturation moment of the main power amplifier CA tube. While ensuring the fallback efficiency, it is also compatible with APT applications and is suitable for low current environments. The simulation results are shown in Figures 8, 9, and 10. The curves shown in Figures 8, 9, and 10 are simulation curves of the technical solution disclosed in this application. The horizontal axis is the output power, the vertical axis in Figure 8 is the gain size, and the vertical axis in Figure 9 is the efficiency, which is used to reflect the performance of the power amplifier. The vertical axis in Figure 10 is the current, where L3 is the main power amplifier CA tube current and L4 is the auxiliary power amplifier PK tube current. It can be seen from Figures 8, 9, and 10 that the auxiliary power amplifier is turned on accurately and timely.

[0080] Corresponding to the above-mentioned auxiliary circuit, the present application further discloses a compensation method for a power amplifier. The compensation method for the power amplifier can be applied to a power amplifier provided with the auxiliary circuit disclosed in any of the above-mentioned embodiments. The compensation method for the power amplifier disclosed in the embodiment of the present application is implemented by the auxiliary circuit. Of course, other circuit structures can also be used to implement the compensation method for the power amplifier disclosed in the embodiment of the present application. As long as any circuit structure can implement the compensation method for the power amplifier disclosed in the embodiment of the present application, it is within the scope of the present method. Specifically, referring to FIG11, the compensation method for the power amplifier may include:

[0081] Step S101: Acquire operating data of the power amplifier;

[0082] Step S102: determining whether the power amplifier enters a saturation state based on the operating data of the power amplifier;

[0083] Step S103: When the power amplifier enters a saturation state, controlling a preset constant current source to output a compensation current to a main power amplifier in the power amplifier.

[0084] Taking the auxiliary circuit disclosed in the embodiment of the present application as an example, by setting a reasonable reference current I ref , the self-bias circuit in the auxiliary circuit can automatically implement steps S102 and S103.

[0085] Corresponding to the fixed power supply bias circuit, referring to FIG12 , the compensation method for the power amplifier may further include, after controlling a preset constant current source to output a compensation current to a main power amplifier in the power amplifier:

[0086] Step S104: obtaining a mirror current of the output current of the constant current source;

[0087] Step S105: using the mirror current as a compensation current of an auxiliary power amplifier in the power amplifier.

[0088] Taking the auxiliary circuit disclosed in the embodiment of the present application as an example, the steps S104 and S105 can be automatically implemented by the fixed power bias circuit in the auxiliary circuit. Corresponding to the above scheme, the present application also discloses a power amplifier, which may include any of the auxiliary circuits described above for use in a power amplifier. By applying the self-bias circuit and the fixed power bias circuit in the auxiliary circuit to the power amplifier, the power amplifier has a higher fallback efficiency and can accurately turn on the auxiliary power amplifier when the main power amplifier of the power amplifier reaches the critical saturation.

[0089] Specifically, referring to FIG13 , the power amplifier disclosed in the embodiment of the present application may include:

[0090] a 90° directional coupler CPL, wherein the input end of the 90° directional coupler serves as the input end of the power amplifier, the first output end of the 90° directional coupler is used to be connected to the main power amplifier branch, and the second output end of the 90° directional coupler is used to be connected to the auxiliary power amplifier branch;

[0091] The main power amplifier branch is the main power amplifier CA in this application. The main power amplifier branch includes at least a first matching network (matching 1) and the self-bias circuit in sequence from the input end to the output end. In this solution, the specific structure and type of the matching network can be set according to user needs.

[0092] The auxiliary power amplifier branch includes at least a second matching network (matching2), the fixed power bias circuit and a 90° phase shift circuit 200 in sequence from the input end to the output end;

[0093] The isolation circuit 300 has an input end connected to the output ends of the main power amplifier branch and the auxiliary power amplifier branch, and an output end of the isolation circuit serves as the output end of the power amplifier.

[0094] Referring to FIG. 14 and FIG. 13 , in FIG. 13 , A represents the constant voltage source 100, the unidirectional transistor, the first amplifier transistor HBT1, and the first voltage drop resistor R1 in the self-bias circuit. The first capacitor C1 and the second amplifier transistor HBT2 in the self-bias circuit are directly connected in series with the main power amplifier branch. B represents the mirror circuit, the third amplifier transistor HBT3, and the second voltage drop resistor R2 in the fixed power bias circuit. The second resistor and the fourth amplifier transistor HBT4 in the fixed power bias circuit are directly connected in series with the auxiliary power amplifier branch.

[0095] The 90° directional coupler CPL may be a coupler in the prior art, and its structural principle can be seen in FIG15 .

[0096] In addition to using a 90° directional coupler CPL for current diversion, the power amplifier shown in FIG13 can also use a power splitter PS (power splitter) to replace the 90° directional coupler CPL, as shown in FIG16 and FIG17. A power splitter is a device that divides the energy of an input signal into two or more equal or unequal outputs. A certain degree of isolation can be ensured between the output ports of the power splitter. In this case, the input end of the power splitter PS serves as the input end of the power amplifier, the first output end of the 90° directional coupler is used to connect to the main power amplifier branch, and the second output end of the power splitter PS is used to connect to the auxiliary power amplifier branch. After replacing the 90° directional coupler CPL with the power splitter PS, the isolation between the two ports (the input end corresponding to the main power amplifier branch and the input end corresponding to the auxiliary power amplifier branch) is improved, thereby avoiding mutual influence between the two signals and preventing abnormal oscillations during PA operation.

[0097] In addition, the specific structure of the 90° phase shift circuit can be designed according to user needs. It can be composed of at least one passive device connected in series and at least one passive device connected in parallel. The passive device can be a capacitor or an inductor. In addition to the above passive devices, other auxiliary components can also be included to ensure the reliability of the circuit. In this regard, the present application also discloses a specific design form of a 90° phase shift circuit. Of course, this design form is only a preferred implementation form. The present application can also further optimize this structure. These optimization methods are also within the scope of protection of the present application. Referring to Figure 18, the 90° phase shift circuit disclosed in the embodiment of the present application can specifically include:

[0098] A first inductor L11, a second inductor L12, a third capacitor C3 and a fourth capacitor C4;

[0099] The first end of the first inductor L11 serves as the input end of the 90° phase shift circuit, and the second end of the first inductor L11 is connected to the first end of the second inductor L12;

[0100] The second end of the second inductor L12 serves as the output end of the 90° phase shift circuit;

[0101] A first end of the third capacitor C3 is connected to the first end of the second inductor L12, and a second end of the third capacitor C3 is grounded;

[0102] A first end of the fourth capacitor C4 is connected to the second end of the second inductor L12 , and a second end of the fourth capacitor C4 is grounded.

[0103] Through the first inductor L11, the second inductor L12, the third capacitor C3 and the fourth capacitor C4C4, a phase shift operation of the input signal can be achieved. By configuring the specific parameters of the first inductor L11, the second inductor L12, the third capacitor C3 and the fourth capacitor C4, a 90° phase shift of the input signal can be achieved.

[0104] The power amplifier disclosed in the above embodiments of the present application may specifically be a Doherty power amplifier.

[0105] Corresponding to the above power amplifier, the present application also discloses an electronic device, which may include any of the above power amplifiers. Specifically, the electronic device may be a terminal device such as a mobile phone, a computer, a PC, or a tablet.

[0106] For the convenience of description, the above system is described as being divided into various modules according to their functions. Of course, when implementing the present invention, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0107] Each embodiment in this specification is described in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple. For relevant parts, refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without expending creative work.

[0108] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0109] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0110] It should also be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0111] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An auxiliary circuit for a power amplifier, characterized in that: include: a self-bias circuit connected to a main power amplifier of the power amplifier; The self-bias circuit comprises: A constant voltage source, a first amplifier tube, a second amplifier tube and a first capacitor; The control end of the first amplifier tube is connected to the output end of the constant voltage source, the control end of the first amplifier tube is also used to obtain a reference current, and the input end of the first amplifier tube is connected to the first power supply; The control end of the second amplifier tube is connected to the output end of the first amplifier tube, the control end of the second amplifier tube is also connected to the second end of the first capacitor, the input end of the second amplifier tube is connected to the second power supply, and the output end of the second amplifier tube serves as the output end of the self-bias circuit; The first end of the first capacitor serves as an input end of the self-bias circuit.

2. The auxiliary circuit for a power amplifier according to claim 1, characterized in that: The constant pressure source comprises: Low dropout linear regulator power supply and unidirectional tube; The output end of the low voltage difference linear regulator power supply is connected to the input end of the one-way tube, and the output end of the one-way tube serves as the output end of the constant voltage source.

3. The auxiliary circuit for a power amplifier according to claim 2, characterized in that: The constant pressure source comprises: The low voltage drop linear regulator power supply is a fixed voltage source or an adjustable voltage source; The one-way tube is a diode or a triode. When the one-way tube is a diode, the anode of the diode is the input end of the one-way tube, and the cathode of the diode is the output end of the one-way tube. When the unidirectional tube is a triode, the base of the triode serves as the input end of the unidirectional tube, and the transmitter of the triode serves as the output end of the unidirectional tube.

4. The auxiliary circuit for a power amplifier according to claim 1, characterized in that: It also includes a fixed power supply bias circuit, which is used to configure the bias current source of the auxiliary power amplifier in the power amplifier as the low voltage difference linear regulator power supply.

5. The auxiliary circuit for a power amplifier according to claim 4, characterized in that: Also includes: The fixed power bias circuit comprises: a current mirror, a third amplifier tube and a fourth amplifier tube; The input end of the current mirror is connected to the output end of the low voltage drop linear regulator power supply; The control end of the third amplifier tube is connected to the output end of the current mirror, and the input end of the third amplifier tube is connected to the first power supply; The control end of the fourth amplifier tube is connected to the output end of the third amplifier tube, the input end of the fourth amplifier tube is connected to the second power supply, and the output end of the fourth amplifier tube is connected to the output end of the fixed power supply bias circuit.

6. A power amplifier compensation method, characterized in that: include: Determining whether the power amplifier enters a saturation state; When the power amplifier enters a saturation state, a preset constant current source is controlled to output a compensation current to a main power amplifier in the power amplifier.

7. The power amplifier compensation method according to claim 6, characterized in that: After controlling a preset constant current source to output a compensation current to a main power amplifier in the power amplifier, the method further includes: Obtaining a mirror current of the output current of the constant current source; The mirror current is used as a compensation current of an auxiliary power amplifier in the power amplifier.

8. A power amplifier, characterized in that: The auxiliary circuit applied to a power amplifier comprises the auxiliary circuit described in any one of claims 1 to 6.

9. The power amplifier according to claim 7, characterized in that: When the auxiliary circuit is the auxiliary circuit according to claim 6, the power amplifier further comprises: A 90° directional coupler, wherein the input end of the 90° directional coupler is used as the input end of the power amplifier, the first output end of the 90° directional coupler is used to be connected to the main power amplifier branch, and the second output end of the 90° directional coupler is used to be connected to the auxiliary power amplifier branch; The main power amplifier branch at least includes a first matching network and the self-bias circuit in sequence from the input end to the output end; The auxiliary power amplifier branch includes at least a second matching network, the fixed power supply bias circuit and a 90° phase shift circuit in sequence from the input end to the output end; An isolation circuit, wherein the input end of the isolation circuit is connected to the output ends of the main power amplifier branch and the auxiliary power amplifier branch, and the output end of the isolation circuit serves as the output end of the power amplifier.

10. An electronic device, characterized in that: A power amplifier comprising any one of claims 8 to 9.

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