Amplifier circuits and electronic devices

Abstract

The present application discloses a power amplifier circuit and an electronic device, which relates to the field of radio frequency and is used to improve the bandwidth of radio frequency signals applicable to power back-off. The power amplifier circuit includes: a phase shift coupling module, a first power amplifier, a second power amplifier, an impedance transformation module, a matching network, and an impedance compensation module; the phase shift coupling module outputs a first radio frequency signal to the first power amplifier and outputs a second radio frequency signal to the second power amplifier; the output end of the first power amplifier is electrically connected to the first end of the impedance transformation module, and the second end of the impedance transformation module, the output end of the second power amplifier, the first end of the matching network, and the first end of the impedance compensation module are electrically connected to a junction; the second end of the impedance compensation module is grounded; the impedance transformation module increases the equivalent resistance of the first power amplifier when the power is backed off; the phase shift coupling module adjusts the phase difference between the first radio frequency signal and the second radio frequency signal; the impedance compensation module reduces the equivalent resistance of the junction when the power is backed off.

Description

Technical Field

[0001] The present application relates to the field of radio frequency, and in particular to a power amplifier circuit and an electronic device. Background Art

[0002] Power amplifiers are used in the power amplifier circuits of electronic devices to amplify the power of radio frequency signals. In the linear region, the output power of the power amplifier increases linearly with the increase of input power. When the input power of the power amplifier increases further, the power amplifier enters the nonlinear region, and the output power of the power amplifier no longer increases with the increase of input power. The output power of the power amplifier reaches saturation, and the efficiency of the power amplifier is the highest at this time. The power amplifier is usually designed so that the saturated output power corresponds to the peak power of the input radio frequency signal, that is, when the radio frequency signal input to the power amplifier reaches the peak power, the output power also reaches saturation, so that the power amplifier works in the linear region as much as possible. However, this means that the power amplifier cannot reach saturation most of the time, so the efficiency is not the highest most of the time.

[0003] In the prior art, the efficiency of power amplification is improved by using the power back-off technology of two power amplifiers. Specifically, the first power amplifier is load modulated by the frequency element so that the power amplifier is more likely to enter the saturation zone in advance as the input power increases, thereby improving the efficiency of the power amplifier in power amplification of small signals (i.e., the power of the RF signal is relatively small). The second power amplifier is used to power amplify large signals (i.e., the power of the RF signal is relatively large), thereby improving the efficiency of power amplification as a whole. However, since the impedance of the frequency element changes with the frequency of the RF signal, the degree of advance of the first power amplifier entering the saturation zone at frequencies other than the center frequency is reduced, and the efficiency is reduced, so the bandwidth of the RF signal applicable to the above power back-off is limited. Summary of the invention

[0004] Embodiments of the present application provide a power amplifier circuit and an electronic device for increasing the bandwidth of a radio frequency signal applicable to power back-off.

[0005] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0006] In a first aspect, a power amplifier circuit is provided, comprising: a phase shift coupling module, a first power amplifier, a second power amplifier, an impedance transformation module, a matching network, and an impedance compensation module; the impedance transformation module and the impedance compensation module are frequency elements, the input end of the phase shift coupling module is used to input a radio frequency signal, the first output end of the phase shift coupling module is electrically connected to the input end of the first power amplifier, and the first output end of the phase shift coupling module is used to output a first radio frequency signal coupled to the radio frequency signal; the second output end of the phase shift coupling module is electrically connected to the input end of the second power amplifier, and the second output end of the phase shift coupling module is used to output a second radio frequency signal coupled to the radio frequency signal; the output end of the first power amplifier is electrically connected to the first end of the impedance transformation module, and the second end of the impedance transformation module, the output end of the second power amplifier, the first end of the matching network, and the first end of the impedance compensation module are electrically connected to a junction; the second end of the matching network is used to output the radio frequency signal after power amplification; the second end of the impedance compensation module is grounded; the impedance transformation module is used to increase the equivalent resistance of the first power amplifier when the power is backed off; the phase shift coupling module is used to adjust the phase difference between the output first radio frequency signal and the second radio frequency signal; the impedance compensation module is used to reduce the equivalent resistance of the junction when the power is backed off.

[0007] The power amplifier circuit provided in the embodiment of the present application, the first power amplifier is used to power amplify a small signal, and the second power amplifier is used to power amplify a large signal, so that the power amplifier circuit can achieve a high level of overall power amplification efficiency through power back-off. The phase shift coupling module adjusts the phase difference between the output first RF signal and the second RF signal to reduce the phase difference between the first RF signal and the second RF signal at the junction point, and tries to make the first RF signal and the second RF signal merge in phase at the junction point to reduce power loss. The impedance compensation module is connected in parallel with the branch where the two power amplifiers are located. The impedance compensation module is a frequency element. At the center frequency, the impedance compensation module can achieve a 90-degree phase shift. The impedance compensation module is equivalent to an open circuit and does not affect the equivalent resistance of the junction point. At frequencies other than the center frequency, the impedance compensation module can achieve phase shifts at other angles, and the equivalent resistance of the impedance compensation module is reduced. Since the impedance compensation module is connected in parallel with the branch where the two power amplifiers are located, the equivalent resistance of the junction point will be reduced when the power is backed off. Due to the impedance transformation effect of the impedance compensation module, the equivalent resistance of the junction point is reduced, which will increase the equivalent resistance of the first power amplifier at frequencies other than the center frequency, thereby improving the efficiency of the first power amplifier. Therefore, the bandwidth of the RF signal applicable to the power amplifier circuit is larger.

[0008] In one possible implementation, the phase difference between the first RF signal and the second RF signal output by the phase shift coupling module is a fixed value, such as 90 degrees or -90 degrees. When the power is backed off, the phase shift angle of the first RF signal by the impedance transformation module changes with the frequency, and the phase shift angle of the impedance transformation module is superimposed on the above-mentioned phase difference, so that at the center frequency, the phase difference between the first RF signal and the second RF signal at the combining point is zero, and the output power of the combining point will not be reduced. At frequencies other than the center frequency, there is a certain phase difference between the first RF signal and the second RF signal at the combining point, which will reduce the output power of the combining point, thereby reducing the overdrive phenomenon of the first power amplifier and the second power amplifier.

[0009] In a possible implementation, the phase shift coupling module includes a coupler, the input end of the coupler is the input end of the phase shift coupling module, the through output end of the coupler is the second output end of the phase shift coupling module, and the coupled output end of the coupler is the first output end of the phase shift coupling module. The impedance transformation module is a first quarter-wavelength line, and the first quarter-wavelength line is used to achieve a -90 degree phase shift of the RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies. The phase shift coupling module uses a coupler, which has a higher degree of integration.

[0010] In a possible implementation, the phase shift coupling module includes a coupler, the input end of the coupler is the input end of the phase shift coupling module, the through output end of the coupler is the first output end of the phase shift coupling module, and the coupled output end of the coupler is the second output end of the phase shift coupling module. The impedance transformation module is a second quarter wavelength line, and the second quarter wavelength line is used to achieve a 90-degree phase shift of the RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies. The phase shift coupling module uses a coupler, which has a higher degree of integration.

[0011] In a possible implementation, the phase-shift coupling module includes a power divider, a first phase-shift network, and a second phase-shift network. The input end of the power divider is the input end of the phase-shift coupling module; the first output end of the power divider is electrically connected to the first end of the first phase-shift network, the second end of the first phase-shift network is the first output end of the phase-shift coupling module, the second output end of the power divider is electrically connected to the first end of the second phase-shift network, and the second end of the second phase-shift network is the second output end of the phase-shift coupling module. The phase-shift coupling module is composed of multiple parts, and the layout can be adjusted more flexibly.

[0012] In one possible implementation, the first phase shift network is a 0-degree phase shift network, which is used to achieve a 0-degree phase shift for the RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies; the second phase shift network and the impedance transformation module use a first quarter-wavelength line, and the first quarter-wavelength line is used to achieve a -90-degree phase shift for the RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies.

[0013] The first phase shift network adopts a 0-degree phase shift network to achieve a 0-degree phase shift for the first RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies. The second phase shift network adopts the first quarter-wavelength line to achieve a -90-degree phase shift for the second RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies. At each frequency, the phase difference between the first RF signal input by the first power amplifier and the second RF signal input by the second power amplifier is always 90 degrees. In addition, the second phase shift network and the impedance transformation module have the same structure and the same phase shift angle at each frequency, so that the phase difference between the first RF signal and the second RF signal at the junction C is equal to the phase shift angle of the first phase shift network, which will reduce the output power of the junction, thereby reducing the overdrive phenomenon.

[0014] In one possible implementation, the first phase shift network is a second quarter-wavelength line, which is used to achieve a 90-degree phase shift for the RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies; the second phase shift network is a 0-degree phase shift network, which is used to achieve a 0-degree phase shift for the RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies; the impedance transformation module is a first quarter-wavelength line, which is used to achieve a -90-degree phase shift for the RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies.

[0015] The first phase shift network adopts the second quarter-wavelength line to achieve a 90-degree phase shift for the first RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies. The second phase shift network adopts a 0-degree phase shift network to achieve a 0-degree phase shift for the second RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies. At each frequency, the phase difference between the first RF signal input by the first power amplifier and the second RF signal input by the second power amplifier is always 90 degrees. In addition, the phase shift angles of the first phase shift network and the first impedance transformation module are opposite, so that the phase difference between the first RF signal and the second RF signal at the junction is equal to the phase shift angle of the second phase shift network, which will reduce the output power of the junction, thereby reducing the overdrive phenomenon.

[0016] In one possible implementation, the first phase shift network is a 0-degree phase shift network, which is used to achieve a 0-degree phase shift for the RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies; the second phase shift network and the impedance transformation module are a second quarter-wavelength line, and the second quarter-wavelength line is used to achieve a 90-degree phase shift for the RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies.

[0017] The first phase shift network adopts a 0-degree phase shift network to achieve a 0-degree phase shift for the second RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies. The second phase shift network adopts a second quarter-wavelength line to achieve a 90-degree phase shift for the first RF signal (shown by the solid line) at the center frequency, and the phase shift angle changes linearly at other frequencies. At each frequency, the phase difference between the first RF signal input by the first power amplifier and the second RF signal input by the second power amplifier is always 90 degrees. In addition, the second phase shift network and the first impedance transformation module have the same structure and the same phase shift angle at each frequency, so that the phase difference between the first RF signal and the second RF signal at the junction is equal to the phase shift angle of the first phase shift network, which will reduce the output power of the junction, thereby reducing the overdrive phenomenon.

[0018] In a possible implementation manner, the impedance compensation module is a quarter-wavelength line.

[0019] At the center frequency, the impedance compensation module can achieve a 90-degree phase shift, and the equivalent resistance of the impedance compensation module is infinite, which is equivalent to an open circuit and does not affect the equivalent resistance of the junction. At frequencies other than the center frequency, the impedance compensation module can achieve phase shifts at other angles, and the equivalent resistance of the impedance compensation module is not ideally infinite. Since the impedance compensation module is connected in parallel with the branches where the two power amplifiers are located, the equivalent resistance of the junction point C will be reduced when the power is backed off. Due to the impedance transformation effect of the impedance compensation module, the equivalent resistance of the junction point is reduced, which will increase the equivalent resistance of the first power amplifier at frequencies other than the center frequency, thereby improving the efficiency of the first power amplifier. Therefore, the bandwidth of the RF signal applicable to this power amplifier circuit is larger.

[0020] In a possible implementation, the first power amplifier is a class AB power amplifier, and the second power amplifier is a class C power amplifier or a class D power amplifier. Because the first power amplifier 331 is a class AB power amplifier, when the input RF signal is a small signal, the first power amplifier starts to work. Because the second power amplifier is a class B power amplifier or a class C power amplifier, when the input RF signal is a small signal, the power of the input RF signal is small and is not enough to trigger the second power amplifier to work, and the second power amplifier is cut off and presents an open circuit state. When the power of the input RF signal increases until it reaches the power back-off point, that is, the RF signal changes from a small signal to a large signal, triggering the second power amplifier to start working. That is, the first power amplifier is used to power amplify small signals, and the second power amplifier is used to power amplify large signals, so that the power amplifier circuit achieves a high level of overall power amplification efficiency through power back-off.

[0021] In a second aspect, an electronic device is provided, comprising an antenna and a power amplifier circuit as described in the first aspect and any embodiment thereof, wherein the power amplifier circuit is used to output a power-amplified radio frequency signal to the antenna.

[0022] The technical effects of the second aspect refer to the technical effects of the first aspect and any of its embodiments, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application;

[0024] Figure 2 A schematic diagram of the structure of a mobile communication module provided in an embodiment of the present application;

[0025] Figure 3 A schematic diagram of the structure of a power amplifier circuit provided in an embodiment of the present application;

[0026] Figure 4 A schematic diagram of the structures of several implementation methods of the quarter-wavelength line provided in the embodiments of the present application;

[0027] Figure 5 A schematic diagram of the structure of another power amplifier circuit provided in an embodiment of the present application;

[0028] Figure 6 A schematic diagram of the change in equivalent resistance of a power amplifier provided in an embodiment of the present application;

[0029] Figure 7 A schematic diagram of the relationship between power back-off and efficiency provided in an embodiment of the present application;

[0030] Figure 8A schematic diagram of output power of a first power amplifier and a second power amplifier provided in an embodiment of the present application;

[0031] Fig. 9 A schematic diagram of the relationship between the frequency of a radio frequency signal and the equivalent resistance of a first power amplifier provided in an embodiment of the present application;

[0032] Fig.10 A schematic diagram of the structure of another power amplifier circuit provided in an embodiment of the present application;

[0033] Fig.11 A schematic diagram of a phase difference between a first radio frequency signal and a second radio frequency signal provided in an embodiment of the present application;

[0034] Fig.12 A schematic diagram of the structure of another power amplifier circuit provided in an embodiment of the present application;

[0035] Fig.13 A schematic diagram of the structure of another power amplifier circuit provided in an embodiment of the present application;

[0036] Fig.14 A schematic diagram of the structure of another power amplifier circuit provided in an embodiment of the present application;

[0037] Fig.15 A schematic diagram of the structure of a phase shift network provided in an embodiment of the present application;

[0038] Fig.16 A schematic diagram of another phase difference between a first radio frequency signal and a second radio frequency signal provided in an embodiment of the present application;

[0039] Fig.17 A schematic diagram of a phase difference between a first radio frequency signal and a second radio frequency signal provided in another embodiment of the present application;

[0040] Fig.18 A schematic diagram of the relationship between PAE and output power provided in an embodiment of the present application;

[0041] Fig.19 A schematic diagram of the relationship between gain and output power provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] First, some concepts involved in this application are described.

[0043] The terms "first", "second", etc. involved in the embodiments of the present application are only used to distinguish features of the same type and cannot be understood as indicating relative importance, quantity, order, etc.

[0044] The terms "exemplary" or "for example" and the like in the embodiments of the present application 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 the terms "exemplary" or "for example" is intended to present the related concepts in a specific way.

[0045] The terms "coupling" and "connection" involved in the embodiments of the present application should be understood in a broad sense. For example, they may refer to a direct physical connection, or an indirect connection achieved through electronic devices, such as a connection achieved through resistors, inductors, capacitors or other electronic devices.

[0046] The saturation, linear and nonlinear regions of a power amplifier. 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 increases further, 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.

[0047] Classification of power amplifiers: According to the current conduction angle of the RF signal, the power amplifier can be divided into Class A (conduction angle of 360 degrees), Class B (conduction angle of 180 degrees), Class C (conduction angle less than 180 degrees), and Class AB (conduction angle between 180 degrees and 360 degrees). Among them, Class A power amplifiers are suitable for scenarios where the RF signal is a small signal, Class B power amplifiers and Class C power amplifiers are suitable for scenarios where the RF signal is a large signal, and Class AB power amplifiers are equivalent to Class A power amplifiers when the RF signal is a small signal, and are equivalent to Class B power amplifiers when the RF signal is a large signal. Among them, small signal refers to the RF signal input to the power amplifier with a small power, and large signal refers to the RF signal input to the power amplifier with a large power.

[0048] The efficiency of a power amplifier refers to the ratio of the output power to the input power of the power amplifier.

[0049] The power added efficiency (PAE) of a power amplifier is equal to the ratio of the power amplifier efficiency to the DC power, indicating how much DC power is converted into RF power.

[0050] Power back-off: Reduce the 1dB compression point of the power amplifier (i.e., the critical point between the linear and nonlinear regions of the power amplifier) ​​by a certain amount (e.g., 6dB-10dB), so that the power amplifier can enter the saturation region earlier as the input power increases, thereby improving the efficiency of the power amplifier in amplifying small signals.

[0051] The embodiment of the present application provides an electronic device, which is an electronic device with a wireless communication function. The electronic device can be mobile or fixed. The electronic device can be deployed on land (for example, indoors or outdoors, handheld or vehicle-mounted, etc.), on the water (for example, ships, etc.), or in the air (for example, airplanes, balloons, and satellites, etc.). The electronic device can be called user equipment (UE), access terminal, terminal unit, subscriber unit, terminal station, mobile station (MS), mobile station, terminal agent or terminal device, etc. For example, the electronic device can be a mobile phone, a tablet computer, a laptop computer, a smart bracelet, a smart screen, a smart watch, a virtual reality (VR) device, an augmented reality (AR) device, a terminal in industrial control, a terminal in self-driving, a terminal in remote medical, a terminal in smart grid, a terminal in transportation safety, a terminal in smart city, a terminal in smart home, etc. The embodiments of the present application do not limit the specific type and structure of the electronic device. A possible structure of the electronic device is described below.

[0052] Taking a mobile phone as an example, Figure 1 A possible structure of the electronic device 101 is shown. The electronic device 101 may include a processor 210, an external memory interface 220, an internal memory 221, a universal serial bus (USB) interface 230, a power management module 240, a battery 241, a wireless charging coil 242, an antenna 1, an antenna 2, a mobile communication module 250, a wireless communication module 260, an audio module 270, a speaker 270A, a receiver 270B, a microphone 270C, an earphone interface 270D, a sensor module 280, a button 290, a motor 291, an indicator 292, a camera 293, a display screen 294, and a subscriber identification module (SIM) card interface 295. Optionally, in some embodiments, an audio digital signal processor (ADSP) 243 is also included.

[0053] It is understood that the structure illustrated in the embodiment of the present application does not constitute a specific limitation on the electronic device 101. In other embodiments of the present application, the electronic device 101 may include more or fewer components than shown in the figure, or combine some components, or split some 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.

[0054] The processor 210 may include one or more processing units, for example, the processor 210 may be a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on chip (SoC), a central processing unit (CPU), an application processor (AP), a network processor (NP), a digital signal processor (DSP), a microcontroller unit (MCU), a programmable logic device (PLD), a modem processor, a graphics processor (GPU), an image signal processor (ISP), a controller, a video codec, and a neural-network processing unit (NPU). Among them, different processing units may be independent devices or integrated into one or more processors. For example, the processor 210 may be an application processor AP. Alternatively, the processor 210 may be integrated into a system on chip (SoC). Alternatively, the processor 210 may be integrated into an integrated circuit (IC) chip. The processor 210 may include an analog front end (AFE) and a micro-controller unit (MCU) in an IC chip.

[0055] The processor 210 executes the antenna feeding control method provided in the embodiment of the present application by executing the program and computer instructions stored in the internal memory 221.

[0056] The processor 210 may also be provided with a memory for storing computer instructions and data. In some embodiments, the memory in the processor 210 is a cache memory. The memory may store computer instructions or data that the processor 210 has just used or circulated. If the processor 210 needs to use the computer instructions or data again, it may be directly called from the memory. This avoids repeated access, reduces the waiting time of the processor 210, and thus improves the efficiency of the system.

[0057] In some embodiments, the processor 210 may include one or more interfaces. The interface may include an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, and / or a USB interface, etc.

[0058] ADSP 243 can be coupled with audio module 270 and sensor module 280, and ADSP 243 can be used to process audio signals and sensor data. When the processor is in a dormant state, ADSP 243 can still keep working, thereby reducing the power consumption of the electronic device.

[0059] It is understandable that the interface connection relationship between the modules illustrated in the embodiment of the present application is only a schematic illustration and does not constitute a structural limitation on the electronic device 101. In other embodiments of the present application, the electronic device 101 may also adopt different interface connection methods in the above embodiments, or a combination of multiple interface connection methods.

[0060] The external memory interface 220 can be used to connect an external memory card, such as a micro SanDisk (Micro SD) card, to expand the storage capacity of the electronic device 101. The external memory card communicates with the processor 210 through the external memory interface 220 to implement a data storage function. For example, files such as music and videos can be stored in the external memory card.

[0061] The internal memory 221 may be used to store computer executable program codes, which include computer instructions. The processor 210 executes various functional applications and data processing of the electronic device 101 by running the computer instructions stored in the internal memory 221. In addition, the internal memory 221 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, a universal flash storage (UFS), etc.

[0062] The memory involved in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct RAM bus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0063] The electronic device 101 can implement audio functions such as music playing and recording through the audio module 270, the speaker 270A, the receiver 270B, the microphone 270C, the headphone interface 270D and the application processor.

[0064] The audio module 270 is used to convert digital audio information into analog audio signal output, and is also used to convert analog audio input into digital audio signal. In some embodiments, the audio module 270 can be arranged in the processor 210, or some functional modules of the audio module 270 can be arranged in the processor 210. The speaker 270A, also known as the "speaker", is used to convert the audio electrical signal into a sound signal. The receiver 270B, also known as the "earpiece", is used to convert the audio electrical signal into a sound signal. The microphone 270C, also known as the "microphone" or "microphone", is used to convert the sound signal into an electrical signal. The electronic device 101 can be provided with at least one microphone 270C. The headphone interface 270D is used to connect a wired headset. The headphone interface 270D can be a USB interface 230, or it can be a 3.5mm open mobile terminal platform (OMTP) standard interface, or a cellular telecommunications industry association of the USA (CTIA) standard interface.

[0065] The button 290 includes a power button, a volume button, etc. The button 290 may be a mechanical button. It may also be a touch button. The electronic device 101 may receive a button input and generate a key signal input related to the user settings and function control of the electronic device 101. The motor 291 may generate a vibration prompt. The motor 291 may be used for an incoming call vibration prompt or for touch vibration feedback. The indicator 292 may be an indicator light, which may be used to indicate the charging status, the change in power, or may be used to indicate messages, missed calls, notifications, etc. The SIM card interface 295 is used to connect a SIM card. The SIM card may be inserted into or removed from the SIM card interface 295 to achieve contact and separation with the electronic device 101. The electronic device 101 may support 1 or N SIM card interfaces, where N is a positive integer greater than 1. The SIM card interface 295 may support a Nano SIM card, a Micro SIM card, a SIM card, etc. In some embodiments, the electronic device 101 uses an embedded SIM (eSIM) card. The eSIM card can be embedded in the electronic device 101 and cannot be separated from the electronic device 101.

[0066] The electronic device 101 can realize the shooting function through the ISP, the camera 293, the video codec, the GPU, the display screen 294, and the application processor. The ISP is used to process the data fed back by the camera 293. In some embodiments, the ISP can be set in the camera 293. The camera 293 is used to capture a static image or a video. In some embodiments, the electronic device 101 may include 1 or N cameras 293, where N is a positive integer greater than 1.

[0067] The electronic device 101 can realize the display function through a GPU, a display screen 294, and an application processor. The GPU is a microprocessor for image processing, which connects the display screen 294 and the application processor. The GPU is used to perform mathematical and geometric calculations for graphics rendering. The processor 210 may include one or more GPUs, which execute computer instructions to generate or change display information.

[0068] The sensor module 280 may include a pressure sensor, a gyroscope sensor, an air pressure sensor, a magnetic sensor, an acceleration sensor, a distance sensor, a proximity light sensor, a fingerprint sensor, a temperature sensor, a touch sensor, an ambient light sensor, an angle sensor, etc. When the display screen 294 is a folding screen, the angle sensor may detect the folding angle of the display screen 294, and the folding angle ranges from 0 to 180 degrees.

[0069] The battery 241 may include one or more batteries to power the load.

[0070] The power management module 240 is used to receive charging input from a charger. The charger may be a wireless charger, such as a wireless charging base, other electronic devices 101 with reverse wireless charging function, etc. The power management module 240 may receive wireless charging input through a wireless charging coil 242 of the electronic device. The charger may also be a wired charger, for example, the power management module 240 may receive charging input from a wired charger through the USB interface 230. The power management module 240 is also called a charging chip.

[0071] The power management module 240 can charge the battery 241 and also power the electronic device. The power management module 240 receives input from the battery 241 and powers the processor 210, the internal memory 221, the external memory interface 220, the display screen 294, the camera 293, and the wireless communication module 260. The power management module 240 can also be used to monitor the capacity, voltage, battery cycle number, battery health status (leakage, impedance) and other parameters of the battery 241. In some other embodiments, the power management module 240 can also be set in the processor 210.

[0072] The display screen 294 is used to display images, videos, etc. The display screen 294 includes a display panel. In some embodiments, the electronic device 101 may include one or more display screens 294 .

[0073] The wireless communication function of the electronic device 101 can be implemented through the antenna 1, the antenna 2, the mobile communication module 250, the wireless communication module 260, the modem processor, etc.

[0074] Antenna 1 and antenna 2 are used to transmit and receive electromagnetic wave signals. Each antenna in electronic device 101 can be used to cover a single or multiple communication frequency bands. Different antennas can also be reused to improve the utilization of 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.

[0075] The mobile communication module 250 can provide solutions for wireless communications including 2G / 3G / 4G / 5G, etc., applied to the electronic device 101. The wireless communication module 260 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 to the electronic device 101. In some embodiments, the antenna 1 of the electronic device 101 is coupled to the mobile communication module 250, and the antenna 2 is coupled to the wireless communication module 260, so that the electronic device 101 can communicate with the network and other devices through wireless communication technology.

[0076] like Figure 2 As shown, the mobile communication module 250 may include a baseband chip 31 , a radio frequency integrated circuit (RFIC) 32 and a power amplifier circuit 33 .

[0077] The baseband chip 31 is used to convert the data from the processor 210 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 210 in the SoC.

[0078] The power amplifier circuit 33 provided in the embodiment of the present application can improve the efficiency of power amplification during power fallback. Figure 3 As shown, an embodiment of the present application provides a power amplifier circuit 33, including: a first power amplifier (also called a carrier power amplifier) ​​331, a second power amplifier (also called a peak power amplifier) ​​332, a matching network 333, a first impedance transformation module 334, and a phase shift coupling module 335.

[0079] The input end of the phase shift coupling module 335 is used to Figure 2 The RFIC 32 shown is electrically connected, and the input end of the phase-shift coupling module 335 is used to input the RF signal. The first output end of the phase-shift coupling module 335 is electrically connected to the input end of the first power amplifier 331, and the first output end of the phase-shift coupling module 335 is used to output the first RF signal obtained by coupling the input RF signal. The second output end of the phase-shift coupling module 335 is electrically connected to the input end of the second power amplifier 332, and the second output end of the phase-shift coupling module 335 is used to output the second RF signal obtained by coupling the input RF signal. The output end of the first power amplifier 331 is electrically connected to the first end of the first impedance transformation module 334. The second end of the first impedance transformation module 334, the output end of the second power amplifier 332, and the first end of the matching network 333 are electrically connected to the junction point C. The second end of the matching network 333 is used to Figure 2 The antenna 34 is shown electrically connected, and the second end of the matching network 333 is used to output the power-amplified radio frequency signal.

[0080] The first power amplifier 331 is used to power amplify the first RF signal. The first power amplifier 331 is a class AB power amplifier, that is, the first power amplifier 331 is equivalent to a class A power amplifier when the first RF signal is a small signal, and is equivalent to a class B power amplifier when the first RF signal is a large signal. The second power amplifier 332 is used to power amplify the second RF signal. The second power amplifier 332 is a class B power amplifier or a class C power amplifier, that is, the second power amplifier 332 starts working when the second RF signal is a large signal. The first power amplifier 331 and the second power amplifier 332 have the same equivalent resistance when saturated, for example, both are Ropt. The equivalent resistance of a power amplifier refers to the output voltage of the power amplifier / the output current of the power amplifier.

[0081] The first impedance transformation module 334 is a frequency element, that is, an element whose equivalent resistance and phase shift angle change with the frequency of the radio frequency signal. The first impedance transformation module 334 plays the role of impedance transformation, and is used to change the equivalent resistance of the first power amplifier 331. The first impedance transformation module 334 can be a quarter-wavelength line, and the wavelength refers to the wavelength corresponding to the center frequency of the radio frequency signal. The first impedance transformation module 334 performs phase shifting on the first radio frequency signal, and the phase shift angle is related to the frequency of the radio frequency signal. Among them, at the center frequency of the radio frequency signal, the first impedance transformation module 334 can produce a 90-degree phase shift on the first radio frequency signal, and the impedance of the first impedance transformation module 334 is equal to the equivalent resistance of the first power amplifier 331 when saturated, so that impedance matching with a reflection coefficient of 0 can be achieved. Therefore, the quarter-wavelength line involved in the embodiment of the present application can also be called a 90-degree phase shift line.

[0082] For example, Figure 4 As shown, the embodiments of the present application provide several implementation methods of quarter-wavelength lines. Figure 4 As shown in A, the quarter-wavelength line can be a microstrip line with an electrical length of 90 degrees. This quarter-wavelength line can achieve a -90 degree phase shift for the RF signal at the center frequency, and the phase shift angle will change linearly at other frequencies.

[0083] like Figure 4 As shown in B, the quarter-wavelength line can be a series inductor π-type network, including capacitor C1, capacitor C2, and inductor L1. The first end of the inductor L1 is electrically connected to the first end of the capacitor C1 and serves as the input end of the series inductor π-type network. The second end of the capacitor C1 is grounded. The second end of the inductor L1 is electrically connected to the first end of the capacitor C2 and serves as the output end of the series inductor π-type network. The second end of the capacitor C2 is grounded. This quarter-wavelength line can achieve a -90 degree phase shift for the RF signal at the center frequency, and the phase shift angle will change linearly at other frequencies.

[0084] like Figure 4 As shown in C, the quarter-wavelength line can be a series capacitor π-type network, including capacitor C1, inductor L1, and inductor L2. The first end of capacitor C1 is electrically connected to the first end of inductor L1 and serves as the input end of the series capacitor π-type network. The second end of inductor L1 is grounded. The second end of capacitor C1 is electrically connected to the first end of inductor L2 and serves as the output end of the series capacitor π-type network. The second end of inductor L2 is grounded. This quarter-wavelength line can achieve a 90-degree phase shift for the RF signal at the center frequency, and the phase shift angle will change linearly at other frequencies.

[0085] like Figure 4As shown in D, the quarter-wavelength line can be a series inductor T-type network, including capacitor C1, inductor L1, and inductor L2, the first end of inductor L1 serves as the input end of the series inductor T-type network, the second end of inductor L1, the first end of inductor L2 and the first end of capacitor C1 are electrically connected, the second end of capacitor C1 is grounded, and the second end of inductor L2 serves as the output end of the series inductor T-type network. This quarter-wavelength line can achieve a -90 degree phase shift for the RF signal at the center frequency, and the phase shift angle will change linearly at other frequencies.

[0086] like Figure 4 As shown in Figure E, the quarter-wavelength line can be a series capacitor T-type network, including capacitor C1, capacitor C2, and inductor L1. The first end of capacitor C1 serves as the input end of the series capacitor T-type network, the second end of capacitor C1, the first end of capacitor C2, and the first end of inductor L1 are electrically connected, the second end of inductor L1 is grounded, and the second end of capacitor C2 serves as the output end of the series capacitor T-type network. This quarter-wavelength line can achieve a 90-degree phase shift for the RF signal at the center frequency, and the phase shift angle will change linearly at other frequencies.

[0087] Figure 4 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 equivalent resistance of the first power amplifier 331.

[0088] The first RF signal and the second RF signal are combined at the junction, and since the first impedance transformation module 334 generates a phase shift on the first RF signal, there is a phase difference between the first RF signal and the second RF signal at the junction C. Therefore, the phase shift coupling module 335 is also used to adjust the phase difference between the output first RF signal and the second RF signal to reduce the phase difference between the first RF signal and the second RF signal at the junction C, and try to make the first RF signal and the second RF signal at the junction C be combined in phase to reduce power loss. The matching network 333 is used to perform impedance transformation on the equivalent resistance (e.g., 10 ohms) of the junction C to obtain the load impedance RL (e.g., 50 ohms), thereby achieving impedance matching.

[0089] In a possible implementation, Figure 5As shown, the phase shift coupling module 335 includes a power divider 3351 and a second impedance transformation module 3352. The input end of the power divider 3351 is the input end of the phase shift coupling module 335, the first output end of the power divider 3351 is the first output end of the phase shift coupling module 335, the second output end of the power divider 3351 is electrically connected to the first end of the second impedance transformation module 3352, and the second end of the second impedance transformation module 3352 is the second output end of the phase shift coupling module 335. The power divider 3351 is used to divide the RF signal inputted from the input end into the first RF signal and the second RF signal, and output the first RF signal through the first output end, and output the second RF signal through the second output end. The power of the first RF signal and the second RF signal are both one-half of the power of the input RF signal.

[0090] The second impedance transformation module 3352 is the same as the first impedance transformation module 334. For example, the second impedance transformation module 3352 is also a frequency element. At the center frequency of the RF signal, the impedance of the second impedance transformation module 3352 is equal to the equivalent resistance of the first power amplifier 331 when saturated. The second impedance transformation module 3352 can be a quarter-wavelength line. Therefore, at any frequency of the RF signal, the phase shift angle of the second RF signal by the second impedance transformation module 3352 is the same as the phase shift angle of the first RF signal by the first impedance transformation module 334, so that the first RF signal and the second RF signal are combined in phase at the combining point C.

[0091] The working principle of the power amplifier circuit 33 to achieve power amplifier power back-off is as follows:

[0092] The equivalent resistance of the power amplifier is equal to the output voltage / output current, such as Figure 6 As shown in A, when the equivalent resistance 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 6 As shown in B, when the output current of the power amplifier is small, the efficiency of the power amplifier can be improved by increasing the equivalent resistance of the power amplifier and then increasing the output voltage of the power amplifier, making it easier for the power amplifier to enter the saturation region in advance.

[0093] Therefore, if Figure 7 middle" Figure 5As shown in the MN section of the "power amplifier circuit shown in the figure", because the second power amplifier 332 is a class B power amplifier or a class C power amplifier, when the input RF signal is a small signal, the power of the input RF signal is small and is not enough to trigger the second power amplifier 332 to work, and the second power amplifier 332 is cut off and presents an open circuit state, and the equivalent resistance of the second power amplifier 332 is infinite (∞). Because the first power amplifier 331 is a class AB power amplifier, when the input RF signal is a small signal, the first power amplifier 331 starts to work, and the first impedance transformation module 334 transforms the equivalent resistance of the first power amplifier 331 to increase the equivalent resistance of the first power amplifier 331, and the load voltage of the first power amplifier 331 increases, so that the first power amplifier 331 enters the saturation state in advance, that is, the first power amplifier 331 is more likely to enter the saturation zone in advance as the input power increases, thereby improving the efficiency of the first power amplifier 331 in power amplification of small signals, thereby improving the efficiency of the power amplifier circuit 33 as a whole. As shown in FIG. Figure 8 As shown by the solid line of the MN segment in A, the output voltage of the first power amplifier 331 increases with the increase of the power of the input RF signal, and the output power of the first power amplifier 331 also increases with the increase of the power of the input RF signal.

[0094] like Figure 7 middle" Figure 5 As shown in the NP segment of the "power amplifier circuit" shown in the figure, when the power of the input RF signal increases until it reaches the power back-off point N, that is, the RF signal changes from a small signal to a large signal, at this time, the equivalent resistance of the first power amplifier 331 is 2Ropt, and the output power of the power amplifier circuit 33 backs off by -6dB, that is, the output power of the power amplifier circuit 33 is one-fourth of the saturated output power. The power of the RF signal input to the power amplifier circuit 33 is relatively large, triggering the second power amplifier 332 to start working. As the power of the input RF signal continues to increase, the equivalent resistance of the first power amplifier 331 decreases from 2Ropt to Ropt, and the equivalent resistance of the second power amplifier 332 decreases from infinity (∞) to Ropt. As shown in FIG. Figure 8 As shown by the solid line of the NP segment of A, the first power amplifier 331 remains in the 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 first power amplifier 331 increases with the increase of the power of the input RF signal. Figure 8 As shown by the solid line of the NP segment in B, the output voltage of the second power amplifier 332 increases with the increase of the power of the input RF signal, and therefore, the output power of the second power amplifier 332 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.

[0095] It should be noted that at the power back-off point N, the output power of the power amplifier circuit 33 is one quarter of the saturated output power. This is because, relative to the fact that both the first power amplifier 331 and the second power amplifier 332 are saturated, at the power back-off point N, only the first power amplifier 331 works, so the output power of the entire power amplifier circuit 33 is halved. Furthermore, since the equivalent resistance of the first power amplifier 331 is 2Ropt, which is twice the equivalent resistance Ropt at saturation, the output power of the first power amplifier 331 is half of the saturated output power. Figure 8 As shown in A, the ratio of the output power of the first power amplifier at the corresponding power back-off point N is 0.5, so that the output power of the power amplifier circuit 33 is further halved.

[0096] like Figure 7 middle" Figure 5 As shown in the power saturation point P of the power amplifier circuit shown in the figure, when the power of the input RF signal continues to increase, so that the first power amplifier 331 and the second power amplifier 332 are both saturated, the equivalent resistance of the first power amplifier 331 and the equivalent resistance of the second power amplifier 332 are both Ropt, and the equivalent resistance of the junction point C is Ropt / 2, and the overall power amplification efficiency of the power amplifier circuit 33 reaches the highest.

[0097] for Figure 7 Although the class B amplifier or class AB amplifier shown has the highest efficiency at the power saturation point P, when the power is reduced, the efficiency will decrease significantly as the power is reduced. Figure 5 Compared with the class B amplifier and the class AB amplifier, the power amplifier circuit shown not only has the highest efficiency at the power saturation point P, but also has higher efficiency in power amplification in the entire MP section.

[0098] like Fig. 9 As shown by the dotted line in the middle, taking the n77 frequency band (3.3GHz-4.2GHz) as an example, for Figure 5In the power amplifier circuit shown, the first impedance transformation module 334 is a frequency element. The impedance of the first impedance transformation module 334 changes with the frequency of the RF signal, which will cause the equivalent resistance of the first power amplifier 331 to change with the frequency of the RF signal. In the power back-off state, when other conditions are the same, at the center frequency, the impedance of the first impedance transformation module 334 is the largest, the equivalent resistance of the first power amplifier 331 is the largest, which is 2Ropt, and the efficiency of the first power amplifier 331 is the highest. At frequencies other than the center frequency, the equivalent resistance of the first impedance transformation module 334 will decrease, so that the equivalent resistance of the first power amplifier 331 is reduced, the output voltage of the first power amplifier 331 is reduced, the advance degree of the first power amplifier 331 entering the saturation zone is reduced, and the efficiency of the first power amplifier 331 is also reduced. That is, the equivalent resistance of the first power amplifier 331 changes significantly with the frequency of the RF signal, and the efficiency of the first power amplifier 331 will also obviously decrease with the frequency change, so the bandwidth of the RF signal applicable to the above power amplifier circuit is limited.

[0099] For this reason, Fig.10 As shown, the embodiment of the present application provides another power amplifier circuit. Figure 5 Based on the power amplifier circuit 33 shown, the power amplifier circuit 33 also includes an impedance compensation module 336, a first end of the impedance compensation module 336 is electrically connected to the junction point C, and a second end of the impedance compensation module 336 is grounded, that is, the impedance compensation module 336 is connected in parallel with the branches where the two power amplifiers are located. The impedance compensation module 336 is a frequency element. Exemplarily, the impedance compensation module 336 can be the quarter-wavelength line mentioned above.

[0100] At the center frequency, the impedance compensation module 336 can achieve a 90-degree phase shift, and the equivalent resistance of the impedance compensation module 336 is infinite, which is equivalent to an open circuit and does not affect the equivalent resistance of the junction C. At frequencies other than the center frequency, the impedance compensation module 336 can achieve other angles of phase shift, and the equivalent resistance of the impedance compensation module 336 is not ideally infinite. Since the impedance compensation module 336 is connected in parallel with the branches where the two power amplifiers are located, the equivalent resistance of the junction C will be reduced when the power is backed off. Due to the impedance transformation effect of the impedance compensation module 336, such as Fig. 9 As shown by the solid line in the middle, the equivalent resistance of the combining point C is reduced, which will increase the equivalent resistance of the first power amplifier 331 at frequencies other than the center frequency, thereby improving the efficiency of the first power amplifier 331. Therefore, the bandwidth of the RF signal applicable to the power amplifier circuit is larger.

[0101] It should be noted that the impedance compensation module 336 is not connected in series between the second power amplifier 332 and the junction C. The reason is that at the power back-off point, the second power amplifier 332 has not started working yet, and the output end of the second power amplifier 332 is open. Such a series connection will change the output end of the second power amplifier 332 from an open circuit to a short circuit due to impedance transformation, change the equivalent resistance of the junction C, and then change the equivalent resistance of the first power amplifier 331, thereby reducing the efficiency of power amplification.

[0102] for Fig.10 In the power amplifier circuit shown in , the second impedance transformation module 3352 adopts a quarter-wavelength line, such as Fig.11 As shown by the dotted line, taking the n77 frequency band (3.3GHz-4.2GHz) as an example, the quarter-wavelength line causes the phase difference between the first RF signal and the second RF signal to change with the frequency, and at any frequency of the RF signal, the phase shift angle of the second impedance transformation module 3352 to the second RF signal is the same as the phase shift angle of the first impedance transformation module 334 to the first RF signal. Although the first RF signal and the second RF signal can be combined in phase at the combining point C, relative to Figure 5 In the power amplifier circuit shown in , the impedance compensation module 336 will reduce the equivalent resistance of the junction C. Due to the impedance conversion effect of the impedance compensation module 336, the equivalent resistance of the junction C is reduced. At frequencies other than the center frequency, the output power of the power amplifier circuit is too large, that is, the output power of the first power amplifier 331 and the second power amplifier 332 is also too large, thereby generating an overdrive phenomenon, which will reduce the linearity of power amplification. For example, Figure 8 As shown, different dotted lines correspond to Fig.10 The different solid lines correspond to different frequencies of the power amplifier circuit shown in Figure 5 At different frequencies of the power amplifier circuit shown in , between the power back-off point N and the power back-off point P, the output voltages of the first power amplifier 331 and the second power amplifier 332 corresponding to the dotted lines are higher.

[0103] It should be noted that Figure 8 The ratio of the power amplifier output power refers to the ratio between the current output power of the power amplifier and the saturated output power. If the ratio is less than 1, it means power back-off. The ratio of the power amplifier output voltage refers to the ratio between the current output voltage of the power amplifier and the output voltage at the saturated output power.

[0104] To this end, the embodiment of the present application further improves the phase shift coupling module 335 so that the phase difference between the first RF signal and the second RF signal output by the phase shift coupling module 335 is a fixed value, that is, the phase difference does not change with the change of the frequency of the RF signal. For example, Fig.11The phase difference shown by the solid line is 90 degrees, or -90 degrees. When the power is backed off, the phase shift angle of the first RF signal of the impedance transformation module changes with the frequency, and the phase shift angle of the impedance transformation module is superimposed on the above phase difference, so that at the center frequency, the phase difference between the first RF signal and the second RF signal at the combining point C is zero, and the output power of the combining point C will not be reduced. At frequencies other than the center frequency, there is a certain phase difference between the first RF signal and the second RF signal at the combining point C, which will reduce the output power of the combining point C, thereby reducing the above overdrive phenomenon.

[0105] In a possible implementation, Fig.12 As shown, the phase shift coupling module 335 includes a coupler 3353, the input end of the coupler 3353 is the input end of the phase shift coupling module 335, the through output end of the coupler 3353 is the second output end of the phase shift coupling module 335, and the coupled output end of the coupler 3353 is the first output end of the phase shift coupling module 335. The coupler 3353 can be a 3dB coupler, and the coupled output end of the coupler 3353 has a 90-degree phase difference with respect to the through output end, that is, there is a 90-degree phase difference between the first RF signal output by the phase shift coupling module 335 and the second RF signal. At this time, the first impedance transformation module 334 adopts Figure 4 The quarter-wavelength line shown in A, B or D in the figure realizes a -90-degree phase shift on the first RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies. This makes the phase difference between the first RF signal and the second RF signal at the junction C to be zero at the center frequency, and does not reduce the output power of the junction C; at frequencies other than the center frequency, the first RF signal and the second RF signal at the junction C have a certain phase difference, which reduces the output power of the junction C, thereby reducing the above-mentioned over-driving phenomenon.

[0106] In another possible implementation, Fig.13 As shown, the phase shift coupling module 335 includes a coupler 3353, the input end of the coupler 3353 is the input end of the phase shift coupling module 335, the through output end of the coupler 3353 is the first output end of the phase shift coupling module 335, and the coupled output end of the coupler 3353 is the second output end of the phase shift coupling module 335. The coupler 3353 can be a 3dB coupler, and the coupled output end of the coupler 3353 has a 90-degree phase difference with respect to the through output end, that is, there is a -90-degree phase difference between the first RF signal output by the phase shift coupling module 335 and the second RF signal. At this time, the first impedance transformation module 334 adopts Figure 4The quarter-wavelength line shown in C or E in the middle realizes a 90-degree phase shift on the first RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies. This makes the phase difference between the first RF signal and the second RF signal at the junction C to be zero at the center frequency, and does not reduce the output power of the junction C; at frequencies other than the center frequency, the first RF signal and the second RF signal at the junction C have a certain phase difference, which reduces the output power of the junction C, thereby reducing the above-mentioned over-driving phenomenon.

[0107] In another possible implementation, Fig.14 As shown, the phase-shift coupling module 335 includes a power divider 3351, a first phase-shift network 3354, and a second phase-shift network 3355. The input end of the power divider 3351 is the input end of the phase-shift coupling module 335. The first output end of the power divider 3351 is electrically connected to the first end of the first phase-shift network 3354, the second end of the first phase-shift network 3354 is the first output end of the phase-shift coupling module 335, the second output end of the power divider 3351 is electrically connected to the first end of the second phase-shift network 3355, and the second end of the second phase-shift network 3355 is the second output end of the phase-shift coupling module 335.

[0108] The first phase shift network 3354 can be used Fig.15 The 0-degree phase shift network shown in FIG. 1 includes an inductor L1, a capacitor C1, an inductor L2, and a capacitor C2 connected in series. Fig.15 In the equation, 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 equivalent resistance of the first power amplifier 331. The second phase shift network 3355 can be used Figure 4 The quarter-wavelength line shown in A, B or D, the first impedance transformation module 334 adopts Figure 4 The quarter-wavelength line shown as A, B or D.

[0109] like Fig.16 As shown, taking the n77 frequency band (3.3GHz-4.2GHz) as an example, the center frequency is 3.8GHz, and the first phase shift network 3354 adopts Fig.15 The 0-degree phase shift network shown in FIG. 3 achieves a 0-degree phase shift for the first RF signal (shown by the solid line) at the center frequency, and the phase shift angle changes linearly at other frequencies. The second phase shift network 3355 uses Figure 4The quarter-wavelength line shown in A, B or D realizes a -90-degree phase shift for the second RF signal (shown by the dotted line) at the center frequency, and the phase shift angle changes linearly at other frequencies. At each frequency, the phase difference between the first RF signal input by the first power amplifier 331 and the second RF signal input by the second power amplifier 332 is always 90 degrees. In addition, the second phase shift network 3355 and the first impedance transformation module 334 have the same structure and the same phase shift angle at each frequency, so that the phase difference between the first RF signal and the second RF signal at the junction C is equal to the phase shift angle of the first phase shift network 3354, which will reduce the output power of the junction C, thereby reducing the above-mentioned over-driving phenomenon.

[0110] Alternatively, the first phase shift network 3354 may be implemented using Figure 4 The quarter-wavelength line shown in C or E, the second phase shift network 3355 adopts Fig.15 The 0-degree phase shift network shown in FIG. 1 is a first impedance transformation module 334. Figure 4 A or B or D shown as a quarter wavelength line.

[0111] like Fig.17 As shown, taking the n77 frequency band (3.3GHz-4.2GHz) as an example, the center frequency is 3.8GHz, and the first phase shift network 3354 adopts Figure 4 The quarter-wavelength line shown in C or E in the figure achieves a 90-degree phase shift on the first RF signal (shown by the solid line) at the center frequency, and the phase shift angle changes linearly at other frequencies. The second phase shift network 3355 adopts Fig.15 The 0-degree phase shift network shown in the figure realizes a 0-degree phase shift for the second RF signal (shown by the dotted line) at the center frequency, and the phase shift angle changes linearly at other frequencies. At each frequency, the phase difference between the first RF signal input by the first power amplifier 331 and the second RF signal input by the second power amplifier 332 is always 90 degrees. In addition, the first phase shift network 3354 and the first impedance transformation module 334 have opposite phase shift angles, so that the phase difference between the first RF signal and the second RF signal at the junction C is equal to the phase shift angle of the second phase shift network 3355, which will reduce the output power of the junction C, thereby reducing the above-mentioned over-driving phenomenon.

[0112] Alternatively, the first phase shift network 3354 may be implemented using Fig.15 The 0-degree phase shift network shown in the figure, the second phase shift network 3355 adopts Figure 4 The quarter-wavelength line shown in C or E in FIG. 1 is a first impedance transformation module 334. Figure 4 The quarter-wavelength line shown in C or E.

[0113] like Fig.17As shown, taking the n77 frequency band (3.3GHz-4.2GHz) as an example, the center frequency is 3.8GHz, and the first phase shift network 3354 adopts Fig.15 The 0-degree phase shift network shown in FIG. 3 achieves a 0-degree phase shift for the second RF signal (shown by the dotted line) at the center frequency, and the phase shift angle changes linearly at other frequencies. The second phase shift network 3355 uses Figure 4 The quarter-wavelength line shown in C or E realizes a 90-degree phase shift for the first RF signal (shown by the solid line) at the center frequency, and the phase shift angle changes linearly at other frequencies. At each frequency, the phase difference between the first RF signal input by the first power amplifier 331 and the second RF signal input by the second power amplifier 332 is always 90 degrees. In addition, the second phase shift network 3355 and the first impedance transformation module 334 have the same structure and the same phase shift angle at each frequency, so that the phase difference between the first RF signal and the second RF signal at the junction C is equal to the phase shift angle of the first phase shift network 3354, which will reduce the output power of the junction C, thereby reducing the above-mentioned over-driving phenomenon.

[0114] Phase shift coupling module 335 adopts Fig.14 The circuit shown in the figure can be arranged more flexibly with inductors and capacitors. Fig.12 or Fig.13 The coupler shown has a higher level of integration.

[0115] Take the n77 frequency band (3.3GHz-4.2GHz) as an example. Fig.18 As shown in , between the power backoff point N and the power saturation point P, Fig.10 , Figure 12-14 The convergence of PAE at different frequencies of the power amplifier circuit shown (indicated by different solid lines) is better than Figure 5 The convergence of PAE of the power amplifier circuit shown in Figure 1 at different frequencies (indicated by different dotted lines). Fig.19 As shown, between the power back-off point N and the power saturation point P, Fig.10 , Figure 12-14 The convergence of the gain of the power amplifier circuit shown at different frequencies (indicated by different solid lines) is better than Figure 5 The gain convergence of the power amplifier circuit at different frequencies is shown (indicated by different dotted lines). Fig.10 , Figure 12-14 The power amplifier circuit shown is applicable to a wider bandwidth of radio frequency signals.

[0116] The power amplifier circuit and electronic device provided by the embodiment of the present application, the first power amplifier is used to power amplify a small signal, and the second power amplifier is used to power amplify a large signal, so that the power amplifier circuit can achieve a high level of overall power amplification efficiency through power back-off. The phase shift coupling module adjusts the phase difference between the output first RF signal and the second RF signal to reduce the phase difference between the first RF signal and the second RF signal at the junction point, and tries to make the first RF signal and the second RF signal merge in phase at the junction point to reduce power loss. The impedance compensation module is connected in parallel with the branch where the two power amplifiers are located. The impedance compensation module is a frequency element. At the center frequency, the impedance compensation module can achieve a 90-degree phase shift. The impedance compensation module is equivalent to an open circuit and does not affect the equivalent resistance of the junction point. At frequencies other than the center frequency, the impedance compensation module can achieve other angles of phase shift, and the equivalent resistance of the impedance compensation module is reduced. Since the impedance compensation module is connected in parallel with the branch where the two power amplifiers are located, the equivalent resistance of the junction point will be reduced when the power is backed off. Due to the impedance transformation effect of the impedance compensation module, the equivalent resistance of the junction point is reduced, which will increase the equivalent resistance of the first power amplifier at frequencies other than the center frequency, thereby improving the efficiency of the first power amplifier. Therefore, the bandwidth of the RF signal applicable to the power amplifier circuit is larger.

[0117] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and modules described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0118] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one device or distributed on multiple devices. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment.

[0119] In addition, each functional module in each embodiment of the present application may be integrated into one device, or each module may exist physically separately, or two or more modules may be integrated into one device.

[0120] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A power amplifier circuit, characterized in that: include: A phase shift coupling module, a first power amplifier, a second power amplifier, an impedance transformation module, a matching network, and an impedance compensation module; the impedance transformation module and the impedance compensation module are frequency elements, The input end of the phase-shift coupling module is used to input a radio frequency signal, the first output end of the phase-shift coupling module is electrically connected to the input end of the first power amplifier, and the first output end of the phase-shift coupling module is used to output a first radio frequency signal obtained by coupling the radio frequency signal; the second output end of the phase-shift coupling module is electrically connected to the input end of the second power amplifier, and the second output end of the phase-shift coupling module is used to output a second radio frequency signal obtained by coupling the radio frequency signal; The output end of the first power amplifier is electrically connected to the first end of the impedance conversion module, and the second end of the impedance conversion module, the output end of the second power amplifier, the first end of the matching network, and the first end of the impedance compensation module are electrically connected to a junction point; the second end of the matching network is used to output the radio frequency signal after power amplification; the second end of the impedance compensation module is grounded; The impedance transformation module is a quarter-wavelength line, which is used to increase the equivalent resistance of the first power amplifier when the power is backed off; the phase difference between the first RF signal and the second RF signal output by the phase shift coupling module is a fixed value; the impedance compensation module is used to reduce the equivalent resistance of the junction when the power is backed off; If the impedance transformation module realizes a -90 degree phase shift on the RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies, the phase difference between the first RF signal and the second RF signal output by the phase shift coupling module is 90 degrees; or, if the impedance transformation module realizes a 90 degree phase shift on the RF signal at the center frequency, and the phase shift angle changes linearly at other frequencies, the phase difference between the first RF signal and the second RF signal output by the phase shift coupling module is -90 degrees; The phase-shift coupling module comprises a power divider, a first phase-shift network, and a second phase-shift network. The input end of the power divider is the input end of the phase-shift coupling module; the first output end of the power divider is electrically connected to the first end of the first phase-shift network, the second end of the first phase-shift network is the first output end of the phase-shift coupling module, the second output end of the power divider is electrically connected to the first end of the second phase-shift network, and the second end of the second phase-shift network is the second output end of the phase-shift coupling module; The first phase shift network is a 0-degree phase shift network, and the second phase shift network is a first quarter-wavelength line; or, the first phase shift network is a second quarter-wavelength line, and the second phase shift network is a 0-degree phase shift network; or, the first phase shift network is a 0-degree phase shift network, and the second phase shift network is a second quarter-wavelength line; the 0-degree phase shift network is used to achieve a 0-degree phase shift for the radio frequency signal at the center frequency, and the phase shift angle changes linearly at other frequencies; the first quarter-wavelength line is used to achieve a -90-degree phase shift for the radio frequency signal at the center frequency, and the phase shift angle changes linearly at other frequencies; the second quarter-wavelength line is used to achieve a 90-degree phase shift for the radio frequency signal at the center frequency, and the phase shift angle changes linearly at other frequencies; the 0-degree phase shift network includes a first inductor, a first capacitor, a second inductor, and a second capacitor connected in series, the first inductor and the second inductor both satisfy L=Ropt / (2πf), the first capacitor and the second capacitor both satisfy C=1 / (2πfRopt), wherein f is the center frequency of the radio frequency signal, and Ropt is the equivalent resistance of the first power amplifier.

2. The circuit according to claim 1, characterized in that The phase-shift coupling module comprises a coupler, the input end of the coupler is the input end of the phase-shift coupling module, the through output end of the coupler is the second output end of the phase-shift coupling module, and the coupling output end of the coupler is the first output end of the phase-shift coupling module.

3. The circuit according to claim 1, characterized in that The phase-shift coupling module comprises a coupler, the input end of the coupler is the input end of the phase-shift coupling module, the through output end of the coupler is the first output end of the phase-shift coupling module, and the coupled output end of the coupler is the second output end of the phase-shift coupling module.

4. The circuit according to any one of claims 1 to 3, characterized in that: The impedance compensation module is a quarter-wavelength line.

5. The circuit according to any one of claims 1 to 3, characterized in that: The first power amplifier is a class AB power amplifier, and the second power amplifier is a class C power amplifier or a class D power amplifier.

6. An electronic device, characterized in that: It comprises an antenna and a power amplifier circuit as described in any one of claims 1 to 5, wherein the power amplifier circuit is used to output a power-amplified radio frequency signal to the antenna.

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