Power amplification circuit, radio frequency chip, and electronic device

Abstract

The present application relates to the technical field of intelligent terminals, and provides a power amplification circuit, a radio frequency chip, and an electronic device, capable of simplifying the structure of a power amplification circuit in a multi-band application scenario. The circuit comprises one common load modulation unit and at least two amplification path groups; each amplification path group receives signals of different frequency bands in different time periods; and the common load modulation unit can perform load modulation on power amplification units within different amplification path groups in different time periods.

Description

A power amplifier circuit, an RF chip, and an electronic device

[0001] This application claims priority to Chinese Patent Application No. 202410952089.5, filed on July 16, 2024, entitled "A Power Amplifier Circuit, Radio Frequency Chip and Electronic Equipment", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of smart terminal technology, and in particular to a power amplifier circuit, a radio frequency chip, and an electronic device. Background Technology

[0003] With the development of high-speed wireless communication technology, the peak-to-average power ratio (PAPR) of modulation signals in modern wireless communication systems is constantly increasing. Complex modulation signals with high PAPR cause the power amplifier in the RF chip to be in a power back-off state most of the time, and the efficiency of the power amplifier will decrease accordingly in the power back-off state.

[0004] Load-modulated balanced power amplifiers (CMPAs) are a new type of power amplifier that offers higher efficiency in power back-off mode compared to traditional amplifiers. However, for multi-band applications, each band requires a separate CPA to improve efficiency. This design is complex, costly, and difficult to miniaturize. Summary of the Invention

[0005] To address the aforementioned technical problems, embodiments of this application provide a power amplifier circuit, an RF chip, and an electronic device, which can simplify the structure of power amplifier circuits in multi-band application scenarios.

[0006] In a first aspect, embodiments of this application provide a power amplifier circuit, comprising: a shared load modulation unit and at least two sets of amplification path groups. Each amplification path group includes a frequency band signal input terminal, a power distribution unit, a power amplification unit, and a frequency band signal output terminal. Different frequency band signal input terminals are used to receive different frequency band signals transmitted by a baseband processor at different time periods. For any set of amplification path groups: the power distribution unit is used to receive the frequency band signal at the frequency band signal input terminal and allocate the frequency band signal into a first signal and a second signal based on the power distribution relationship of the power distribution unit; the power amplification unit is used to amplify the first signal and transmit the amplified first signal to the frequency band signal output terminal; the frequency band signal output terminal is used to transmit the signal at the frequency band signal output terminal to an antenna; and the shared load modulation unit is used to modulate the second signal and transmit the modulated second signal to the power amplification unit, wherein the modulated second signal is used to fuse with the first signal to perform load modulation on the power amplification unit.

[0007] Based on the above scheme, when the power amplifier circuit receives signals from different frequency bands at different time periods, it can achieve load modulation of the power amplifier units corresponding to different frequency bands under different frequency band signals through a shared load modulation unit. Compared with the power amplifier circuit structure where each frequency band corresponds to a separate load modulation unit, the shared load modulation unit in this scheme significantly simplifies the structure of the power amplifier circuit in multi-band applications, thereby reducing circuit costs. Due to the shared structure, this scheme integrates the structure where each frequency band corresponds to a separate power amplifier circuit in multi-band applications, thus enabling chip miniaturization design.

[0008] Furthermore, in the power amplifier circuit of this scheme, when the power amplifier unit amplifies the frequency band signal, the load modulation unit modulates the load of the power amplifier unit. This increases the efficiency of the power amplifier unit when amplifying the frequency band signal. Therefore, even when the power amplifier circuit operates in a power back-off state, its efficiency is still improved to some extent.

[0009] For example, the amplification pathway group can be two, three or more groups. In the following description of the embodiments of this application, only two groups are used as an example to illustrate the scheme.

[0010] For example, the baseband processor may be the baseband subsystem mentioned below.

[0011] For example, different frequency band signal input terminals are used to receive different frequency band signals sent by the baseband processor at different time periods, meaning that only one frequency band signal input terminal has a frequency band signal input at any given time. If there are two frequency band signal input terminals, a first frequency band signal input terminal and a second frequency band signal input terminal, then only the first frequency band signal input terminal has a first frequency band signal input at any given time, or only the second frequency band signal input terminal has a second frequency band signal input at any given time, and the frequency band ranges of the first frequency band signal and the second frequency band signal are different.

[0012] According to the first aspect, for any set of amplification paths: the input terminal of the power distribution unit is connected to the frequency band signal input terminal; the first output terminal of the power distribution unit is connected to the input terminal of the power amplifier unit; the second output terminal of the power distribution unit is connected to any one of the input terminals of the common load modulation unit; the output terminal of the common load modulation unit is connected to the isolation terminal of the power amplifier unit; and the output terminal of the power amplifier unit is connected to the frequency band signal output terminal.

[0013] Based on the above scheme, for each amplification path, the shared load modulation unit is connected to its internal power distribution unit and power amplification unit. In other words, multiple amplification paths can share a single power amplification unit, which simplifies the power amplification circuit structure in multi-band application scenarios.

[0014] For example, the power distribution unit may be a power divider, as mentioned below.

[0015] For example, the number of input terminals of the shared load modulation unit is the same as the number of amplification path groups. If there are 2 amplification path groups, then there are 2 input terminals of the shared load modulation unit; if there are 3 amplification path groups, then there are 3 input terminals of the shared load modulation unit.

[0016] According to the first aspect, or any implementation of the first aspect above, at least two amplification path groups include a first amplification path group and a second amplification path group. The first amplification path group includes a first frequency band signal input terminal, a first power distribution unit, a first power amplification unit, and a first frequency band signal output terminal. The second amplification path group includes a second frequency band signal input terminal, a second power distribution unit, a second power amplification unit, and a second frequency band signal output terminal. Different frequency band signals transmitted at different time periods include a first frequency band signal transmitted in a first time period and a second frequency band signal transmitted in a second time period. In the first time period, the first frequency band signal input terminal is used to receive the first frequency band signal transmitted by the baseband processor. The first power distribution unit is used to allocate the first frequency band signal into a first signal and a second signal based on the power distribution relationship of the first power distribution unit. The first power amplification unit is used to amplify the first signal and... The first signal is transmitted to the first frequency band signal output terminal; the first frequency band signal output terminal is used to send the signal at the first frequency band signal output terminal to the antenna; the shared load modulation unit is used to modulate the second signal and transmit the modulated second signal to the first power amplification unit; in the second time period, the second frequency band signal input terminal is used to receive the second frequency band signal sent by the baseband processor; the second power allocation unit is used to allocate the second frequency band signal into the first signal and the second signal based on the power allocation relationship of the second power allocation unit; the second power amplification unit is used to amplify the first signal and transmit the amplified first signal to the second frequency band signal output terminal; the second frequency band signal output terminal is used to send the signal at the second frequency band signal output terminal to the antenna; the shared load modulation unit is used to modulate the second signal and transmit the modulated second signal to the second power amplification unit.

[0017] Based on the above scheme, a power amplifier circuit structure with two amplification path groups is provided. This scheme corresponds to a dual-band application scenario, namely the dual-band application scenario mentioned in the embodiments below. It can achieve load modulation of the first power amplifier unit by using a shared load modulation unit when the first frequency band is working and the second frequency band is not working, thereby improving the efficiency of the first power amplifier unit; conversely, when the second frequency band is working and the first frequency band is not working, load modulation of the second power amplifier unit is achieved by using a shared load modulation unit, thereby improving the efficiency of the second power amplifier unit. Load modulation of both power amplifier units can be achieved using a single shared load modulation unit, resulting in a simple circuit structure and high integration.

[0018] For example, the first signal and the second signal corresponding to different frequency bands are different. Although both are described as the first signal and the second signal, since the first frequency band signal and the second frequency band signal are different, the first signal allocated by the first frequency band signal and the first signal allocated by the second frequency band signal are different, and the second signal allocated by the first frequency band signal and the second signal allocated by the second frequency band signal are also different.

[0019] For example, the power allocation relationship of the first power allocation unit can be to allocate two signals, each reduced by 3dB. In the first time period, the strength of the first frequency band signal is 10dBm, and the first power allocation unit allocates the 10dBm signal as a first signal of 7dBm and a second signal of 7dBm. The power allocation relationship of the second power allocation unit can be to allocate one signal reduced by 4dB and one signal reduced by 5dB. In the first time period, the strength of the first frequency band signal is 10dBm, and the first power allocation unit allocates the 10dBm signal as a first signal of 6dBm and a second signal of 5dBm.

[0020] For example, in a dual-band application scenario, the first signal can be the first power signal and the third power signal mentioned below, and the second signal can be the second power signal and the fourth power signal mentioned below.

[0021] According to the first aspect, or any implementation of the first aspect above, the input terminal of the first power distribution unit is connected to the input terminal of the first frequency band signal; the first output terminal of the first power distribution unit is connected to the input terminal of the first power amplification unit; the second output terminal of the first power distribution unit is connected to the first input terminal of the common load modulation unit; the output terminal of the common load modulation unit is connected to the isolation terminal of the first power amplification unit; the output terminal of the first power amplification unit is connected to the output terminal of the first frequency band signal; the input terminal of the second power distribution unit is connected to the input terminal of the second frequency band signal; the first output terminal of the second power distribution unit is connected to the input terminal of the second power amplification unit; the second output terminal of the second power distribution unit is connected to the second input terminal of the common load modulation unit; the output terminal of the common load modulation unit is connected to the isolation terminal of the second power amplification unit; and the output terminal of the second power amplification unit is connected to the output terminal of the second frequency band signal.

[0022] According to the first aspect, or any implementation of the first aspect above, the shared load modulation unit includes a shared power amplifier and at least two phase shifting units; for any one of the phase shifting units, the phase shifting unit is used to perform phase shifting processing on the second signal and transmit the phase-shifted second signal to the shared power amplifier; the shared power amplifier is used to amplify the phase-shifted second signal and transmit the amplified second signal to the power amplification unit.

[0023] Based on the above solution, in multi-band application scenarios, the shared load modulation unit only includes one shared power amplifier. Compared to the original circuit that required designing multiple power amplifiers for multiple frequency bands, this reduces the number of power amplifiers required, as the load modulation function can be achieved with just one shared power amplifier. Because the number of power amplifiers is reduced, the design of input impedance matching circuits, output impedance matching circuits, and power supply control circuits for these power amplifiers is also reduced, significantly lowering the circuit cost.

[0024] For example, the number of phase shifting units is the same as the number of frequency bands. If there are two frequency bands, then there are also two phase shifting units.

[0025] For example, if there are two phase shifting units, they can be the first phase shifting unit and the second phase shifting unit mentioned below, wherein the first phase shifting unit can shift the phase by 165° and the second phase shifting unit can shift the phase by 150°.

[0026] For example, the phase shifting unit can be a phase shifting circuit made up of components such as capacitors and inductors, or it can be a transmission line that realizes phase shifting.

[0027] According to the first aspect, or any implementation of the first aspect above, for any phase shifting unit, the input terminal of the phase shifting unit is connected to the second output terminal of the power distribution unit, the output terminal of the phase shifting unit is connected to the input terminal of the common power amplifier, and the output terminal of the common power amplifier is connected to the isolation terminal of the power amplification unit.

[0028] According to the first aspect, or any implementation of the first aspect above, the power amplification unit includes a first coupler, a second coupler, a first power amplifier, a second power amplifier, and a first resistor; the first coupler is used to divide the first signal into a first sub-signal and a second sub-signal; the first power amplifier is used to amplify the first sub-signal; the second power amplifier is used to amplify the second sub-signal; the second coupler is used to combine the amplified first sub-signal and the amplified second sub-signal into a first combined signal, and transmit the first combined signal to the frequency band signal output terminal; the first resistor is used to suppress noise.

[0029] For example, both the first coupler and the second coupler can be 3dB couplers.

[0030] For example, both the first power amplifier and the second power amplifier can amplify by 10dB.

[0031] For example, in a dual-band application scenario, the first coupler can be the first coupler and the third coupler mentioned below, and the second coupler can be the second coupler and the fourth coupler mentioned below.

[0032] For example, in a dual-band application scenario, the first power amplifier can be the first power amplifier and the third power amplifier mentioned below, and the second power amplifier can be the second power amplifier and the fourth power amplifier mentioned below.

[0033] According to the first aspect, or any implementation of the first aspect above, the first signal terminal of the first coupler is connected to the first output terminal of the power distribution unit, the second signal terminal of the first coupler is connected to the input terminal of the first power amplifier, the third signal terminal of the first coupler is connected to the input terminal of the second power amplifier, and the isolation terminal of the first coupler is connected to the first terminal of the first resistor; the second terminal of the first resistor is grounded; the first signal terminal of the second coupler is connected to the frequency band signal output terminal, the second signal terminal of the second coupler is connected to the output terminal of the first power amplifier, the third signal terminal of the second coupler is connected to the output terminal of the second power amplifier, and the isolation terminal of the second coupler is connected to the output terminal of the common load modulation unit.

[0034] According to the first aspect, or any implementation of the first aspect above, the power distribution unit includes a power divider.

[0035] According to the first aspect, or any implementation of the first aspect above, the shared load modulation unit further includes at least two first switching units; the output terminal of the phase shifting unit is connected to the input terminal of the shared power amplifier through any one of the first switching units.

[0036] Based on the above scheme, by setting the first switching unit, power leakage between the phase shifting units corresponding to different frequency bands can be avoided, specifically the position of node N1 in the attached figure.

[0037] For example, the first switching unit may be switch 1 and switch 3 mentioned below.

[0038] For example, the first switching unit can be any device with switching function, such as a transistor.

[0039] According to the first aspect, or any implementation of the first aspect above, it further includes at least two second switching units; the output terminal of the common power amplifier is connected to the isolation terminal of the power amplifier unit through any one of the second switching units.

[0040] Based on the above scheme, by setting a second switching unit, power leakage can be avoided at the node where the output of the common power amplifier is connected to the isolation terminal of each power amplifier unit, specifically at the location of node N2 in the attached figure.

[0041] For example, the second switching unit may be switch 2 and switch 4 mentioned below.

[0042] For example, the second switching unit can be any device with switching function, such as a transistor.

[0043] According to the first aspect, or any implementation of the first aspect above, the power amplification unit further includes a phase-shift compensation unit; the phase-shift compensation unit is used to perform phase-shift processing on the first signal; the first coupler is used to divide the phase-shifted first signal into a first sub-signal and a second sub-signal; the first signal terminal of the first coupler is connected to the first output terminal of the power distribution unit through the phase-shift compensation unit.

[0044] Based on the above scheme, by adjusting the position of the phase shifting unit, that is, by adjusting the position of the phase shifting unit located in the shared load modulation unit to the power amplifier unit, the required phase difference relationship between the first signal and the second signal can also be achieved. With the required phase difference relationship between the first signal and the second signal, the shared load modulation unit can perform load modulation on the power amplifier unit.

[0045] For example, if the phase shifting unit shifts the phase by 165°, then the phase shift compensation unit can shift the phase by -165°, that is, they can have opposite phase relationships.

[0046] According to the first aspect, or any implementation of the first aspect above, the power distribution relationship of the power distribution units in each amplification path group is the same. The shared load modulation unit includes a shared power amplifier and at least two second resistors. For any one of the second resistors, the first end of the second resistor is connected to the second output terminal of the power distribution unit, the second end of the second resistor is connected to the input terminal of the shared power amplifier, and the output terminal of the shared power amplifier is connected to the isolation terminal of the power amplification unit. The second resistor is used to reduce the signal strength of the second signal. The shared power amplifier is used to amplify the second signal after the signal strength has been reduced, and to transmit the amplified second signal to the power amplification unit.

[0047] Based on the above scheme, the power distribution units in each amplification path group can be designed to be exactly the same. That is, when the power distribution relationship of the power distribution units in each amplification path group is the same, power leakage of the signal at the position (node ​​N1) between each phase shifting unit can be avoided.

[0048] According to the first aspect, or any implementation of the first aspect above, it further includes at least one fixed phase shifting unit; the output terminal of the shared load modulation unit is connected to the isolation terminal of the power amplifier unit through any one of the fixed phase shifting units.

[0049] Based on the above scheme, the fixed phase shifter can provide high-impedance isolation to other non-operating frequency bands while operating in one frequency band, thus avoiding power leakage.

[0050] For example, a fixed-phase shifting unit can be a phase-shifting circuit made up of components such as capacitors and inductors, or it can be a transmission line that realizes phase shifting.

[0051] For example, a fixed-phase shifting unit can shift the phase by 90°.

[0052] Secondly, embodiments of this application provide a radio frequency chip, which includes at least one power amplifier circuit as described in the first aspect and any implementation thereof.

[0053] The second aspect and any implementation thereof correspond to the first aspect and any implementation thereof, respectively. The technical effects of the second aspect and any implementation thereof are similar to those of the first aspect and any implementation thereof, and will not be repeated here.

[0054] Thirdly, embodiments of this application provide an electronic device, which includes at least one radio frequency chip as described in the second aspect and any implementation thereof.

[0055] The third aspect and any implementation thereof correspond to the second aspect and any implementation thereof, respectively. The technical effects of the third aspect and any implementation thereof are similar to those of the second aspect and any implementation thereof, and will not be repeated here. Attached Figure Description

[0056] Figure 1 is a schematic diagram of the communication system of the terminal provided in an embodiment of this application;

[0057] Figure 2 is a schematic diagram of an application scenario provided by an embodiment of this application;

[0058] Figure 3 is a schematic diagram comparing the efficiency of various power amplifiers provided in the embodiments of this application under different power back-off degrees;

[0059] Figure 4 is a schematic diagram of another application scenario provided by an embodiment of this application;

[0060] Figure 5 shows the circuit structure of a load-modulated balanced power amplifier provided in an embodiment of this application;

[0061] Figure 6 shows the circuit structure of a load modulation balanced power amplifier for a dual-band application scenario provided in an embodiment of this application;

[0062] Figure 7 is a schematic diagram of a power amplifier circuit provided in an embodiment of this application;

[0063] Figure 8 is a schematic diagram of another power amplifier circuit provided in an embodiment of this application;

[0064] Figure 9 is a schematic diagram of another power amplifier circuit provided in an embodiment of this application;

[0065] Figure 10 is a schematic diagram of the circuit structure of an exemplary radio frequency switch;

[0066] Figures 11a-11d are schematic diagrams of the power amplifier circuit in four different cases provided in the embodiments of this application. Detailed Implementation

[0067] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0068] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0069] The terms "first" and "second," etc., used in the specification and claims of this application are used to distinguish different objects, not to describe a specific order of objects. For example, "first target object" and "second target object," etc., are used to distinguish different target objects, not to describe a specific order of target objects.

[0070] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0071] In the description of the embodiments in this application, unless otherwise stated, "multiple" means two or more. For example, multiple processing units means two or more processing units; multiple systems means two or more systems.

[0072] For ease of description, the relevant concepts involved in the embodiments of this application will first be introduced:

[0073] Peak-to-average power ratio (PAPR) refers to the ratio of a signal's maximum instantaneous power to its average power. PAPR is a key indicator of signal volatility, and the complexity of the signal directly affects its magnitude. Generally speaking, the more complex the signal, the higher its PAPR will be.

[0074] The operating region of a power amplifier (or simply power amplifier): As the input power increases, a power amplifier can operate in different regions, with two key regions being the linear region (or amplification region) and the saturation region. In the linear region, the power amplifier maintains a linear relationship between input and output power; that is, the output power is a linear amplification of the input power. In the saturation region, even if the input power continues to increase, the output power will not increase further, reaching a power saturation point (the point where the amplifier's output power no longer increases with input power). The linear region produces virtually no signal distortion, while the saturation region does.

[0075] Power back-off in power amplifiers refers to the intentional design of a power amplifier so that its maximum output power is slightly below the power saturation point. This results in an average output power that is further away from the power saturation point. Power back-off allows signals to be amplified without distortion.

[0076] The relationship between Peak-to-Average Power Ratio (PAPR) and power back-off: To achieve high transmission rates and reliable low latency, 5G communication systems require more complex signal modulation methods to improve spectrum utilization and communication reliability. However, this leads to an increase in the PAPR of the modulated signal. An increased PAPR means that the maximum instantaneous power of the modulated signal is much higher than its average power. The PAPR of modulated signals in modern wireless communication systems is constantly increasing, and in the future, the PAPR of 5G modulated signals may even reach 12dB. To maintain the linearity of the power amplifier, the higher the PAPR, the greater the power back-off required by the power amplifier.

[0077] For example, to facilitate understanding, assume the power amplifier's power saturation point is 20dBm. With a peak-to-average power ratio (PAPR) of 4dB, the maximum instantaneous output power of the power signal is 19dBm, and the average output power drops back to 15dBm. This means the power amplifier operates at an output power close to 15dBm most of the time. If the PAPR is increased to 10dB, the maximum instantaneous output power of the power signal is still 19dBm, but the average output power drops back to 9dBm. This means the power amplifier operates at an output power close to 9dBm most of the time.

[0078] Power amplifiers can be classified according to their static operating state (i.e., their operating state when there is no signal input) into Class AB power amplifiers (power amplifier set to Class AB static operating mode), Class B power amplifiers (power amplifier set to Class B operating mode), and Class C power amplifiers (power amplifier set to Class C static operating mode), etc. Specifically, a Class C power amplifier requires a small power input signal to turn on its internal transistors, thus turning the entire Class C power amplifier into its operating region; a Class B power amplifier requires an even smaller power input signal to turn on its internal transistors, thus turning the entire Class B power amplifier into its operating region; a Class AB power amplifier has its internal transistors in a critical state of conduction when there is no signal input, and it will directly turn on once a signal is input, thus turning the entire Class AB power amplifier into its operating region.

[0079] This application provides a terminal, which can be a mobile phone, computer, tablet computer, personal digital assistant (PDA), in-vehicle computer, television, smart wearable device, smart home device, or other electronic device with a power amplifier. This application does not impose any special limitations on the specific form of the above-mentioned electronic device.

[0080] The specific structure and uses of the terminal provided in the embodiments of this application are described below.

[0081] As shown in Figure 1, Figure 1 illustrates a schematic diagram of the communication system of the terminal provided in the embodiment of this application. The terminal includes an application subsystem, memory, mass storage, baseband subsystem, radio frequency front end (RFFE) devices, radio frequency integrated circuit (RFIC), and antenna (ANT). These devices can be coupled through various interconnect buses or other electrical connection methods.

[0082] In Figure 1, ANT_1 represents the first antenna, ANT_N represents the Nth antenna, and N is a positive integer greater than 1. Tx represents the transmit path, Rx represents the receive path, and different numbers represent different paths. FBRx represents the feedback receive path, PRx represents the main receive path, and DRx represents the diversity receive path. HB represents high frequency, and LB represents low frequency, referring to the relative high and low frequencies. BB represents baseband. It should be understood that the markings and components in Figure 1 are for illustrative purposes only and represent only one possible implementation. Embodiments of this application also include other implementations.

[0083] The radio frequency (RF) subsystem may include the aforementioned RF front-end (RFFE) devices and RF integrated circuits (RFICs). Specifically, the RF subsystem may include antenna switches, antenna tuners, low-noise amplifiers (LNAs), power amplifiers (PAs), mixers, local oscillators (LOs), filters, and other electronic components, which may be integrated into one or more chips as needed. Antennas can sometimes be considered part of the RF subsystem.

[0084] The radio frequency (RF) subsystem can be further divided into an RF receive path and an RF transmit path. The RF receive path receives RF signals via an antenna, processes these signals (e.g., amplification, filtering, and down-conversion) to obtain a baseband signal, and then transmits it to the baseband subsystem. The RF transmit path receives baseband signals from the baseband subsystem, processes these baseband signals (e.g., up-conversion, amplification, and filtering) to obtain an RF signal, and finally radiates this RF signal into space via an antenna.

[0085] For example, the aforementioned electronic components can be separately disposed in the antenna, RF front-end circuit, and RF chip as needed. The RF chip can be composed of devices such as mixers and local oscillators. The local oscillator provides the local oscillator signal; the mixer mixes the RF signal with the local oscillator signal provided by the local oscillator. The RF chip is sometimes also called a receiver, transmitter, or transceiver. The RF front-end circuit can be composed of electronic components such as filters, low-noise amplifiers, power amplifiers, duplexers, and RF switches. RF switches are used to switch between RF signal reception and transmission, and between different frequency bands; duplexers isolate the RF signal transmission and reception paths, ensuring normal operation of reception and transmission when sharing the same antenna; filters retain signals within a specific frequency band while filtering out signals outside that band; low-noise amplifiers amplify the RF signal in the receiving channel; and power amplifiers amplify the RF signal in the transmitting channel.

[0086] In this case, the antenna, RF front-end circuit, and RF chip are independent and can be manufactured and sold separately. Of course, the RF subsystem can also use different components or different integration methods based on power consumption and performance requirements. For example, some components belonging to the RF front-end circuit can be integrated into the RF chip, or even the antenna and RF front-end circuit can be integrated into the RF chip.

[0087] In the embodiments of this application, the power amplifier in the RF front-end circuit can be integrated into the RF chip, or it can be not integrated into the RF chip. For ease of explanation, the embodiments of this application integrate the power amplifier into the RF chip.

[0088] The baseband subsystem can extract useful information or data bits from the baseband signal, or convert information or data bits into baseband signals to be transmitted. These information or data bits can represent user data such as voice, text, and video, or control information. For example, the baseband subsystem can perform signal processing operations such as modulation and demodulation, encoding and decoding. Different wireless access technologies, such as 5G NR and 4G LTE, often have slightly different baseband signal processing operations. Therefore, to support the convergence of multiple mobile communication modes, the baseband subsystem can include multiple processing cores or multiple HACs (Hybrid Access Centers). The baseband subsystem is generally integrated into one or more chips; the chip integrating the baseband subsystem is generally called a baseband integrated circuit (BBIC).

[0089] For example, the baseband subsystem can be a standalone chip, referred to as a modem chip. The hardware components of the baseband subsystem can be manufactured and sold as modem chips. Modem chips are sometimes also referred to as baseband chips or baseband processors. Alternatively, the baseband subsystem can be further integrated into a System-on-Chip (SoC), manufactured and sold as SoC chips. The software components of the baseband subsystem can be built into the chip's hardware components before the chip leaves the factory, or they can be imported into the chip's hardware components from other non-volatile memory after the chip leaves the factory, or they can be downloaded and updated online via a network.

[0090] Furthermore, since radio frequency (RF) signals are analog signals, and the baseband subsystem primarily processes digital signals, electronic devices also require analog-to-digital (ADC) converters. ADCs include analog-to-digital converters (ADCs) that convert analog signals to digital signals, and digital-to-analog converters (DACs) that convert digital signals to analog signals. It should be understood that ADCs can be located in either the baseband subsystem or the RF subsystem.

[0091] The application subsystem can serve as the main control system or main computing system of the electronic device. It runs the main operating system and applications, manages the hardware and software resources of the entire electronic device, and provides a user interface. The application subsystem may include one or more processing cores. Furthermore, it may also include driver software related to other subsystems (such as the baseband subsystem). The baseband subsystem may also include one or more processing cores, as well as hardware accelerators (HACs) and caches.

[0092] The above describes the structure of the communication system of the terminal provided in the embodiments of this application. The power amplifier is a crucial component of the radio frequency subsystem, used to amplify the signal from the transmission channel. The amplified signal is transmitted to the antenna, which radiates the signal into space, enabling communication between the terminal and the base station.

[0093] In this embodiment, the power amplifier can be integrated into a radio frequency (RF) chip. Specifically, as shown in Figure 2, it is a schematic diagram of an application scenario provided by this embodiment. The power amplifier can receive the baseband signal transmitted by the baseband subsystem, amplify the baseband signal, and transmit the amplified signal to the antenna, which then radiates the signal into space. An RF switch is also included between the power amplifier and the antenna. This RF switch can turn the path between the power amplifier and the antenna on or off, thereby enabling switching between different frequency bands.

[0094] Research has shown that while power back-off allows power amplifiers to amplify signals without distortion, the efficiency of the power amplifier decreases as its output power decreases (because power back-off reduces the output power of the power amplifier). In the application scenario shown in Figure 2, the power amplifier needs to operate in power back-off mode when receiving signals from the baseband subsystem and amplifying them for transmission to the antenna. In power back-off mode, the efficiency of the power amplifier decreases, leading to increased power consumption and increased heat generation in the RF chip. If the power amplifier operates in a low-efficiency state for an extended period, its lifespan will be significantly reduced, thus affecting the performance of the RF chip.

[0095] If the power amplifier integrated in the RF chip shown in Figure 2 is a conventional power amplifier, the above problem is more serious. This is because conventional power amplifiers (such as Class AB and Class B power amplifiers) have a significant reduction in efficiency during power back-off, resulting in extremely high power consumption.

[0096] Load-modulated balanced amplifiers (LMBAs) are a type of power amplifier architecture that has emerged in recent years. In the context of power back-off, LMBAs offer advantages such as extended bandwidth and improved efficiency under power back-off conditions, making them a new research hotspot in fields such as communication base stations and mobile terminals.

[0097] For example, Figure 3 illustrates a comparison of the efficiency of a load-modulated balanced power amplifier, a Class B power amplifier, and a Class AB power amplifier under different power back-off levels. High efficiency can be achieved at the power saturation point (corresponding to 0dB, i.e., no power back-off) for each power amplifier. When power back-off begins, the efficiency of traditional Class AB or Class B power amplifiers decreases significantly; however, the load-modulated balanced power amplifier shows improved efficiency under power back-off, for example, maintaining high efficiency compared to traditional power amplifiers even at a 10dB back-off.

[0098] Therefore, embodiments of this application can integrate a load-modulated balanced power amplifier into the RF chip shown in Figure 2. Specifically, as shown in Figure 4, embodiments of this application can apply a load-modulated balanced power amplifier to the RF chip. In this way, when the load-modulated balanced power amplifier in the RF chip receives a signal transmitted by the baseband subsystem and amplifies the signal to send it to the antenna, it can improve efficiency even under power back-off. The load-modulated balanced power amplifier consumes less power than traditional power amplifiers, thus reducing the heat generated by the RF chip.

[0099] The circuit structure of the load-modulated balanced power amplifier and its working principle when applied to radio frequency systems are briefly explained below.

[0100] Figure 5 shows the circuit structure of a load-modulated balanced power amplifier. This circuit structure includes an input terminal, a power divider 1, a main power amplifier branch, an auxiliary power amplifier branch, and an output terminal. The input terminal is connected to the baseband subsystem, and the output terminal is connected to the antenna. The power divider 1 receives the signal transmitted by the baseband subsystem and then distributes it into two power signals. One power signal is amplified by the main power amplifier branch and then transmitted to the antenna from the output terminal. The other power signal is phase-shifted and amplified by the auxiliary power amplifier branch before being transmitted to the main power amplifier branch. This adjusts the load impedance of the main power amplifier within the main power amplifier branch, thereby improving the efficiency of the main power amplifier.

[0101] It should be noted that the efficiency of the main power amplifier reaches its maximum when its output impedance matches the load impedance (i.e., the input impedance presented by the device connected to the output of the main power amplifier), that is, when the output impedance of the main power amplifier is equal to the load impedance. If the output impedance of the main power amplifier does not match the load impedance, some signal will be reflected back to the main power amplifier, which will waste some energy and reduce the efficiency of the main power amplifier. For the entire load-modulated balanced power amplifier shown in Figure 5, its efficiency mainly depends on the efficiency of the two main power amplifiers. The higher the efficiency of the two main power amplifiers, the higher the efficiency of the entire load-modulated balanced power amplifier.

[0102] Specifically, the main power amplifier branch can include coupler 1, coupler 2, main power amplifier 1, and main power amplifier 2, forming a balanced power amplifier structure. Coupler 1 can evenly distribute the power signal input to the main power amplifier branch into two signals. The two signals enter main power amplifier 1 and main power amplifier 2 respectively. After being amplified by main power amplifier 1 and main power amplifier 2, the two amplified signals are obtained. Coupler 2 can re-merge the two amplified signals into one signal, and the merged signal is transmitted to the antenna through the output terminal. The auxiliary power amplifier branch includes phase shifter 1 and auxiliary power amplifier 1. Phase shifter 1 can perform phase shift processing on the power signal input to the auxiliary power amplifier branch. The auxiliary power amplifier branch can further amplify the power signal. The signal after phase shift processing and amplification is transmitted to the isolation terminal ISO of coupler 2. This signal can be merged with the output signals of main power amplifier 1 and main power amplifier 2 at coupler 2 respectively. In this way, the output impedance of main power amplifier 1 and main power amplifier 2 can be load modulated respectively, that is, the load impedance of main power amplifier 1 and main power amplifier 2 can be adjusted to make the output impedance of main power amplifier 1 and the load impedance more matched.

[0103] It is worth noting that the output impedance of main power amplifiers 1 and 2 decreases as their output power increases. Therefore, in a load-modulated balanced power amplifier, if the output power of main power amplifiers 1 and 2 increases, the isolation terminal ISO of coupler 2 in the auxiliary power amplifier branch acting on the main power amplifier branch can reduce the load impedance of main power amplifiers 1 and 2 in the main power amplifier branch. This makes the output impedance of main power amplifier 1 more matched with its load impedance, and the output impedance of main power amplifier 2 more matched with its load impedance.

[0104] In the circuit structure of the load-modulated balanced power amplifier shown in Figure 5, main power amplifiers 1 and 2 can be configured in Class AB quiescent mode, while auxiliary power amplifier 1 can be configured in Class B or Class C quiescent mode. The power amplifiers in Class B or Class C quiescent mode will turn on later than those in Class AB quiescent mode. Therefore, main power amplifiers 1 and 2 will turn on immediately upon receiving a signal input, while auxiliary power amplifier 1 will turn on later than main power amplifiers 1 and 2.

[0105] The working principle of a load-modulated balanced power amplifier is explained below:

[0106] The load-modulated balanced power amplifier has several different operating states, which can be roughly divided into the following three stages according to the signal strength input to the power divider 1:

[0107] I. Stage where the main power amplifier branch circuit operates independently.

[0108] The baseband signal strength received at the input of power divider 1 from the baseband subsystem is low. At this signal strength, the signal strength input to auxiliary power amplifier 1 is insufficient to turn it on. Therefore, the auxiliary power amplifier branch is in a disconnected state, and only the main power amplifier branch operates independently. The specific working principle is as follows:

[0109] After power divider 1 distributes the power of the baseband signal, it splits the signal into two lower-power signals: a first lower-power signal and a second lower-power signal.

[0110] For the main power amplifier branch, coupler 1 further distributes the power of the first low-power signal, splitting it into two smaller signals, signal 1 and signal 2, with even lower signal strength. Main power amplifier 1 amplifies signal 1 to obtain amplified signal 1, and main power amplifier 2 amplifies signal 2 to obtain amplified signal 2. Coupler 2 then combines amplified signal 1 and amplified signal 2 into a single signal, which is output from the output terminal and ultimately transmitted to the antenna. Because the baseband signal strength is low at this point, the output power of main power amplifiers 1 and 2 (i.e., amplified signal 1 and amplified signal 2) is low, and the output impedance of main power amplifiers 1 and 2 is relatively high, resulting in a lower signal strength at the output terminal.

[0111] For the auxiliary power amplifier branch, the strength of the second low-power signal input to auxiliary power amplifier 1 is not strong enough to turn on auxiliary power amplifier 1, so the auxiliary power amplifier branch is essentially in the off state.

[0112] II. Load modulation stage of auxiliary power amplifier branch.

[0113] The baseband signal strength received at the input of power divider 1 from the baseband subsystem is greater than a first threshold. At this signal strength, the signal strength input to auxiliary power amplifier 1 is sufficient to turn it on, thus the auxiliary power amplifier branch is in a conducting state. At this time, the main power amplifier branch and the auxiliary power amplifier branch operate simultaneously, and the auxiliary power amplifier branch modulates the load of the main power amplifier branch. The specific working principle is as follows:

[0114] When the baseband signal strength received by the input terminal of power divider 1 from the baseband subsystem reaches the first threshold, auxiliary power amplifier 1 of the auxiliary power amplifier branch is just at the critical state of conduction, corresponding to the position of 10dB power backoff in Figure 3. If the baseband signal strength continues to increase (increases to greater than the first threshold), then the auxiliary power amplifier branch will be turned on. At this time, the power signal transmitted by the auxiliary power amplifier branch will act on the isolation terminal ISO of coupler 2 in the main power amplifier branch, thereby realizing load modulation of the output impedance of main power amplifier 1 and main power amplifier 2, that is, adjusting (specifically reducing) the load impedance of main power amplifier 1 and main power amplifier 2 respectively. At this time, the power signal of the auxiliary power amplifier branch enters the isolation terminal ISO of coupler 2. This power signal will be superimposed with the power signals output by main power amplifier 1 and main power amplifier 2. The superimposed signal is finally transmitted to the antenna through the output terminal.

[0115] Because the baseband signal strength is high at this time, the output power of main power amplifier 1 and main power amplifier 2 is high, and the output impedance of main power amplifier 1 and main power amplifier 2 is low (the auxiliary power amplifier branch acts on the isolation terminal ISO of coupler 2, which can reduce the load impedance of main power amplifier 1 and main power amplifier 2), and finally the signal strength output from the output terminal is high.

[0116] III. Output power saturation stage.

[0117] The baseband signal strength received at the input of power divider 1 from the baseband subsystem is greater than or equal to the second threshold. When the baseband signal strength reaches the second threshold, the signal strength input to main power amplifier 1, main power amplifier 2, and auxiliary power amplifier 1 has caused all three amplifiers to simultaneously reach saturation, meaning their output power has reached its saturation point and will not increase further. At this point, the output power reaches its maximum.

[0118] The above is a brief introduction to load-modulated balanced power amplifiers. In the context of power back-off, load-modulated balanced power amplifiers significantly improve efficiency compared to traditional power amplifiers because they utilize the auxiliary power amplifier branch to load-modulate the main power amplifier branch.

[0119] For dual-band applications, Figure 6 shows the circuit structure of a load-modulated balanced power amplifier for such applications. In dual-band applications, a separate load-modulated balanced power amplifier circuit needs to be designed for each frequency band.

[0120] Specifically, the circuit structure includes a band 1 input terminal, a power divider 1, a main power amplifier branch 1, an auxiliary power amplifier branch 1, and a band 1 output terminal. The band 1 input terminal is connected to the baseband subsystem, and the band 1 output terminal is connected to the antenna. The power divider 1 receives signals within the band 1 range transmitted by the baseband subsystem and then distributes these signals into two power signals. One power signal is amplified by the main power amplifier branch 1 and then transmitted to the antenna from the band 1 output terminal. The other power signal is phase-shifted and amplified by the auxiliary power amplifier branch 1 before being transmitted to the main power amplifier branch 1. This adjusts the load impedance of the main power amplifier within the main power amplifier branch 1, thereby improving the efficiency of the main power amplifier.

[0121] Similarly, the circuit structure also includes a band 2 input terminal, a power divider 2, a main power amplifier branch 2, an auxiliary power amplifier branch 2, and a band 2 output terminal. The band 2 input terminal is connected to the baseband subsystem, and the band 2 output terminal is connected to the antenna. The power divider 2 receives signals within the band 2 range transmitted by the baseband subsystem and then distributes these signals into two power signals. One power signal is amplified by the main power amplifier branch 2 and then transmitted to the antenna from the band 2 output terminal. The other power signal is phase-shifted and amplified by the auxiliary power amplifier branch 2 and then transmitted to the main power amplifier branch 2, thereby adjusting the load impedance of the main power amplifier within the main power amplifier branch 1 and improving the efficiency of the main power amplifier.

[0122] For different frequency bands, the circuit parameters of the corresponding load-modulated balanced power amplifiers need to be designed separately. That is, for frequency band 1, power divider 1, coupler 1, coupler 2, main power amplifier 1, main power amplifier 2, phase shifter 1, and auxiliary power amplifier 1 all need to be designed according to the characteristics of frequency band 1; for frequency band 2, power divider 2, coupler 3, coupler 4, main power amplifier 3, main power amplifier 4, phase shifter 2, and auxiliary power amplifier 2 all need to be designed according to the characteristics of frequency band 2. The two frequency bands are independent of each other, and each band contains three power amplifiers. In practical applications, each power amplifier requires separate design of its corresponding input / output impedance matching circuit, power supply control circuit, etc., making the structural design relatively complex and difficult to miniaturize.

[0123] In reality, many applications don't require both frequency bands to work simultaneously; instead, one band operates while the other remains inactive. For example, a phone might have two SIM cards from different carriers: SIM card 1 for carrier 1 and SIM card 2 for carrier 2. Different carriers use different frequency bands. When a user makes a call, they select either SIM card 1 or SIM card 2. If they choose SIM card 1, only the frequency band corresponding to carrier 1 will be used, not the frequency band corresponding to carrier 2. Similarly, if they choose SIM card 2, only the frequency band corresponding to carrier 2 will be used, not the frequency band corresponding to carrier 1.

[0124] Therefore, in dual-band application scenarios where one frequency band operates while the other does not, this application provides a power amplifier circuit that can be applied to the RF chip shown in Figure 2. The power amplifier circuit provided in this application includes a first power divider, a second power divider, a first power amplification unit, a second power amplification unit, and a shared load modulation unit. The first power divider receives and distributes power to a first frequency band signal, the second power divider receives and distributes power to a second frequency band signal, the first power amplification unit amplifies the first frequency band signal, the second power amplification unit amplifies the second frequency band signal, and the shared load modulation unit allows the first and second frequency band signals to share a single load modulation unit, simplifying the circuit structure, reducing circuit cost, and achieving chip miniaturization.

[0125] The power amplifier circuit provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0126] Figure 7 shows a schematic diagram of a power amplifier circuit provided in an embodiment of this application. The power amplifier circuit may include a first frequency band signal input terminal, a second frequency band signal input terminal, a first power divider, a second power divider, a first power amplifier unit, a second power amplifier unit, a common load modulation unit, a first frequency band signal output terminal, and a second frequency band signal output terminal. The first power amplifier unit may include a first coupler, a second coupler, a first power amplifier PA1, a second power amplifier PA2, and a first resistor R1; the second power amplifier unit may include a third coupler, a fourth coupler, a third power amplifier PA3, a fourth power amplifier PA4, and a second resistor R2; the common load modulation unit may include a first phase shifting unit, a second phase shifting unit, and a common power amplifier PA.

[0127] The first signal terminal of the first coupler is connected to the first output terminal of the first power divider, the second signal terminal of the first coupler is connected to the input terminal of the first power amplifier PA1, the third signal terminal of the first coupler is connected to the input terminal of the second power amplifier PA2, and the isolation terminal ISO of the first coupler is connected to the first terminal of the first resistor R1; the second terminal of the first resistor R1 is grounded. The first signal terminal of the second coupler is connected to the first frequency band signal output terminal, the second signal terminal of the second coupler is connected to the output terminal of the first power amplifier PA1, the third signal terminal of the second coupler is connected to the output terminal of the second power amplifier PA2, and the isolation terminal ISO of the second coupler is connected to the output terminal of the common power amplifier PA and the isolation terminal ISO of the fourth coupler.

[0128] The first signal terminal of the third coupler is connected to the first output terminal of the second power divider; the second signal terminal of the third coupler is connected to the input terminal of the third power amplifier PA3; the third signal terminal of the third coupler is connected to the input terminal of the fourth power amplifier PA4; the isolation terminal ISO of the third coupler is connected to the first terminal of the second resistor R2; the second terminal of the second resistor R2 is grounded; the first signal terminal of the fourth coupler is connected to the second frequency band signal output terminal; the second signal terminal of the fourth coupler is connected to the output terminal of the third power amplifier PA3; and the third signal terminal of the fourth coupler is connected to the output terminal of the fourth power amplifier PA4.

[0129] The input terminal of the first phase shifting unit is connected to the second output terminal of the first power divider. The output terminal of the first phase shifting unit is connected to the input terminal of the common power amplifier PA and the output terminal of the second phase shifting unit. The input terminal of the second phase shifting unit is connected to the second output terminal of the second power divider.

[0130] The input terminal of the first power divider is connected to the input terminal of the first frequency band signal, and the input terminal of the second power divider is connected to the input terminal of the second frequency band signal.

[0131] When operating in the first frequency band and not in the second frequency band (i.e., there is a signal input at the first frequency band signal input terminal, but no signal input at the second frequency band signal input terminal), the first power divider can receive the first frequency band signal transmitted by the baseband subsystem and perform power distribution on the first frequency band signal, that is, it can split the first frequency band signal into two equal or unequal first power signals and second power signals. For example, if the strength of the first frequency band signal transmitted by the baseband subsystem is 10dBm, the first power divider can distribute a 7dBm first power signal and a 7dBm second power signal (assuming that the signal at the first output terminal of the first power divider is reduced by 3dB, and the signal at the second output terminal is reduced by 3dB). The first signal terminal of the first coupler can receive the 7dBm first power signal, and then the first coupler further distributes the power of the first power signal, specifically, it can distribute a 4dBm first power sub-signal and a 4dBm second power sub-signal. The first power amplifier amplifies the 4dBm first power sub-signal (assuming amplification of 10dB) to obtain a 14dBm first power sub-amplified signal; the second power amplifier amplifies the 4dBm second power sub-signal (assuming amplification of 10dB) to obtain a 14dBm second power sub-amplified signal. The second coupler receives the 14dBm first power sub-amplified signal through its second signal terminal and the 14dBm second power sub-amplified signal through its third signal terminal. These two signals are combined into a single 17dBm signal, which is then superimposed on the signal input to the isolation terminal of the second coupler. The superimposed signal is finally output through the first frequency band signal output terminal and ultimately to the antenna.

[0132] The first phase-shifting unit can perform phase-shifting processing on the second power signal (for example, according to the characteristics of the first frequency band signal, the first power signal and the second power signal need to have a phase difference of 165°, so the first phase-shifting unit can shift the second power signal by 165°). The shared power amplifier PA can amplify the second power signal. The signal after phase-shifting and amplification is transmitted to the isolation terminal ISO of the second coupler, which can respectively load modulate the output impedance of the first power amplifier PA1 and the second power amplifier PA2, thereby improving the efficiency of the first power amplifier PA1 and the second power amplifier PA2.

[0133] Similarly, when the second frequency band is operating and the first frequency band is not (i.e., there is a signal input at the second frequency band signal input terminal, but no signal input at the first frequency band signal input terminal), the second power divider can receive the second frequency band signal transmitted by the baseband subsystem and perform power distribution on the second frequency band signal, that is, it can split the second frequency band signal into two equal or unequal third power signals and fourth power signals. For example, if the strength of the second frequency band signal transmitted by the baseband subsystem is 10dBm, the second power divider can distribute a 6dBm third power signal and a 5dBm fourth power signal (assuming that the signal at the first output terminal of the second power divider is reduced by 4dB and the signal at the second output terminal is reduced by 5dB). The first signal terminal of the third coupler can receive the 6dBm third power signal and then further distribute the power of the third power signal, specifically distributing a 3dBm third power sub-signal and a 3dBm fourth power sub-signal. The third power amplifier amplifies the 3dBm third power sub-signal (assuming amplification of 10dB) to obtain a 13dBm amplified third power sub-signal; the fourth power amplifier amplifies the 3dBm fourth power sub-signal (assuming amplification of 10dB) to obtain a 13dBm amplified fourth power sub-signal. The fourth coupler receives both the 13dBm third and fourth power sub-signals through its second and third signal terminals, combining them into a single 16dBm signal. This combined signal is then superimposed on the signal input to the isolation terminal of the fourth coupler. The superimposed signal is finally output through the second frequency band signal output terminal and ultimately to the antenna.

[0134] The second phase-shifting unit can perform phase-shifting processing on the fourth power signal (for example, according to the characteristics of the second frequency band signal, the third power signal and the fourth power signal need to have a phase difference of 150°, so the second phase-shifting unit can shift the fourth power signal by 150°). The common power amplifier PA can amplify the fourth power signal. The signal after phase-shifting and amplification is transmitted to the isolation terminal ISO of the fourth coupler, which can then perform load modulation on the output impedance of the third power amplifier PA3 and the fourth power amplifier PA4, thereby improving the efficiency of the third power amplifier PA3 and the fourth power amplifier PA4.

[0135] In dual-band applications, as shown in Figure 7, the power amplifier circuit structure includes only one common load modulation unit (PA). Compared to the structure shown in Figure 6, this circuit structure reduces the number of auxiliary power amplifiers. Reducing the number of auxiliary power amplifiers also eliminates the need for corresponding input impedance matching circuits, output impedance matching circuits, and power supply control circuits, significantly lowering the cost of circuit design. Furthermore, this circuit structure integrates the independent circuit designs for the two frequency bands into a single unit, facilitating chip miniaturization.

[0136] Furthermore, the power amplifier circuit shown in FIG7 provided in this application embodiment can improve the efficiency of the power amplifier circuit even under power back-off because the shared load modulation unit can perform load modulation on the main power amplifier inside the first power amplifier unit when operating in the first frequency band and on the main power amplifier inside the second power amplifier unit when operating in the second frequency band.

[0137] It is worth noting that in the power amplifier circuit shown in Figure 7, the first power divider, first coupler, second coupler, first main power amplifier, second main power amplifier, first resistor, and first phase shifter are all designed to adapt to the characteristics of the first frequency band; the second power divider, third coupler, fourth coupler, third main power amplifier, fourth main power amplifier, second resistor, and second phase shifter are all designed to adapt to the characteristics of the second frequency band. For a shared power amplifier, it can be designed to adapt to both the first and second frequency bands simultaneously. For example, the input and output impedance matching of the shared power amplifier can be designed to cover a wideband configuration that simultaneously encompasses both the first and second frequency bands.

[0138] In a load-modulated balanced power amplifier, the auxiliary power amplifier is used to assist the main power amplifier in its operation. Its output power is smaller than that of the main power amplifier, and its role in the overall load-modulated balanced power amplifier is merely auxiliary. Therefore, the auxiliary power amplifiers for both frequency bands can be replaced by a shared power amplifier. Other components are highly correlated with the frequency band signals, so they are not suitable for sharing.

[0139] This application also provides a power amplifier circuit, the specific circuit structure of which is shown in Figure 8. Compared with the circuit structure shown in Figure 7, this circuit adds four switches: switch 1, switch 2, switch 3, and switch 4. Switch 1 is positioned between the output of the first phase-shifting unit and the input of the common power amplifier PA; switch 2 is positioned between the output of the common power amplifier PA and the isolation terminal ISO of the second coupler; switch 3 is positioned between the output of the second phase-shifting unit and the input of the common power amplifier PA; and switch 4 is positioned between the output of the common power amplifier PA and the isolation terminal ISO of the fourth coupler. Switch 1 and the first phase-shifting unit can be interchanged, and switch 3 and the second phase-shifting unit can also be interchanged.

[0140] Based on the circuit structure shown in Figure 7, when the first frequency band is working and the second frequency band is not working, switches 1 and 2 can be controlled to be in the ON state, and switches 3 and 4 can be controlled to be in the OFF state. When the second frequency band is working and the first frequency band is not working, switches 1 and 2 can be controlled to be in the OFF state, and switches 3 and 4 can be controlled to be in the ON state. In this way, frequency band 1 and frequency band 2 do not affect each other, and the first phase shifting unit and the second phase shifting unit are decoupled, as are the second coupler and the fourth coupler, thereby avoiding power leakage problems.

[0141] This is because, without adding a switch, the outputs of the first and second phase-shifting units would be directly coupled together (corresponding to node N1), and the isolation terminals ISO of the second and fourth couplers would also be directly coupled together (corresponding to node N2). Therefore, the power signal flows in both vertical and horizontal directions at nodes N1 and N2, leading to power leakage when one frequency band is active while the other is inactive.

[0142] To decouple the two frequency bands in design or application and avoid power leakage, this application embodiment also provides another power amplifier circuit. Figure 9 shows another power amplifier circuit provided in this application embodiment. This power amplifier circuit may include a first frequency band signal input terminal, a first frequency band signal output terminal, a second frequency band signal input terminal, a second frequency band signal output terminal, a first power divider, a second power divider, a first power amplifier unit, a second power amplifier unit, and a common load modulation unit. The first and second frequency band signal input terminals are both connected to the baseband subsystem, and the first and second frequency band signal output terminals are both connected to the antenna. The first power amplifier unit may include a first coupler, a second coupler, a first power amplifier PA1, a second power amplifier PA2, a first resistor R1, and a first phase-shift compensation unit; the second power amplifier unit may include a third coupler, a fourth coupler, a third power amplifier PA3, a fourth power amplifier PA4, a second resistor R2, and a second phase-shift compensation unit; the common load modulation unit may include a third resistor, a fourth resistor, and a common power amplifier PA.

[0143] The first signal terminal of the first coupler is connected to the first output terminal of the first power divider through the first phase-shift compensation unit. The second signal terminal of the first coupler is connected to the input terminal of the first power amplifier PA1. The third signal terminal of the first coupler is connected to the input terminal of the second power amplifier PA2. The isolation terminal ISO of the first coupler is connected to the first terminal of the first resistor R1. The second terminal of the first resistor R1 is grounded. The first signal terminal of the second coupler is connected to the first frequency band signal output terminal. The second signal terminal of the second coupler is connected to the output terminal of the first power amplifier PA1. The third signal terminal of the second coupler is connected to the output terminal of the second power amplifier PA2. The isolation terminal ISO of the second coupler is connected to the output terminal of the common power amplifier PA and the isolation terminal ISO of the fourth coupler, respectively.

[0144] The first signal terminal of the third coupler is connected to the first output terminal of the second power divider through the second phase-shift compensation unit. The second signal terminal of the third coupler is connected to the input terminal of the third power amplifier PA3. The third signal terminal of the third coupler is connected to the input terminal of the fourth power amplifier PA4. The isolation terminal ISO of the third coupler is connected to the first terminal of the second resistor R2. The second terminal of the second resistor R2 is grounded. The first signal terminal of the fourth coupler is connected to the second frequency band signal output terminal. The second signal terminal of the fourth coupler is connected to the output terminal of the third power amplifier PA3. The third signal terminal of the fourth coupler is connected to the output terminal of the fourth power amplifier PA4.

[0145] The first end of the third resistor R3 is connected to the second output terminal of the first power divider. The second end of the third resistor R3 is connected to the input terminal of the common power amplifier PA and the first end of the fourth resistor R4. The second end of the fourth resistor R4 is connected to the second output terminal of the second power divider.

[0146] The input terminal of the first power divider is connected to the input terminal of the first frequency band signal, and the input terminal of the second power divider is connected to the input terminal of the second frequency band signal.

[0147] Through experimental simulations, the inventors discovered that designing the first and second power dividers to be exactly the same would prevent power leakage at the junction point N1. Designing the first and second power dividers to be exactly the same means that their power division ratios are exactly the same, for example, each distributing two signals, each reduced by 3dB. Simultaneously, both the first and second power dividers also need to be designed to cover two frequency bands.

[0148] It should be noted that in practical applications, the power signal strength output by the shared load modulation unit needs to differ for different frequency bands. In the circuit structure shown in Figure 9, the first and second power dividers are designed in exactly the same form, and the shared power amplifier PA is shared by both frequency bands. This means that it is impossible to achieve differentiated adjustment between the two frequency bands by adjusting the two power dividers and the shared power amplifier PA. Therefore, the third resistor R3 and the fourth resistor R4 can achieve different signal attenuation, thus allowing the power signal strength output by the shared load modulation unit for the two frequency bands to differ.

[0149] In addition, compared with the circuit structure shown in FIG. 7, the circuit structure shown in FIG. 9 provided in the embodiment of this application changes the position of the first phase shifting unit in FIG. 7 to the position of the first phase shifting compensation unit shown in FIG. 9, and changes the position of the second phase shifting unit in FIG. 7 to the position of the second phase shifting compensation unit shown in FIG. 9, so that the two phase shifting compensation units will not be coupled.

[0150] Referring to Figure 9, when the first frequency band is operating and the second frequency band is not operating (i.e., there is a signal input at the first frequency band signal input terminal, but no signal input at the second frequency band signal input terminal), the first power divider can receive the first frequency band signal transmitted by the baseband subsystem and perform power distribution on the first frequency band signal, that is, it can divide the first frequency band signal into two equal or unequal first power signals and second power signals. For example, if the strength of the first frequency band signal transmitted by the baseband subsystem is 10dBm, the first power divider can distribute a 7dBm first power signal and a 7dBm second power signal (assuming that the signal at the first output terminal of the first power divider is reduced by 3dB, and the signal at the second output terminal is reduced by 3dB). The first phase-shift compensation unit can perform phase-shift processing on the 7dBm first power signal (for example, according to the characteristics of the first frequency band signal, the first power signal and the second power signal need to have a phase difference of 165°, so the first phase-shift compensation unit can shift the second power signal by -165°). The first signal terminal of the first coupler can receive the phase-shifted 7dBm first power signal, and then the first coupler performs power distribution on the first power signal again, specifically distributing a 4dBm first power sub-signal and a 4dBm second power sub-signal. The first power amplifier can amplify the 4dBm first power sub-signal to obtain a 14dBm first power sub-amplified signal (assuming amplification of 10dB); the second power amplifier can amplify the 4dBm second power sub-signal to obtain a 14dBm second power sub-amplified signal (assuming amplification of 10dB). The second coupler receives a 14dBm first power sub-amplified signal through the second signal terminal and a 14dBm second power sub-amplified signal through the third signal terminal. These two signals are combined into a single 17dBm signal, which is then superimposed on the signal input to the isolation terminal of the second coupler. The superimposed signal is finally output through the first frequency band signal output terminal and ultimately output to the antenna.

[0151] The third resistor R3 can reduce the strength of the second power signal (for example, reduce the strength of the 7dBm second power signal by 1dB, so that the strength of the second power signal becomes 6dBm). The common power amplifier PA is used to amplify the second power signal. The amplified signal is transmitted to the isolation terminal ISO of the second coupler, which can load modulate the output impedance of the first power amplifier PA1 and the second power amplifier PA2, thereby improving the efficiency of the first power amplifier PA1 and the second power amplifier PA2.

[0152] Similarly, when the second frequency band is operating and the first frequency band is not (i.e., there is no signal input at the first frequency band signal input terminal, but a signal input at the second frequency band signal input terminal), the second power divider can receive the second frequency band signal transmitted by the baseband subsystem and perform power distribution on the second frequency band signal. That is, it can split the second frequency band signal into two equal or unequal third and fourth power signals. In this case, the second power divider and the first power divider are exactly the same, and the power division ratio is also the same. For example, if the strength of the second frequency band signal transmitted by the baseband subsystem is 10dBm, the second power divider can distribute a 7dBm third power signal and a 7dBm fourth power signal (the second power divider is exactly the same as the first power divider; therefore, the signal at the first output terminal of the second power divider is reduced by 3dB, and the signal at the second output terminal is reduced by 3dB). The second phase-shift compensation unit can perform phase-shift processing on the 7dBm third power signal (for example, according to the characteristics of the second frequency band signal, the third power signal and the fourth power signal need to have a phase difference of 150°, so the second phase-shift compensation unit can shift the second power signal by -150°). The first signal terminal of the third coupler can receive the phase-shifted 7dBm third power signal, and then the third coupler performs power distribution on the third power signal again, specifically distributing a 4dBm third power sub-signal and a 4dBm fourth power sub-signal. The third power amplifier is used to amplify the 4dBm third power sub-signal to obtain a 14dBm third power sub-amplified signal (assuming amplification of 10dB); the fourth power amplifier is used to amplify the 4dBm fourth power sub-signal to obtain a 14dBm fourth power sub-amplified signal (assuming amplification of 10dB). The fourth coupler receives a 14dBm third power sub-amplified signal through the second signal terminal and a 14dBm fourth power sub-amplified signal through the third signal terminal. It combines these two signals into a single 17dBm signal, which is then superimposed with the signal input to the isolation terminal of the fourth coupler. The superimposed signal is finally output through the second frequency band signal output terminal and ultimately output to the antenna.

[0153] The fourth resistor R4 can reduce the strength of the fourth power signal (for example, reducing the strength of the 7dBm fourth power signal by 2dB, making the strength of the fourth power signal 5dBm). The shared power amplifier PA can amplify the fourth power signal. The amplified signal is transmitted to the isolation terminal ISO of the fourth coupler, which can load modulate the output impedance of the third power amplifier PA3 and the fourth power amplifier PA4, thereby improving the efficiency of the third power amplifier PA3 and the fourth power amplifier PA4.

[0154] It is worth noting that the above description of Figure 9 does not take into account the addition of a 90° phase-shifting unit near node N2 (the dashed box in Figure 8).

[0155] To ensure that all the output power of the shared power amplifier PA flows to the isolation terminal ISO of the second coupler when operating in the first frequency band, a high-impedance state (equivalent to an open circuit) needs to be presented at junction point N2 when looking towards the isolation terminal ISO of the fourth coupler. Similarly, to ensure that all the output power of the shared power amplifier PA flows to the isolation terminal ISO of the fourth coupler when operating in the second frequency band, a high-impedance state needs to be presented at junction point N2 when looking towards the isolation terminal ISO of the second coupler. In other words, to decouple the isolation terminals ISO of the second and fourth couplers, a high-impedance state needs to be presented at junction point N2 when looking towards the isolation terminal ISO of the fourth coupler when operating in the first frequency band; and a high-impedance state needs to be presented at junction point N2 when looking towards the isolation terminal ISO of the second coupler when operating in the second frequency band.

[0156] In practical applications, an RF switch is connected between the first frequency band signal output terminal and the antenna, and an RF switch is connected between the second frequency band signal output terminal and the antenna. When the first frequency band is not working, the RF switch connecting the first frequency band signal output terminal and the antenna will be disconnected; when the second frequency band is not working, the RF switch connecting the second frequency band signal output terminal and the antenna will be disconnected.

[0157] For example, as shown in Figure 10, the circuit structure of the RF switch consists of a series transistor M1 and a parallel transistor M2, which can be further divided into two structures (structure 1 and structure 2 in Figure 10). When the RF switch is off, the series transistor M1 is off and the parallel transistor M2 is connected to ground; when the RF switch is on, the series transistor M1 is on and the parallel transistor M2 is off. Depending on the different circuit structures of the RF switches connected to the first frequency band signal output terminal and the second frequency band signal output terminal, the following four cases can be identified:

[0158] Case 1 (refer to Figure 11a): Structure 1 where the first frequency band signal output terminal is connected to an RF switch and the second frequency band signal output terminal is connected to an RF switch.

[0159] When the first frequency band is not operating and the second frequency band is operating, the series transistor M1 connected to the switch at the first frequency band signal output terminal is open, resulting in high impedance at the first frequency band signal output terminal. Additionally, the second and third signal terminals (i.e., the two -3dB ports) of the second coupler are connected to the first power amplifier PA1 and the second power amplifier PA2. When the first frequency band is not operating, these two ports are essentially open-circuit. The first frequency band signal output terminal will exhibit low impedance after passing through the isolation terminal ISO of the second coupler (the isolation terminal of the coupler acts as an impedance converter, transforming high impedance to low impedance and low impedance to high impedance). Therefore, a 90° phase shift needs to be added near the isolation terminal ISO of the second coupler. This involves adding a 90° phase shift unit between the output terminal of the common power amplifier PA and the isolation terminal ISO of the second coupler, effectively performing a quarter-wavelength impedance transformation (again, transforming high impedance to low impedance and low impedance to high impedance). This results in high impedance when viewed from the junction point N2 towards the isolation terminal ISO of the second coupler, achieving high-impedance isolation of the first frequency band when the second frequency band is operating.

[0160] When the first frequency band is operating and the second frequency band is not operating, the second frequency band signal output terminal is connected to the series transistor M1 of the switch. At this time, the series transistor M1 is open, so the second frequency band signal output terminal presents high impedance. Additionally, the second and third signal terminals (i.e., the two -3dB ports) of the fourth coupler are connected to the third power amplifier PA3 and the fourth power amplifier PA4. When the second frequency band is not operating, these two ports are essentially open-circuit. The second frequency band signal output terminal presents low impedance after passing through the isolation terminal ISO of the fourth coupler. Therefore, a 90° phase shift needs to be added near the isolation terminal ISO of the fourth coupler. That is, a 90° phase shift unit needs to be added between the output terminal of the common power amplifier PA and the isolation terminal ISO of the fourth coupler, which acts as a quarter-wavelength impedance transformation. Thus, looking from the junction point N2 towards the isolation terminal ISO of the fourth coupler, high impedance is presented, achieving high-impedance isolation of the second frequency band when the first frequency band is operating.

[0161] Therefore, Case 1 requires adding a 90° phase shift unit (to achieve phase shift within the second frequency band) between the output of the common power amplifier PA and the isolation terminal ISO of the second coupler, and also requires adding a 90° phase shift unit (to achieve phase shift within the first frequency band) between the output of the common power amplifier PA and the isolation terminal ISO of the fourth coupler. The specific circuit structure is shown in Figure 11a.

[0162] Case 2 (refer to Figure 11b): Structure 1, where the first frequency band signal output terminal is connected to an RF switch, and Structure 2, where the second frequency band signal output terminal is connected to an RF switch.

[0163] When the first frequency band is not working and the second frequency band is working, the series transistor M1 connected to the switch at the output terminal of the first frequency band signal is disconnected. Therefore, the output terminal of the first frequency band signal presents high impedance. The output terminal of the first frequency band signal presents low impedance after passing through the isolation terminal ISO of the second coupler. Therefore, a 90° phase shift needs to be added near the isolation terminal ISO of the second coupler. That is, a 90° phase shift unit is added between the output terminal of the common power amplifier PA and the isolation terminal ISO of the second coupler to play the role of quarter-wavelength impedance transformation. In this way, when looking from the junction point N2 to the isolation terminal ISO of the second coupler, a high impedance is presented, so as to achieve high impedance isolation of the first frequency band when the second frequency band is working.

[0164] When the first frequency band is operating and the second frequency band is not operating, the parallel transistor M2 connected to the switch at the second frequency band signal output terminal is conducting to ground. Therefore, the second frequency band signal output terminal presents low impedance. The second frequency band signal output terminal, after passing through the isolation terminal ISO of the fourth coupler, will present high impedance, thus eliminating the need for additional phase shifting. This results in high impedance when viewed from the junction point N2 towards the isolation terminal ISO of the fourth coupler, achieving high-impedance isolation of the second frequency band while the first frequency band is operating.

[0165] Therefore, in case 2, it is only necessary to add a 90° phase shifting unit (to achieve phase shifting in the second frequency band) between the output of the common power amplifier PA and the isolation terminal ISO of the second coupler. It is not necessary to add a phase shifting unit between the output of the common power amplifier PA and the isolation terminal ISO of the fourth coupler. The specific circuit structure is shown in Figure 11b.

[0166] Case 3 (refer to Figure 11c): Structure 2, where the first frequency band signal output terminal is connected to an RF switch, and Structure 1, where the second frequency band signal output terminal is connected to an RF switch.

[0167] When the first frequency band is not operating and the second frequency band is operating, the parallel transistor M2 connected to the switch at the output terminal of the first frequency band is conducting to ground. Therefore, the output terminal of the first frequency band presents low impedance. The output terminal of the first frequency band, after passing through the isolation terminal ISO of the second coupler, will present high impedance, thus eliminating the need for additional phase shifting. This results in high impedance when viewed from the junction point N2 towards the isolation terminal ISO of the second coupler, achieving high-impedance isolation of the first frequency band when the second frequency band is operating.

[0168] When the first frequency band is working and the second frequency band is not working, the second frequency band signal output terminal is connected to the series transistor M1 of the switch. At this time, the series transistor M1 is open, so the second frequency band signal output terminal presents high impedance. The second frequency band signal output terminal presents low impedance after passing through the isolation terminal ISO of the fourth coupler. Therefore, a 90° phase shift needs to be added near the isolation terminal ISO of the fourth coupler. That is, a 90° phase shift unit is added between the output terminal of the common power amplifier PA and the isolation terminal ISO of the fourth coupler, which plays the role of quarter-wavelength impedance transformation. In this way, when looking from the junction point N2 to the isolation terminal ISO of the fourth coupler, a high impedance is presented, so as to achieve high impedance isolation of the second frequency band when the first frequency band is working.

[0169] Therefore, in case 3, it is not necessary to add a phase shifting unit between the output of the common power amplifier PA and the isolation terminal ISO of the second coupler. It is only necessary to add a 90° phase shifting unit (to achieve phase shifting within the first frequency band) between the output of the common power amplifier PA and the isolation terminal ISO of the fourth coupler. The specific circuit structure is shown in Figure 11c.

[0170] Case 4 (refer to Figure 11d): Structure 2 with the first frequency band signal output terminal connected to the RF switch and the second frequency band signal output terminal connected to the RF switch.

[0171] When the first frequency band is not operating and the second frequency band is operating, the parallel transistor M2 connected to the switch at the output terminal of the first frequency band is conducting to ground. Therefore, the output terminal of the first frequency band presents low impedance. The output terminal of the first frequency band, after passing through the isolation terminal ISO of the second coupler, will present high impedance, thus eliminating the need for additional phase shifting. This results in high impedance when viewed from the junction point N2 towards the isolation terminal ISO of the second coupler, achieving high-impedance isolation of the first frequency band when the second frequency band is operating.

[0172] When the first frequency band is operating and the second frequency band is not operating, the parallel transistor M2 connected to the switch at the output terminal of the second frequency band signal is conducting. Therefore, the output terminal of the second frequency band signal presents low impedance. The output terminal of the second frequency band signal, after passing through the isolation terminal ISO of the fourth coupler, will present high impedance, thus eliminating the need for additional phase shifting. This results in high impedance when viewed from the junction point N2 towards the isolation terminal ISO of the fourth coupler, achieving high-impedance isolation of the second frequency band while the first frequency band is operating.

[0173] Therefore, in case 4, it is not necessary to add a phase shifting unit between the output of the power amplifier and the isolation terminal ISO of the second coupler, nor is it necessary to add a phase shifting unit between the output of the power amplifier and the isolation terminal ISO of the fourth coupler. The specific circuit structure is shown in Figure 11d.

[0174] It is important to note that the 90° phase-shifting unit is used to phase-shift another frequency band while operating in one band, achieving high impedance isolation. Furthermore, the operating frequency band must be designed for low insertion loss to ensure that the output power of the shared power amplifier (PA) is not affected by high losses, thus minimizing its efficiency. Therefore, the second and fourth couplers also need to be designed to cover both frequency bands.

[0175] Furthermore, it should be noted that the power dividers, couplers, power amplifiers, and other devices mentioned in the embodiments of this application can all adopt any specific circuit structure that has the functions of a power divider, coupler, and power amplifier. This application does not impose any limitations on the specific internal circuit structure of these devices, as long as the corresponding functions can be achieved. Moreover, the phase-shifting units and phase-shifting compensation units mentioned in the embodiments of this application can be set according to specific phase-shifting requirements. For a 90° phase-shifting unit, it can be designed to achieve a 90° phase shift. The unit that achieves the phase shift can specifically be a phase-shifting circuit composed of components such as capacitors and inductors, or it can utilize a transmission line to achieve the corresponding phase shift. This application does not impose any limitations on this.

[0176] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A power amplification circuit, characterized by, The method comprises the following steps: A common load modulation unit and at least two groups of amplification paths are provided, and the amplification path group comprises a frequency band signal input end, a power distribution unit, a power amplifier unit and a frequency band signal output end; Different frequency band signal input ends are used to receive different frequency band signals sent by a baseband processor at different time periods; For any one of the amplification path groups: The power distribution unit is used to receive the frequency band signal at the frequency band signal input end and distribute the frequency band signal into a first signal and a second signal based on the power distribution relationship of the power distribution unit; The power amplifier unit is used to amplify the first signal and transmit the amplified first signal to the frequency band signal output end; The frequency band signal output end is used to send the signal at the frequency band signal output end to an antenna; The common load modulation unit is used to modulate the second signal and transmit the modulated second signal to the power amplifier unit, wherein the modulated second signal is used to fuse with the first signal to load modulate the power amplifier unit.

2. The circuit of claim 1, wherein, For any one of the amplification path groups: The input end of the power distribution unit is connected with the frequency band signal input end, the first output end of the power distribution unit is connected with the input end of the power amplifier unit, the second output end of the power distribution unit is connected with any one of the input ends of the common load modulation unit, the output end of the common load modulation unit is connected with the isolation end of the power amplifier unit, and the output end of the power amplifier unit is connected with the frequency band signal output end.

3. The circuit of claim 1, wherein, The at least two groups of amplification paths comprise a first amplification path group and a second amplification path group, the first amplification path group comprises a first frequency band signal input end, a first power distribution unit, a first power amplifier unit and a first frequency band signal output end, the second amplification path group comprises a second frequency band signal input end, a second power distribution unit, a second power amplifier unit and a second frequency band signal output end, and different frequency band signals sent at different time periods comprise a first frequency band signal sent at a first time period and a second frequency band signal sent at a second time period; In the first time period, the first frequency band signal input end is used to receive the first frequency band signal sent by the baseband processor, the first power distribution unit is used to distribute the first frequency band signal into a first signal and a second signal based on the power distribution relationship of the first power distribution unit, the first power amplifier unit is used to amplify the first signal and transmit the amplified first signal to the first frequency band signal output end, and the first frequency band signal output end is used to send the signal at the first frequency band signal output end to an antenna; The common load modulation unit is used to modulate the second signal and transmit the modulated second signal to the first power amplifier unit. In the second time period, the second frequency band signal input end is configured to receive a second frequency band signal transmitted by the baseband processor; the second power distribution unit is configured to distribute the second frequency band signal into a first signal and a second signal based on a power distribution relationship of the second power distribution unit; the second power amplification unit is configured to amplify the first signal and transmit the amplified first signal to the second frequency band signal output end; and the second frequency band signal output end is configured to transmit a signal at the second frequency band signal output end to an antenna. The common load modulation unit is configured to modulate the second signal and transmit the modulated second signal to the second power amplification unit.

4. The circuit of claim 3, wherein, The input end of the first power distribution unit is connected to the first frequency band signal input end, the first output end of the first power distribution unit is connected to the input end of the first power amplification unit, and the second output end of the first power distribution unit is connected to the first input end of the common load modulation unit; the output end of the common load modulation unit is connected to the isolation end of the first power amplification unit; and the output end of the first power amplification unit is connected to the first frequency band signal output end. The input end of the second power distribution unit is connected to the second frequency band signal input end, the first output end of the second power distribution unit is connected to the input end of the second power amplification unit, and the second output end of the second power distribution unit is connected to the second input end of the common load modulation unit; the output end of the common load modulation unit is connected to the isolation end of the second power amplification unit; and the output end of the second power amplification unit is connected to the second frequency band signal output end.

5. The circuit of claim 2, wherein, The common load modulation unit comprises a common power amplifier and at least two phase shift units. For any one of the phase shift units, the phase shift unit is configured to perform phase shift processing on the second signal and transmit the phase-shifted second signal to the common power amplifier; and the common power amplifier is configured to perform amplification processing on the phase-shifted second signal and transmit the amplified second signal to the power amplification unit.

6. The circuit of claim 5, wherein, For any one of the phase shift units, the input end of the phase shift unit is connected to the second output end of the power distribution unit, the output end of the phase shift unit is connected to the input end of the common power amplifier, and the output end of the common power amplifier is connected to the isolation end of the power amplification unit.

7. The circuit of claim 2, wherein, The power amplification unit comprises a first coupler, a second coupler, a first power amplifier, a second power amplifier, and a first resistor. The first coupler is configured to divide the first signal into a first sub-signal and a second sub-signal; and the first power amplifier is configured to amplify the first sub-signal. The second power amplifier is configured to amplify the second sub-signal; the second coupler is configured to combine the amplified first sub-signal and the amplified second sub-signal into a first combined signal, and transmit the first combined signal to the frequency band signal output end; and the first resistor is configured to suppress noise.

8. The circuit of claim 7, wherein, The first signal end of the first coupler is connected with the first output end of the power distribution unit, the second signal end of the first coupler is connected with the input end of the first power amplifier, the third signal end of the first coupler is connected with the input end of the second power amplifier, and the isolation end of the first coupler is connected with the first end of the first resistor; the second end of the first resistor is grounded; the first signal end of the second coupler is connected with the frequency band signal output end, the second signal end of the second coupler is connected with the output end of the first power amplifier, the third signal end of the second coupler is connected with the output end of the second power amplifier, and the isolation end of the second coupler is connected with the output end of the common load modulation unit.

9. The circuit of claim 1, wherein, The power distribution unit comprises a power divider.

10. The circuit of claim 6, wherein, The common load modulation unit further comprises at least two first switch units. The output end of the phase shift unit is connected with the input end of the common power amplifier through any one of the first switch units.

11. The circuit of claim 10, wherein, The common load modulation unit further comprises at least two second switch units. The output end of the common power amplifier is connected with the isolation end of the power amplification unit through any one of the second switch units.

12. The circuit of claim 8, wherein, The power amplification unit further comprises a phase shift compensation unit. The phase shift compensation unit is configured to perform phase shift processing on the first signal; and the first coupler is configured to divide the phase shift processed first signal into a first sub-signal and a second sub-signal. The first signal end of the first coupler is connected with the first output end of the power distribution unit through the phase shift compensation unit.

13. The circuit of claim 12, wherein, The power distribution relationship of the power distribution unit in each amplification path group is the same, the common load modulation unit comprises a common power amplifier and at least two second resistors; For any one of the second resistors, the first end of the second resistor is connected with the second output end of the power distribution unit, the second end of the second resistor is connected with the input end of the common power amplifier, and the output end of the common power amplifier is connected with the isolation end of the power amplification unit. The second resistor is configured to reduce the signal strength of the second signal; and the common power amplifier is configured to amplify the second signal with reduced signal strength, and transmit the amplified second signal to the power amplification unit.

14. The circuit of claim 13, wherein, The common load modulation unit further comprises at least one fixed phase shift unit; and the output end of the common load modulation unit is connected with the isolation end of the power amplification unit through any one of the fixed phase shift units.

15. A radio frequency chip, comprising: The power amplification circuit comprises the power amplification circuit according to any one of claims 1-14.

16. An electronic device, comprising: The radio frequency chip comprises the radio frequency chip according to claim 15.

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