Power amplifier circuit, radio frequency chip and electronic equipment

Abstract

The present application provides a power amplifier circuit, a radio frequency chip, and an electronic device, which relate to the field of intelligent terminal technology and can simplify the structure of the power amplifier circuit in a multi-band application scenario. The circuit includes a common load modulation unit and at least two groups of amplification path groups, each group of amplification path groups receives different frequency band signals in different time periods, and a common load modulation unit can perform load modulation on the power amplifier units in different amplification path groups in different time periods.

Description

Technical Field

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

[0002] With the development of high-speed wireless communication technology, the peak-to-average ratio of modulated signals in modern wireless communication systems continues to increase. Complex modulated signals with a high peak-to-average ratio will cause the power amplifier in the RF chip to be in a power-backed state most of the time. In the power-backed state, the efficiency of the power amplifier will be reduced accordingly.

[0003] As a new type of power amplifier, the load modulation balanced power amplifier has higher efficiency in the power back-off state compared to the traditional amplifier. However, for multi-band application scenarios, each band must be equipped with a load modulation balanced power amplifier to improve the efficiency of the power amplifier. The circuit design of this structure is complex, the cost is high, and it is not easy to achieve chip miniaturization. Summary of the invention

[0004] In order to solve the above technical problems, the embodiments of the present application provide a power amplifier circuit, a radio frequency chip and an electronic device, which can simplify the structure of the power amplifier circuit in a multi-band application scenario.

[0005] In the first aspect, an embodiment of the present application provides a power amplifier circuit, which includes: a shared load modulation unit and at least two groups of amplification path groups, the amplification path groups including a frequency band signal input terminal, a power distribution unit, a power amplifier unit and a frequency band signal output terminal; different frequency band signal input terminals are used to respectively receive different frequency band signals sent by a baseband processor in different time periods; for any group of amplification path groups: a power distribution unit is used to receive the frequency band signal at the frequency band signal input terminal, 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; a power amplifier 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 send the signal at the frequency band signal output terminal to an antenna; a shared 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 merge with the first signal to load modulate the power amplifier unit.

[0006] Based on the above scheme, when the power amplifier circuit receives different frequency band signals in different time periods, a common load modulation unit can be used to realize load modulation of the power amplifier units corresponding to different frequency bands under different frequency band signals. Compared with the power amplifier circuit structure in which each frequency band corresponds to a load modulation unit, each frequency band in this scheme shares a common load modulation unit, so the structure of the power amplifier circuit in the multi-band application scenario can be significantly simplified, thereby reducing the circuit cost. Due to the existence of the shared structure, the structure of a power amplifier circuit corresponding to each frequency band in the multi-band application scenario is integrated together, so the present scheme can realize the miniaturization design of the chip.

[0007] In addition, in the power amplifier circuit of the present solution, when the power amplifier unit amplifies the frequency band signal, the load modulation unit performs load modulation on the power amplifier unit, so that the power amplifier unit in the power amplifier circuit can increase the efficiency of the power amplifier unit when amplifying the frequency band signal. In this way, even if the power amplifier circuit works in a power fallback state, its efficiency is improved to a certain extent.

[0008] Exemplarily, the amplification path groups may be two, three or more groups. In the following description of the embodiments of the present application, only two groups are used as an example to illustrate the solution.

[0009] Exemplarily, the baseband processor may be the baseband subsystem mentioned below.

[0010] Exemplarily, different frequency band signal input terminals are used to respectively receive different frequency band signals sent by the baseband processor in different time periods, which means that only one frequency band signal input terminal has a frequency band signal input at the same 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 the same time, or only the second frequency band signal input terminal has a second frequency band signal input at the same time, and the frequency band ranges of the first frequency band signal and the second frequency band signal are different.

[0011] According to the first aspect, for any group of amplification path groups: the input end of the power distribution unit is connected to the frequency band signal input end, the first output end of the power distribution unit is connected to the input end of the power amplification unit, and the second output end of the power distribution unit is connected to any one of the input ends of the common load modulation unit; the output end of the common load modulation unit is connected to the isolation end of the power amplification unit; and the output end of the power amplification unit is connected to the frequency band signal output end.

[0012] Based on the above scheme, for each group of amplification paths, the shared load modulation unit is connected to the internal power distribution unit and power amplification unit thereof, that is, multiple groups of amplification paths can share one power amplification unit, thereby making the power amplification circuit structure in multi-band application scenarios simpler.

[0013] Exemplarily, the power distribution unit may be a power divider mentioned below.

[0014] Exemplarily, the number of input ends of the shared load modulation unit is the same as the number of amplification path groups. If the number of amplification path groups is 2, the number of input ends of the shared load modulation unit is 2; if the number of amplification path groups is 3, the number of input ends of the shared load modulation unit is 3.

[0015] According to the first aspect, or any implementation of the first aspect above, at least two groups of 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 end, a first power distribution unit, a first power amplification unit and a first frequency band signal output end, and the second amplification path group includes a second frequency band signal input end, a second power distribution unit, a second power amplification unit and a second frequency band signal output end; different frequency band signals sent in different time periods include a first frequency band signal sent in the first time period and a second frequency band signal sent in the 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 the first signal and the 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 amplify the amplified signal the first signal after modulation 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; a 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.

[0016] Based on the above scheme, a power amplifier circuit structure is provided when there are two amplification path groups. This scheme corresponds to a dual-band application scenario, that is, a dual-band application scenario mentioned in the embodiments below. It can be achieved that when the first frequency band is working and the second frequency band is not working, the first power amplifier unit is load modulated by a shared load modulation unit to improve the efficiency of the first power amplifier unit; when the second frequency band is working and the first frequency band is not working, the second power amplifier unit is load modulated by a shared load modulation unit to improve the efficiency of the second power amplifier unit. Load modulation of two power amplifier units can be achieved using a shared load modulation unit, and the circuit structure is simple and highly integrated.

[0017] Exemplarily, the first signal and the second signal corresponding to different frequency band signals are different. Although both are expressed 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 from the first frequency band signal and the first signal allocated from the second frequency band signal are different, and the second signal allocated from the first frequency band signal and the second signal allocated from the second frequency band signal are also different.

[0018] Exemplarily, the power allocation relationship of the first power allocation unit may 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 into a first signal of 7dBm and a second signal of 7dBm; the power allocation relationship of the second power allocation unit may 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 into a first signal of 6dBm and a second signal of 5dBm.

[0019] Exemplarily, in a dual-band application scenario, the first signal may be the first power signal and the third power signal mentioned below, and the second signal may be the second power signal and the fourth power signal mentioned below.

[0020] According to the first aspect, or any implementation of the first aspect above, 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; 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; the output end of the second power amplification unit is connected to the second frequency band signal output end.

[0021] 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 second signal after the phase shifting processing to the shared power amplifier; the shared power amplifier is used to amplify the second signal after the phase shifting processing, and transmit the second signal after the amplification processing to the power amplifier unit.

[0022] Based on the above solution, in a multi-band application scenario, the shared load modulation unit includes only one shared power amplifier. Compared with the original circuit that needs to design multiple power amplifiers for multiple frequency bands, the design of a certain number of power amplifiers can be reduced, and the load modulation function can be realized with only one shared power amplifier. Since a certain number of power amplifiers are reduced, the design of the input impedance matching circuit, output impedance matching circuit and power supply control circuit of these power amplifiers will also be reduced, greatly reducing the cost of the circuit.

[0023] Exemplarily, the number of phase shifting units is the same as the number of frequency bands. If the number of frequency bands is two, the number of phase shifting units is also two.

[0024] Exemplarily, if there are two phase shifting units, they may be the first phase shifting unit and the second phase shifting unit mentioned below, wherein the first phase shifting unit may shift the phase by 165°, and the second phase shifting unit may shift the phase by 150°.

[0025] Exemplarily, the phase shift unit may be a phase shift circuit formed by connecting components such as capacitors and inductors, or may be a section of a transmission line that realizes phase shift.

[0026] According to the first aspect, or any implementation method of the first aspect above, for any phase shifting unit, the input end of the phase shifting unit is connected to the second output end of the power distribution unit, the output end of the phase shifting 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.

[0027] 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 end; the first resistor is used to suppress noise.

[0028] Exemplarily, the first coupler and the second coupler may both be 3dB couplers.

[0029] Exemplarily, the first power amplifier and the second power amplifier may both amplify by 10 dB.

[0030] Exemplarily, for a dual-band application scenario, the first coupler may be the first coupler and the third coupler mentioned below, and the second coupler may be the second coupler and the fourth coupler mentioned below.

[0031] Exemplarily, for a dual-band application scenario, the first power amplifier may be the first power amplifier and the third power amplifier mentioned below, and the second power amplifier may be the second power amplifier and the fourth power amplifier mentioned below.

[0032] According to the first aspect, or any implementation of the first aspect above, the first signal end of the first coupler is connected to the first output end of the power distribution unit, the second signal end of the first coupler is connected to the input end of the first power amplifier, the third signal end of the first coupler is connected to the input end of the second power amplifier, and the isolation end of the first coupler is connected to 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 to the frequency band signal output end, the second signal end of the second coupler is connected to the output end of the first power amplifier, the third signal end of the second coupler is connected to the output end of the second power amplifier, and the isolation end of the second coupler is connected to the output end of the common load modulation unit.

[0033] According to the first aspect, or any implementation of the first aspect above, the power distribution unit includes a power divider.

[0034] According to the first aspect, or any implementation of the first aspect above, the common load modulation unit further includes at least two first switch units; the output end of the phase shift unit is connected to the input end of the common power amplifier through any one of the first switch units.

[0035] Based on the above solution, by providing the first switch unit, it is possible to avoid power leakage of the signal at the position between the phase shift units corresponding to different frequency bands, specifically at the position of the node N1 in the figure.

[0036] Illustratively, the first switch unit may be switch 1 and switch 3 mentioned below.

[0037] Exemplarily, the first switch unit may be any device having a switch function, such as a transistor.

[0038] According to the first aspect, or any implementation of the first aspect above, it also includes at least two second switch units; the output end of the common power amplifier is connected to the isolation end of the power amplification unit through any one of the second switch units.

[0039] Based on the above solution, by setting a second switch unit, power leakage can be avoided at the node where the output end of the common power amplifier is connected to the isolation end of each power amplification unit, specifically the node N2 in the figure.

[0040] Illustratively, the second switch unit may be switch 2 and switch 4 mentioned below.

[0041] Exemplarily, the second switch unit may be any device having a switch function, such as a transistor.

[0042] According to the first aspect, or any implementation method of the first aspect above, the power amplification unit also includes a phase shift compensation unit; the phase shift compensation unit is used to perform phase shift processing on the first signal; a first coupler is used to divide the first signal after phase shift processing into a first sub-signal and a second sub-signal; the first signal end of the first coupler is connected to the first output end of the power distribution unit through the phase shift compensation unit.

[0043] Based on the above scheme, by adjusting the position of the phase shifter, that is, adjusting the position of the phase shifter located in the common load modulation unit to the power amplification unit, it is also possible to achieve a phase difference relationship between the first signal and the second signal that is actually required. If the first signal and the second signal have a phase difference relationship that is actually required, then the common load modulation unit can perform load modulation on the power amplification unit.

[0044] Exemplarily, if the phase shift unit shifts the phase by 165°, the phase compensation unit may shift the phase by -165°, that is, they may have an opposite phase relationship.

[0045] 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, and the common load modulation unit includes a common power amplifier and at least two second resistors; for any second resistor, the first end of the second resistor is connected to the second output end of the power distribution unit, the second end of the second resistor 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; the second resistor is used to reduce the signal strength of the second signal; the common power amplifier is used to amplify the second signal after the signal strength is reduced, and transmit the amplified second signal to the power amplification unit.

[0046] Based on the above scheme, the power distribution units in each amplifying path group can be designed to be exactly the same, that is, when the power distribution relationship of the power distribution units in each amplifying path group is the same, power leakage of the signal at the position between each phase shift unit (node ​​N1) can be avoided.

[0047] According to the first aspect, or any implementation of the first aspect above, it also includes at least one fixed phase shift unit; the output end of the common load modulation unit is connected to the isolation end of the power amplification unit through any fixed phase shift unit.

[0048] Based on the above solution, when the fixed phase shift unit is working in one frequency band, it can perform high impedance isolation on other non-working frequency bands to avoid power leakage.

[0049] Exemplarily, the fixed phase shift unit may be a phase shift circuit formed by connecting components such as capacitors and inductors, or may be a section of transmission line that realizes phase shift.

[0050] Exemplarily, the fixed phase shift unit can shift the phase by 90°.

[0051] In a second aspect, an embodiment of the present application provides a radio frequency chip, which includes at least one power amplifier circuit corresponding to the above-mentioned first aspect and any one of the implementation methods of the first aspect.

[0052] The second aspect and any implementation of the second aspect correspond to the first aspect and any implementation of the first aspect respectively. The technical effects corresponding to the second aspect and any implementation of the second aspect can refer to the technical effects corresponding to the above-mentioned first aspect and any implementation of the first aspect, which will not be repeated here.

[0053] In a third aspect, an embodiment of the present application provides an electronic device, which includes at least one radio frequency chip corresponding to the above-mentioned second aspect and any one of the implementation methods of the second aspect.

[0054] The third aspect and any implementation of the third aspect correspond to the second aspect and any implementation of the second aspect, respectively. The technical effects corresponding to the third aspect and any implementation of the third aspect can refer to the technical effects corresponding to the above-mentioned second aspect and any implementation of the second aspect, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 A schematic diagram of a communication system of a terminal provided in an embodiment of the present application;

[0056] Figure 2 A schematic diagram of an application scenario provided for an embodiment of the present application;

[0057] Figure 3 A schematic diagram comparing the efficiencies of various power amplifiers provided in an embodiment of the present application at different power back-off levels;

[0058] Figure 4 A schematic diagram of another application scenario provided for an embodiment of the present application;

[0059] Figure 5 A circuit structure of a load-modulated balanced power amplifier provided in an embodiment of the present application;

[0060] Figure 6 A circuit structure of a load-modulated balanced power amplifier for a dual-band application scenario provided in an embodiment of the present application;

[0061] Figure 7 A schematic diagram of the structure of a power amplifier circuit provided in an embodiment of the present application;

[0062] Figure 8 A schematic diagram of the structure of another power amplifier circuit provided in an embodiment of the present application;

[0063] Fig. 9 A schematic diagram of the structure of another power amplifier circuit provided in an embodiment of the present application;

[0064] Fig.10 is a schematic diagram of a circuit structure of an RF switch shown as an example;

[0065] Figure 11a-Figure 11d The following are schematic diagrams of the structures of the power amplifier circuits in four situations provided in the embodiments of the present application. DETAILED DESCRIPTION

[0066] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0067] The term "and / or" in this article is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0068] The terms "first" and "second" in the description and claims of the embodiments of the present application are used to distinguish different objects rather than to describe a specific order of objects. For example, a first target object and a second target object are used to distinguish different target objects rather than to describe a specific order of target objects.

[0069] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0070] In the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" refers to two or more than two. For example, multiple processing units refer to two or more processing units; multiple systems refer to two or more systems.

[0071] For ease of description, firstly, the relevant concepts involved in the embodiments of the present application are introduced:

[0072] Signal Peak-to-Average Power Ratio (PAPR): refers to the ratio of the maximum instantaneous power of the signal to the average power of the signal. The peak-to-average power ratio is a key indicator for measuring signal volatility. The complexity of the signal directly affects the size of the peak-to-average power ratio. Generally speaking, the more complex the signal, the larger the corresponding peak-to-average power ratio will be.

[0073] Working area of ​​power amplifier (PA): As the input power increases, the power amplifier can work in different working areas, of which the two key areas are the linear area (or amplification area) and the saturation area. In the linear area, the power amplifier can maintain a linear relationship between input power and output power, that is, the output power is a linear amplification of the input power; in the saturation area, even if the input power continues to increase, the output power will not increase, but reach a power saturation point where it will not increase any more (the saturation point refers to the point where the amplifier output power no longer increases with the input power). There is basically no signal distortion in the linear area, but there will be signal distortion in the saturation area.

[0074] Power back-off of a power amplifier: refers to the intentional design of a power amplifier to make its maximum output power slightly lower than the power saturation point, so that the average output power is far away from the power saturation point. Through power back-off, the signal can be amplified without distortion.

[0075] The relationship between peak-to-average ratio and power back-off: In order to achieve high transmission rates and reliable low latency, 5G communication systems need to use more complex signal modulation methods to improve spectrum utilization and communication reliability, but this will cause the peak-to-average ratio of the modulated signal to increase. The increase in the peak-to-average ratio of the modulated signal means that the maximum instantaneous power of the modulated signal is much higher than its average power. The peak-to-average ratio of modulated signals in modern wireless communication systems continues to increase, and the peak-to-average ratio of 5G modulated signals in the future will even reach 12dB. In order to maintain the linearity of the power amplifier, the larger the peak-to-average ratio, the greater the power back-off required for the power amplifier.

[0076] For example, for ease of understanding, assume that the power saturation point of the power amplifier is 20dBm. The peak-to-average ratio is 4dB, the maximum instantaneous output power of the power signal is 19dBm, and the average output power of the power signal falls back to 15dBm, that is, the power amplifier works at an output power close to 15dBm most of the time; if the peak-to-average ratio is increased to 10dB, the maximum instantaneous output power of the power signal is 19dBm, and the average output power of the power signal falls back to 9dBm, that is, the power amplifier works at an output power close to 9dBm most of the time.

[0077] Types of power amplifiers: Power amplifiers can be divided into class AB power amplifiers (setting the power amplifier to class AB static working mode), class B power amplifiers (setting the power amplifier to class B working mode) and class C power amplifiers (setting the power amplifier to class C static working mode) according to their static working state (i.e. the working state when there is no signal input). Among them, the class C power amplifier needs to input a small power signal to turn on its internal transistors, so that the entire class C power amplifier is turned on and enters the working area; the class B power amplifier needs to input a smaller power signal to turn on its internal transistors, so that the entire class B power amplifier is turned on and enters the working area; the class AB power amplifier puts its internal transistors in a critical state of conduction when there is no signal input, and turns on directly once there is a signal input, so that the entire class AB power amplifier is turned on and enters the working area.

[0078] The embodiment of the present application provides a terminal. The terminal provided in the embodiment of the present application can be an electronic device with a power amplifier, such as a mobile phone, a computer, a tablet computer, a personal digital assistant (PDA), a car computer, a television, a smart wearable device, a smart home device, etc. The embodiment of the present application does not specifically limit the specific form of the above-mentioned electronic device.

[0079] The specific structure and purpose of the terminal provided in the embodiment of the present application are described below.

[0080] like Figure 1 As shown, Figure 1 A schematic diagram of a communication system of a terminal provided in an embodiment of the present application is shown, wherein the terminal includes an application subsystem, memory, massive storage, a baseband subsystem, a radio frequency front end (RFFE) device, a radio frequency integrated circuit (RFIC), and an antenna (ANT), and these devices may be coupled via various interconnection buses or other electrical connection methods.

[0081] Figure 1 In the figure, ANT_1 represents the first antenna, ANT_N represents the Nth antenna, and N is a positive integer greater than 1. Tx represents the transmission path, Rx represents the reception path, and different numbers represent different paths. FBRx represents the feedback reception path, PRx represents the main reception path, and DRx represents the diversity reception path. HB represents high frequency, and LB represents low frequency, and the two refer to the relative high and low frequencies. BB represents baseband. It should be understood that Figure 1The marks and components are for illustration purposes only and are only used as a possible implementation method. The embodiments of the present application also include other implementation methods.

[0082] The RF subsystem may include the above-mentioned RF front end (RFFE) devices and radio frequency integrated circuits (RFIC). Specifically, the RF subsystem may include antenna switches, antenna tuners, low noise amplifiers (LNA), power amplifiers (PA), mixers, local oscillators (LO), filters and other electronic devices, which may be integrated into one or more chips as needed. The antenna may sometimes be considered as part of the RF subsystem.

[0083] The RF subsystem can be further divided into an RF receive path and an RF transmit path. The RF receive path can receive RF signals through an antenna, process the RF signals (such as amplification, filtering and down-conversion) to obtain baseband signals, and pass them to the baseband subsystem. The RF transmit path can receive baseband signals from the baseband subsystem, perform RF processing (such as up-conversion, amplification and filtering) on ​​the baseband signals to obtain RF signals, and finally radiate the RF signals into space through an antenna.

[0084] Exemplarily, the above-mentioned electronic devices can be separately arranged in the antenna, the RF front-end circuit and the RF chip as needed. The RF chip can be composed of devices such as a mixer and a local oscillator. Among them, the local oscillator is used to provide a local oscillator signal; the mixer is used to mix the RF signal with the local oscillator signal provided by the local oscillator. The RF chip is sometimes also called a receiver, a transmitter or a transceiver. The RF front-end circuit can be composed of electronic devices such as filters, low-noise amplifiers, power amplifiers, duplexers, and RF switches. The RF switch is used to realize the switching of RF signal reception and transmission, and the switching between different frequency bands; the duplexer is used to isolate the transmission path and the receiving path of the RF signal, so as to ensure that the reception and transmission can work normally when sharing the same antenna; the filter is used to retain the signal within a specific frequency band and filter out the signal outside the specific frequency band; the low-noise amplifier is used to amplify the RF signal of the receiving channel; the power amplifier is used to amplify the RF signal of the transmitting path.

[0085] 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 devices or different integration methods based on power consumption and performance requirements. For example, some devices belonging to the RF front-end circuit are integrated into the RF chip, or even the antenna and RF front-end circuit are integrated into the RF chip.

[0086] In the embodiment of the present application, the power amplifier in the RF front-end circuit may be integrated into the RF chip, or may not be integrated into the RF chip. For ease of description, the embodiment of the present application integrates the power amplifier into the RF chip.

[0087] The baseband subsystem can extract useful information or data bits from the baseband signal, or convert the information or data bits into a baseband signal to be sent. These information or data bits can be data representing user data such as voice, text, video, or control information. For example, the baseband subsystem can implement signal processing operations such as modulation and demodulation, encoding, and decoding. Different wireless access technologies, such as 5G NR and 4G LTE, often have different baseband signal processing operations. Therefore, in order to support the integration of multiple mobile communication modes, the baseband subsystem may include multiple processing cores or multiple HACs at the same time. The baseband subsystem is generally integrated into one or more chips, and the chip that integrates the baseband subsystem is generally called a baseband processor chip (baseband intergreted circuit, BBIC).

[0088] Exemplarily, the baseband subsystem can be used as an independent chip, which can be called a modem chip. The hardware components of the baseband subsystem can be manufactured and sold in units of modem chips. Modem chips are sometimes also called baseband chips or baseband processors. In addition, the baseband subsystem can also be further integrated into a system on chip (SoC) and manufactured and sold in units of SoC chips. The software components of the baseband subsystem can be built into the hardware components of the chip before the chip leaves the factory, or can be imported from other non-volatile memories into the hardware components of the chip after the chip leaves the factory, or these software components can be downloaded and updated online through the network.

[0089] In addition, since the RF signal is an analog signal, the signal processed by the baseband subsystem is mainly a digital signal, and the electronic device also needs an analog-to-digital converter. The analog-to-digital converter includes an analog-to-digital converter (ADC) that converts an analog signal into a digital signal, and a digital-to-analog converter (DAC) that converts a digital signal into an analog signal. It should be understood that the analog-to-digital converter can be set in the baseband subsystem or in the RF subsystem.

[0090] Among them, the application subsystem can be used as the main control system or main computing system of the electronic device to run the main operating system and application programs, manage the software and hardware resources of the entire electronic device, and provide a user interface for users. The application subsystem may include one or more processing cores. In addition, the application subsystem 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.

[0091] The above is a structural description of the communication system of the terminal provided in the embodiment of the present application. Among them, the power amplifier is an important component of the radio frequency subsystem, which is used to amplify the signal of the transmission channel. The amplified signal is transmitted to the antenna, and the antenna radiates the signal into space, so that the terminal can communicate with the base station.

[0092] In the embodiment of the present application, the power amplifier may be integrated into a radio frequency chip. Figure 2 As shown, it is a schematic diagram of an application scenario provided by an embodiment of the present application. The power amplifier can receive the baseband signal sent by the baseband subsystem, amplify the baseband signal, transmit the amplified signal to the antenna, and the antenna radiates the signal into space. Among them, there is also a radio frequency switch between the power amplifier and the antenna, and the radio frequency switch can open or disconnect the path between the power amplifier and the antenna, so as to realize the switching between the signals of each frequency band.

[0093] After research, it was found that although power back-off can enable the power amplifier to amplify the signal without distortion, the efficiency of the power amplifier will decrease as its output power decreases (because power back-off causes the output power of the power amplifier to decrease). Figure 2In the application scenario shown, when the power amplifier receives the signal sent by the baseband subsystem and amplifies the signal to send it to the antenna, the power amplifier needs to work in a power-backed state. In the power-backed state, the efficiency of the power amplifier will decrease, which will increase the power consumption of the power amplifier and make the RF chip more prone to heat. If the power amplifier works in a low-efficiency state for a long time, the life of the power amplifier will be greatly reduced, which will affect the relevant performance of the RF chip.

[0094] If in Figure 2 The power amplifier integrated in the RF chip shown is a traditional power amplifier, and the above problem is more serious because the efficiency of traditional power amplifiers (such as class AB power amplifiers and class B power amplifiers) is greatly reduced when the power is backed off, which will cause the power amplifier to have a huge power consumption.

[0095] Load Modulated Balanced Amplifier (LMBA) is a power amplifier structure that has emerged in recent years. In the context of power backoff, LMBA has the advantages of expanding bandwidth and improving efficiency under power backoff, and has become a new research hotspot in the fields of communication base stations and mobile terminals.

[0096] For example, Figure 3 The figure shows a comparison diagram of the efficiency of load-modulated balanced power amplifiers, class B power amplifiers, and class AB power amplifiers at different power back-off levels. At the power saturation point of each power amplifier (corresponding to 0dB, i.e., no power back-off), very high efficiency can be achieved. When the power starts to back off, for traditional class AB power amplifiers or class B power amplifiers, their efficiency will drop significantly with the power back-off; for load-modulated balanced power amplifiers, the efficiency can be improved to a certain extent under power back-off, for example, when backed off by 10dB, it still has a very high efficiency compared to traditional power amplifiers.

[0097] Therefore, the embodiment of the present application can integrate the load modulation balanced power amplifier into Figure 2 In the RF chip shown. Specifically, Figure 4 As shown, the embodiment of the present application can apply the load modulation balanced power amplifier to the RF chip. In this way, when the load modulation balanced power amplifier in the RF chip receives the signal sent by the baseband subsystem and amplifies the signal to send it to the antenna, it can also improve a certain efficiency under power back-off. The load modulation balanced power amplifier consumes less power than the traditional power amplifier when applied, so it can also reduce the heat generated by the RF chip.

[0098] The following is a brief description of the circuit structure of the load modulated balanced power amplifier and its working principle when applied to the radio frequency system.

[0099] like Figure 5 As shown, it is a circuit structure of a load modulated balanced power amplifier. The circuit structure includes an input end, a power divider 1, a main power amplifier branch, an auxiliary power amplifier branch and an output end. Among them, the input end is connected to the baseband subsystem, and the output end is connected to the antenna. The power divider 1 can receive the signal sent by the baseband subsystem, and then distribute the signal into two power signals, one of which is amplified by the main power amplifier branch and transmitted to the antenna from the output end; the other power signal is phase-shifted and amplified by the auxiliary power amplifier branch, and then the signal is transmitted to the main power amplifier branch, thereby adjusting the load impedance of the main power amplifier inside the main power amplifier branch, thereby improving the efficiency of the main power amplifier.

[0100] It should be noted that when the output impedance of the main power amplifier matches the load impedance (i.e. the input impedance of the device connected to the output end of the main power amplifier), that is, when the output impedance of the main power amplifier is equal to the load impedance, the efficiency of the main power amplifier can reach the maximum. If the output impedance of the main power amplifier does not match the load impedance, then part of the signal will be reflected back to the main power amplifier, which will waste a certain amount of energy and reduce the efficiency of the main power amplifier. Figure 5 For the entire load modulation balanced power amplifier shown in the figure, 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 modulation balanced power amplifier.

[0101] Specifically, the main power amplifier branch may include a coupler 1, a coupler 2, a main power amplifier 1 and a main power amplifier 2, and the main power amplifier branch forms a balanced power amplifier structure. The coupler 1 may evenly distribute the power signal input to the main power amplifier branch into two signals, and the two signals enter the main power amplifier 1 and the main power amplifier 2 respectively. After the main power amplifier 1 and the main power amplifier 2 amplify the signals, two amplified signals are obtained. The coupler 2 may re-combine the two amplified signals into one signal, and the combined signal is transmitted to the antenna through the output end. The auxiliary power amplifier branch includes a phase shifter 1 and an auxiliary power amplifier 1. The 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 processing is transmitted to the isolation end ISO of the coupler 2. The signal can be merged with the signals output by the main power amplifier 1 and the main power amplifier 2 at the coupler 2, respectively. In this way, the output impedance of the main power amplifier 1 and the main power amplifier 2 can be load modulated respectively, that is, the load impedance of the main power amplifier 1 and the main power amplifier 2 is adjusted so that the output impedance of the main power amplifier 1 is more matched with the load impedance, and the output impedance of the main power amplifier 2 is more matched with the load impedance.

[0102] It is worth noting that, for the main power amplifier 1 and the main power amplifier 2, their output impedance will decrease as their output power increases. Therefore, in the load modulation balanced power amplifier, if the output power of the main power amplifier 1 and the main power amplifier 2 increases, the auxiliary power amplifier branch acts on the isolation end ISO of the coupler 2 of the main power amplifier branch, which can reduce the load impedance of the main power amplifier 1 and the main power amplifier 2 in the main power amplifier branch, so that the output impedance of the main power amplifier 1 is more matched with the load impedance of the main power amplifier 1, and the output impedance of the main power amplifier 2 is more matched with the load impedance of the main power amplifier 2.

[0103] exist Figure 5 In the circuit structure of the load modulated balanced power amplifier shown, the main power amplifier 1 and the main power amplifier 2 can be set to the class AB static working mode, and the auxiliary power amplifier 1 can be set to the class B static working mode or the class C static working mode. Among them, the power amplifier in the class B static working mode or the class C static working mode is turned on later than the power amplifier in the class AB static working mode. Therefore, the main power amplifier 1 and the main power amplifier 2 are turned on once a signal is input, and the auxiliary power amplifier 1 is turned on later than the main power amplifier 1 and the main power amplifier 2.

[0104] The working principle of the load modulation balanced power amplifier is explained below:

[0105] The load-modulated balanced power amplifier has several different working states. According to the signal strength input to the input end of the power divider 1, it can be roughly divided into the following three stages:

[0106] 1. The main power amplifier branch works independently.

[0107] The baseband signal strength sent by the baseband subsystem received at the input end of the power divider 1 is low. Under this signal strength, the signal strength input to the auxiliary power amplifier 1 is not enough to turn on the auxiliary power amplifier 1, so the auxiliary power amplifier branch is in a disconnected state. At this time, only the main power amplifier branch works alone. The specific working principle is as follows:

[0108] After the power divider 1 distributes the power of the baseband signal, two paths of a first low-power signal and a second low-power signal with lower signal strength are obtained.

[0109] For the main power amplifier branch, coupler 1 distributes the power of the first low-power signal again, and separates two small signals 1 and 2 with lower signal strength; main power amplifier 1 amplifies small signal 1 to obtain amplified signal 1, and main power amplifier 2 amplifies small signal 2 to obtain amplified signal 2; coupler 2 then combines amplified signal 1 and amplified signal 2 into one signal, which is output from the output end and finally transmitted to the antenna. Since the baseband signal strength is low at this time, the output power of main power amplifier 1 and main power amplifier 2 (i.e., amplified signal 1 and amplified signal 2) is low, the output impedance of main power amplifier 1 and main power amplifier 2 is large, and the strength of the signal output from the output end is low.

[0110] For the auxiliary power amplifier branch, the strength of the second low-power signal input to the auxiliary power amplifier 1 at this time is not sufficient to turn on the auxiliary power amplifier 1, so the auxiliary power amplifier branch is equivalent to being in a disconnected state.

[0111] 2. The auxiliary power amplifier branch performs load modulation stage.

[0112] The baseband signal strength sent by the baseband subsystem received by the input end of the power divider 1 is greater than the first threshold value. Under this signal strength, the signal strength input to the auxiliary power amplifier 1 is sufficient to turn on the auxiliary power amplifier 1, so the auxiliary power amplifier branch is in the on state. At this time, the main power amplifier branch and the auxiliary power amplifier branch work at the same time, and the auxiliary power amplifier branch acts on the main power amplifier branch to load modulate the main power amplifier branch. The specific working principle is as follows:

[0113] When the baseband signal strength sent by the baseband subsystem received by the input end of the power divider 1 reaches the first threshold, the auxiliary power amplifier 1 of the auxiliary power amplifier branch is just in the critical state of conduction, which corresponds to Figure 3 The position where the medium power is backed off by 10dB. If the baseband signal strength continues to increase (increases to be greater than the first threshold), 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 the coupler 2 in the main power amplifier branch, thereby realizing load modulation of the output impedance of the main power amplifier 1 and the main power amplifier 2, that is, adjusting (specifically reducing) the load impedance of the main power amplifier 1 and the load impedance of the main power amplifier 2 respectively. At this time, the power signal of the auxiliary power amplifier branch enters the isolation terminal ISO of the coupler 2, and the power signal will be superimposed with the power signals output by the main power amplifier 1 and the main power amplifier 2. The superimposed signal is finally transmitted to the antenna through the output terminal.

[0114] Since the baseband signal strength is high at this time, the output power of the main power amplifier 1 and the main power amplifier 2 is high, and the output impedance of the main power amplifier 1 and the main power amplifier 2 is low (the auxiliary power amplifier branch acts on the isolation terminal ISO of the coupler 2, which can reduce the load impedance of the main power amplifier 1 and the load impedance of the main power amplifier 2), and finally the strength of the signal output from the output terminal is high.

[0115] 3. Output power saturation stage.

[0116] The baseband signal strength sent by the baseband subsystem received at the input end of the power divider 1 is greater than or equal to the second threshold. When the baseband signal strength reaches the second threshold, the signal strengths input to the main power amplifier 1, the main power amplifier 2 and the auxiliary power amplifier 1 have made the main power amplifier 1, the main power amplifier 2 and the auxiliary power amplifier 1 reach saturation at the same time, that is, the output power of the three power amplifiers has reached the output power saturation point and will not continue to increase. At this time, the output power of the output end reaches the maximum.

[0117] The above is a brief introduction to the load modulation balanced power amplifier. In the context of power back-off, the load modulation balanced power amplifier uses the auxiliary power amplifier branch to load modulate the main power amplifier branch, so compared with the traditional power amplifier, the efficiency can be significantly improved.

[0118] For dual-band application scenarios, such as Figure 6 FIG. 1 is a circuit structure of a load modulation balanced power amplifier for a dual-band application scenario. In a dual-band application scenario, a load modulation balanced power amplifier circuit needs to be designed and adapted for each frequency band.

[0119] Specifically, the circuit structure includes a band 1 input, a power divider 1, a main power amplifier branch 1, an auxiliary power amplifier branch 1 and a band 1 output. The band 1 input is connected to the baseband subsystem, and the band 1 output is connected to the antenna. The power divider 1 can receive a signal within the band 1 range sent by the baseband subsystem, and then distribute the signal into two power signals, one of which is amplified by the main power amplifier branch 1 and transmitted to the antenna from the band 1 output; the other power signal is phase-shifted and amplified by the auxiliary power amplifier branch 1, and then transmitted to the main power amplifier branch 1, thereby adjusting the load impedance of the main power amplifier inside the main power amplifier branch 1, thereby improving the efficiency of the main power amplifier.

[0120] Similarly, the circuit structure also includes a band 2 input, a power divider 2, a main power amplifier branch 2, an auxiliary power amplifier branch 2 and a band 2 output. The band 2 input is connected to the baseband subsystem, and the band 2 output is connected to the antenna. The power divider 2 can receive a signal within the band 2 range sent by the baseband subsystem, and then distribute the signal into two power signals, one of which is amplified by the main power amplifier branch 2 and transmitted to the antenna from the band 2 output; 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 inside the main power amplifier branch 1, thereby improving the efficiency of the main power amplifier.

[0121] For different frequency bands, the circuit parameters of the corresponding load-modulated balanced power amplifier need to be designed separately. That is to say, 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 frequency band contains three power amplifiers. In actual applications, each power amplifier needs to be designed with its corresponding input and output impedance matching circuits, power supply control circuits, etc. The structural design is relatively complex, and it is not easy to achieve chip miniaturization.

[0122] In fact, many application scenarios do not require dual-band operation at the same time, but one frequency band works while the other does not work. For example, a mobile phone has two SIM cards of two operators, SIM card 1 is for operator 1, and SIM card 2 is for operator 2. Different frequency bands are used for different operators. When a user uses a mobile phone to make a call, he will choose card 1 or card 2. If he chooses to make a call through card 1, then only the frequency band corresponding to operator 1 will be used, and the frequency band corresponding to operator 2 will not be used; similarly, if the user chooses to make a call through card 2, then only the frequency band corresponding to operator 2 will be used, and the frequency band corresponding to operator 1 will not be used.

[0123] Therefore, in a dual-band application scenario where one frequency band works and the other frequency band does not work, an embodiment of the present application provides a power amplifier circuit, which can be applied to Figure 2 In the RF chip shown. The power amplifier circuit provided in the embodiment of the present application includes a first power divider, a second power divider, a first power amplifying unit, a second power amplifying unit and a shared load modulation unit. The first frequency band signal is received and power is distributed through the first power divider, and the second frequency band signal is received and power is distributed through the second power divider. The first frequency band signal can be amplified through the first power amplifying unit, and the second frequency band signal can be amplified through the second power amplifying unit. The shared load modulation unit can realize that the first frequency band signal and the second frequency band signal share one load modulation unit, which can simplify the circuit structure, reduce the circuit cost, and achieve the effect of chip miniaturization design.

[0124] The power amplifier circuit provided in the embodiment of the present application is described in detail below with reference to the accompanying drawings.

[0125] like Figure 7 As shown, it is a schematic diagram of the structure of a power amplifier circuit provided in an embodiment of the present 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 shift unit, a second phase shift unit and a common power amplifier PA.

[0126] The first signal end of the first coupler is connected to the first output end of the first power divider, the second signal end of the first coupler is connected to the input end of the first power amplifier PA1, the third signal end of the first coupler is connected to the input end of the second power amplifier PA2, the isolation end ISO of the first coupler is connected to the first end of the first resistor R1; the second end of the first resistor R1 is grounded; the first signal end of the second coupler is connected to the first frequency band signal output end, the second signal end of the second coupler is connected to the output end of the first power amplifier PA1, the third signal end of the second coupler is connected to the output end of the second power amplifier PA2, and the isolation end ISO of the second coupler is respectively connected to the output end of the common power amplifier PA and the isolation end ISO of the fourth coupler.

[0127] The first signal end of the third coupler is connected to the first output end of the second power divider, the second signal end of the third coupler is connected to the input end of the third power amplifier PA3, the third signal end of the third coupler is connected to the input end of the fourth power amplifier PA4, the isolation end ISO of the third coupler is connected to the first end of the second resistor R2; the second end of the second resistor R2 is grounded; the first signal end of the fourth coupler is connected to the second frequency band signal output end, the second signal end of the fourth coupler is connected to the output end of the third power amplifier PA3, and the third signal end of the fourth coupler is connected to the output end of the fourth power amplifier PA4.

[0128] The input end of the first phase shift unit is connected to the second output end of the first power divider, the output end of the first phase shift unit is respectively connected to the input end of the common power amplifier PA and the output end of the second phase shift unit, and the input end of the second phase shift unit is connected to the second output end of the second power divider.

[0129] The input end of the first power divider is connected to the first frequency band signal input end, and the input end of the second power divider is connected to the second frequency band signal input end.

[0130] When the first frequency band is working and the second frequency band is not working (that is, there is a signal input at the first frequency band signal input end and no signal input at the second frequency band signal input end). The first power divider can receive the first frequency band signal sent by the baseband subsystem and perform power distribution on the first frequency band signal, that is, the first frequency band signal can be divided into two equal or unequal first power signals and second power signals. Exemplarily, the strength of the first frequency band signal sent by the baseband subsystem is 10dBm, and the first power divider can distribute a first power signal of 7dBm and a second power signal of 7dBm (assuming that the signal at the first output end of the first power divider is reduced by 3dB, and the signal at the second output end is reduced by 3dB). The first signal end of the first coupler can receive the first power signal of 7dBm, and then the first coupler performs power distribution on the first power signal again, specifically, it can distribute a first power sub-signal of 4dBm and a second power sub-signal of 4dBm. The first power amplifier can amplify the 4dBm first power sub-signal (assuming a 10dB amplification) to obtain a 14dBm first power sub-amplified signal; the second power amplifier can amplify the 4dBm second power sub-signal (assuming a 10dB amplification) to obtain a 14dBm second power sub-amplified signal. The second coupler receives the 14dBm first power sub-amplified signal through the second signal terminal and the 14dBm second power sub-amplified signal through the third signal terminal, combines the two signals into a 17dBm signal, and then superimposes the signal input from the isolation terminal of the second coupler. The superimposed signal is finally output through the first frequency band signal output terminal and finally output to the antenna.

[0131] The first phase shift unit can perform phase shift 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 are required to have a phase difference of 165°, then the first phase shift unit can shift the second power signal by 165°), and the common power amplifier PA can amplify the second power signal. The signal after phase shift processing and amplification processing is transmitted to the isolation end ISO of the second coupler, and the output impedance of the first power amplifier PA1 and the second power amplifier PA2 can be load modulated respectively, thereby improving the efficiency of the first power amplifier PA1 and the second power amplifier PA2.

[0132] Similarly, when the second frequency band is working and the first frequency band is not working (that is, there is a signal input at the second frequency band signal input end, and there is no signal input at the first frequency band signal input end). The second power divider can receive the second frequency band signal sent by the baseband subsystem, and perform power distribution on the second frequency band signal, that is, the second frequency band signal can be divided into two equal or unequal third power signals and fourth power signals. Exemplarily, the strength of the second frequency band signal sent by the baseband subsystem is 10dBm, and the second power divider can distribute a third power signal of 6dBm and a fourth power signal of 5dBm (assuming that the signal at the first output end of the second power divider is reduced by 4dB, and the signal at the second output end is reduced by 5dB). The first signal end of the third coupler can receive the third power signal of 6dBm, and then perform power distribution on the third power signal again, specifically distributing a third power sub-signal of 3dBm and a fourth power sub-signal of 3dBm. The third power amplifier is used to amplify the third power sub-signal of 3dBm (assuming amplification of 10dB) to obtain a third power sub-amplified signal of 13dBm; the fourth power amplifier is used to amplify the fourth power sub-signal of 3dBm (assuming amplification of 10dB) to obtain a fourth power sub-amplified signal of 13dBm. The fourth coupler receives the third power sub-amplified signal of 13dBm through the second signal end, and receives the fourth power sub-amplified signal of 13dBm through the third signal end, combines the two signals into a 16dBm signal, and then superimposes the signal input from the isolation end of the fourth coupler, and the superimposed signal is finally output through the second frequency band signal output end, and finally output to the antenna.

[0133] The second phase shift unit can perform phase shift 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 are required to have a phase difference of 150°, then the second phase shift unit can shift the fourth power signal by 150°), and the common power amplifier PA can amplify the fourth power signal, and the signal after phase shift processing and amplification processing is transmitted to the isolation end ISO of the fourth coupler, and then the output impedance of the third power amplifier PA3 and the fourth power amplifier PA4 can be load modulated, thereby improving the efficiency of the third power amplifier PA3 and the fourth power amplifier PA4.

[0134] In dual-band application scenarios, Figure 7 It can be seen from the circuit structure of the power amplifier circuit shown in FIG. 1 that the shared load modulation unit includes only one shared power amplifier PA. Figure 6 The circuit structure shown can reduce one auxiliary power amplifier, and after reducing one auxiliary power amplifier, the corresponding input impedance matching circuit, output impedance matching circuit and power supply control circuit can also be reduced, thereby greatly reducing the cost of circuit design. Figure 6The structure shown integrates the independent circuit designs of the two frequency bands into one, which is conducive to the miniaturization of the chip design.

[0135] In addition, the embodiments of the present application provide Figure 7 In the power amplifier circuit shown, since the shared load modulation unit can load modulate the main power amplifier inside the first power amplifier unit when operating in the first frequency band, and load modulate the main power amplifier inside the second power amplifier unit when operating in the second frequency band, the efficiency of the power amplifier circuit can be improved even under power backoff.

[0136] It is worth noting that in Figure 7 In the power amplifier circuit, the first power divider, the first coupler, the second coupler, the first main power amplifier, the second main power amplifier, the first resistor and the first phase shifter are all designed and adapted according to the characteristics of the first frequency band; the second power divider, the third coupler, the fourth coupler, the third main power amplifier, the fourth main power amplifier, the second resistor and the second phase shifter are all designed and adapted according to the characteristics of the second frequency band. For the shared power amplifier, it can be designed to adapt to the first frequency band and the second frequency band at the same time. For example, the input and output impedance matching of the shared power amplifier can be designed to be a broadband form that covers both the first frequency band and the second frequency band.

[0137] For load modulation balanced power amplifiers, the auxiliary power amplifier is used to assist the main power amplifier in working. Its output power is smaller than that of the main power amplifier, and its role in the entire load modulation balanced power amplifier is only an auxiliary role. Therefore, the auxiliary power amplifiers of the two frequency bands can be replaced by a common power amplifier, while other devices have a high correlation with the frequency band signals, so other devices are not suitable for sharing.

[0138] The present application also provides a power amplifier circuit, the specific circuit structure is as follows Figure 8 Compared with Figure 7 The circuit structure shown in the figure has four additional switches, namely switch 1, switch 2, switch 3 and switch 4. Switch 1 is set between the output end of the first phase shift unit and the input end of the common power amplifier PA, switch 2 is set between the output end of the common power amplifier PA and the isolation end ISO of the second coupler, switch 3 is set between the output end of the second phase shift unit and the input end of the common power amplifier PA, and switch 4 is set between the output end of the common power amplifier PA and the isolation end ISO of the fourth coupler. Switch 1 can also be exchanged with the first phase shift unit, and switch 3 can also be exchanged with the second phase shift unit.

[0139] based on Figure 7In the circuit structure shown, 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 can be made to have no influence on each other, so that the first phase shift unit and the second phase shift unit are decoupled, and the second coupler and the fourth coupler are decoupled, thereby avoiding the problem of power leakage.

[0140] This is because, if no switch is added, the output ends of the first phase shift unit and the second phase shift unit will be directly coupled together (corresponding to the position of node N1), and the isolation end ISO of the second coupler and the isolation end ISO of the fourth coupler will be directly coupled together (corresponding to the position of node N2). Therefore, the power signal flows in two directions, up and down, at the nodes N1 and N2. When one frequency band is working and the other frequency band is not working, there will be a problem of power leakage.

[0141] In order to decouple the two frequency bands from each other in design or application and avoid power leakage, the present application also provides another power amplifier circuit. Fig. 9 As shown, another power amplifier circuit provided by an embodiment of the present application. The 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 shared load modulation unit. Among them, the first frequency band signal input terminal and the second frequency band signal input terminal are both connected to the baseband subsystem, and the first frequency band signal output terminal and the second frequency band signal output terminal 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 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 compensation unit; the shared load modulation unit may include a third resistor, a fourth resistor and a shared power amplifier PA.

[0142] The first signal end of the first coupler is connected to the first output end of the first power divider through the first phase shift compensation unit, the second signal end of the first coupler is connected to the input end of the first power amplifier PA1, the third signal end of the first coupler is connected to the input end of the second power amplifier PA2, the isolation end ISO of the first coupler is connected to the first end of the first resistor R1; the second end of the first resistor R1 is grounded; the first signal end of the second coupler is connected to the first frequency band signal output end, the second signal end of the second coupler is connected to the output end of the first power amplifier PA1, the third signal end of the second coupler is connected to the output end of the second power amplifier PA2, and the isolation end ISO of the second coupler is respectively connected to the output end of the common power amplifier PA and the isolation end ISO of the fourth coupler.

[0143] The first signal end of the third coupler is connected to the first output end of the second power divider through the second phase shift compensation unit, the second signal end of the third coupler is connected to the input end of the third power amplifier PA3, the third signal end of the third coupler is connected to the input end of the fourth power amplifier PA4, the isolation end ISO of the third coupler is connected to the first end of the second resistor R2; the second end of the second resistor R2 is grounded; the first signal end of the fourth coupler is connected to the second frequency band signal output end, the second signal end of the fourth coupler is connected to the output end of the third power amplifier PA3, and the third signal end of the fourth coupler is connected to the output end of the fourth power amplifier PA4.

[0144] The first end of the third resistor R3 is connected to the second output end of the first power divider, the second end of the third resistor R3 is respectively connected to the input end of the common power amplifier PA and the first end of the fourth resistor R4, and the second end of the fourth resistor R4 is connected to the second output end of the second power divider.

[0145] The input end of the first power divider is connected to the first frequency band signal input end, and the input end of the second power divider is connected to the second frequency band signal input end.

[0146] The inventors have found through experimental simulation that if the first power divider and the second power divider are designed in exactly the same form, it can be achieved that no power leakage occurs at the junction N1. The first power divider and the second power divider are designed in exactly the same form, which means that their power division ratios are exactly the same, for example, both distribute two signals with each signal reduced by 3dB. At the same time, the first power divider and the second power divider also need to be designed as power dividers that can cover two frequency bands.

[0147] It should be noted that in practical applications, for different frequency bands, the strength of the power signal output by the shared load modulation unit needs to be different. Fig. 9In the circuit structure shown, the first power divider and the second power divider are both in the same form, and the common power amplifier PA is shared by the two frequency bands, that is, it is impossible to achieve differentiated regulation of the two frequency bands by adjusting the two power dividers and the common power amplifier PA. Therefore, the third resistor R3 and the fourth resistor R4 can achieve different signal attenuation, that is, the strength of the power signal output by the common load modulation unit of the two frequency bands can be different.

[0148] In addition, the embodiments of the present application provide Fig. 9 The circuit structure shown is compared with Figure 7 The circuit structure shown in Figure 7 The position of the first phase shift unit in is changed to Fig. 9 The position of the first phase compensation unit shown in FIG. Figure 7 The position of the second phase shift unit in is changed to Fig. 9 The position of the second phase compensation unit is shown so that the two phase compensation units will not have a coupling relationship.

[0149] Reference Fig. 9, when the first frequency band is working and the second frequency band is not working (that is, there is a signal input at the first frequency band signal input end and no signal input at the second frequency band signal input end). The first power divider can receive the first frequency band signal sent by the baseband subsystem and perform power distribution on the first frequency band signal, that is, the first frequency band signal can be divided into two equal or unequal first power signals and second power signals. Exemplarily, the strength of the first frequency band signal sent by the baseband subsystem is 10dBm, and the first power divider can distribute a first power signal of 7dBm and a second power signal of 7dBm (assuming that the signal at the first output end of the first power divider is reduced by 3dB, and the signal at the second output end is reduced by 3dB). The first phase 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°, then the first phase compensation unit can shift the second power signal by -165°), the first signal end of the first coupler can receive the 7dBm first power signal after phase shift processing, and then the first coupler performs power distribution on the first power signal again, specifically, distributes 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 a 10dB amplification); the second power amplifier can amplify the 4dBm second power sub-signal to obtain a 14dBm second power sub-amplified signal (assuming a 10dB amplification). The second coupler receives the first power sub-amplified signal of 14dBm through the second signal end, and receives the second power sub-amplified signal of 14dBm through the third signal end, combines the two signals into a 17dBm signal, and then superimposes the signal with the signal input from the isolation end of the second coupler. The superimposed signal is finally output through the first frequency band signal output end and finally output to the antenna.

[0150] The third resistor R3 can reduce the strength of the second power signal (for example, the strength of the second power signal of 7dBm is reduced by 1dB, and the strength of the second power signal becomes 6dBm). The common power amplifier PA is used to amplify the second power signal, and the amplified signal is transmitted to the isolation end ISO of the second coupler. The output impedance of the first power amplifier PA1 and the second power amplifier PA2 can be load modulated, thereby improving the efficiency of the first power amplifier PA1 and the second power amplifier PA2.

[0151] Similarly, when the second frequency band is working and the first frequency band is not working (that is, there is no signal input at the first frequency band signal input end, and there is a signal input at the second frequency band signal input end). The second power divider can receive the second frequency band signal sent by the baseband subsystem and perform power distribution on the second frequency band signal, that is, the second frequency band signal can be divided into two equal or unequal third power signals and fourth power signals. At this time, the second power divider and the first power divider are exactly the same, and the power division ratio is also the same. Exemplarily, the strength of the second frequency band signal sent by the baseband subsystem is 10dBm, and the second power divider can distribute a third power signal of 7dBm and a fourth power signal of 7dBm (the second power divider is exactly the same as the first power divider, so the signal at the first output end of the second power divider is reduced by 3dB, and the signal at the second output end 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°, then the second phase shift compensation unit can shift the second power signal by -150°), the first signal end of the third coupler can receive the 7dBm third power signal after phase shift processing, and then the third coupler performs power distribution on the third power signal again, specifically, distributes 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 a 10dB amplification); the fourth power amplifier is used to amplify the 4dBm fourth power sub-signal to obtain a 14dBm fourth power sub-amplified signal (assuming a 10dB amplification). The fourth coupler receives the third power sub-amplified signal of 14dBm through the second signal end, and receives the fourth power sub-amplified signal of 14dBm through the third signal end, combines the two signals into a 17dBm signal, and then superimposes the signal with the signal input from the isolation end of the fourth coupler. The superimposed signal is finally output through the second frequency band signal output end and finally output to the antenna.

[0152] The fourth resistor R4 can reduce the strength of the fourth power signal (for example, the strength of the fourth power signal of 7dBm is reduced by 2dB, and the strength of the fourth power signal becomes 5dBm), and the common power amplifier PA can amplify the fourth power signal, and the amplified signal is transmitted to the isolation end ISO of the fourth coupler, and the output impedance of the third power amplifier PA3 and the fourth power amplifier PA4 can be load modulated, thereby improving the efficiency of the third power amplifier PA3 and the fourth power amplifier PA4.

[0153] It is worth noting that the above Fig. 9 The descriptions do not consider adding a 90° phase shift unit near the N2 node ( Figure 8 (the dotted box in the figure).

[0154] In order to ensure that the output power of the shared power amplifier PA flows entirely to the isolation terminal ISO of the second coupler when operating in the first frequency band, it is necessary to present a high impedance state (i.e., equivalent to a disconnected open circuit state) when looking at the isolation terminal ISO of the fourth coupler at the junction point N2; in order to ensure that the output power of the shared power amplifier PA flows entirely to the isolation terminal ISO of the fourth coupler when operating in the second frequency band, it is necessary to present a high impedance state when looking at the isolation terminal ISO of the second coupler at the junction point N2. In other words, in order to decouple the isolation terminal ISO of the second coupler from the isolation terminal ISO of the fourth coupler, it is necessary to present a high impedance state when looking at the isolation terminal ISO of the fourth coupler at the junction point N2 when operating in the first frequency band; and present a high impedance state when looking at the isolation terminal ISO of the second coupler at the junction point N2 when operating in the second frequency band.

[0155] In actual application, 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 connected between the first frequency band signal output terminal and the antenna will be disconnected; when the second frequency band is not working, the RF switch connected between the second frequency band signal output terminal and the antenna will be disconnected.

[0156] For example, Fig.10 As shown, the circuit structure of the RF switch is composed of a series transistor M1 and a parallel transistor M2, which can specifically include two structures (such as Fig.10 When the RF switch is turned off, the series transistor M1 is turned off and the parallel transistor M2 is turned on to the ground; when the RF switch is turned on, the series transistor M1 is turned on and the parallel transistor M2 is turned off. According to 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, it can be divided into the following four cases:

[0157] Case 1 (refer to Fig.11a ): The first frequency band signal output end is connected to the structure 1 of the RF switch, and the second frequency band signal output end is connected to the structure 1 of the RF switch.

[0158] When the first frequency band is not working and the second frequency band is working, the signal output end of the first frequency band is connected to the series transistor M1 of the switch. At this time, the series transistor M1 is disconnected, so the signal output end of the first frequency band presents high impedance. In addition, the second signal end and the third signal end (i.e., 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 working, these two ports are equivalent to an open circuit state. The signal output end of the first frequency band will present low impedance after passing through the isolation end ISO of the second coupler (the isolation end of the coupler has the function of transforming impedance, i.e., high impedance becomes low impedance, and low impedance becomes high impedance). Therefore, it is necessary to add a 90° phase shift near the isolation end ISO of the second coupler, i.e., add a 90° phase shift unit between the output end of the common power amplifier PA and the isolation end ISO of the second coupler, which plays the role of quarter-wavelength impedance transformation (also the role of transforming impedance, i.e., high impedance becomes low impedance, and low impedance becomes high impedance). In this way, high impedance is presented when looking from the junction point N2 to the isolation end ISO of the second coupler, so as to achieve high impedance isolation of the first frequency band when working in the second frequency band.

[0159] When the first frequency band is working and the second frequency band is not working, the second frequency band signal output end is connected to the series transistor M1 of the switch, and the series transistor M1 is disconnected at this time, so the second frequency band signal output end presents high impedance. In addition, the second signal end and the third signal end (i.e., the two -3dB ports) of the fourth coupler are connected to the third power amplifier PA3 and the fourth power amplifier PA4, and when the second frequency band is not working, these two ports are equivalent to an open circuit state. The second frequency band signal output end will present low impedance after passing through the isolation end ISO of the fourth coupler, so it is necessary to add a 90° phase shift near the isolation end ISO of the fourth coupler, that is, to add a 90° phase shift unit between the output end of the common power amplifier PA and the isolation end ISO of the fourth coupler, which plays a role of quarter-wavelength impedance transformation, so that high impedance is presented when looking from the junction point N2 to the isolation end ISO of the fourth coupler, so as to achieve high impedance isolation of the second frequency band when working in the first frequency band.

[0160] Therefore, in case 1, it is necessary to add a 90° phase shift unit between the output end of the common power amplifier PA and the isolation end ISO of the second coupler (to achieve phase shift within the second frequency band), and it is also necessary to add a 90° phase shift unit between the output end of the common power amplifier PA and the isolation end ISO of the fourth coupler (to achieve phase shift within the first frequency band). The specific circuit structure is as follows: Fig.11a shown.

[0161] Case 2 (refer to Fig.11b ): The first frequency band signal output end is connected to structure 1 of the RF switch, and the second frequency band signal output end is connected to structure 2 of the RF switch.

[0162] When the first frequency band is not working and the second frequency band is working, the signal output end of the first frequency band is connected to the series transistor M1 of the switch. At this time, the series transistor M1 is disconnected, so the signal output end of the first frequency band presents high impedance, and the signal output end of the first frequency band will present low impedance after passing through the isolation end ISO of the second coupler. Therefore, it is necessary to add a 90° phase shift near the isolation end ISO of the second coupler, that is, to add a 90° phase shift unit between the output end of the common power amplifier PA and the isolation end ISO of the second coupler, which plays a quarter-wavelength impedance transformation role. In this way, high impedance is presented when looking from the junction point N2 to the isolation end ISO of the second coupler, so as to achieve high-impedance isolation of the first frequency band when working in the second frequency band.

[0163] When the first frequency band is working and the second frequency band is not working, the second frequency band signal output end is connected to the parallel transistor M2 of the switch. At this time, the parallel transistor M2 is turned on to the ground, so the second frequency band signal output end presents low resistance, and the second frequency band signal output end will present high resistance after passing through the isolation end ISO of the fourth coupler, and obviously no additional phase shift is required. In this way, high resistance is presented when looking from the junction point N2 to the isolation end ISO of the fourth coupler, so as to achieve high resistance isolation of the second frequency band when working in the first frequency band.

[0164] Therefore, in case 2, it is only necessary to add a 90° phase shift unit between the output end of the common power amplifier PA and the isolation end ISO of the second coupler (to achieve phase shift within the second frequency band), and it is not necessary to add a phase shift unit between the output end of the common power amplifier PA and the isolation end ISO of the fourth coupler. The specific circuit structure is as follows: Fig.11b shown.

[0165] Case 3 (refer to Fig.11c ): The first frequency band signal output end is connected to structure 2 of the RF switch, and the second frequency band signal output end is connected to structure 1 of the RF switch.

[0166] When the first frequency band is not working and the second frequency band is working, the first frequency band signal output end is connected to the parallel transistor M2 of the switch. At this time, the parallel transistor M2 is turned on to the ground, so the first frequency band signal output end presents low resistance, and the first frequency band signal output end will present high resistance after passing through the isolation end ISO of the second coupler, and obviously no additional phase shift is required. In this way, high resistance is presented when looking from the junction point N2 to the isolation end ISO of the second coupler, so as to achieve high resistance isolation of the first frequency band when working in the second frequency band.

[0167] When the first frequency band is working and the second frequency band is not working, the signal output end of the second frequency band is connected to the series transistor M1 of the switch. At this time, the series transistor M1 is disconnected, so the signal output end of the second frequency band presents high impedance, and the signal output end of the second frequency band will present low impedance after passing through the isolation end ISO of the fourth coupler. Therefore, it is necessary to add a 90° phase shift near the isolation end ISO of the fourth coupler, that is, add a 90° phase shift unit between the output end of the common power amplifier PA and the isolation end ISO of the fourth coupler to play a quarter-wavelength impedance transformation role. In this way, high impedance is presented when looking from the combination point N2 to the isolation end ISO of the fourth coupler, so as to achieve high-impedance isolation of the second frequency band when working in the first frequency band.

[0168] Therefore, in case 3, there is no need to add a phase shift unit between the output end of the common power amplifier PA and the isolation end ISO of the second coupler. It is only necessary to add a 90° phase shift unit (to achieve phase shift within the first frequency band) between the output end of the common power amplifier PA and the isolation end ISO of the fourth coupler. The specific circuit structure is as follows: Fig.11c shown.

[0169] Case 4 (refer to Fig.11d ): The first frequency band signal output end is connected to the structure 2 of the RF switch, and the second frequency band signal output end is connected to the structure 2 of the RF switch.

[0170] When the first frequency band is not working and the second frequency band is working, the first frequency band signal output end is connected to the parallel transistor M2 of the switch. At this time, the parallel transistor M2 is turned on to the ground, so the first frequency band signal output end presents low resistance, and the first frequency band signal output end will present high resistance after passing through the isolation end ISO of the second coupler, and obviously no additional phase shift is required. In this way, high resistance is presented when looking from the junction point N2 to the isolation end ISO of the second coupler, so as to achieve high resistance isolation of the first frequency band when working in the second frequency band.

[0171] When the first frequency band is working and the second frequency band is not working, the second frequency band signal output end is connected to the parallel transistor M2 of the switch, and the parallel transistor M2 is turned on at this time, so the second frequency band signal output end presents low resistance, and the second frequency band signal output end will present high resistance after passing through the isolation end ISO of the fourth coupler, and obviously no additional phase shift is required. In this way, high resistance is presented when looking from the junction point N2 to the isolation end ISO of the fourth coupler, so as to achieve high resistance isolation of the second frequency band when working in the first frequency band.

[0172] Therefore, in case 4, it is not necessary to add a phase shift unit between the output end of the power amplifier and the isolation end ISO of the second coupler, nor is it necessary to add a phase shift unit between the output end of the power amplifier and the isolation end ISO of the fourth coupler. The specific circuit structure is as follows: Fig.11d shown.

[0173] It should be noted that the 90° phase shift unit is used to shift the phase of another frequency band when working in one frequency band to achieve high impedance isolation. The working frequency band must also be designed with low insertion loss to ensure that the output power of the shared power amplifier PA will not be affected by high loss in the working frequency band and affect its efficiency. Therefore, the second coupler and the fourth coupler also need to be designed to cover two frequency bands.

[0174] In addition, it is worth noting that the power dividers, couplers, power amplifiers and other devices mentioned in the embodiments of the present application can adopt any specific circuit structure with power divider functions, coupler functions and power amplifier functions. The present application does not impose any restrictions on the specific circuit structures inside these devices, as long as the corresponding functions can be achieved. Moreover, the phase shift unit and phase shift compensation unit mentioned in the embodiments of the present application can be set according to the specific phase shift requirements. For the 90° phase shift unit, it can be designed to achieve a 90° phase shift. The unit that realizes the phase shift can be a phase shift circuit formed by connecting components such as capacitors and inductors, or it can be a corresponding phase shift achieved by using a section of transmission line. The present application does not impose any restrictions on this.

[0175] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A power amplifier circuit, characterized in that: include: A shared load modulation unit and at least two amplification path groups, wherein the amplification path groups include a frequency band signal input terminal, a power distribution unit, a power amplification unit and a frequency band signal output terminal; The different frequency band signal input terminals are used to respectively receive different frequency band signals sent by the baseband processor in different time periods; For any set of the amplification pathways: 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 amplification 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 the antenna; 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 merge with the first signal to load modulate the power amplification unit; For any set of the amplification pathways: The input end of the power distribution unit is connected to the frequency band signal input end, the first output end of the power distribution unit is connected to the input end of the power amplification unit, and the second output end of the power distribution unit is connected to any one of the input ends of the common load modulation unit; the output end of the common load modulation unit is connected to the isolation end of the power amplification unit; and the output end of the power amplification unit is connected to the frequency band signal output end.

2. The circuit according to claim 1, characterized in that At least two groups of the 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 end, a first power distribution unit, a first power amplification unit and a first frequency band signal output end, and the second amplification path group includes a second frequency band signal input end, a second power distribution unit, a second power amplification unit and a second frequency band signal output end; different frequency band signals sent in different time periods include a first frequency band signal sent in the first time period and a second frequency band signal sent in the second time period; In the first time period, the first frequency band signal input terminal is used to receive the first frequency band signal sent by the baseband processor; the first power allocation unit is used to allocate the first frequency band signal into a first signal and a second signal based on the power allocation relationship of the first power allocation unit; the first power amplification unit is used to amplify the first signal and transmit the amplified first signal 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 common 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 distribution unit is used to distribute the second frequency band signal into the first signal and the second signal based on the power distribution relationship of the second power distribution 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 common load modulation unit is used to modulate the second signal and transmit the modulated second signal to the second power amplification unit.

3. The circuit according to claim 2, characterized in that 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; 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, 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; the output end of the second power amplification unit is connected to the second frequency band signal output end.

4. The circuit according to claim 1, characterized in that The common load modulation unit includes a common 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 second signal after the phase shifting processing to the common power amplifier; the common power amplifier is used to amplify the second signal after the phase shifting processing, and transmit the second signal after the amplification processing to the power amplification unit.

5. The circuit according to claim 4, characterized in that For any one of the phase shifting units, the input end of the phase shifting unit is connected to the second output end of the power distribution unit, the output end of the phase shifting 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.

6. The circuit according to claim 1, characterized in that 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 equally 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 end; the first resistor is used to suppress noise.

7. The circuit according to claim 6, characterized in that The first signal end of the first coupler is connected to the first output end of the power distribution unit, the second signal end of the first coupler is connected to the input end of the first power amplifier, the third signal end of the first coupler is connected to the input end of the second power amplifier, and the isolation end of the first coupler is connected to 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 to the frequency band signal output end, the second signal end of the second coupler is connected to the output end of the first power amplifier, the third signal end of the second coupler is connected to the output end of the second power amplifier, and the isolation end of the second coupler is connected to the output end of the common load modulation unit.

8. The circuit according to claim 1, characterized in that The power distribution unit includes a power divider.

9. The circuit according to claim 5, characterized in that The common load modulation unit further includes at least two first switch units; The output end of the phase shift unit is connected to the input end of the common power amplifier through any one of the first switch units.

10. The circuit according to claim 9, characterized in that Also comprising at least two second switch units; The output end of the common power amplifier is connected to the isolation end of the power amplification unit through any one of the second switch units.

11. The circuit according to claim 7, characterized in that The power amplification unit also 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 first signal after the phase shift processing into a first sub-signal and a second sub-signal; The first signal end of the first coupler is connected to the first output end of the power distribution unit through the phase shift compensation unit.

12. The circuit according to claim 11, characterized in that The power distribution relationship of the power distribution units in each amplification path group is the same, and the common load modulation unit includes a common power amplifier and at least two second resistors; For any one of the second resistors, a first end of the second resistor is connected to a second output end of the power distribution unit, a second end of the second resistor is connected to an input end of the common power amplifier, and an output end of the common power amplifier is connected to an isolation end of the power amplification unit; The second resistor is used to reduce the signal strength of the second signal; the common power amplifier is used to amplify the second signal after the signal strength is reduced, and transmit the amplified second signal to the power amplification unit.

13. The circuit according to claim 12, characterized in that It also includes at least one fixed phase shift unit; the output end of the common load modulation unit is connected to the isolation end of the power amplification unit through any one of the fixed phase shift units.

14. A radio frequency chip, characterized in that: Comprising the power amplifier circuit as described in any one of claims 1-13.

15. An electronic device, characterized in that: Comprising the radio frequency chip as claimed in claim 14.

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