A multi-stage amplifier, radio frequency circuit and electronic device

Abstract

The application discloses a kind of multistage amplifier, radio frequency circuit and electronic equipment, it is related to multistage amplifier design field, including output selector, first stage amplifier, second stage amplifier, third stage amplifier until N+1 stage amplifier.The first N stage amplifier includes amplifier, power detector and interstage selector, wherein, power detection switch can detect whether the signal that this stage amplifier outputs satisfies preset target power;If yes, then directly output signal is output to output selector by interstage selector and output signal is output by output selector;If not, then continue to transmit output signal to next stage amplifier until output signal satisfies preset target power.Therefore, the power of output signal can be amplified to different preset target power by using one multistage amplifier in the application, the number of multistage amplifier required by radio frequency circuit is reduced, so as to reduce the power consumption and volume of radio frequency circuit.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of multi-stage amplifier design, in particular to a multi-stage amplifier, a radio frequency circuit and an electronic device. BACKGROUND

[0002] The architecture of radio frequency circuits is basically similar, generally composed of radio frequency transceiver, switch, low noise amplifier and power amplifier, etc. It can be seen that the amplifier is widely used in radio frequency circuits, and the radio frequency circuit often needs a variety of different amplification stages of amplifier to amplify the power of the input signal to the target power. The number of stages of the amplifier circuit commonly used in the prior art is fixed, so when the radio frequency circuit needs input signals of multiple target powers, multiple amplifiers with different amplification stages need to be set, which increases the overall power consumption and volume of the radio frequency circuit. SUMMARY

[0003] The purpose of the present application is to provide a multi-stage amplifier, a radio frequency circuit and an electronic device, which can use one multi-stage amplifier to achieve the purpose of amplifying the power of the output signal to different preset target powers, thereby reducing the number of multi-stage amplifiers required by the radio frequency circuit, and reducing the power consumption and volume of the radio frequency circuit.

[0004] To solve the above technical problems, the present application provides a multi-stage amplifier, comprising an output selector, a first-stage amplifier, a second-stage amplifier, a third-stage amplifier and an N+1-stage amplifier, wherein N is a positive integer;

[0005] The i-th stage amplifier comprises an amplifier, a power detector and an inter-stage selector connected in sequence, the input end of the amplifier is the input end of the i-th stage amplifier, the first output end of the inter-stage selector is the first output end of the i-th stage amplifier, the second output end of the inter-stage selector is the second output end of the i-th stage amplifier, the first output end of the i-th stage amplifier is connected with the i-th input end of the output selector, the second output end of the i-th stage amplifier is connected with the input end of the i+1-th stage amplifier, the input end of the first-stage amplifier is the input end of the multi-stage amplifier, and 1≤i≤N;

[0006] The N+1-stage amplifier comprises the amplifier, the input end of the amplifier is the input end of the N+1-stage amplifier, the output end of the amplifier is the output end of the N+1-stage amplifier connected with the N+1-th input end of the output selector, and the output end of the output selector is the output end of the multi-stage amplifier;

[0007] The power detector is used to detect whether the power of the output signal of the amplifier connected with the power detector is the preset target power; if yes, the first output end of the inter-stage selector connected with the power detector is controlled to be turned on; if no, the second output end of the inter-stage selector connected with the power detector is controlled to be turned on.

[0008] The output selector is used to output the signal received by the input end of the output selector.

[0009] Preferably, the input matching network with the input end connected with the input end of the first-stage amplifier is further included, and the input end of the input matching network is used as the input end of the multi-stage amplifier.

[0010] The input matching network is used to filter the input signal of the multi-stage amplifier and match the output impedance of the input signal with the input impedance of the first-stage amplifier.

[0011] Preferably, the inter-stage matching network arranged between the second output end of the i-stage amplifier and the input end of the i+1-stage amplifier is further included.

[0012] The inter-stage matching network is used to filter the inter-stage signal output by the second output end of the i-stage amplifier and match the output impedance of the i-stage amplifier with the input impedance of the i+1-stage amplifier.

[0013] Preferably, the output matching network with the input end connected with the output end of the output selector is further included, and the output end of the output matching network is used as the output end of the multi-stage amplifier.

[0014] The output matching network is used to filter the output signal output by the output selector and match the input impedance of the output signal with the load connected with the multi-stage amplifier.

[0015] Preferably, the input matching network, the output matching network and the inter-stage matching network are any one or a combination of more than one of L-type matching network, T-type matching network or π-type matching network.

[0016] The L-type matching network includes a first capacitor and a first inductor, two ends of the first capacitor are used as the input end of the L-type matching network, one end of the first capacitor is connected with one end of the first inductor, and the other end of the first capacitor and the other end of the first inductor are used as the output end of the L-type matching network.

[0017] The T-shaped matching network comprises a second capacitor, a third capacitor and a second inductor, two ends of the second capacitor serving as input ends of the T-shaped matching network, two ends of the second inductor being connected to a first end of the second capacitor and a first end of the third capacitor respectively, a second end of the second capacitor being connected to a second end of the third capacitor, and two ends of the third capacitor serving as output ends of the T-shaped matching network.

[0018] The π-shaped matching network comprises a fourth capacitor, a fifth capacitor, a third inductor and a fourth inductor, the third inductor and the fourth inductor being connected in series and a common end of the series connection being connected to a first end of the fourth capacitor, a first end of the series connection and a second end of the fourth capacitor serving as input ends of the π-shaped matching network, another end of the series connection being connected to a first end of the fifth capacitor, a second end of the fifth capacitor being connected to the second end of the fourth capacitor, and two ends of the fifth capacitor serving as output ends of the π-shaped matching network.

[0019] Preferably, the N+1th amplifier further comprises an output power detector and an output prompting module.

[0020] The input end of the output power detector is connected to the output end of the amplifier in the N+1th amplifier, the output signal of the N+1th amplifier is transmitted to the N+1th input end of the output selector, and a trigger signal is generated when it is detected that the power of the output signal of the N+1th amplifier is not the preset target power.

[0021] The output prompting module is used for generating prompting information for prompting that the amplification multiple of the multi-stage amplifier does not meet the requirement when the trigger signal is received.

[0022] Preferably, the output selector is a single-pole multi-throw switch, and the inter-stage selectors are single-pole double-throw switches.

[0023] The N+1th stationary ends of the single-pole multi-throw switch serve as the N+1th input ends of the output selector, and the moving end of the single-pole multi-throw switch serves as the output end of the output selector.

[0024] The moving end of the single-pole double-throw switch serves as the input end of the inter-stage selector, the first stationary end of the single-pole double-throw switch serves as the first output end of the inter-stage selector, and the second stationary end of the single-pole double-throw switch serves as the second output end of the inter-stage selector.

[0025] To solve the above technical problems, the application further provides a radio frequency circuit comprising the multi-stage amplifier.

[0026] Preferably, the radio frequency circuit further comprises a radio frequency chip, a signal processing circuit and a transmitting antenna.

[0027] The radio frequency chip is configured to transmit an input signal to the multi-stage amplifier so that the multi-stage amplifier amplifies power of the input signal to a preset target power;

[0028] The signal processing circuit is configured to filter and integrate an output signal of the multi-stage amplifier, and output the filtered and integrated output signal to the transmitting antenna.

[0029] The transmitting antenna is configured to transmit the filtered and integrated output signal.

[0030] To solve the above technical problems, the application further provides an electronic device comprising the radio frequency circuit.

[0031] To sum up, the application provides a multi-stage amplifier, a radio frequency circuit and an electronic device, which comprise an output selector, a first-stage amplifier, a second-stage amplifier, a third-stage amplifier and an N+1-stage amplifier. The first N-stage amplifiers each comprise an amplifier, a power detector and an inter-stage selector. The power detector is configured to detect whether the output signal of the amplifier meets a preset target power. If yes, the output signal is directly output to the output selector by the inter-stage selector and then output by the output selector. If not, the output signal is continuously transmitted to the next-stage amplifier until the output signal meets the preset target power. Therefore, the application can amplify the power of the output signal to different preset target powers by using one multi-stage amplifier, thereby reducing the number of multi-stage amplifiers required by the radio frequency circuit and reducing the power consumption and volume of the radio frequency circuit. BRIEF DESCRIPTION OF DRAWINGS

[0032] To make the technical solutions in the embodiments of the application clearer, the following briefly introduces the drawings needed in the prior art and the embodiments. Obviously, the drawings in the following description only show some embodiments of the application, and for those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0033] Figure 1 A structural schematic diagram of a multi-stage amplifier provided by the application;

[0034] Figure 2 A working flow schematic diagram of a multi-stage amplifier provided by the application. DETAILED DESCRIPTION

[0035] The core of the application is to provide a multi-stage amplifier, a radio frequency circuit and an electronic device, which can amplify the power of the output signal to different preset target powers by using one multi-stage amplifier, thereby reducing the number of multi-stage amplifiers required by the radio frequency circuit and reducing the power consumption and volume of the radio frequency circuit.

[0036] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0037] Please refer to Figure 1 , Figure 1 A structure schematic diagram of a multi-stage amplifier is provided in the present application, and the multi-stage amplifier comprises an output selector 1, a first-stage amplifier, a second-stage amplifier, a third-stage amplifier and an N+1-stage amplifier, wherein N is a positive integer;

[0038] The i-stage amplifier comprises an amplifier 2, a power detector 3 and an inter-stage selector 4 connected in sequence, the input end of the amplifier 2 is the input end of the i-stage amplifier, the first output end of the inter-stage selector 4 is the first output end of the i-stage amplifier, the second output end of the inter-stage selector 4 is the second output end of the i-stage amplifier, the first output end of the i-stage amplifier is connected with the i-input end of the output selector 1, the second output end of the i-stage amplifier is connected with the input end of the i+1-stage amplifier, the input end of the first-stage amplifier is the input end of the multi-stage amplifier, and 1≤i≤N;

[0039] The N+1-stage amplifier comprises an amplifier 2, the input end of the amplifier 2 is the input end of the N+1-stage amplifier, the output end of the amplifier 2 is the output end of the N+1-stage amplifier and is connected with the N+1-input end of the output selector 1, and the output end of the output selector 1 is the output end of the multi-stage amplifier;

[0040] The power detector 3 is used for detecting whether the power of the output signal of the amplifier 2 connected with the power detector 3 is a preset target power; if yes, the first output end of the inter-stage selector 4 connected with the power detector 3 is controlled to be conductive; if no, the second output end of the inter-stage selector 4 connected with the power detector 3 is controlled to be conductive;

[0041] The output selector 1 is used for outputting the signal received by the input end of the output selector 1.

[0042] The multi-stage amplifier provided in the application can automatically output a signal with a preset target power, specifically, the multi-stage amplifier specifically comprises an N+1 stage amplifier, wherein, the first N stage amplifiers each comprise an amplifier 2, a power detector 3 and an inter-stage selector 4, the power detector 3 can detect the power of the amplifier 2 connected thereto, and after detecting that the power of the signal output by the amplifier 2 connected thereto reaches the preset target power, the power detector 3 controls the first output end of the inter-stage selector 4 connected thereto to be turned on, that is, the signal output by the amplifier 2 in the stage where the power detector 3 is located is directly transmitted to the output selector 1 so that the output selector 1 outputs the signal; when detecting that the power of the signal output by the amplifier 2 connected thereto does not reach the preset target power, the power detector 3 controls the second output end of the inter-stage selector 4 connected thereto to be turned on, that is, the signal output by the amplifier 2 in the stage where the power detector 3 is located is transmitted to the next stage amplifier 2 so as to continue to amplify the power of the signal until the preset target power is met.

[0043] Please refer to Figure 2 , Figure 2 for the working flowchart of the multi-stage amplifier provided in the application, Figure 2 in which Poutn is the power of the signal output by the Nth stage amplifier, Pneed is the preset target power, and SPNT is the output selector 1. After the input signal is transmitted to the amplifier 2 in the first stage amplifier through the input matching network, the power detector 3 in the first stage amplifier detects whether the power of the signal output by the amplifier 2 is the preset target power, if yes, the signal is directly output through the SPNT, if not, the signal is transmitted to the inter-stage matching network connected with the first stage amplifier to repeat the above operation.

[0044] In summary, the application provides a multi-stage amplifier, which comprises an output selector 1, a first stage amplifier, a second stage amplifier, a third stage amplifier and an N+1 stage amplifier. The first N stage amplifiers each comprise an amplifier 2, a power detector 3 and an inter-stage selector 4, wherein the power detection switch can detect whether the signal output by the amplifier 2 in the stage meets the preset target power; if yes, the output signal is directly output to the output selector 1 through the inter-stage selector 4 and then output by the output selector 1; if not, the output signal is continuously transmitted to the next stage amplifier 2 until the output signal meets the preset target power. Therefore, the application can amplify the power of the output signal to different preset target powers by using one multi-stage amplifier, thereby reducing the number of multi-stage amplifiers required by the radio frequency circuit, and thus reducing the power consumption and volume of the radio frequency circuit.

[0045] On the basis of the above embodiment:

[0046] As a preferred embodiment, the application further comprises an input matching network connected with the input end of the first stage amplifier, the input end of the input matching network serving as the input end of the multi-stage amplifier.

[0047] The input matching network is used to filter the input signal of the multi-stage amplifier and match the input impedance of the input signal with the input impedance of the first-stage amplifier.

[0048] In the embodiment, the input matching network is arranged at the input end of the first-stage amplifier, the input end of the input matching network is taken as the input end of the multi-stage amplifier, and the input signal is input to the first-stage amplifier through the input matching network. The input matching network filters the input signal input to the multi-stage amplifier to ensure the power of the required frequency signal, suppresses the harmonic components outside the required frequency, and matches the input signal with the input impedance of the first-stage amplifier, so that the amplifier 2 obtains the maximum excitation power. It should be noted that the specific circuit structure of the input matching network is not particularly limited in the present application, and can be selected according to the actual situation.

[0049] As a preferred embodiment, the inter-stage matching network is further arranged between the second output end of the i-th stage amplifier and the input end of the i+1-th stage amplifier.

[0050] The inter-stage matching network is used to filter the inter-stage signal output from the second output end of the i-th stage amplifier and match the output impedance of the i-th stage amplifier with the input impedance of the i+1-th stage amplifier.

[0051] In the embodiment, the inter-stage matching network is arranged between the amplifiers 2 in the first N stages of amplifiers, the inter-stage matching network filters the inter-stage signal output from the output end of the amplifier 2 to ensure the power of the working frequency of the load, suppresses the harmonic components and interference outside the working frequency, and performs impedance matching to transmit the signal power to the load, so that the amplifier 2 further obtains the maximum excitation power. It should be noted that the specific circuit structure of the inter-stage matching network is not particularly limited in the present application, and can be selected according to the actual situation.

[0052] As a preferred embodiment, the output matching network connected with the output end of the output selector 1 is further arranged at the input end of the multi-stage amplifier, and the output end of the output matching network is taken as the output end of the multi-stage amplifier.

[0053] The output matching network is used to filter the output signal output from the output selector 1 and match the input impedance of the output signal with the load connected with the multi-stage amplifier.

[0054] In the embodiment, an output matching network is arranged at the output end of the output selector 1, which functions to match the input impedance of the output signal with the load connected to the multi-stage amplifier, transforms the external load resistance into the optimal load resistance required by the amplifier 2, so as to ensure the maximum output power, and filters the output signal at the output of the output selector 1, further optimizes the working performance of the multi-stage amplifier, thereby ensuring the performance of the radio frequency circuit. It should be noted that the specific circuit structure of the output matching network is not particularly limited in the present application, and can be selected according to the actual situation.

[0055] As a preferred embodiment, the input matching network, the output matching network and the inter-stage matching network are any one or a combination of more than one of L-type matching network, T-type matching network or π-type matching network.

[0056] The L-type matching network comprises a first capacitor and a first inductor, two ends of the first capacitor serving as input ends of the L-type matching network, one end of the first capacitor being connected with one end of the first inductor, and the other end of the first capacitor and the other end of the first inductor serving as output ends of the L-type matching network.

[0057] The T-type matching network comprises a second capacitor, a third capacitor and a second inductor, two ends of the second capacitor serving as input ends of the T-type matching network, two ends of the second inductor being connected with a first end of the second capacitor and a first end of the third capacitor respectively, a second end of the second capacitor being connected with a second end of the third capacitor, and two ends of the third capacitor serving as output ends of the T-type matching network.

[0058] The π-type matching network comprises a fourth capacitor, a fifth capacitor, a third inductor and a fourth inductor, the third inductor and the fourth inductor being connected in series and having a common end connected with a first end of the fourth capacitor, a first end of the circuit connected in series and a second end of the fourth capacitor serving as input ends of the π-type matching network, the other end of the circuit connected in series being connected with a first end of the fifth capacitor, a second end of the fifth capacitor being connected with the second end of the fourth capacitor, and two ends of the fifth capacitor serving as output ends of the π-type matching network.

[0059] The input matching network, the interstage matching network and the output matching network are formed by series-parallel connection of capacitors and inductors, and the standard impedance of the radio frequency circuit is usually 50 ohms. The input matching network, the interstage matching network and the output matching network have roughly similar functions, one of which is to filter to ensure the power of the required frequency signal and suppress harmonic components and interference outside the required frequency, and the other of which is to match the impedance to enable all high-frequency signals to be transmitted to the load point. When the input impedance is matched, the transmission line obtains the maximum power; in the case of output impedance matching, only voltage waves and current waves travelling towards the terminal exist on the transmission line, and the energy carried by the waves is completely absorbed by the load. The input matching network, the interstage matching network and the output matching network can each be any one of an L-type matching network, a T-type matching network or a π-type matching network, thereby achieving the above functions and further optimizing the performance of the multi-stage amplifier.

[0060] As a preferred embodiment, the N+1th amplifier further comprises an output power detector and an output prompting module;

[0061] The input end of the output power detector is connected to the output end of the amplifier 2 in the N+1th amplifier, for transmitting the output signal of the N+1th amplifier to the N+1th input end of the output selector and generating a trigger signal when it is detected that the power of the output signal of the N+1th amplifier is not the preset target power;

[0062] The output prompting module is configured to generate prompting information for prompting that the amplification factor of the multi-stage amplifier does not meet the requirements when the trigger signal is received.

[0063] In actual applications, the power of the input signal may not reach the preset target power after the input signal is amplified by the first amplifier to the N+1th amplifier, in which case the structure of the multi-stage amplifier needs to be adjusted or the input signal needs to be adjusted. Therefore, in this embodiment, the output power detector and the output prompting module are arranged in the N+1th amplifier, which is the last stage of the multi-stage amplifier. The output power detector is configured to output the output signal of the amplifier 2 in the N+1th amplifier to avoid the working personnel from considering that the multi-stage amplifier itself is faulty, and to detect whether the power of the output signal of the N+1th amplifier, i.e. the final output signal of the multi-stage amplifier, is the preset target power. When the power of the final output signal of the multi-stage amplifier is not the preset target power, the output prompting module is triggered to generate prompting information so that the working personnel can timely adjust the structure of the multi-stage amplifier or the frequency of the input signal, thereby further optimizing the performance of the multi-stage amplifier.

[0064] As a preferred embodiment, the output selector 1 is a single-pole multi-throw switch, and the interstage selectors 4 are single-pole double-throw switches;

[0065] The N+1 fixed terminals of the single-pole multi-throw switch are respectively connected to the N+1 input terminals of the output selector 1, and the movable terminal of the single-pole multi-throw switch is connected to the output terminal of the output selector 1.

[0066] The movable terminal of the single-pole double-throw switch is connected to the input terminal of the inter-stage selector 4, the first fixed terminal of the single-pole double-throw switch is connected to the first output terminal of the inter-stage selector 4, and the second fixed terminal of the single-pole double-throw switch is connected to the second output terminal of the inter-stage selector 4.

[0067] In the embodiment, the inter-stage selector 4 is a single-pole double-throw switch, and the output selector 1 is a single-pole multi-throw switch. When the power detector 3 in the i-th amplifier detects that the power of the signal output by the amplifier 2 connected thereto is the preset target power, the fixed terminal of the single-pole double-throw switch is controlled to be connected to the first fixed terminal so as to directly transmit the signal to the i-th fixed terminal of the single-pole multi-throw switch, and then the signal is output through the movable terminal of the single-pole multi-throw switch; when the power detector 3 in the former N amplifiers detects that the power of the signal output by the amplifier 2 connected thereto does not reach the preset target power, the movable terminal of the single-pole double-throw switch is controlled to be connected to the second fixed terminal so as to transmit the signal to the i+1-th amplifier for further amplification. Moreover, the single-pole multi-throw switch is selected as the output selector 1, and the single-pole double-throw switch is selected as the inter-stage selector 4, which is low in cost and easy to implement.

[0068] The application further provides a radio frequency circuit comprising the multi-stage amplifier.

[0069] For the radio frequency circuit provided by the application, refer to the embodiments of the multi-stage amplifier, which will not be repeated here.

[0070] As a preferred embodiment, the radio frequency circuit further comprises a radio frequency chip, a signal processing circuit and a transmitting antenna.

[0071] The radio frequency chip is configured to transmit an input signal to the multi-stage amplifier, so that the multi-stage amplifier amplifies the power of the input signal to the preset target power.

[0072] The signal processing circuit is configured to filter and integrate the output signal of the multi-stage amplifier, and output the filtered and integrated output signal to the transmitting antenna.

[0073] The transmitting antenna is configured to transmit the filtered and integrated output signal.

[0074] In the embodiment, the radio frequency chip further comprises a radio frequency chip, a signal processing circuit and a transmitting antenna, the radio frequency chip transmits an input signal to a multi-stage amplifier, the multi-stage amplifier amplifies the power of the input signal to a preset target power, the signal processing circuit can comprise a filtering circuit and a mixing circuit to filter and integrate the output signal of the multi-stage amplifier, and output the filtered and integrated signal to the transmitting antenna, the transmitting antenna transmits the output signal to realize the function of the radio frequency circuit, and the radio frequency circuit provided in the embodiment can automatically realize the function of amplifying the power of the input signal to the preset target power.

[0075] The application further provides an electronic device comprising the radio frequency circuit.

[0076] It should be noted that the electronic device provided in the application can be a watch, a bracelet, earphones, a head-mounted wearable device, or a smart home device such as a sound box, a camera, etc., and can also be a mobile phone, a gamepad or a positioner, etc., which are not particularly limited in the application.

[0077] It should be noted that in the present specification, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0078] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-stage amplifier, characterized by, It includes an output selector, a first-stage amplifier, a second-stage amplifier, a third-stage amplifier, and so on up to the (N+1)th stage amplifier, where N is a positive integer; The i-th stage amplifier comprises an amplifier, a power detector and an inter-stage selector connected in sequence, the input end of the amplifier serving as the input end of the i-th stage amplifier, the first output end of the inter-stage selector serving as the first output end of the i-th stage amplifier, the second output end of the inter-stage selector serving as the second output end of the i-th stage amplifier, the first output end of the i-th stage amplifier being connected with the i-th input end of the output selector, the second output end of the i-th stage amplifier being connected with the input end of the (i+1)-th stage amplifier, the input end of the first stage amplifier serving as the input end of the multi-stage amplifier, ; The N+1 stage amplifier includes the amplifier, the input terminal of the amplifier serves as the input terminal of the N+1 stage amplifier, the output terminal of the amplifier serves as the output terminal of the N+1 stage amplifier and is connected to the N+1th input terminal of the output selector, and the output terminal of the output selector serves as the output terminal of the multi-stage amplifier. The power detector is used to detect whether the power of the output signal of the amplifier connected to the power detector is a preset target power; if yes, the first output terminal of the interstage selector connected to the power detector is turned on; if no, the second output terminal of the interstage selector connected to the power detector is turned on. The output selector is used to output the signal received at the input terminal of the output selector; The multi-stage amplifier is configured such that, for any stage from the first stage to the Nth stage, when its power detector detects that the output signal power of that stage reaches the preset target power, the output signal is guided to the output selector through the inter-stage selector of that stage and output, without flowing through subsequent amplifier stages; if the output signal power does not reach the preset target power, it is guided to the next stage amplifier through the inter-stage selector of that stage for further amplification. The N+1 stage amplifier also includes an output power detector and an output indication module; The input terminal of the output power detector is connected to the output terminal of the amplifier in the (N+1)th stage amplifier, and is used to transmit the output signal of the (N+1)th stage amplifier to the (N+1)th input terminal of the output selector, and generate a trigger signal when the power of the output signal of the (N+1)th stage amplifier is not the preset target power. The output prompt module is used to generate a prompt message when the trigger signal is received, indicating that the amplification factor of the multi-stage amplifier does not meet the requirements.

2. The multi-stage amplifier of claim 1, wherein, It also includes an input matching network whose output is connected to the input of the first stage amplifier, wherein the input of the input matching network serves as the input of the multi-stage amplifier; The input matching network is used to filter the input signal of the multi-stage amplifier and match the output impedance of the input signal with the input impedance of the first-stage amplifier.

3. The multi-stage amplifier of claim 2, wherein, It also includes an interstage matching network located between the second output of the i-th stage amplifier and the input of the (i+1)-th stage amplifier; The interstage matching network is used to filter the interstage signal output from the second output terminal of the i-th stage amplifier and to perform impedance matching between the output impedance of the i-th stage amplifier and the input impedance of the (i+1)-th stage amplifier.

4. The multi-stage amplifier of claim 3, wherein, It also includes an output matching network whose input is connected to the output of the output selector, and the output of the output matching network serves as the output of the multi-stage amplifier. The output matching network is used to filter the output signal output by the output selector and to impedance match the input impedance of the output signal with the load connected to the multistage amplifier.

5. The amplifier circuit of claim 4, wherein, The input matching network, the output matching network, and the inter-stage matching network are any one or more of a combination of L-type matching networks or T-type matching networks or a combination of L-type matching networks or T-type matching networks. The L-type matching network comprises a first capacitor and a first inductor, two ends of the first capacitor serving as input ends of the L-type matching network, one end of the first capacitor being connected with one end of the first inductor, the other end of the first capacitor and the other end of the first inductor serving as output ends of the L-type matching network; The T-type matching network comprises a second capacitor, a third capacitor and a second inductor, two ends of the second capacitor serving as input ends of the T-type matching network, two ends of the second inductor being connected with a first end of the second capacitor and a first end of the third capacitor respectively, a second end of the second capacitor being connected with a second end of the third capacitor, two ends of the third capacitor serving as output ends of the T-type matching network; The The type matching network includes a fourth capacitor, a fifth capacitor, a third inductor and a fourth inductor, the third inductor and the fourth inductor are connected in series, and the common end of the third inductor and the fourth inductor is connected with the first end of the fourth capacitor, the first end of the circuit connected in series and the second end of the fourth capacitor are the input end of the type matching network. The other end of the circuit connected in series is connected with the first end of the fifth capacitor, the second end of the fifth capacitor is connected with the second end of the fourth capacitor, and the two ends of the fifth capacitor are the output end of the type matching network. The other end of the circuit connected in series is connected with the first end of the fifth capacitor, the second end of the fifth capacitor is connected with the second end of the fourth capacitor, and the two ends of the fifth capacitor are the output end of the type matching network.

6. The multi-stage amplifier of any one of claims 1 to 5, wherein, The output selector is a single-pole multi-throw switch, and each inter-stage selector is a single-pole double-throw switch; N+1 fixed ends of the single-pole multi-throw switch serve as N+1 input ends of the output selector respectively, and a moving end of the single-pole multi-throw switch serves as an output end of the output selector; A moving end of the single-pole double-throw switch serves as an input end of the inter-stage selector, a first fixed end of the single-pole double-throw switch serves as a first output end of the inter-stage selector, and a second fixed end of the single-pole double-throw switch serves as a second output end of the inter-stage selector.

7. A radio frequency circuit, characterized by The multi-stage amplifier comprises the multi-stage amplifier as claimed in any one of claims 1 to 6.

8. The radio frequency circuit of claim 7, wherein, The radio frequency chip, the signal processing circuit and the transmitting antenna are further included. The radio frequency chip is configured to transmit an input signal to the multi-stage amplifier, so that the multi-stage amplifier amplifies power of the input signal to a preset target power. The signal processing circuit is configured to filter and integrate an output signal of the multi-stage amplifier, and output the filtered and integrated output signal to the transmitting antenna. The transmitting antenna is configured to transmit the filtered and integrated output signal.

9. An electronic device, comprising: The radio frequency circuit comprises the radio frequency circuit as claimed in any one of claims 7 to 8.

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