power detection circuit

Abstract

The application provides a power detection circuit, which comprises a first triode, a low-pass circuit, a voltage dividing circuit, a first resistor, a first radio frequency rectifying circuit, a second radio frequency rectifying circuit and a third radio frequency rectifying circuit; the low-pass circuit is used for filtering out high-frequency interference; the voltage signal output by the emitter of the first triode is proportionally reduced by the voltage dividing circuit; the first radio frequency rectifying circuit, the second radio frequency rectifying circuit and the third radio frequency rectifying circuit are all used for converting alternating current into unidirectional pulsating direct current. The power detection circuit of the application can improve the power dynamic range and has better linearity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wireless communication, and in particular to a power detection circuit. BACKGROUND

[0002] With the continuous development of wifi technology, wifi7 is also becoming more and more popular, and the power accuracy of the corresponding wifi communication system is also put forward higher requirements. In the application of wifi products, the power calibration adopts the detection voltage (VDET) power detection method, that is, the radio frequency signal is converted into a DC voltage signal, and then fed back to the system, and the system controls the power amplifier to transmit the corresponding power signal by detecting the size of the voltage.

[0003] In addition, the system will detect the corresponding detection voltage value at each power point, and then form a set of voltage vs (voltage-current) power data stored in the system. Therefore, when the system calibrates the power, the voltage corresponding to each power point is expected to have a certain gap, and the gap cannot be too large or too small, commonly known as linearity.

[0004] The power detection circuit of the related art is shown in Figure 1 The radio frequency signal passes through the direct current blocking capacitor C1 and is coupled into the triode Q. The collector and base of the triode Q form a diode function for radio frequency signal rectification. The bias resistor R1 controls the bias of the triode Q with diode function. The capacitor C2, the resistor R2 and the resistor R3 form a low-pass load network to input a reference radio frequency detection voltage. The resistor R2 and the resistor R3 are a voltage division structure, and the ratio of the resistor R2 and the resistor R3 will affect the output size of the detection voltage.

[0005] As shown in Figure 2 The horizontal axis is the power of the radio frequency signal, and the vertical axis is the voltage output after rectification. Although the power detection circuit in the related art can achieve a relatively accurate power, it can be seen from Figure 2 that the output voltage curve of the power interval of 5~30dBm presents an exponential type, and the voltage of the power interval of -20~5dBm is almost constant. Therefore, the power detection circuit in the related art not only has a small power dynamic range, but also has poor linearity, which is difficult to apply to a wifi detection system. SUMMARY

[0006] In view of the deficiencies of the above related art, the present application proposes a new power detection circuit to solve the problem that the power detection circuit in the related art not only has a small power dynamic range, but also has poor linearity.

[0007] In order to solve the above technical problems, the present application provides a power detection circuit, which comprises a first triode, a low-pass circuit, a voltage dividing circuit, a first resistor, a first radio frequency rectifier circuit, a second radio frequency rectifier circuit and a third radio frequency rectifier circuit.

[0008] The collector of the first triode is connected to a power supply voltage.

[0009] The input end of the low-pass circuit is connected to the emitter of the first triode, and the output end of the low-pass circuit is grounded, for filtering out high-frequency interference.

[0010] The input end of the voltage dividing circuit is connected to the input end of the low-pass circuit, and the output end of the voltage dividing circuit is used for outputting a detection voltage, for proportionally reducing the voltage signal output by the emitter of the first triode.

[0011] The first end of the first resistor is used for connecting to a power supply voltage, and the second end of the first resistor is connected to the base of the first triode.

[0012] The first input end of the first radio frequency rectifier circuit is used for connecting to a power supply voltage, the second input end of the first radio frequency rectifier circuit is used for connecting to a radio frequency signal, and the output end of the first radio frequency rectifier circuit is connected to the base of the first triode, for converting alternating current into unidirectional pulsating direct current.

[0013] The first input end of the second radio frequency rectifier circuit is used for connecting to a power supply voltage, the second input end of the second radio frequency rectifier circuit is used for connecting to a radio frequency signal, and the output end of the second radio frequency rectifier circuit is connected to the base of the first triode, for converting alternating current into unidirectional pulsating direct current.

[0014] The first input end of the third radio frequency rectifier circuit is used for connecting to a power supply voltage, the second input end of the third radio frequency rectifier circuit is used for connecting to a radio frequency signal, and the output end of the third radio frequency rectifier circuit is connected to the base of the first triode, for converting alternating current into unidirectional pulsating direct current.

[0015] Preferably, the power detection circuit further comprises a first capacitor, the first end of the first capacitor is connected to the collector of the first triode, and the second end of the first capacitor is grounded.

[0016] Preferably, the low-pass circuit comprises a second resistor and a second capacitor; the first end of the second resistor and the first end of the second capacitor are connected and serve as the input end of the low-pass circuit, and the second end of the second resistor and the second end of the second capacitor are connected and serve as the output end of the low-pass circuit.

[0017] Preferably, the voltage dividing circuit comprises a third resistor and a fourth resistor; a first end of the third resistor is an input end of the voltage dividing circuit, a second end of the third resistor is an output end of the voltage dividing circuit, a first end of the fourth resistor is connected to the second end of the third resistor, and a second end of the fourth resistor is grounded.

[0018] Preferably, the first radio frequency rectifying circuit comprises a second transistor, a fifth resistor, a third capacitor, a third transistor, a sixth resistor, a seventh resistor, and a fourth capacitor.

[0019] A collector of the second transistor is an output end of the first radio frequency rectifying circuit, and an emitter of the second transistor is grounded.

[0020] A first end of the fifth resistor is connected to a first end of the first resistor, and the first end of the fifth resistor is a first input end of the first radio frequency rectifying circuit.

[0021] A first end of the third capacitor is a second input end of the first radio frequency rectifying circuit.

[0022] Collectors of the third transistor are respectively connected to a second end of the fifth resistor and a second end of the third capacitor, and an emitter of the third transistor is grounded.

[0023] The sixth resistor is connected to the collector of the third transistor and a base of the third transistor.

[0024] The seventh resistor is connected to the base of the third transistor and a base of the second transistor.

[0025] A first end of the fourth capacitor is connected to the base of the second transistor, and a second end of the fourth capacitor is grounded.

[0026] Preferably, the second radio frequency rectifying circuit comprises a fourth transistor, an eighth resistor, a fifth capacitor, a fifth transistor, a ninth resistor, a tenth resistor, and a sixth capacitor.

[0027] A collector of the fourth transistor is connected to the collector of the second transistor, and the collector of the fourth transistor is an output end of the second radio frequency rectifying circuit, and an emitter of the fourth transistor is grounded.

[0028] A first end of the eighth resistor is connected to the first end of the fifth resistor, and the first end of the eighth resistor is a first input end of the second radio frequency rectifying circuit.

[0029] A first end of the fifth capacitor is a second input end of the second radio frequency rectifying circuit.

[0030] The collector of the fifth triode is connected to the second end of the eighth resistor and the second end of the fifth capacitor respectively, and the emitter of the fifth triode is grounded;

[0031] The two ends of the ninth resistor are connected to the collector of the fifth triode and the base of the fifth triode respectively;

[0032] The two ends of the tenth resistor are connected to the base of the fifth triode and the base of the fourth triode respectively;

[0033] The first end of the sixth capacitor is connected to the base of the fourth triode, and the second end of the sixth capacitor is grounded.

[0034] Preferably, the third radio frequency rectifying circuit comprises a sixth triode, an eleventh resistor, a seventh capacitor, a seventh triode, a twelfth resistor, a thirteenth resistor and an eighth capacitor;

[0035] The collector of the sixth triode is connected to the collector of the fourth triode and serves as an output end of the third radio frequency rectifying circuit, and the emitter of the fourth triode is grounded;

[0036] The first end of the eleventh resistor is connected to the first end of the eighth resistor and serves as a first input end of the third radio frequency rectifying circuit;

[0037] The first end of the seventh capacitor is connected to the second end of the fifth capacitor and serves as a second input end of the third radio frequency rectifying circuit;

[0038] The collector of the seventh triode is connected to the second end of the eleventh resistor and the second end of the seventh capacitor respectively, and the emitter of the seventh triode is grounded;

[0039] The two ends of the twelfth resistor are connected to the collector of the seventh triode and the base of the seventh triode respectively;

[0040] The two ends of the thirteenth resistor are connected to the base of the seventh triode and the base of the sixth triode respectively;

[0041] The first end of the eighth capacitor is connected to the base of the sixth triode, and the second end of the eighth capacitor is grounded.

[0042] Compared with the related art, the power detection circuit in the application can improve the power dynamic range of the power detection circuit and has better linearity by adding the first radio frequency rectifying circuit, the second radio frequency rectifying circuit and the third radio frequency rectifying circuit for converting alternating current into unidirectional pulsating direct current and connecting the first resistor to only the base of the first triode. BRIEF DESCRIPTION OF DRAWINGS

[0043] The application will be described in detail below with reference to the drawings. The above and other aspects of the present application will become more apparent and more readily appreciated from the following detailed description, with reference to the accompanying drawings, in which:

[0044] Figure 1 A circuit diagram of a power detection circuit provided for the related art;

[0045] Figure 2 A graph of an output voltage and power of the power detection circuit provided for the related art;

[0046] Figure 3 A circuit diagram of a power detection circuit provided for the embodiment of the present application;

[0047] Figure 4 A graph of a detection voltage and power of the power detection circuit provided for the embodiment of the present application. DETAILED DESCRIPTION

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application; the description and claims herein and the above description of drawings herein use the term "including" and "comprising," along with their derivatives, to mean "including but not limited to," "including and

[0049] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily all directed to the same

[0050] 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 of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort fall within the scope of protection of the present application.

[0051] The embodiment of the present application provides a power detection circuit 100, which is combined with Figure 3As shown, it comprises a first triode Q1, a low pass circuit 1, a voltage dividing circuit 2, a first resistor R1, a first radio frequency rectifier circuit 3, a second radio frequency rectifier circuit 4 and a third radio frequency rectifier circuit 5.

[0052] The collector of the first triode Q1 is used to access the power supply voltage VDD; the first triode Q1 acts as a shot, and the base receives voltage from the emitter.

[0053] The input end of the low pass circuit 1 is connected to the emitter of the first triode Q1, and the output end of the low pass circuit 1 is grounded, which is used to filter out high frequency interference. In this embodiment, the low pass circuit 1 comprises a second resistor R2 and a second capacitor C2; the first end of the second resistor R2 and the first end of the second capacitor C2 are connected and commonly used as the input end of the low pass circuit 1, and the second end of the second resistor R2 and the second end of the second capacitor C2 are connected and commonly used as the output end of the low pass circuit 1.

[0054] The input end of the voltage dividing circuit 2 is connected to the input end of the low pass circuit 1, and the output end of the voltage dividing circuit 2 is used to output the detection voltage VDET, which is used to reduce the voltage signal output by the emitter of the first triode Q1 in proportion to the required voltage, and directly affects the size of the voltage output by the emitter of the first triode Q1. In this embodiment, the voltage dividing circuit 2 comprises a third resistor R3 and a fourth resistor R4; the first end of the third resistor R3 is used as the input end of the voltage dividing circuit 2, the second end of the third resistor R3 is used as the output end of the voltage dividing circuit 2, the first end of the fourth resistor R4 is connected to the second end of the third resistor R3, and the second end of the fourth resistor R4 is grounded.

[0055] The first end of the first resistor R1 is used to access the power supply voltage VDD, and the second end of the first resistor R1 is connected to the base of the first triode Q1. The first resistor R1 is used to adjust the voltage of the first triode Q1.

[0056] The first input end of the first radio frequency rectifier circuit 3 is used to access the power supply voltage VDD, the second input end of the first radio frequency rectifier circuit 3 is used to access the radio frequency signal, and the output end of the first radio frequency rectifier circuit 3 is connected to the base of the first triode Q1, which is used to convert alternating current into unidirectional pulsating direct current.

[0057] In this embodiment, the first radio frequency rectifier circuit 3 comprises a second triode Q2, a fifth resistor R5, a third capacitor C3, a third triode Q3, a sixth resistor R6, a seventh resistor R7 and a fourth capacitor C4.

[0058] The collector of the second triode Q2 is used as the output end of the first radio frequency rectifier circuit 3, the emitter of the second triode Q2 is grounded, and the direct current signal rectified by the third triode Q3 is amplified and output to the base of the first triode Q1.

[0059] The first end of the fifth resistor R5 is connected to the first end of the first resistor R1, and serves as the first input end of the first radio frequency rectifier circuit 3, and as a bias resistor.

[0060] The first end of the third capacitor C3 serves as the second input end of the first radio frequency rectifier circuit 3, and as a coupling and DC blocking capacitor.

[0061] The collector of the third transistor Q3 is connected to the second end of the fifth resistor R5 and the second end of the third capacitor C3, respectively, and the emitter of the third transistor Q3 is grounded.

[0062] The two ends of the sixth resistor R6 are connected to the collector of the third transistor Q3 and the base of the third transistor Q3, respectively, and serve as a diode voltage regulator rectifier resistor formed by the third transistor Q3.

[0063] The two ends of the seventh resistor R7 are connected to the base of the third transistor Q3 and the base of the second transistor Q2, respectively.

[0064] The first end of the fourth capacitor C4 is connected to the base of the second transistor Q2, and the second end of the fourth capacitor C4 is grounded, which cooperates with the seventh resistor R7 to serve as an RC filter circuit.

[0065] The first input end of the second radio frequency rectifier circuit 4 is used to access the power supply voltage VDD, the second input end of the second radio frequency rectifier circuit 4 is used to access the radio frequency signal, and the output end of the second radio frequency rectifier circuit 4 is connected to the base of the first transistor Q1, for converting alternating current into unidirectional pulsating direct current.

[0066] In this embodiment, the second radio frequency rectifier circuit 4 includes a fourth transistor Q4, an eighth resistor R8, a fifth capacitor C5, a fifth transistor Q5, a ninth resistor R9, a tenth resistor R10, and a sixth capacitor C6.

[0067] The collector of the fourth transistor Q4 is connected to the collector of the second transistor Q2, and serves as the output end of the second radio frequency rectifier circuit 4, and the emitter of the fourth transistor Q4 is grounded, for amplifying and outputting the direct current signal rectified by the fifth transistor Q5 to the base of the first transistor Q1.

[0068] The first end of the eighth resistor R8 is connected to the first end of the fifth resistor R5, and serves as the first input end of the second radio frequency rectifier circuit 4, and as a bias resistor.

[0069] The first end of the fifth capacitor C5 serves as the second input end of the second radio frequency rectifier circuit 4, and as a coupling and DC blocking capacitor.

[0070] The collector of the fifth transistor Q5 is connected to the second end of the eighth resistor R8 and the second end of the fifth capacitor C5, respectively, and the emitter of the fifth transistor Q5 is grounded.

[0071] The two ends of the ninth resistor R9 are connected to the collector of the fifth transistor Q5 and the base of the fifth transistor Q5 respectively, and the fifth transistor Q5 forms a diode voltage stabilizing rectifier resistance.

[0072] The two ends of the tenth resistor R10 are connected to the base of the fifth transistor Q5 and the base of the fourth transistor Q4 respectively.

[0073] The first end of the sixth capacitor C6 is connected to the base of the fourth transistor Q4, and the second end of the sixth capacitor C6 is grounded, which cooperates with the tenth resistor R10 to form an RC filter circuit.

[0074] The first input end of the third radio frequency rectifier circuit 5 is used to access the power supply voltage VDD, the second input end of the third radio frequency rectifier circuit 5 is used to access the radio frequency signal, and the output end of the third radio frequency rectifier circuit 5 is connected to the base of the first transistor Q1, which is used to convert alternating current into unidirectional pulsating direct current.

[0075] In this embodiment, the third radio frequency rectifier circuit 5 includes a sixth transistor Q6, an eleventh resistor R11, a seventh capacitor C7, a seventh transistor Q7, a twelfth resistor R12, a thirteenth resistor R13, and an eighth capacitor C8.

[0076] The collector of the sixth transistor Q6 is connected to the collector of the fourth transistor Q4, and serves as the output end of the third radio frequency rectifier circuit 5, and the emitter of the fourth transistor Q4 is grounded, which is used to amplify the direct current signal rectified by the seventh transistor Q7 and output to the base of the first transistor Q1.

[0077] The first end of the eleventh resistor R11 is connected to the first end of the eighth resistor R8, and serves as the first input end of the third radio frequency rectifier circuit 5, and as a bias resistor.

[0078] The first end of the seventh capacitor C7 is connected to the second end of the fifth capacitor C5, and serves as the second input end of the third radio frequency rectifier circuit 5, and as a coupling and direct current blocking capacitor.

[0079] The collector of the seventh transistor Q7 is connected to the second end of the eleventh resistor R11 and the second end of the seventh capacitor C7 respectively, and the emitter of the seventh transistor Q7 is grounded.

[0080] The two ends of the twelfth resistor R12 are connected to the collector of the seventh transistor Q7 and the base of the seventh transistor Q7 respectively, and the seventh transistor Q7 forms a diode voltage stabilizing rectifier resistance.

[0081] The two ends of the thirteenth resistor R13 are connected to the base of the seventh transistor Q7 and the base of the sixth transistor Q6 respectively.

[0082] The first end of the eighth capacitor C8 is connected to the base of the fourth triode Q4, and the second end of the eighth capacitor C8 is grounded, and the eighth capacitor C8 and the thirteenth resistor R13 together serve as an RC filter circuit.

[0083] The first radio frequency rectifier circuit 3, the second radio frequency rectifier circuit 4 and the third radio frequency rectifier circuit 5 are respectively used for converting alternating current of the high-power signal, the medium-power signal and the low-power signal into unidirectional pulsating direct current, so as to be synthesized into one output for mutual compensation, thereby ensuring that the high-power signal, the medium-power signal and the low-power signal all have good linearity.

[0084] In addition, the power detection circuit 100 of the embodiment further includes a first capacitor C1, the first end of the first capacitor C1 is connected to the collector of the first triode Q1, and the second end of the first capacitor C1 is grounded, which is equivalent to that the first end of the first capacitor C1, the first end of the first resistor R1 and the collector of the first triode Q1 are connected and then connected to the power supply voltage VDD. The first capacitor C1 is used for filtering.

[0085] As shown in Figure 4 It can be seen that the power dynamic range of the power detection circuit 100 in the embodiment is between-20dBm and 20dBm, and the overall linearity is good, especially in the power range of-10 to 20dBm, which is basically completely linear.

[0086] Compared with the related art, the power detection circuit 100 in the present application adds the first radio frequency rectifier circuit 3, the second radio frequency rectifier circuit 4 and the third radio frequency rectifier circuit 5 for converting alternating current into unidirectional pulsating direct current, and the first resistor R1 is only connected to the base of the first triode Q1, so that the power dynamic range of the power detection circuit 100 can be improved, and the linearity is better.

[0087] It should be noted that the above-described various embodiments with reference to the accompanying drawings are only used to illustrate the present application and not to limit the scope of the present application, and those skilled in the art should understand that the modifications or equivalent replacements of the present application without departing from the spirit and scope of the present application should be covered in the scope of the present application. In addition, unless otherwise indicated in the context, the word in singular form includes the plural form, and vice versa. In addition, unless otherwise specified, all or part of any embodiment can be used in combination with all or part of any other embodiment.

Claims

1. A power detection circuit, characterized in that, The power detection circuit includes a first transistor, a low-pass circuit, a voltage divider circuit, a first resistor, a first RF rectifier circuit, a second RF rectifier circuit, and a third RF rectifier circuit. The collector of the first transistor is used to connect to the power supply voltage; The input terminal of the low-pass circuit is connected to the emitter of the first transistor, and the output terminal of the low-pass circuit is grounded to filter out high-frequency interference. The input terminal of the voltage divider circuit is connected to the input terminal of the low-pass circuit, and the output terminal of the voltage divider circuit is used to output a detection voltage to proportionally reduce the voltage signal output by the emitter of the first transistor. The first end of the first resistor is used to connect to the power supply voltage, and the second end of the first resistor is connected to the base of the first transistor; The first input terminal of the first RF rectifier circuit is used to connect to the power supply voltage, the second input terminal of the first RF rectifier circuit is used to connect to the RF signal, and the output terminal of the first RF rectifier circuit is connected to the base of the first transistor to convert AC power into unidirectional pulsating DC power. The first input terminal of the second RF rectifier circuit is used to connect to the power supply voltage, the second input terminal of the second RF rectifier circuit is used to connect to the RF signal, and the output terminal of the second RF rectifier circuit is connected to the base of the first transistor to convert AC power into unidirectional pulsating DC power. The first input terminal of the third RF rectifier circuit is used to connect to the power supply voltage, the second input terminal of the third RF rectifier circuit is used to connect to the RF signal, and the output terminal of the third RF rectifier circuit is connected to the base of the first transistor to convert AC power into unidirectional pulsating DC power. The first radio frequency rectifier circuit includes a second transistor, a fifth resistor, a third capacitor, a third transistor, a sixth resistor, a seventh resistor, and a fourth capacitor; The collector of the second transistor serves as the output terminal of the first radio frequency rectifier circuit, and the emitter of the second transistor is grounded. The first end of the fifth resistor is connected to the first end of the first resistor and serves as the first input terminal of the first radio frequency rectifier circuit. The first terminal of the third capacitor serves as the second input terminal of the first radio frequency rectifier circuit. The collector of the third transistor is connected to the second terminal of the fifth resistor and the second terminal of the third capacitor, respectively, and the emitter of the third transistor is grounded. The two ends of the sixth resistor are respectively connected to the collector of the third transistor and the base of the third transistor; The two ends of the seventh resistor are respectively connected to the base of the third transistor and the base of the second transistor; The first terminal of the fourth capacitor is connected to the base of the second transistor, and the second terminal of the fourth capacitor is grounded.

2. The power detection circuit as described in claim 1, characterized in that, The power detection circuit further includes a first capacitor, the first end of which is connected to the collector of the first transistor, and the second end of which is grounded.

3. The power detection circuit as described in claim 1, characterized in that, The low-pass circuit includes a second resistor and a second capacitor; the first end of the second resistor and the first end of the second capacitor are connected and together serve as the input terminal of the low-pass circuit, and the second end of the second resistor and the second end of the second capacitor are connected and together serve as the output terminal of the low-pass circuit.

4. The power detection circuit as described in claim 3, characterized in that, The voltage divider circuit includes a third resistor and a fourth resistor; the first end of the third resistor serves as the input terminal of the voltage divider circuit, the second end of the third resistor serves as the output terminal of the voltage divider circuit, the first end of the fourth resistor is connected to the second end of the third resistor, and the second end of the fourth resistor is grounded.

5. The power detection circuit as described in claim 1, characterized in that, The second RF rectifier circuit includes a fourth transistor, an eighth resistor, a fifth capacitor, a fifth transistor, a ninth resistor, a tenth resistor, and a sixth capacitor; The collector of the fourth transistor is connected to the collector of the second transistor and serves as the output terminal of the second RF rectifier circuit; the emitter of the fourth transistor is grounded. The first end of the eighth resistor is connected to the first end of the fifth resistor and serves as the first input terminal of the second RF rectifier circuit. The first terminal of the fifth capacitor serves as the second input terminal of the second radio frequency rectifier circuit. The collector of the fifth transistor is connected to the second terminal of the eighth resistor and the second terminal of the fifth capacitor, respectively, and the emitter of the fifth transistor is grounded. The two ends of the ninth resistor are respectively connected to the collector of the fifth transistor and the base of the fifth transistor; The two ends of the tenth resistor are respectively connected to the base of the fifth transistor and the base of the fourth transistor; The first terminal of the sixth capacitor is connected to the base of the fourth transistor, and the second terminal of the sixth capacitor is grounded.

6. The power detection circuit as described in claim 5, characterized in that, The third radio frequency rectifier circuit includes a sixth transistor, an eleventh resistor, a seventh capacitor, a seventh transistor, a twelfth resistor, a thirteenth resistor, and an eighth capacitor. The collector of the sixth transistor is connected to the collector of the fourth transistor and serves as the output terminal of the third RF rectifier circuit; the emitter of the fourth transistor is grounded. The first end of the eleventh resistor is connected to the first end of the eighth resistor and serves as the first input terminal of the third radio frequency rectifier circuit. The first terminal of the seventh capacitor is connected to the second terminal of the fifth capacitor and serves as the second input terminal of the third radio frequency rectifier circuit. The collector of the seventh transistor is connected to the second terminal of the eleventh resistor and the second terminal of the seventh capacitor, respectively, and the emitter of the seventh transistor is grounded. The two ends of the twelfth resistor are respectively connected to the collector of the seventh transistor and the base of the seventh transistor; The two ends of the thirteenth resistor are respectively connected to the base of the seventh transistor and the base of the sixth transistor; The first terminal of the eighth capacitor is connected to the base of the sixth transistor, and the second terminal of the eighth capacitor is grounded.

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