Power detector circuit and power signal detection method based on current feedback loop

Abstract

The present invention discloses a power detector circuit based on a current feedback loop and a power signal detection method, comprising a high-power detection branch, a wide-band low-noise amplifier and a low-power detection branch. The power detection method is as follows: for a low-power input signal, it is first amplified by a wide-band low-noise amplifier and then detected by a low-power detection branch. For a high-power input signal, it is detected by a high-power detection branch. Both the high-power detection branch and the low-power detection branch adopt a current feedback loop structure, comprising a radio frequency current square unit, a root mean square current square unit, a transconductance amplifier and an output buffer. The current feedback loop converts an input radio frequency voltage signal into a root mean square current signal, and the output buffer converts the root mean square current signal into a root mean square voltage signal for output. The present invention realizes wide dynamic range root mean square power detection through the current feedback loop, and expands the dynamic range by cascading two-stage current feedback loops and a wide-band low-noise amplifier.

Description

Technical Field

[0001] The present invention relates to the technical field of power detectors, and in particular to a root mean square power detector circuit based on a current feedback loop and a power signal detection method thereof. Background Art

[0002] With the development of modern wireless communication technology, power detectors are widely used in RF applications such as transmitters and receivers. In transmitters, power detectors are used to detect the output power of power amplifiers and automatic power control to meet communication protocol requirements while saving power. In receivers, power detectors are used to implement signal strength indication and automatic gain control to improve the dynamic range of received signals. In addition, power detectors are also widely used in signal amplitude modulation and demodulation, built-in self-test, six-port test and other systems.

[0003] At present, the commonly used power detector is the root mean square power detector. Since the root mean square power detector can average the signal according to time and can accurately measure the root mean square power of various types of high peak-to-average ratio dynamic signals and noise signals, it is widely used in radio frequency communication and test systems. However, the commonly used root mean square power detector is a single-stage root mean square power detector, which has defects such as insufficient dynamic range. When the power difference between the detected transmitted signal and the received signal is huge, the root mean square power detector needs to have a fairly wide dynamic range to meet the detection needs of both low-power and high-power signals. However, the traditional design technology of the root mean square power detector with a wide dynamic range cannot meet the requirements of modern integrated circuit design. For example, the root mean square power detector based on Joule heating requires a complex packaging process and is easily affected by the heat of the adjacent circuit coupled from the substrate, so it is not suitable for the design of monolithic integrated circuits; the root mean square power detector based on diodes has a large drift with temperature and requires an additional temperature compensation circuit, which limits its scope of use; the root mean square power detector based on a diode-connected PMOS tube as a load exhibits a large measurement error when measuring a high-power input signal.

[0004] A multi-stage RMS power detector is provided in the prior art, which can overcome the problem of insufficient dynamic range of the above-mentioned single-stage RMS power detector. However, the commonly used multi-stage RMS power detector is a cascade structure of a multi-stage attenuator and a power detector, or a cascade structure of a multi-stage gain amplifier and a power detector, with multiple output ports, and a complex method is required to determine which output port can correctly reflect the input signal power. Therefore, it has become an urgent problem to be solved by those skilled in the art to invent a multi-stage RMS power detector with a simple circuit structure that can not only further expand the dynamic range, but also simplify the output signal discrimination method. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a root mean square power detector expansion circuit based on a current feedback loop, which has a simple and reasonable circuit structure design, can expand the dynamic range of the power signal detected, and can simplify the power signal detection method.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] On the one hand, the present invention provides a current feedback loop, which includes a root mean square current square unit and a buffer, and is characterized in that it also includes a radio frequency current square unit and a first amplifier, the first amplifier's in-phase input terminal and inverting input terminal are respectively connected to the output terminals of the radio frequency current square unit and the root mean square current square unit, the input terminal of the radio frequency current square unit is the input terminal of the radio frequency voltage signal, the input terminal of the root mean square current square unit is respectively connected to the output terminal of the first amplifier and the input terminal of the buffer, the input terminal of the buffer is connected to the output terminal of the first amplifier, the output terminal of the buffer is the voltage output terminal of the entire power detector, and the output voltage of the power supply output terminal is a DC voltage.

[0008] Furthermore, the RMS current square unit is used as a feedback network to receive the feedback current output by the first amplifier, convert it into a square current signal, and generate a square voltage signal on its load, which is injected into the inverting input terminal of the first amplifier; the circuit structure of the RMS current square unit includes transistors Q1, Q2, Q3, Q4, Q5, resistors R1, R2, R e , R base , Ra, capacitor C1;

[0009] Furthermore, the circuit structure of the RF current square unit is consistent with the structure of the RMS current square unit, and the RF current square unit serves as an input impedance terminal, and is used to convert the input RF voltage signal into a square current signal and filter it, and generate a filtered square voltage signal on its load, and inject it into the in-phase input terminal of the first amplifier;

[0010] Furthermore, the first amplifier is a transconductance amplifier, which is used as a feedforward amplifier to amplify the error signal between the RF current square unit and the RMS current square unit, and convert the error signal into a feedback current. The buffer is used to copy the feedback current and convert the feedback current into a voltage signal, which is output after buffering. The output DC voltage is a RMS voltage corresponding to the input RF signal power. The circuit structure of the transconductance amplifier and buffer includes transistors Q6 to Q7. 22 , resistor R3~R 17 .

[0011] The root mean square power detection is performed using the root mean square power detector based on the current feedback loop, and the root mean square power signal detection method includes: using the RF current square unit as an impedance terminal, converting the input RF voltage signal into a square current signal and filtering it, and generating a filtered square voltage signal on its load, and injecting it into the in-phase input terminal of the transconductance amplifier;

[0012] The root mean square current square unit, the radio frequency current square unit and the transconductance amplifier together constitute a current mode feedback loop, wherein the feedback current is squared by the root mean square current square unit, and a square voltage is generated on its load, which is injected into the inverting input terminal of the transconductance amplifier. When the loop is established, the feedback current is the root mean square current corresponding to the input radio frequency signal power.

[0013] The output buffer copies the feedback current of the current feedback loop, converts it into a voltage signal, and outputs it after buffering, which is a root mean square voltage corresponding to the input radio frequency signal power.

[0014] On the other hand, the present invention provides a root mean square power detector expansion circuit based on the proposed current feedback loop, including a high-power detection branch and a low-power detection branch, characterized in that it also includes a second amplifier, the input end of the high-power detection branch and the input end of the second amplifier are input ends of the power signal, the output end of the second amplifier is connected to the input end of the low-power detection branch, the output end of the high-power detection branch outputs a first voltage signal Vout_A, the output end of the low-power detection branch outputs a second voltage signal Vout_B, and the high-power detection branch and the low-power detection branch both include a current feedback loop;

[0015] The power signal includes a low-power signal and a high-power signal. The high-power detection branch and the low-power detection branch are respectively used to detect the power signal. The second amplifier is used to amplify the low-power signal.

[0016] Furthermore, the high-power detection branch includes a second capacitor, and the low-power detection branch includes a third capacitor. One end of the first capacitor is connected to the input end of the power signal, and the other end is respectively connected to the input end of the high-power detection branch and the input end of the second amplifier. One end of the third capacitor is connected to the output end of the second amplifier, and the other end of the third capacitor is connected to the input end of the low-power detection branch.

[0017] The second amplifier is a wideband low noise amplifier, which is a wideband low noise amplifier based on a dual feedback loop of current-current feedback and voltage-voltage feedback. The dual feedback wideband low noise amplifier structure includes a transistor Q 23 ~Q29 , resistor R 18 ~R 24 .

[0018] Furthermore, the low-power signal refers to a signal with a power less than 0 dBm, the high-power signal refers to a signal with a power greater than 0 dBm, and the dynamic range of the input power signal is -45 dBm to 15 dBm.

[0019] The power signal detection is realized by utilizing the above-mentioned root mean square power detector expansion circuit. The power signal detection method includes: for a low-power input signal, that is, an input signal whose signal power is less than the sensitivity of a high-power detection branch, it is first amplified by a wide-band low-noise amplifier and then detected by a low-power detection branch; for a high-power input signal, that is, an input signal whose signal power is greater than the sensitivity of a high-power detection branch, it is directly detected by the high-power detection branch.

[0020] The beneficial effects brought by the technical solution provided by the present invention are as follows:

[0021] (1) The present invention provides a wide dynamic range root mean square power detector circuit based on a current feedback loop. The power detector includes a second amplifier. The second amplifier is connected to a low-power detection branch, which can effectively amplify the low-power signal, thereby expanding the output voltage signal of the low-power detection branch, that is, achieving an expansion of the dynamic range of the power signal, thereby overcoming the weaknesses of traditional root mean square power detectors, such as a small dynamic range and susceptibility to temperature drift.

[0022] (2) The present invention is based on a current feedback loop. The RF current square unit, the RMS current square unit and the first amplifier in the current feedback loop form a cascaded two-stage current feedback loop, which converts the input RF voltage signal into a RMS current signal. The output buffer converts the RMS current signal into a RMS voltage signal for output, so that the power detector can realize RMS power detection. The setting of the first amplifier can amplify the output RMS voltage signal of the power detector. When it is applied to the power detector, it plays a role in expanding the dynamic range of the power signal.

[0023] (3) The present invention provides an expansion circuit of a power detector circuit. The expansion circuit is a two-stage segmented power detection structure, which includes not only a high-power detection branch, but also a low-power detection branch and a second amplifier connected to the low-power detection branch. Compared with the traditional multi-stage power detection method, it not only has a larger dynamic range, but also simplifies the structural design to be simple and reasonable, reduces the investment cost, and simplifies the complexity of the power signal detection method, thereby improving the detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 is the system block diagram of the proposed RMS power detector expansion circuit based on current feedback loop;

[0026] Figure 2 It is a circuit schematic diagram of the radio frequency current square unit of the present invention;

[0027] Figure 3 is a circuit schematic diagram of the RMS current square unit of the present invention;

[0028] Figure 4 is a circuit schematic diagram of a transconductance amplifier and an output buffer of the present invention;

[0029] Figure 5 is a circuit schematic diagram of a root mean square power detector circuit of the present invention;

[0030] Figure 6 It is a schematic diagram of the state of the proposed RF current square unit when there is no signal input and when there is signal input;

[0031] Figure 7 The schematic diagram of the circuit of the broadband low noise amplifier of the present invention is shown in FIG.

[0032] Among them, the figure marks include: 1-RF current square unit, 2-RMS current square unit, 3-transconductance amplifier, 4-output buffer, 5-high power detection branch, 6-wide band low noise amplifier, 7-low power detection branch. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, device, product or equipment that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0035] In one embodiment of the present invention, an extended circuit of a root mean square power detector circuit based on a current feedback loop is provided. Figure 1 The current feedback loop includes an RF current square unit 1, a root mean square current square unit 2, a transconductance amplifier 3 and a buffer 4.

[0036] The input end of the RF current square unit 1 is the input end of the RF voltage signal, and the output end is connected to the in-phase input end of the transconductance amplifier 3. The input end of the RMS current square unit 2 is connected to the output end of the transconductance amplifier 3, and the output end is connected to the inverting input end of the transconductance amplifier 3. The input end of the RMS current square unit 2 is connected to the input end of the buffer 4 and the output end of the transconductance amplifier 3, and the output end is the DC voltage output end of the entire power detector.

[0037] The RF current square unit 1 acts as an input impedance terminal, converts the input RF voltage signal into a square current signal and filters it, and generates a filtered square voltage signal on its load, which is injected into the in-phase input terminal of the transconductance amplifier. The circuit structure of the RF current square unit 1 is as follows: Figure 2 As shown, there are five transistors, Q1, Q2, Q3, Q4, and Q5, with resistance values ​​of R1, R2, and R e , R a , R base The 6 resistors and capacitor C1.

[0038] The RMS current square unit 2 serves as a feedback network, receives the feedback current output by the transconductance amplifier 3, converts it into a square current signal, and generates a square voltage signal on its load, which is injected into the inverting input terminal of the transconductance amplifier 3. The circuit structure of the RMS current square unit 2 is as follows: Figure 3 As shown, there are five transistors, Q1, Q2, Q3, Q4, and Q5, with resistance values ​​of R1, R2, and R e , R a , R base of 6 resistors.

[0039] The transconductance amplifier 3 is used as a feedforward amplifier to amplify the error signal between the RF current square unit 1 and the RMS current square unit 2 and convert it into a feedback current. The output buffer 4 is used to copy the feedback current of the current feedback loop and convert the feedback current into a voltage signal, which is output after buffering. The voltage signal is the RMS voltage corresponding to the input RF signal power. The circuit structure of the transconductance amplifier 3 and the output buffer 4 is shown in FIG. Figure 4 As shown, including Q6 to Q 22 A total of 17 transistors and R3 to R 17 There are 15 resistors in total.

[0040] In one embodiment of the present invention, a root mean square power detector circuit is provided. Figure 5 , including a high-power detection branch 5, a wide-band low-noise amplifier 6 and a low-power detection branch 7. The input end of the high-power detection branch 5 is the input end of the RF voltage signal, and the output end is the first DC voltage output port V of the dynamic root mean square power detector. OUT_A (This voltage is the root mean square voltage corresponding to the input RF signal power) and is connected to the input end of the wideband low noise amplifier 6. The input end of the wideband low noise amplifier 6 is connected to the output end of the high power detection branch 5, and the output end is connected to the low power detection branch 7. The input end of the low power detection branch 7 is connected to the output end of the wideband low noise amplifier 6, and the output end is the second DC output port V of the dynamic range expansion circuit. OUT_B (This voltage is the RMS voltage corresponding to the input RF signal power).

[0041] The circuit structure of the high-power detection branch 5 is the same as that of the low-power detection branch 7. For a low-power input signal, that is, an input signal whose signal power is less than the sensitivity of the high-power detection branch 5, it is first amplified by the wide-band low-noise amplifier 6 and then detected by the low-power detection branch 7; for a high-power input signal, that is, an input signal whose signal power is greater than the sensitivity of the high-power detection branch 5, it is directly detected by the high-power detection branch 5.

[0042] See Figure 7 The wideband low noise amplifier 6 adopts a dual feedback wideband low noise amplifier structure including current-current feedback and voltage-voltage feedback. 23 To Q 29 A total of 7 transistors and R 18 To R 24 A total of 7 resistors are included. The wide-band low-noise amplifier 6 can effectively amplify low-power signals without introducing excessive noise, and can achieve 50 ohm input impedance matching without relying on an external matching circuit.

[0043] The working principle of the root mean square power detector circuit based on the current feedback loop and the dynamic range extension circuit thereof provided by the present invention is as follows:

[0044] like Figure 1 As shown, the extended circuit of the proposed current feedback loop RMS power detector circuit includes an RF current square unit, an RMS current square unit, a transconductance amplifier and an output buffer, which can convert the input RF signal power into a DC output voltage.

[0045] The current square unit is the core device of the whole current feedback loop RMS power detector, which squares and filters the input signal. Compared with the RF current square unit, the RMS current square unit has no filter capacitor C1 and works in DC state. The input impedance R of the RF current square unit is in_det for:

[0046]

[0047] Among them, gm Q2 and gm Q4 are the transconductances of transistors Q2 and Q4, I0 is the static bias current of transistors Q1, Q2, Q3, and Q4, V T is the thermal voltage of the transistor. When the static bias current I0 is a current proportional to the absolute temperature, the input impedance does not change with temperature. The RF current square unit acts as an impedance terminal, which converts the RF input voltage V rf Converted to RF input current I rf , the relationship is:

[0048]

[0049] The states of the RF current square unit when there is no signal input and when there is a signal input are as follows: Figure 6 When there is no signal input, the base bias voltage of the transistor Q4 connected in the form of a diode is V0, and the base voltages of Q1 and Q2 are V bias . Ignore the resistor R e and R base The voltage drop on the transistor can be obtained from the voltage-current relationship of the transistor:

[0050]

[0051]

[0052] Is is the reverse saturation current of the transistor. When there is an RF signal input, the base voltage of the transistor Q4 becomes V X , and the current flowing through transistor Q4 becomes I', and the current flowing through transistor Q2 becomes I", so the following relationship can be obtained:

[0053]

[0054]

[0055] I′=I"+I rf (7)

[0056] From formulas (3) to (7), we can get the output current I OUT , current gain A I and square current I SQR They are:

[0057]

[0058]

[0059]

[0060] Expanding formula (10) into a Taylor series, we can obtain:

[0061] When|I rf |<<4*I0 (11)

[0062] Formula (11) shows that when |I rf |<<4*I0, the RF current square unit will input the RF current square; when |I rf |>>2*I0, the absolute value of the input RF current is taken, that is:

[0063] When|I rf |>>2*I0, I SQR ≈|I rf |-2*I0 (12)

[0064] Increase the resistance R appropriately a The input current can be reduced, thereby increasing the maximum power that the power detector can detect; however, too large a resistor R a The thermal noise generated will limit the sensitivity of the power detector. In fact, the choice of resistor R a 500 ohms is a good choice. Transistor Q5, resistor R1 and resistor R2 form an active load circuit, and its AC impedance R load for

[0065]

[0066] From formula (13), we can see that R load As the input signal power increases, it decreases, preventing V OUTIf the current drops too much, the transistors Q1, Q2, Q3, and Q4 will enter the saturation region, and the subsequent transconductance amplifier will deviate from the working range. Capacitor C1 plays the role of signal filtering, short-circuiting the high-frequency components in the current to the AC ground. Therefore, in the entire current feedback loop, only the RF current square unit works in the RF frequency band, which greatly reduces the bandwidth requirements for the transconductance amplifier and the output buffer, and helps to achieve low-power design. The RMS current square unit is completely symmetrical with the RF current square unit and works in the DC state, so the filter capacitor can be removed.

[0067] like Figure 1 As shown in FIG. 1 , the entire current feedback loop RMS power detector includes a transconductance amplifier and an output buffer in addition to the current square unit, as shown in FIG. Figure 3 As shown. Transistor Q 12 The feedback current is replicated and fed to the resistor R 13 The root mean square voltage is generated on the transistor and then output after being buffered by the output buffer. 16 The function of is to compensate the input voltage drop of the RMS current square unit, so that the transistor Q 11 and Q 12 The collector voltage of the transconductance amplifier is the same, thus achieving accurate replication of the current. When the loop is established, the two input terminals of the transconductance amplifier have the same voltage, that is:

[0068]

[0069] Among them I back is the feedback current of the loop, injected into the RMS current square unit. Formula (14) can be simplified as:

[0070]

[0071] Select the resistor R 13 Equal to the input impedance R in_det , then the RMS output voltage can be expressed as:

[0072]

[0073] Formula (15) shows that the proposed current feedback loop RMS power detector can calculate the true RMS power value of the input RF signal.

[0074] In order to further expand the dynamic range, the present invention uses a segmented power detection method. The proposed two-stage RMS power detection structure is as follows: Figure 4 As shown, it includes two current feedback loops, a root mean square power detector and a wide-band low noise amplifier. The wide-band low noise amplifier uses a Meyer amplifier structure with voltage-voltage and current-current dual feedback, which can amplify low-power signals without introducing excessive noise. Its input impedance Rin_amp The input impedance of the power detector is R in for:

[0075]

[0076] No additional matching network is required to achieve input impedance matching. Figure 4 As shown, for an RF input signal, the two channels each generate a DC output signal V OUT_A and V OUT_B Unlike the traditional multi-stage RMS power detector structure, which requires a complex method to decide which output should be used to estimate the signal power, the proposed discrimination scheme is very simple. When the signal power indicated by the high-power branch is greater than its sensitivity, V OUT_A is used to indicate signal power, otherwise V OUT_B It is used to indicate the signal power. This benefits from the wide dynamic range characteristics of the proposed current feedback loop RMS power detector, otherwise more gain stages are needed to expand the dynamic range, and each stage will have a corresponding DC output, which requires a more complex decision method to measure the output results of each stage.

[0077] In order to extend the dynamic range as much as possible, the two current feedback loop rms power detectors must have the same transfer characteristics. The loop gain of the current feedback loop rms power detector has an important influence on its transfer characteristics. The loop gain of the entire current feedback loop is:

[0078]

[0079] Among them G m and V diff are the transconductance and input differential voltage of the transconductance amplifier, respectively. From formula (11), we can see that the larger the static bias current I0 is, the larger the maximum input signal power allowed by the square law relationship is; however, as shown in formula (18), the larger I0 is, the smaller the loop gain of the current feedback loop is, which not only reduces the loop establishment speed, but also makes the loop more sensitive to mismatch. This phenomenon is particularly obvious when a low-power signal is input. As shown in formula (18), the loop gain is proportional to the input differential voltage V diff When a low power signal is input, the initial V diff is very small, so the loop gain is much smaller than when a high-power signal is input, and the error caused by mismatch is more obvious. For the proposed two-stage power detection structure, if the transfer function of the two-stream feedback loop RMS power detector does not match, the dynamic range of power detection will be limited. Therefore, it is necessary to carefully select the size of I0 to compromise between the maximum detectable input power and loop gain.

[0080] The root mean square power detection circuit based on the current feedback loop and the dynamic range extension circuit thereof provided by the present invention are preferably applied to the radio frequency receiver and transmitter signal chain, and can be applied to the root mean square power measurement of simple and / or complex waveforms. The dynamic range of the input power signal of the root mean square power detection circuit based on the current feedback loop is 30dB, and the dynamic range of the extension circuit of the root mean square power detection circuit is 60dB, so it is suitable for measuring signals with a large dynamic range and a high peak-to-average ratio. It not only has a very wide dynamic range, but also simplifies the output signal discrimination scheme.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A power detector circuit, comprising a high-power detection branch and a low-power detection branch, characterized in that: It also includes a second amplifier, the input end of the high-power detection branch and the input end of the second amplifier are input ends of the power signal, the output end of the second amplifier is connected to the input end of the low-power detection branch, the output end of the high-power detection branch outputs a first voltage signal Vout_A, and the output end of the low-power detection branch outputs a second voltage signal Vout_B, and the high-power detection branch and the low-power detection branch both include a current feedback loop; The power signal includes a low-power signal and a high-power signal, the high-power detection branch and the low-power detection branch are respectively used to detect the power signal, and the second amplifier is used to amplify the low-power signal; The current feedback loop includes a root mean square current square unit and a buffer, and is characterized in that it also includes a radio frequency current square unit and a first amplifier, wherein the in-phase input terminal and the inverting input terminal of the first amplifier are respectively connected to the output terminals of the radio frequency current square unit and the root mean square current square unit, the input terminal of the radio frequency current square unit is the input terminal of the radio frequency voltage signal, the input terminal of the root mean square current square unit is respectively connected to the output terminal of the first amplifier and the input terminal of the buffer, the input terminal of the buffer is connected to the output terminal of the first amplifier, and the output terminal of the buffer is the voltage output terminal of the entire power detector.

2. The power detector circuit according to claim 1, characterized in that The power detector circuit also includes a first capacitor, the high-power detection branch includes a second capacitor, and the low-power detection branch includes a third capacitor. One end of the first capacitor is connected to the input end of the power signal, and the other end is respectively connected to the input end of the high-power detection branch and the input end of the second amplifier. One end of the third capacitor is connected to the output end of the second amplifier, and the other end of the third capacitor is connected to the input end of the low-power detection branch.

3. The power detector circuit according to claim 2, characterized in that The second amplifier is a wideband low noise amplifier, which is a dual feedback wideband low noise amplifier structure including current-current feedback and voltage-voltage feedback, and the dual feedback wideband low noise amplifier structure includes a transistor Q 23 ~Q 29 , resistor R 18 ~R 24 ; Transistor Q 23 The base of the 19 Connect to transistor Q 23 The collector of transistor Q 23 The emitter of transistor Q 24 The collector of is connected; Transistor Q 24 The collector of transistor Q 24 The base of transistor Q 24 The emitter of transistor Q 25 The collector of is connected; Transistor Q 25 The collector of transistor Q 25 The base of transistor Q 25 The emitter is connected in series with a resistor R 20 And the resistor R 22 Grounding; Transistor Q 26 The collector of transistor Q 23 The base of transistor Q 26 The base of transistor Q 27 The collector of transistor Q 26 The emitter of 23 Grounding; Transistor Q 27 The base of the 21 Connect to transistor Q 29 The base of transistor Q 27 The collector of 18 Connect to transistor Q 23 The collector of transistor Q 27 The emitter of 22 Grounding; Transistor Q 28 The base of transistor Q 26 The emitter of transistor Q 28 The collector of transistor Q 26 The collector of transistor Q 28 The emitter of transistor Q 29 The base and collector of Transistor Q 29 The emitter of 24 Ground.

4. The power detector circuit according to claim 1, characterized in that: The root mean square current square unit is a feedback network, and the root mean square current square unit is used to receive the feedback current output by the first amplifier, convert it into a square current signal, and generate a square voltage signal on its load, and inject it into the inverting input terminal of the first amplifier. The circuit structure of the root mean square current square unit includes transistors Q1, Q2, Q3, Q4, Q5, resistors R1, R2, R e , R base , Ra, capacitor C1; The base of transistor Q1 is connected to the base of transistor Q2, the collector of transistor Q1 is connected to the collector of transistor Q2, and the emitter of transistor Q1 is connected to the base of transistor Q2 through resistor R e Connect to the collector of transistor Q3; The collector of transistor Q2 is connected to the collector of transistor Q5 through resistor R1, and the emitter of transistor Q2 is connected to the collector of transistor Q5 through resistor R e Connected to the collector of transistor Q4; The base of transistor Q3 is connected to the base of transistor Q4, and the emitter of transistor Q3 is connected to the base of transistor Q4 through resistor R e Grounding; The base of transistor Q4 is connected through resistor R base Connected to the collector of transistor Q4, the emitter of transistor Q4 is connected through resistor R e Grounding; The base of the transistor Q5 is used to receive the feedback current output by the first amplifier, and the emitter of the transistor Q5 is connected to the collector of the transistor Q1 through the resistor R2; One end of the resistor Ra is connected to the base of the transistor Q4, and the other end is used to generate a square voltage signal; The capacitor C1 is connected in parallel to both ends of the resistor R1.

5. The power detector circuit according to claim 4, characterized in that The circuit structure of the RF current square unit is consistent with the structure of the RMS current square unit. The RF current square unit is an input impedance terminal. The RF current square unit is used to convert the input RF voltage signal into a square current signal and filter it, and generate a filtered square voltage signal on its load, which is injected into the in-phase input terminal of the first amplifier.

6. The power detector circuit according to claim 5, characterized in that The first amplifier is a transconductance amplifier, and the circuit structure of the transconductance amplifier and the buffer includes transistors Q6 to Q 22 , resistor R3~R 17 ; The base of transistor Q6 and the base of transistor Q7 are connected to the error signal, the collector of transistor Q6 is connected to the collector of Q9, and the emitter of transistor Q6 is connected to Q 15 The collector of is connected; The collector of transistor Q7 is connected to the collector of Q8, and the emitter of transistor Q7 is connected to Q 15 The collector of is connected; The base of transistor Q8 is connected to the base of transistor Q9, and the emitter of transistor Q8 is connected to Q 11 The collector; The base of transistor Q9 and transistor Q 10 The base of transistor Q9 is connected to the collector of transistor Q 10 The collector of transistor Q9 is connected to Q through resistor R4. 11 The collector; Transistor Q 10 The collector and transistor Q 11 The base of transistor Q 10 The emitter of Q is connected through resistor R3 11 The collector; Transistor Q 11 The base connection Q 10 The collector of transistor Q 11 The emitter of is connected to transistor Q through resistor R6 12 The base of Transistor Q 12 The collector of transistor Q is grounded. 12 The emitter of is connected to the base of transistor Q8; Transistor Q 13 The base of transistor Q is connected to the bias current through resistor R8. 13 The collector of transistor Q 12 The base of transistor Q 13 The emitter of is grounded through resistor R7; Transistor Q 14 The base and transistor Q 15 The base of transistor Q 14 The collector of transistor Q is connected through resistor R9 13 The base of transistor Q 14 The emitter is grounded; Transistor Q 15 The collector of transistor Q6 is connected to the emitter of transistor Q7. 15 The emitter is grounded; Transistor Q 16 The base of the transistor Q 18 The base of transistor Q 16 The collector of 14 Connected to the RMS current square unit, transistor Q 16 The emitter of 10 And transistor Q 22 The emitter of is connected; Transistor Q 17 The collector and transistor Q 21 The collector of transistor Q 17 The emitter of 11 And transistor Q 22 The emitter of is connected; Transistor Q 18 The collector of transistor Q22 is connected to the emitter of transistor Q22. 18 The emitter and transistor Q 20 The base of is connected; Transistor Q 19 The base of transistor Q is connected to the bias voltage. 19 The collector and transistor Q 20 The base of transistor Q 19 The emitter is grounded; Transistor Q 20 The base of transistor Q 19 The collector of transistor Q 20 The collector of is grounded; Transistor Q 21 The base of the 13 Connect the base of transistor Q18, transistor Q 21 The collector of transistor Q 17 The collector of transistor Q 21 The emitter of 15 Grounding; Transistor Q 22 The base of transistor Q is connected to a voltage source. 22 The collector of 16 and resistor R 17 Grounding; Resistor R 12 One end is connected to transistor Q through capacitor C2 18 The other end is connected to the base of transistor Q 16 The collector; The transconductance amplifier is used as a feedforward amplifier to amplify the error signal between the RF current square unit and the RMS current square unit, and convert the error signal into a feedback current. The buffer is used to replicate the feedback current and convert the feedback current into a voltage signal, which is output after buffering. The output voltage is a RMS voltage corresponding to the input RF signal power.

7. A method for detecting a power signal using the power detector circuit of claim 1, characterized in that: The method includes: for the low-power signal, first amplifying it by the second amplifier and then detecting it by the low-power detection branch; for the high-power signal, directly detecting it by the high-power detection branch, so that the output end of the high-power detection branch or the output end of the low-power detection branch outputs a first voltage signal Vout_A and a second voltage signal Vout_B respectively, and the first voltage signal Vout_A and the second voltage signal Vout_B are both root mean square voltages corresponding to the input radio frequency signal power.

8. The method for power signal detection according to claim 7, characterized in that: The high-power detection branch and the low-power detection branch both include a current feedback loop. The high-power detection branch and the low-power detection branch are connected through a first amplifier to form a cascaded two-stage current feedback loop. The input RF voltage signal is converted into a root mean square current signal through the cascaded two-stage current feedback loop, and the buffer converts the root mean square current signal into the root mean square voltage signal for output.

9. A radio frequency receiver or transmitter, characterized in that: The RF receiver or transmitter includes the power detector circuit according to claim 1, wherein the power detector circuit is used to detect the power signal input to the RF receiver or transmitter and output a root mean square voltage with a wide dynamic range, and the current feedback loop converts the input RF voltage signal into the root mean square current signal.

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