CN112946359A - Power detector circuit based on current feedback loop and power signal detection method - Google Patents

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

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CN112946359A
CN112946359A CN202110119136.4A CN202110119136A CN112946359A CN 112946359 A CN112946359 A CN 112946359A CN 202110119136 A CN202110119136 A CN 202110119136A CN 112946359 A CN112946359 A CN 112946359A
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current
power
signal
amplifier
low
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杨浩涵
樊晓华
蔡青松
杨中
陈文亚
宋佳音
付江铎
郭晓旭
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Jiangsu Jicui Intelligent Integrated Circuit Design Technology Research Institute Co ltd
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    • G01—MEASURING; TESTING
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Abstract

The invention discloses a power detector circuit based on a current feedback loop and a power signal detection method, wherein the power detector circuit comprises a high-power detection branch, a broadband low-noise amplifier and a low-power detection branch, and the power detection method comprises the following steps: for a low-power input signal, a broadband low-noise amplifier amplifies the low-power input signal, and then the low-power input signal is detected by a low-power detection branch, for a high-power input signal, the high-power detection branch and the low-power detection branch are all in a current feedback loop structure and comprise a radio frequency current square unit, a root mean square current square unit, a transconductance amplifier and an output buffer, wherein 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.

Description

Power detector circuit based on current feedback loop and power signal detection method
Technical Field
The invention relates to the technical field of power detectors, in particular to a root-mean-square power detector circuit based on a current feedback loop and a power signal detection method thereof.
Background
With the development of modern wireless communication technology, power detectors are widely used in radio frequency applications such as emitters and receivers. In a transmitter, a power detector is used to detect the output power of a power amplifier and to automatically control the power to meet communication protocol requirements while saving power consumption. In a receiver, a power detector is used to implement signal strength indication and automatic gain control to improve the dynamic range of the received signal. Besides, the power detector is also widely applied to systems such as signal amplitude modulation and demodulation, built-in self test, six-port test and the like.
The currently used power detector is a root mean square power detector, and the root mean square power detector can average signals 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-containing signals, so that the power detector is widely applied to radio frequency communication and test systems. However, the currently commonly used rms power detector is a single-stage rms power detector, and has the defects of insufficient dynamic range and the like, and when the detected transmit signal and receive signal have great power difference, the rms power detector needs to have a quite wide dynamic range to simultaneously meet the detection requirements of a low-power signal and a high-power signal. However, the conventional rms power detector design technology with wide dynamic range cannot meet the requirements of modern integrated circuit design, for example, the rms power detector based on joule heating requires a complex packaging process, and is susceptible to the heat of adjacent circuits coupled to the substrate, so that the design technology is not suitable for the design of a monolithic integrated circuit; the diode-based RMS power detector has large drift along with temperature, needs an additional temperature compensation circuit and limits the application range of the diode-based RMS power detector; the RMS power detector based on the diode-connected PMOS transistor as a load shows a large measurement error when measuring a high-power input signal.
The prior art provides a multi-stage rms power detector, which can overcome the problem of insufficient dynamic range of the single-stage rms power detector, but the conventional commonly used multi-stage rms power detector has a multi-stage attenuator and power detector cascade structure or a multi-stage gain amplifier and power detector cascade structure, has multiple output ports, and needs a complicated method to determine which output port can correctly reflect the input signal power. Therefore, the present invention is directed to a multi-stage rms power detector with a simple circuit structure, which can not only further expand the dynamic range, but also simplify the output signal determination method, and thus, a problem to be solved by those skilled in the art is urgently needed.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides the RMS power detector expansion circuit based on the current feedback loop, the circuit structure design is simple and reasonable, the dynamic range of the detected power signal can be expanded, and the power signal detection method can be simplified.
In order to achieve the purpose, the invention adopts the following technical scheme:
in one aspect, the present invention provides a current feedback loop, which includes a root mean square current square unit and a buffer, and is characterized by further including a radio frequency current square unit and a first amplifier, wherein a non-inverting input terminal and an inverting input terminal of the first amplifier are respectively connected to the radio frequency current square unit and an output terminal of the root mean square current square unit, an input terminal of the radio frequency current square unit is an input terminal of a radio frequency voltage signal, an input terminal of the root mean square current square unit is respectively connected to an output terminal of the first amplifier and an input terminal of the buffer area, an input terminal of the buffer is connected to an output terminal of the first amplifier, an output terminal of the buffer is a voltage output terminal of the whole power detector, and an output voltage of the power output terminal is a direct current voltage.
Further, the rms current squaring unit is used as a feedback network, and is configured to receive a feedback current output by the first amplifier, convert the feedback current into a squared current signal, generate a squared voltage signal on a load of the squared current signal, and inject the squared voltage signal into an inverting input terminal of the first amplifier; the circuit structure of the RMS current squaring unit comprises a triode Q1、Q2、Q3、Q4、Q5Resistance R1、R2、Re、RbaseRa, capacitor C1；
Furthermore, the circuit structure of the radio frequency current square unit is consistent with that of the root mean square current square unit, and the radio frequency current square unit is used as an input impedance terminal and is used for converting the input radio frequency voltage signal into a square current signal, filtering the square current signal, generating a filtered square voltage signal on a load of the square current signal, and injecting the filtered square voltage signal into the non-inverting input end of the first amplifier;
further, the first amplifier is a transconductance amplifier, the transconductance amplifier is used as a feed-forward amplifier and is configured to amplify an error signal between the radio frequency current squaring unit and the root-mean-square current squaring unit and convert the error signal into a feedback current, the buffer is configured to copy the feedback current and convert the feedback current into a voltage signal, the voltage signal is buffered and then output, and the output dc voltage is a root-mean-square voltage corresponding to the power of the input radio frequency signal. The circuit structure of the transconductance amplifier and the buffer comprises a triode Q6～Q22Resistance R3～R17。
The RMS power detection is performed by using an RMS power detector based on the current feedback loop, and the RMS power signal detection method comprises the following steps: the radio frequency current square unit is used as an impedance terminal, an input radio frequency voltage signal is converted into a square current signal and filtered, a filtered square voltage signal is generated on a load of the square current signal, and the square current signal is injected into a non-inverting input end of the transconductance amplifier;
the RMS current squaring unit, the RF current squaring unit and the transconductance amplifier jointly form a current mode feedback loop, wherein after the feedback current is squared by the RMS current squaring unit, a square voltage is generated on a load of the feedback current and injected into an inverting input end of the transconductance amplifier, and when the loop is established, the feedback current is the RMS current corresponding to the power of the input RF signal.
The output buffer copies the feedback current of the current feedback loop, converts the feedback current into a voltage signal, and outputs the voltage signal after buffering, namely the root mean square voltage corresponding to the power of the input radio frequency signal.
On the other hand, the invention provides a root mean square power detector extension circuit based on the proposed current feedback loop, which comprises a high-power detection branch and a low-power detection branch, and is characterized by further comprising a second amplifier, wherein the input end of the high-power detection branch and the input end of the second amplifier are input ends of power signals, the output end of the second amplifier is connected with 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 comprise current feedback loops;
the power signals comprise low-power signals and high-power signals, the high-power detection branch and the low-power detection branch are respectively used for detecting the power signals, and the second amplifier is used for amplifying the low-power signals.
Furthermore, the high-power detection branch comprises a second capacitor, the low-power detection branch comprises a third capacitor, one end of the first capacitor is connected with the input end of the power signal, the other end of the first capacitor is respectively connected with 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 with the output end of the second amplifier, and the other end of the third capacitor is connected with the input end of the low-power detection branch.
The second amplifier is a broadband low noise amplifier, the broadband low noise amplifier is a broadband low noise amplifier of a double feedback loop based on current-current feedback and voltage-voltage feedback, and the structure of the double feedback broadband low noise amplifier comprises a triode Q23～Q29Resistance R18～R24。
Further, the low-power signal refers to a signal with power less than 0dBm, the high-power signal refers to a signal with power greater than 0dBm, and the dynamic range of the input power signal is-45 dBm to 15 dBm.
The RMS power detector extension circuit is utilized to realize power signal detection, and the power signal detection method comprises the following steps: for a low-power input signal, namely an input signal with the signal power smaller than the sensitivity of the high-power detection branch circuit, the low-power input signal is amplified by a broadband low-noise amplifier and then detected by the low-power detection branch circuit; for a high-power input signal, i.e. an input signal with a signal power greater than the sensitivity of the high-power detection branch, the high-power detection branch directly detects the input signal.
The technical scheme provided by the invention has the following beneficial effects:
(1) the invention provides a RMS power detector circuit with a wide dynamic range based on a current feedback loop, wherein the power detector comprises a second amplifier which is connected with a low-power detection branch circuit, so that a low-power signal can be effectively amplified, the output voltage signal of the low-power detection branch circuit is enlarged, namely the dynamic range of the power signal is enlarged, and the defects that the traditional RMS power detector has a small dynamic range and is easily influenced by temperature drift are overcome.
(2) The invention is based on the current feedback loop, the radio frequency current square unit, the root mean square current square unit and the first amplifier in the current feedback loop form a cascade two-stage current feedback loop, an input radio frequency voltage signal is converted into a root mean square current signal, an output buffer converts the root mean square current signal into a root mean square voltage signal to be output, so that the power detector can realize root mean square power detection, the arrangement of the first amplifier can enlarge the output root mean square voltage signal of the power detector, and when the first amplifier is applied to the power detector, the effect of enlarging the dynamic range of the power signal is achieved.
(3) The invention provides an expansion circuit of a power detector circuit, which is a two-stage sectional type power detection structure, and the structure comprises a high-power detection branch, a low-power detection branch and a second amplifier connected with the low-power detection branch.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a system block diagram of the proposed RMS power detector extension circuit based on a current feedback loop;
FIG. 2 is a schematic circuit diagram of the RF current squaring cell of the present invention;
FIG. 3 is a circuit schematic of the RMS current squaring cell of the present invention;
FIG. 4 is a circuit schematic of a transconductance amplifier and an output buffer of the present invention;
FIG. 5 is a circuit schematic of the RMS power detector circuit of the present invention;
fig. 6 is a schematic diagram of the proposed rf current squaring cell in the absence and presence of signal inputs;
fig. 7 is a schematic circuit diagram of the wideband low noise amplifier of the present invention.
Wherein the reference numerals include: the device comprises a radio frequency current square unit 1, a root mean square current square unit 2, a transconductance amplifier 3, an output buffer 4, a high-power detection branch 5, a broadband low-noise amplifier 6 and a low-power detection branch 7.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, article, or device that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or device.
In one embodiment of the present invention, an extended circuit of an rms power detector circuit based on a current feedback loop is provided, and referring to fig. 1, the current feedback loop includes an rf current squaring unit 1, an rms current squaring unit 2, a transconductance amplifier 3, and a buffer 4.
The input end of the radio frequency current square unit 1 is the input end of a radio frequency voltage signal, the output end of the radio frequency current square unit is connected with the non-inverting input end of the transconductance amplifier 3, the input end of the root mean square current square unit 2 is connected with the output end of the transconductance amplifier 3, the output end of the root mean square current square unit is connected with the inverting input end of the transconductance amplifier 3, the input end of the root mean square current square unit 2 is connected with the input end of the buffer 4 and the output end of the transconductance amplifier 3, and the output end of the.
The rf current squaring unit 1 is used as an input impedance terminal, converts an input rf voltage signal into a squared current signal, filters the squared current signal, generates a filtered squared voltage signal on a load, and injects the filtered squared voltage signal into a non-inverting input terminal of a transconductance amplifier, and the circuit structure of the rf current squaring unit 1 is shown in fig. 2 and includes Q1、Q2、Q3、Q4、Q5Five triodes with resistance of R1、R2、Re、Ra、R base6 resistors, and a capacitor C1。
The rms current squaring unit 2 serves as a feedback network, receives the feedback current output by the transconductance amplifier 3, converts the feedback current into a square current signal, generates a square voltage signal on a load of the feedback current signal, and injects the square voltage signal into an inverting input end of the transconductance amplifier 3. The RMS current squaring cell 2 circuit configuration is shown in FIG. 3 and includes Q1、Q2、Q3、Q4、Q5Five triodes with resistance of R1、R2、Re、Ra、R base6 resistors.
The transconductance amplifier 3 serves as a feed forward amplifier for amplifying an error signal between the rf current squaring unit 1 and the rms current squaring unit 2 and converting it into a feedback current. And the output buffer 4 is used for copying the feedback current of the current feedback loop, converting the feedback current into a voltage signal, and outputting the voltage signal after buffering, wherein the voltage signal is the root mean square voltage corresponding to the power of the input radio frequency signal. The circuit configuration of the transconductance amplifier 3 and the output buffer 4 is shown in fig. 4 and includes Q6To Q22Total 17 triodes and R3To R17There are 15 resistors in total.
In an embodiment of the present invention, there is further provided a rms power detector circuit, referring to fig. 5, including a high power detection branch 5, a wide band low noise amplifier 6 and a low power detection branch 7, wherein an input terminal of the high power detection branch 5 is an input terminal of a radio frequency voltage signal, and an output terminal thereof is an output terminal of the high power detection branch 5A first DC voltage output port V of the RMS power detectorOUT_A(this voltage is a root mean square voltage corresponding to the power of the input radio frequency signal) and is connected to the input terminal of the wide band low noise amplifier 6. The input end of the broadband low-noise amplifier 6 is connected with the output end of the high-power detection branch 5, and the output end of the broadband low-noise amplifier is connected with the low-power detection branch 7. The input end of the low-power detection branch circuit 7 is connected with the output end of the broadband low-noise amplifier 6, and the output end is a second direct current output port V of the dynamic range expansion circuitOUT_B(this voltage is the rms voltage corresponding to the input rf signal power).
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, namely an input signal with the signal power smaller than the sensitivity of the high-power detection branch 5, the low-power input signal is firstly amplified by the broadband low-noise amplifier 6 and then detected by the low-power detection branch 7; for high power input signals, i.e. input signals with a signal power greater than the sensitivity of the high power detection branch 5, the high power detection branch 5 directly detects the input signals.
Referring to fig. 7, the wide band lna 6 employs a dual feedback wide band lna architecture including current-current feedback and voltage-voltage feedback, consisting of Q23To Q29Total 7 triodes and R18To R24A total of 7 resistors. The broadband low-noise amplifier 6 can effectively amplify a low-power signal without introducing excessive noise, and can realize 50-ohm input impedance matching without depending on an external matching circuit.
The invention provides a root-mean-square power detector circuit based on a current feedback loop and a dynamic range expansion circuit thereof, and the working principle is as follows:
as shown in fig. 1, the proposed circuit for the current feedback loop rms power detector circuit includes an rf current squaring unit, an rms current squaring unit, a transconductance amplifier and an output buffer, which can convert the input rf signal power into a dc output voltage.
The current squaring cell being the whole current inverseThe feed-loop RMS power detector is a core device that squares and filters the input signal. Compared with the radio frequency current square unit, the RMS current square unit has no filter capacitor C1And operates in a dc state. Input impedance R of radio frequency current square unitin_detComprises the following steps:
Figure BDA0002921840110000071
wherein, gmQ2And gmQ4Are respectively a triode Q2And Q4Transconductance of (1)0Is a triode Q1、Q2、Q3、Q4Static bias current of, VTIs the thermal voltage of a triode. When the static bias current I0The input impedance is not changed along with the temperature change when the current is in direct proportion to the absolute temperature. The RF current square unit is used as an impedance terminal for inputting RF voltage VrfConversion to radio frequency input current IrfThe relationship is:
Figure BDA0002921840110000072
the states of the rf current squaring cell when there is no signal input and when there is a signal input are shown in fig. 6. A diode-connected transistor Q when no signal is inputted4Base bias voltage of V0，Q1、Q2Has a base voltage of Vbias. Neglecting the resistance ReAnd RbaseThe voltage drop over can be obtained from the voltage-current relationship of the transistor:
Figure BDA0002921840110000073
Figure BDA0002921840110000081
is the reverse saturation current of the triode, when the radio frequency signal Is input, the triode Q4Is changed to VXAnd the current flowing through the transistor Q4 becomes I', flows through the transistor Q2Becomes I ", and then the following relationship can be obtained:
Figure BDA0002921840110000082
Figure BDA0002921840110000083
I′＝I"+Irf (7)
the output current I can be obtained from the formulas (3) to (7)OUTCurrent gain AISum squared current ISQRRespectively as follows:
Figure BDA0002921840110000084
Figure BDA0002921840110000085
Figure BDA0002921840110000086
expanding equation (10) into a taylor series yields:
Figure BDA0002921840110000087
when Irf|＜＜4*I0(11)
Equation (11) shows that when Irf|＜＜4*I0When the radio frequency current is input, the radio frequency current squaring unit squares the input radio frequency current; when Irf|＞＞2*I0And then, taking an absolute value of the input radio frequency current, namely:
when Irf|＞＞2*I0When, ISQR≈|Irf|-2*I0 (12)
Suitably increasing the resistance RaThe input current may be reduced, thereby increasing the maximum power that the power detector can detect; however, an excessive resistance RaThe resulting thermal noise will limit the sensitivity of the power detector. The fact that the resistance R is chosena500 ohms is a good choice. Triode Q5Resistance R1And a resistance R2An active load circuit is formed, the alternating current impedance R of whichloadIs composed of
Figure BDA0002921840110000091
As can be seen from the formula (13), RloadV is prevented from decreasing with increasing input signal powerOUTDrop too much to cause the transistor Q1、Q2、Q3、Q4Entering a saturation region and deviating the transconductance amplifier of the later stage from the working region. Capacitor C1The short-circuit acts as a signal filter, and short-circuits the high-frequency components of the current to the AC ground. Therefore, only the radio frequency current square unit in the whole current feedback loop works in a radio frequency band, the bandwidth requirements on the transconductance amplifier and the output buffer are greatly reduced, and the low-power-consumption design is facilitated. The RMS current squaring unit is completely symmetrical to the RF current squaring unit and operates in a DC state, so that the filter capacitor can be eliminated.
As shown in fig. 1, the whole current feedback loop rms power detector includes a transconductance amplifier and an output buffer in addition to a current squaring cell, as shown in fig. 3. Triode Q12Reproducing feedback current and at resistor R13The RMS voltage is generated and buffered by an output buffer before being output. Triode Q16The function of the transistor is to compensate the input voltage drop of the RMS unit so that the transistor Q11And Q12Are identical so that an accurate copy of the current is achieved. When the loop is set up, the two inputs of the transconductance amplifier have the same voltage, i.e.:
Figure BDA0002921840110000092
wherein IbackIs the feedback current of the loop, and is injected into the square unit of the root mean square current. Equation (14) can be simplified as:
Figure BDA0002921840110000093
selection resistor R13Equal to the input impedance Rin_detThen the rms output voltage can be expressed as:
Figure BDA0002921840110000094
equation (15) shows that the proposed current feedback loop rms power detector can calculate the true rms power value for the input rf signal.
To further extend the dynamic range, the present invention uses a segmented power detection method. The proposed two-stage rms power detection architecture is shown in fig. 4, and includes two current feedback loop rms power detectors and a wideband low noise amplifier. The wide-band low-noise amplifier adopts a voltage-voltage and current-current double-feedback Meyer amplifier structure, can amplify a low-power signal without introducing excessive noise, and has an input impedance Rin_ampIs 50 ohms. Input impedance R of the whole power detectorinComprises the following steps:
Figure BDA0002921840110000102
input impedance matching can be achieved without an additional matching network. As shown in FIG. 4, for a radio frequency input signal, two channels each generate a DC output signal VOUT_AAnd VOUT_B. With the conventional multi-stage RMS power detector structure, it is necessary to do so repeatedlyThe proposed decision scheme is very simple, since it is complicated to decide which output should be used to estimate the signal power. When the signal power indicated by the high-power branch is greater than the sensitivity, VOUT_AIs used to indicate signal power, otherwise VOUT_BIs used to indicate the signal power. This benefits from the wide dynamic range characteristic of the proposed rms power detector, which otherwise requires more gain stages to extend the dynamic range, and each stage has a corresponding dc output, which requires more complex decision methods to measure the output result of each stage.
In order to extend the dynamic range as much as possible, the two-way current feedback loop rms power detector must have the same transfer characteristics. The loop gain of the current feedback loop rms power detector has a significant impact on its transfer characteristics. The loop gain of the whole current feedback loop is as follows:
Figure BDA0002921840110000101
wherein G ismAnd VdiffRespectively, the transconductance of the transconductance amplifier and the input differential voltage. As can be seen from equation (11), the quiescent bias current I0The larger the square law relationship allows the larger the maximum input signal power; however, as shown in equation (18), I0The larger the loop gain of the current feedback loop, the less this not only reduces the speed of loop set-up, but also makes the loop more sensitive to mismatch. This phenomenon is particularly noticeable at low power signal inputs. As shown in equation (18), the loop gain is proportional to the input differential voltage Vdiff. When a small power signal is input, an initial VdiffAnd is small, the loop gain is much smaller than at the input of a high power signal, and errors due to mismatch are more significant. For the proposed two-stage power detection architecture, the dynamic range of power detection is limited if the transfer functions of the two-way stream feedback loop rms power detector do not match. Therefore, careful selection of I is required0Is traded off between maximum detectable input power and loop gain.
The RMS power detection circuit based on the current feedback loop and the dynamic range expansion circuit thereof are preferably applied to signal links of a radio frequency receiver and a transmitter, can be applied to RMS power measurement of simple and/or complex waveforms, and are suitable for measuring signals with large dynamic range and high peak-to-average ratio, wherein the dynamic range of an input power signal of the RMS power detection circuit based on the current feedback loop is 30dB, and the dynamic range of the expansion circuit of the RMS power detection circuit is 60 dB. Not only has very wide dynamic range, but also simplifies the output signal discrimination scheme.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims (10)

1. A power detector circuit comprises a high-power detection branch circuit and a low-power detection branch circuit, and is characterized by further comprising a second amplifier, wherein the input end of the high-power detection branch circuit and the input end of the second amplifier are input ends of power signals, the output end of the second amplifier is connected with the input end of the low-power detection branch circuit, the output end of the high-power detection branch circuit outputs a first voltage signal Vout _ A, the output end of the low-power detection branch circuit outputs a second voltage signal Vout _ B, and the high-power detection branch circuit and the low-power detection branch circuit both comprise current feedback loops;
the power signals comprise low-power signals and high-power signals, the high-power detection branch and the low-power detection branch are respectively used for detecting the power signals, and the second amplifier is used for amplifying the low-power signals.
2. The power detector circuit of claim 1, further comprising a first capacitor, wherein the high power detection branch comprises a second capacitor, and wherein the low power detection branch comprises a third capacitor, wherein one end of the first capacitor is connected to the input terminal of the power signal, and the other end of the first capacitor is connected to the input terminal of the high power detection branch and the input terminal of the second amplifier, respectively, one end of the third capacitor is connected to the output terminal of the second amplifier, and the other end of the third capacitor is connected to the input terminal of the low power detection branch.
3. The power detector circuit of claim 2, wherein the second amplifier is a wideband low noise amplifier having a dual feedback wideband low noise amplifier structure including current-current feedback and voltage-voltage feedback, the dual feedback wideband low noise amplifier structure including a triode Q23～Q29Resistance R18～R24。
4. A current feedback loop for the power detector circuit of claim 1 or 3, comprising a rms current squaring unit, a buffer, and further comprising a rf current squaring unit, a first amplifier, wherein a non-inverting input terminal and an inverting input terminal of the first amplifier are respectively connected to the rf current squaring unit and an output terminal of the rms current squaring unit, an input terminal of the rf current squaring unit is an input terminal of a rf voltage signal, an input terminal of the rms current squaring unit is respectively connected to an output terminal of the first amplifier and an input terminal of the buffer, an input terminal of the buffer is connected to an output terminal of the first amplifier, and an output terminal of the buffer is a voltage output terminal of the entire power detector.
5. The current feedback loop of claim 4, wherein the RMS current squaring unit is a feedback network, the RMS current squaring unit is configured to receive a feedback current output by the first amplifier, convert the feedback current into a squared current signal, generate a squared voltage signal on a load thereof, and inject the squared current signal into the inverting input terminal of the first amplifier, and the RMS current squaring unit has a circuit structure comprising a transistor Q1、Q2、Q3、Q4、Q5Resistance R1、R2、Re、RbaseRa, capacitor C1。
6. The current feedback loop of claim 5, wherein the circuit structure of the RF current squaring unit is identical to that of the RMS current squaring unit, the RF current squaring unit is an input impedance terminal, and the RF current squaring unit is configured to convert the input RF voltage signal into a squared current signal, filter the squared current signal, generate a filtered squared voltage signal on a load of the RF current squaring unit, and inject the filtered squared voltage signal into a non-inverting input of the first amplifier.
7. The current feedback loop of claim 6, wherein the first amplifier is a transconductance amplifier, and the circuit structure of the transconductance amplifier and the buffer comprises a triode Q6～Q22Resistance R3～R17The transconductance amplifier is used as a feed-forward amplifier and is used for amplifying an error signal between the radio frequency current square unit and the root-mean-square current square unit and converting the error signal into a feedback current, the buffer is used for copying the feedback current and converting the feedback current into a voltage signal, the voltage signal is output after buffering, and the output voltage is the root-mean-square voltage corresponding to the power of the input radio frequency signal.
8. A method of detecting a power signal using the rms power detector of claim 1 and the current feedback loop of claim 7, the method comprising: for the low-power signal, the second amplifier amplifies the low-power signal, and then the low-power signal is detected by the low-power detection branch circuit; for the high-power signal, the high-power detection branch is used for detecting directly, so that the output end of the high-power detection branch or the output end of the low-power detection branch respectively outputs a first voltage signal Vout _ A and a second voltage signal Vout _ B, and the first voltage signal Vout _ A and the second voltage signal Vout _ B are root-mean-square voltages corresponding to the power of the input radio-frequency signal.
9. The method according to claim 8, wherein the high power detection branch and the low power detection branch each 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, an input radio frequency 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.
10. A radio frequency receiver or transmitter comprising the power detector of claim 1 or 3, wherein the power detector comprises the current feedback loop of claim 7, wherein the rms power detector is configured to detect an input power signal of the radio frequency receiver or transmitter and output a wide dynamic range rms voltage, and wherein the current feedback loop converts the input radio frequency voltage signal into the rms current signal.
CN202110119136.4A 2021-01-28 2021-01-28 Power detector circuit based on current feedback loop and power signal detection method Pending CN112946359A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI797835B (en) * 2021-07-29 2023-04-01 大陸商昂寶電子（上海）有限公司 Power signal detection circuit and method
CN117233458A (en) * 2023-11-10 2023-12-15 成都明夷电子科技有限公司 Power detection circuit and power detection system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI797835B (en) * 2021-07-29 2023-04-01 大陸商昂寶電子（上海）有限公司 Power signal detection circuit and method
CN117233458A (en) * 2023-11-10 2023-12-15 成都明夷电子科技有限公司 Power detection circuit and power detection system
CN117233458B (en) * 2023-11-10 2024-03-19 成都明夷电子科技股份有限公司 Power detection circuit and power detection system

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