Double closed-loop resonant pressure sensor based on parameter pumping

Abstract

The invention provides a double-closed-loop resonant pressure sensor based on parameter pumping, and belongs to the technical field of sensors, and the pressure sensor comprises a single resonator, a first driving electrode and a second driving electrode of the single resonator are respectively used for applying an AC driving signal to the single resonator and applying a parameter pumping AC signal to the single resonator, the frequency of the parameter pumping alternating current signal is the sum of the frequencies of the first-order mode and the second-order mode of the single resonator, and the first detection electrode and the second detection electrode of the parameter pumping alternating current signal are used for detecting the resonant frequency and the amplitude of the single resonator; the closed-loop control circuit is used for carrying out differential amplification on the vibration signals detected by the first detection electrode and the second detection electrode to obtain second-order modal vibration signals, adjusting the second-order modal vibration signals and then feeding back and applying the adjusted second-order modal vibration signals to the first driving electrode so as to maintain self-excited vibration of the single resonator; and the parameter pumping feedback control loop is used for detecting the amplitude of the second-order modal vibration signal, comparing the amplitude with a reference amplitude to obtain an error signal, and generating a parameter pumping alternating current signal according to the error signal.

Description

Technical Field

[0001] This application relates to the field of sensor technology, and more specifically, to a parametrically pumped dual-closed-loop resonant pressure sensor. Background Technology

[0002] Resonant MEMS pressure sensors, with their advantages of high precision and high stability, have been widely used in semiconductors, industrial control, and meteorological monitoring. Current research mainly focuses on the fundamental modal sensing and closed-loop design of resonators, and achieves decoupling compensation of parameters such as pressure and temperature by integrating multiple resonators or multiple sensors. However, this approach leads to complex sensor structures, increasing the difficulty of design and manufacturing.

[0003] Micromechanical resonators typically possess an infinite number of modes. In existing resonant sensor applications, the fundamental mode is widely used for detecting various parameters due to its high signal-to-noise ratio (SNR), while higher-order modes are neglected due to their lower SNR. Compared to the fundamental mode, higher-order modes have higher response frequencies, which often translates to higher sensing sensitivity and resolution. Utilizing higher-order modes to achieve multimodal sensing is one effective way to overcome the detection limits of existing resonant sensors and simultaneously address the coupling of multiple measured parameters. In recent years, researchers have paid close attention to the modal coupling and nonlinear vibration characteristics of resonators. Through modal coupling, some vibrational energy from the fundamental mode can be transferred to higher-order modes, enhancing the response amplitude of the higher-order modes and significantly improving their SNR. Simultaneously, modal coupling implies the possible presence of two or more modal frequencies in the vibration signal. Therefore, employing modal coupling helps to achieve multimodal sensing, improve the detection performance of resonant sensors, and solve the problem of multiple cross-coupled physical parameters in the sensor output.

[0004] Parametric pumping provides a controllable and easily implemented approach to achieve intermodal parametric coupling. It requires only an additional parametric excitation signal of a specific frequency to couple complex modes of a resonator, eliminating the need for complex resonator design and error control. When the frequency of the parametric pump signal is the sum of the frequencies of multiple intrinsic modes of the resonator, the quality factor and vibration amplitude of the resonator can be amplified. Utilizing this effect, single-resonator multimodal pressure sensing can be realized, simplifying the sensor structure, reducing the sensor core size, solving the problem of temperature-pressure coupling in the sensor output, and simultaneously improving the overall performance of the sensor. Summary of the Invention

[0005] In view of this, this application provides a dual closed-loop resonant pressure sensor based on parametric pumping.

[0006] One aspect of this application provides a parametric pump-based dual-closed-loop resonant pressure sensor, comprising: a single resonator having a first driving electrode, a second driving electrode, a first detection electrode, a second detection electrode, and a resonant beam; the first driving electrode and the second driving electrode are disposed on one side of the resonant beam; the first detection electrode and the second detection electrode are disposed on the other side of the resonant beam; the first driving electrode and the second driving electrode are symmetrically arranged with respect to the first detection electrode and the second detection electrode; the first driving electrode is used to apply an AC driving signal to the single resonator; the second driving electrode is used to apply a parametric pump AC signal to the single resonator, the frequency of the parametric pump AC signal being the frequency of the first-order mode and the second-order mode of the single resonator. The circuit comprises: a frequency and an amplitude; the first and second detection electrodes for detecting the resonant frequency and amplitude of the single resonator; a closed-loop control circuit, with its first input connected to the first detection electrode and its second input connected to the second detection electrode, for differentially amplifying the vibration signals detected by the first and second detection electrodes to obtain a second-order modal vibration signal, and applying the second-order modal vibration signal to the first driving electrode after phase adjustment and gain control to maintain the self-excited vibration of the single resonator, wherein the single resonator operates in antisymmetric second-order mode; and a parameter pump feedback control loop for detecting the amplitude of the second-order modal vibration signal, comparing it with a reference amplitude to obtain an error signal, and generating the parameter pump AC signal based on the error signal.

[0007] According to an embodiment of this application, it further includes: a readout circuit for reading the resonant frequency of the second-order modal vibration signal and the sum of the frequencies of the first-order and second-order modes of the single resonator; and a decoupling circuit for decoupling the two detected physical quantities of pressure and temperature based on the resonant frequency of the second-order modal vibration signal and the sum of the frequencies of the first-order and second-order modes of the single resonator.

[0008] According to embodiments of this application, the closed-loop control circuit is a phase-locked loop-based closed-loop control circuit or a self-gain control-based closed-loop control circuit.

[0009] According to an embodiment of this application, the closed-loop control circuit based on self-gain control includes: a first current-to-voltage conversion circuit for converting a first vibration signal of the resonant beam into an electrical signal; a second current-to-voltage conversion circuit for converting a second vibration signal of the resonant beam into an electrical signal; a differential amplifier circuit for differentially amplifying and comparing the first vibration signal and the second vibration signal to improve the signal-to-noise ratio of the second-order modal vibration signal and filter out the first-order modal coupled vibration signal and the feedthrough signal of the parameter pump; a phase-shifting amplifier circuit for adjusting the phase of the second-order modal vibration signal; and an automatic gain control circuit for performing gain control based on the phase-adjusted second-order modal vibration signal and for feedback adjustment of the AC drive signal to maintain the self-excited vibration of the single resonator.

[0010] According to an embodiment of this application, the parameter pump feedback control loop includes: an amplitude detection circuit for detecting the amplitude of the second-order modal vibration signal; an amplitude error control circuit for comparing the second-order modal vibration signal with a reference amplitude to generate the error signal; and a voltage-controlled oscillator for generating the parameter pump AC signal based on the error signal so that the amplitude of the resonator reaches the reference amplitude.

[0011] This application proposes a parametric pump-based dual-closed-loop resonant pressure sensor. The core sensing structure is a single resonator with two driving electrodes and two detection electrodes on either side. AC driving signals and parametric pump AC signals are applied to the resonator through the two driving electrodes, while the resonant frequency and amplitude are detected in real time through the detection electrodes. The resonator operates in antisymmetric second-order mode via a closed-loop control circuit. The vibration signals detected by the two detection electrodes are differentially divided after current-to-voltage conversion to improve the signal-to-noise ratio of the second-order mode vibration signal and filter out common-mode noise and other coupled vibration signals, outputting the second-order mode frequency f2 of the resonator. The parametric pump feedback control loop amplifies the quality factor of the second-order mode of the resonator and the vibration signal, and outputs the first and second-order mode frequencies of the resonator and f1+f2. Since different modes have different sensitivities to pressure / temperature, the two frequency parameters f2 and f1+f2 can decouple the two physical quantities of pressure and temperature, thus realizing multimodal sensing with a single resonator. This solves the problem of temperature-pressure coupling in the sensor output, and helps to further simplify the sensor structure, reduce the size of the sensor core, and improve the overall performance of the sensor. Attached Figure Description

[0012] The above and other objects, features and advantages of this application will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0013] Figure 1A schematic diagram illustrating the electrode configuration of a parametrically pumped dual-closed-loop resonant pressure sensor according to an embodiment of this application is shown.

[0014] Figure 2 This schematically illustrates the amplification effect of parametric pumping on resonator vibration according to an embodiment of this application;

[0015] Figure 3 The illustration shows a schematic diagram of dual-closed-loop control of a parametrically pumped dual-closed-loop resonant pressure sensor according to an embodiment of this application. Detailed Implementation

[0016] The embodiments of this application will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of this application. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of this application for ease of explanation. However, it will be apparent that one or more embodiments may be implemented without these specific details. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0017] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0018] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0019] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0020] This application provides a parametric pump-based dual-closed-loop resonant pressure sensor, comprising: a single resonator, a closed-loop control circuit, and a parametric pump feedback control loop. The resonator operates in second-order mode via a conventional closed-loop control circuit. When the parametric pump signal frequency is the sum of the first-order and second-order mode frequencies of the resonator, the first and second-order mode vibration signals of the resonator are amplified. Utilizing this effect, by applying an additional parametric pump signal, the signal-to-noise ratio of the second-order mode of the resonator is improved, and closed-loop feedback of the parametric pump signal is achieved through amplitude error control. Based on the dual-closed-loop system, the second-order mode frequency f2 of the resonator and the parametric pump frequency (the sum of the first and second-order mode frequencies of the resonator, f1 + f2) can be output, realizing multi-mode sensing using only a single resonator.

[0021] Figure 1 The diagram illustrates the electrode configuration of a parametrically pumped dual-closed-loop resonant pressure sensor according to an embodiment of this application.

[0022] like Figure 1 As shown, the single resonator 1 has a first driving electrode 2-1, a second driving electrode 2-2, a first detection electrode 2-3, a second detection electrode 2-4, and a resonant beam; the first driving electrode 2-1 and the second driving electrode 2-2 are disposed on one side of the resonant beam; the first detection electrode 2-3 and the second detection electrode 2-4 are disposed on the other side of the resonant beam; the first driving electrode 2-1 and the second driving electrode 2-2 are symmetrically arranged with the first detection electrode 2-3 and the second detection electrode 2-4. The first driving electrode 2-1 is used to apply an AC driving signal v to the single resonator 1. ac The second driving electrode 2-2 is used to apply the parameter pumping AC signal v to the single resonator 1. p Parameter pump AC signal v p The frequency fp is the sum of the frequencies of the first and second modes of the single resonator 1, i.e., f1 + f2; the first detection electrode 2-3 and the second detection electrode 2-4 are used to detect the resonant frequency and amplitude of the single resonator 1, which are based on the detected current i. out The conversion is obtained. Furthermore, this resonator is also powered by a DC power supply v. dc The power supply continues to oscillate.

[0023] Figure 2 The diagram illustrates the amplification effect of parameter pumping on resonator vibration according to an embodiment of this application.

[0024] like Figure 2 As shown, when a parametric pump AC signal v is applied to the resonator 1 through the second driving electrode 2-2... p Its frequency fp is the sum of the frequencies of the first and second modes of the resonator, i.e., f1+f2. The vibration response and quality factor of the first and second modes of the resonator will be amplified.

[0025] Utilize Figure 2 The amplification effect is addressed in the embodiments of this application as follows: Figure 3 The dual closed-loop control method shown.

[0026] Figure 3 The illustration shows a schematic diagram of dual-closed-loop control of a parametrically pumped dual-closed-loop resonant pressure sensor according to an embodiment of this application.

[0027] like Figure 3 As shown, the parameter-pumped dual-closed-loop resonant pressure sensor includes a conventional resonator closed-loop control loop (shown as an automatic gain control loop) and a parameter-pumped feedback control loop.

[0028] The closed-loop control circuit can be based on a phase-locked loop (PLL) or on automatic gain control (AGC). Taking an AGC-based closed-loop circuit as an example, the first input terminal of the closed-loop control circuit is connected to the first detection electrode 2-3, and the second input terminal is connected to the second detection electrode 2-4. This is used to differentially amplify the vibration signals detected by the first and second detection electrodes 2-3 to obtain a second-order modal vibration signal. After phase adjustment and gain control, the second-order modal vibration signal is applied to the first driving electrode 2-1 to maintain the self-excited vibration of the single resonator 1. The single resonator 1 operates in the antisymmetric second-order mode.

[0029] like Figure 3 As shown, the AGC loop includes a first current-to-voltage conversion circuit (corresponding to...) Figure 3 One current-to-voltage conversion stage), and the second current-to-voltage conversion circuit (corresponding to) Figure 3 Another current-to-voltage conversion stage), differential amplifier circuit (corresponding to) Figure 3 Differential amplifier stage), phase-shifting amplifier circuit (corresponding) Figure 3 Phase-shifting amplification stage) and automatic gain control circuit (corresponding to) Figure 3(Automatic gain control loop). The single resonator 1 operates in antisymmetric second-order mode via a closed-loop automatic gain control circuit. The first detection electrode 2-3 and the second detection electrode 2-4 detect the first and second vibration signals of the resonant beam, respectively. The first and second current-to-voltage conversion circuits convert the first and second vibration signals of the resonant beam into electrical signals, respectively. A differential amplifier circuit amplifies and compares the first and second vibration signals differentially to improve the signal-to-noise ratio of the second-order mode vibration signal and filter out the first-order mode coupled vibration signal and the feedthrough signal from the parameter pump. One path of the differentially amplified second-order mode vibration signal directly outputs the second-order mode resonant frequency f2. The other path, after phase adjustment by a phase-shifting amplifier circuit, undergoes gain control by the automatic gain control circuit and is applied to the first driving electrode 2-1 to maintain the resonator's self-excited vibration.

[0030] The parameter pump feedback control loop is used to detect the amplitude of the second-order modal vibration signal, compare it with the reference amplitude to obtain the error signal, and generate the parameter pump AC signal based on the error signal.

[0031] like Figure 3 As shown, the parameter pump feedback control loop and the automatic gain control (AGC) loop share the current-to-voltage conversion stage and the differential amplification stage, and also include an amplitude detection circuit (corresponding to...). Figure 3 (Signal amplitude detection stage), reference amplitude input, amplitude error control circuit (corresponding to) Figure 3 The system consists of an amplitude error control circuit and a voltage-controlled oscillator (VCO). The amplitude detection circuit detects the amplitude of the second-order modal vibration signal. The amplitude error control circuit compares the second-order modal vibration signal with a reference amplitude to generate an error signal, which, after processing, is output to the VCO. Based on the error signal, the VCO generates an AC signal with a frequency close to the sum of the first and second-order mode frequencies of the resonator, increasing the resonator amplitude to the reference amplitude level. Another output directly yields the sum of the first and second-order mode frequencies of the resonator, f1 + f2.

[0032] When the parameter pump signal is applied to the second driving electrode 2-2, the second-order mode vibration signal, the first-order mode coupled vibration signal, and the parameter pump feedthrough signal in the output signal of the resonator will be coupled together. Through the differential detection of the first detection electrode 2-3 and the second detection electrode 2-4, the first-order mode coupled vibration signal and the parameter pump feedthrough signal can be effectively filtered out, leaving only the second-order mode vibration signal of the resonator, thus ensuring the stability of the dual closed loop.

[0033] Optionally, the amplitude error control link in the parameter pump feedback control loop can adopt proportional-integral (PI) control, proportional-integral-derivative (PID) control, proportional-integral-derivative (PID) control with feedforward, polynomial fitting control combined with second-order modal frequency, and nonlinear control, etc., to control the voltage-controlled oscillator to generate the corresponding frequency signal, so that the resonator vibration signal can be amplified.

[0034] Because parameter pumping improves the quality factor and amplifies the signal of modal vibration signals, it helps to enhance the stability and resolution of resonant pressure sensors. In the entire dual-loop system, the second-order modal resonant frequency f2, the first and second-order modal frequencies, and f1+f2 of the resonator can be read out. Through higher-order modal vibrations, frequencies, and outputs, the sensitivity of the resonant pressure sensor is improved.

[0035] Building upon this, the parameter-pumped dual-closed-loop resonant pressure sensor can further include a readout circuit and a decoupling circuit. The readout circuit reads the resonant frequency f2 of the second-order modal vibration signal and the frequency sum f1+f2 of the first and second modes of the single resonator. The decoupling circuit decouples the two detected physical quantities—pressure and temperature—based on the resonant frequency of the second-order modal vibration signal and the frequency sum of the first and second modes of the single resonator, thus realizing multi-mode sensing with a single resonator. This sensor design solves the problem of temperature-pressure coupling in the sensor output and helps to further simplify the sensor structure and reduce the sensor core size.

[0036] In summary, the parameter-pumped dual-closed-loop resonant pressure sensor provided in this application has two closed loops: a traditional resonator closed-loop control loop and a parameter pump feedback control loop. This dual-closed-loop system can read out the second-order modal resonant frequency f2, the first and second-order modal frequencies of the resonator, and f1+f2, improving the sensor's sensitivity and enabling multi-mode sensing with a single resonator. It also solves the problem of temperature-pressure coupling in the sensor output and helps to further simplify the sensor structure and reduce the sensor core size. Through the parameter pump feedback loop, the parameter pump's effect on improving the quality factor and amplifying the resonator modal vibration signal helps to improve the stability and resolution of the resonant pressure sensor. Furthermore, through the second-order modal antisymmetry characteristic and differential detection with dual detection electrodes, the first-order modal coupled vibration signal and the parameter pump feedthrough signal can be effectively filtered out, leaving only the second-order modal vibration signal of the resonator, ensuring the stability of the dual closed loop. This dual-closed-loop circuit structure is simple and can be implemented using ordinary analog or digital circuits.

[0037] The embodiments of this application have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of this application. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Without departing from the scope of this application, those skilled in the art can make various substitutions and modifications, all of which should fall within the scope of this application.

Claims

1. A dual-closed-loop resonant pressure sensor based on parametric pumping, characterized in that, include: A single resonator has a first driving electrode, a second driving electrode, a first detection electrode, a second detection electrode, and a resonant beam; the first driving electrode and the second driving electrode are disposed on one side of the resonant beam; the first detection electrode and the second detection electrode are disposed on the other side of the resonant beam; the first driving electrode and the second driving electrode are symmetrically arranged with the first detection electrode and the second detection electrode. The first driving electrode is used to apply an AC driving signal to the single resonator; the second driving electrode is used to apply a parameter pump AC signal to the single resonator, the frequency of which is the sum of the frequencies of the first-order mode and the second-order mode of the single resonator; the first detection electrode and the second detection electrode are used to detect the resonant frequency and amplitude of the single resonator; A closed-loop control circuit has a first input terminal connected to the first detection electrode and a second input terminal connected to the second detection electrode. It is used to differentially amplify the vibration signals detected by the first and second detection electrodes to obtain a second-order modal vibration signal. The second-order modal vibration signal is then phase-adjusted and gain-controlled before being applied to the first driving electrode to maintain the self-excited vibration of the single resonator. The single resonator operates in antisymmetric second-order mode. The parameter pump feedback control loop is used to detect the amplitude of the second-order modal vibration signal, compare it with the reference amplitude to obtain an error signal, and generate the parameter pump AC signal based on the error signal.

2. The dual-closed-loop resonant pressure sensor based on parametric pumping according to claim 1, characterized in that, Also includes: The readout circuit is used to read the resonant frequency of the second-order modal vibration signal and the sum of the frequencies of the first-order and second-order modes of the single resonator; The decoupling circuit is used to decouple the two detected physical quantities, pressure and temperature, based on the resonant frequency of the second-order modal vibration signal and the sum of the frequencies of the first-order and second-order modes of the single resonator.

3. The dual-closed-loop resonant pressure sensor based on parametric pumping according to claim 1, characterized in that, The closed-loop control circuit is either a phase-locked loop-based closed-loop control circuit or a self-gain control-based closed-loop control circuit.

4. The dual-closed-loop resonant pressure sensor based on parametric pumping according to claim 3, characterized in that, The closed-loop control circuit based on self-gain control includes: The first current-to-voltage conversion circuit is used to convert the first vibration signal of the resonant beam into an electrical signal; The second current-to-voltage conversion circuit is used to convert the second vibration signal of the resonant beam into an electrical signal; A differential amplifier circuit is used to differentially amplify and compare the first vibration signal and the second vibration signal to improve the signal-to-noise ratio of the second-order modal vibration signal and filter out the first-order modal coupled vibration signal and the feedthrough signal of the parameter pump. A phase-shifting amplifier circuit is used to adjust the phase of the second-order modal vibration signal; An automatic gain control circuit is used to perform gain control based on the phase-adjusted second-order modal vibration signal and to provide feedback adjustment to the AC drive signal in order to maintain the self-excited vibration of the single resonator.

5. The dual-closed-loop resonant pressure sensor based on parametric pumping according to claim 1, characterized in that, The parameter pump feedback control loop includes: An amplitude detection circuit is used to detect the amplitude of the second-order modal vibration signal; An amplitude error control circuit is used to compare the second-order modal vibration signal with the reference amplitude to generate the error signal; A voltage-controlled oscillator is used to generate the parameter pump AC signal based on the error signal so that the amplitude of the resonator reaches the reference amplitude.

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