A high-gain automatic phase modulation quartz beam accelerometer control circuit

Abstract

A high-gain automatic phase modulation quartz beam accelerometer control circuit includes a feedthrough suppression module. The feedthrough suppression module and the quartz beam resonator form a parallel resonant unit. The output of the parallel resonant unit is connected to the input of a front-end amplification module. The output of the front-end amplification module is connected to the input of a high-pass filter module and the first input of an automatic phase control module. The output of the high-pass filter module is connected to the first input of a dynamic phase shifting module. The second input of the dynamic phase shifting module is connected to the output of the automatic phase control module. The output of the dynamic phase shifting module is connected to the input of a low-pass filter module, a square wave shaping module, an amplitude control module, and a differential drive module. The output of the differential drive module is connected to the input of the feedthrough suppression module, the drive end of the quartz beam resonator, and the second input of the automatic phase control module. This invention achieves low-noise driving of a high-impedance quartz beam and dynamically compensates for loop phase errors to improve the stability and resolution of the accelerometer.

Description

Technical Field

[0001] This invention belongs to the technical field of microelectromechanical systems (MEMS) inertial instruments or inertial devices, specifically relating to a high-gain automatic phase modulation quartz beam accelerometer control circuit. Background Technology

[0002] Inertial sensors based on the resonant principle are playing an increasingly important role in navigation and guidance, gravity detection, and oil exploration due to their advantages of high precision, high stability, and high resolution. Quartz vibrating beam accelerometers are a type of resonant accelerometer. The vibrating beam resonator, made based on the unique piezoelectric properties of quartz, achieves an extremely high quality factor. Its ultra-stable lattice structure ensures long-term stability and repeatability in complex environments, making it the preferred solution for high-precision acceleration measurement. Quartz vibrating beam accelerometers can modulate the inertial force in the sensitive direction onto a continuously oscillating carrier frequency, outputting a stable quasi-digital signal. This eliminates the need for traditional analog-to-digital conversion, allowing direct input into a digital system for processing, thus improving measurement accuracy while reducing production costs.

[0003] The control circuit of quartz resonant beam accelerometers currently mainly adopts a feedback scheme based on inverters, such as the patent application entitled "A Signal Processing Circuit Based on Quartz Resonator" (Publication No.: CN207910744U). This scheme detects the output signal of the quartz resonant beam by biasing the inverter in its linear operating region. The second-stage inverter compensates for the phase required for positive feedback, thereby forming a self-excited oscillation. Although the inverter has extremely high linear gain, for quartz resonant beams with distributed noise, the gain of the transimpedance inverter as the front-end circuit is limited by bandwidth and noise, thus limiting the resolution of the accelerometer. To drive high-impedance quartz resonant accelerometers, excitation circuits based on two-stage inverters have been proposed, such as the patent application titled "An Excitation Circuit for a Quartz Resonant Accelerometer" (Publication No.: CN110988397A). This design adds an inverting amplifier stage after the conventional control circuit. While this alleviates the gain and bandwidth limitations of the front-end circuit, the added amplifier introduces more noise. This noise is ultimately modulated to the carrier sideband through the closed-loop circuit, increasing the system's phase noise. This manifests as increased white noise and quantization noise at the quartz resonant accelerometer output, reducing the accelerometer's stability and resolution. Furthermore, existing quartz resonant accelerometer control circuits all use fixed-phase feedback. Although this can compensate for phase deviations caused by non-ideal factors to some extent, when the accelerometer operates at full scale and across the entire temperature range, the resonant frequency and phase error will shift. Fixed-phase feedback will introduce excessive or even opposite phase compensation, leading to degraded system performance and reduced accelerometer scaling factor, full-temperature stability, and repeatability. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a high-gain automatic phase modulation quartz beam accelerometer control circuit, which realizes low-noise driving of high-impedance quartz beam and dynamically compensates for loop phase error to improve the stability and resolution of the accelerometer.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A high-gain automatic phase modulation quartz beam accelerometer control circuit includes a feedthrough suppression module. The feedthrough suppression module and the quartz beam resonator are connected in parallel to form a parallel resonant unit. The output of the parallel resonant unit is connected to the input of a front-end amplification module. The output of the front-end amplification module is connected to the input of a high-pass filter module and the first input of an automatic phase control module. The output of the high-pass filter module is connected to the first input of a dynamic phase shifting module. The second input of the dynamic phase shifting module is connected to the output of the automatic phase control module. The output of the dynamic phase shifting module is connected to the input of a low-pass filter module. The output of the low-pass filter module is connected to the input of a square wave shaping module. The output of the square wave shaping module is connected to the input of an amplitude control module. The output of the amplitude control module is connected to the input of a differential drive module. The output of the differential drive module is connected to the input of the feedthrough suppression module, the drive end of the quartz beam resonator, and the second input of the automatic phase control module.

[0007] The feedthrough suppression module is implemented using a compensation capacitor.

[0008] The aforementioned front-end amplification module consists of an operational amplifier, resistors, and capacitors forming a two-stage two-port network, with the two stages connected in series; or it can be implemented by any number and combination of integrators and differentiators, such as single-stage integrators, integrator-integrator cascades, and differentiator-differentiator cascades.

[0009] The high-pass filter module and low-pass filter module are implemented in a second-order active manner and can be replaced with passive filters or higher-order active filters.

[0010] The dynamic phase-shifting module consists of an active phase shifter and a voltage-controlled variable resistor, which is composed of two P-channel metal-oxide-semiconductor field-effect transistors (PMOS) connected in parallel.

[0011] The square wave shaping module is implemented using a comparator or an operational amplifier operating in an open loop.

[0012] The amplitude control module is implemented using a negative feedback operational amplifier.

[0013] The differential drive module is implemented using a differential driver.

[0014] The automatic phase control module includes an analog-to-digital converter (ADC), a phase-frequency detector (PFD), a low-pass filter, a PID controller, and a digital-to-analog converter (DAC). The ADC is implemented using digital circuitry. The ADC converts the analog signals output from the differential drive module and the front-end amplifier module into digital signals, which then enter the PFD. The PFD is connected to the low-pass filter, which outputs a voltage signal proportional to the phase difference between the two input signals. The PID controller converts the output signal of the low-pass filter into a control signal. After passing through the DAC, the output signal becomes the control signal for the voltage-controlled variable resistor in the dynamic phase-shifting module. Changes in resistance cause the phase of the control circuit to lead or lag, eliminating the deviation between the oscillation frequency of the loop and the natural frequency of the quartz resonator.

[0015] The aforementioned phase-frequency detector (PFD) is composed of a D flip-flop, an AND gate, an inverter, a PMOS, and an NMOS connected in sequence. The low-pass filter and PID controller are implemented using digital circuits or analog circuits.

[0016] The aforementioned frequency and phase detector (PFD) employs a multiplication phase detector, an EXOR phase detector, a JK trigger-type phase detector, etc.

[0017] The control circuit is composed of a mixture of analog and digital circuits, or is implemented using integrated circuit (ASIC) technology.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] (1) The front-end amplification module decouples the constraint between gain and bandwidth, enabling it to provide higher gain for the quartz beam resonator within a large bandwidth. Using capacitors as the main gain element does not introduce additional noise, achieving a higher output signal-to-noise ratio and improving the resolution and stability of the quartz beam accelerometer.

[0020] (2) The automatic phase control module can detect the phase difference between the driving signal of the quartz beam resonator and the output signal of the front-end amplification module in real time, and control the dynamic phase shifting module to adjust the oscillation frequency of the loop to follow the natural frequency of the quartz beam resonator, thus ensuring the linearity of the scaling factor of the quartz beam accelerometer. The improvement of the effective quality factor also greatly enhances the stability and resolution of the accelerometer.

[0021] (3) The circuit of the present invention can be implemented by application-specific integrated circuit (ASIC) technology, thereby further reducing system power consumption and cost, and realizing the miniaturization of inertial navigation system. Attached Figure Description

[0022] Figure 1 This is a circuit block diagram of an embodiment of the present invention.

[0023] Figure 2This is a schematic diagram of the circuit structure and noise of the front-end amplification module in an embodiment of the present invention.

[0024] Figure 3 This is a circuit diagram of the high-pass filter module, dynamic phase shift module, low-pass filter module, square wave shaping module, amplitude control module, and differential drive module in an embodiment of the present invention.

[0025] Figure 4 This is a circuit diagram of the automatic phase control module according to an embodiment of the present invention. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] like Figure 1 As shown, a high-gain automatic phase modulation quartz beam accelerometer control circuit includes a feedthrough suppression module 2. The feedthrough suppression module 2 and the quartz beam resonator 1 are connected in parallel to form a parallel resonant unit. The output of the parallel resonant unit is connected to the input of the front-end amplification module 3. The output of the front-end amplification module 3 is connected to the input of the high-pass filter module 4 and the first input of the automatic phase control module 6. The front-end amplification module 3 and the high-pass filter module 4 form an interface signal extraction unit. The output of the high-pass filter module 4 is connected to the first input of the dynamic phase shifting module 5. The second input of the dynamic phase shifting module 5 is connected to the output of the automatic phase control module 6. The output of phase module 5 is connected to the input of low-pass filter module 7. The output of low-pass filter module 7 is connected to the input of square wave shaping module 8. The output of square wave shaping module 8 is connected to the input of amplitude control module 9. The output of amplitude control module 9 is connected to the input of differential drive module 10. The output of differential drive module 10 is connected to the input of feedthrough suppression module 2, the drive end of quartz resonator 1, and the second input of automatic phase control module 6. Automatic phase control module 6 and dynamic phase shift module 5 form dynamic phase modulation unit. Low-pass filter module 7 and square wave shaping module 8 form the output stage of control circuit and drive amplitude control module 9.

[0028] When the control circuit is powered on, the instantaneous current generates distributed noise. The output noise of the differential drive module 10 drives the quartz beam resonator 1 to vibrate randomly. This noise is superimposed with the thermal noise generated by the Brownian motion of the quartz beam resonator 1 itself. Through the inverse piezoelectric effect, this noise is converted into an electrical signal that the circuit can recognize. This signal is then converted into a high-gain voltage signal by the front-end amplification module 3. The signal is then fed back to the drive end of the quartz beam resonator 1 through the subsequent high-pass filter module 4, dynamic phase shift module 5, low-pass filter module 7, square wave shaping module 8, amplitude control module 9, and differential drive module 10, forming a positive feedback loop. When the loop satisfies self-excited oscillation... Under the conditions that the loop gain is greater than 1 and the phase error is 0, the amplitude of the quartz beam resonator 1 will be continuously amplified and eventually stabilized at the maximum amplitude that the driving signal can produce. At this time, the loop gain is equal to 1. The quartz beam resonator 1 has an extremely high quality factor. Noise outside the passband is almost completely suppressed, and the signal inside the passband obtains high gain to form oscillation. After the control circuit is started, it will work at the natural frequency of the quartz beam resonator 1. The vibration amplitude of the quartz beam resonator 1 is determined by the amplitude control module 9, which achieves the maximum signal-to-noise ratio and the lowest phase noise without exciting significant nonlinear dynamic characteristics.

[0029] When an acceleration load occurs in the sensitive direction of the quartz beam accelerometer, the quartz beam resonator 1 experiences axial stress, causing its natural frequency to shift. The center frequency of the loop passband will also shift to the same extent. The oscillation frequency of the control circuit always follows the natural frequency of the quartz beam resonator 1, enabling high-precision detection of load acceleration. Under varying temperature conditions, the material parameters of the quartz beam resonator 1 will drift. The thermal stress generated by the integration of heterogeneous materials and the pre-stress of the encapsulation will cause unpredictable drift in the natural frequency of the quartz beam resonator 1. Within the limited loop bandwidth, the oscillation frequency will deviate from the natural frequency of the quartz beam resonator 1, reducing the effective quality factor of the control circuit. The automatic phase control module 6 compares the signal from the drive end of the quartz beam resonator 1 with the output signal from the front-end amplification module 3, and controls the dynamic phase shifting module 5 to adjust the loop phase, eliminating the error between the oscillation frequency and the natural frequency of the quartz beam resonator, and improving the scaling factor linearity and stability of the accelerometer.

[0030] In this embodiment, the control circuit is a closed-loop self-excited oscillation system. It does not require an input signal. After being powered on, it can be excited by distributed noise and automatically oscillate at the natural frequency of the quartz beam resonator 1. The square wave signal output by the square wave shaping module 8 is used as the output of the control circuit, and its frequency characterizes the magnitude of the acceleration that the quartz beam accelerometer is sensitive to.

[0031] like Figure 2As shown in (a), the front-end amplification module 3 consists of operational amplifiers U1 and U2, resistors R1 and R2, and capacitors C1, C2, and C3. The inverting input of operational amplifier U1 is connected to the output of the quartz resonator 1. Resistor R1 and capacitor C1 are connected in parallel between the inverting input and output of operational amplifier U1. The output of operational amplifier U1 is connected to one end of capacitor C2, and the other end of capacitor C2 is connected to the inverting input of operational amplifier U2. Capacitor C3 and resistor R2 are connected in parallel between the inverting input and output of operational amplifier U2. Operational amplifier U1, resistor R1, and capacitor C1 form the first-stage front-end interface circuit, and operational amplifier U2, capacitors C2 and C3, and resistor R2 form the second-stage amplification circuit. The first-stage front-end interface circuit is equivalent to an integrator, providing high gain through capacitor C1. Resistor R1 provides a DC feedback path for operational amplifier U1 to avoid output signal saturation caused by input bias voltage. s and C in The input and parasitic capacitances of the front-end amplification module 3 are formed; the second-stage amplification circuit is equivalent to a differentiator, which provides a stable AC gain for the front-end amplification module 3 within the operating frequency range of the quartz resonator 1. The gain is determined by capacitor C2 and resistor R2, and the bandwidth is determined by capacitor C3; the front-end amplification module 3 has bandpass characteristics, and the gain in the passband is (C2 / C1)R2.

[0032] Compared to the traditional transimpedance inverter front-end circuit, the aforementioned front-end amplifier module 3 has the following advantages: (1) It decouples the constraint between gain and bandwidth of the traditional transimpedance inverter front-end circuit. The gain of the aforementioned front-end amplifier module 3 is provided by capacitors C2 and C1, and resistor R2 can be small, so that operational amplifiers or inverters operating in the linear region with the same gain-bandwidth product can release greater bandwidth performance. (2) It achieves lower noise. The transimpedance inverter front-end circuit is provided with gain by capacitors, so it will obtain lower noise than the traditional inverter which relies on resistors to provide gain. At the same time, the noise of operational amplifiers U1 and U2 is significantly suppressed by the first-stage integrator, and the thermal noise of resistor R2 is suppressed by the capacitance ratio C2 / C1. (3) Since the first-stage front-end interface circuit uses a large resistor R1, it has sufficient phase margin and therefore there is no stability risk. The second-stage amplifier circuit has its own differential characteristics, which makes the input bias voltage negligible, thus improving the accuracy of signal detection.

[0033] like Figure 2As shown in (b), the noise of the front-end amplification module 3 includes the noise of operational amplifiers U1 and U2, and the noise of resistors R1 and R2. The total noise is dominated by the noise of resistor R2 in the low-frequency and operating frequency ranges, but since capacitors C2 / C1 provide most of the gain, the noise of resistor R2 is much smaller than the resistance noise of a traditional inverter. In the high-frequency range above the operating frequency range, the total noise is mainly dominated by the noise of operational amplifier U1, because the differential characteristics of the second-stage amplification circuit provide a higher gain for high-frequency noise.

[0034] The aforementioned front-end amplification module 3 can also be implemented by any number and combination of integrators and differentiators, such as single-stage integrators, integrator-integrator cascades, and differentiator-differentiator cascades.

[0035] like Figure 3 As shown, the circuits of the high-pass filter module, dynamic phase-shifting module, low-pass filter module, square wave shaping module, amplitude control module, and differential drive module consist of operational amplifiers U3, U4, U5, U7, and U8, comparator U6, and resistors R3, R4, R5, R6, R7, R8, R9, and R1. 10 R 11 R 12 R 13 R 14 The system consists of capacitors C4, C5, C6, C7, and C8, and MOSFETs M1 and M2. Operational amplifier U3, resistors R3, R4, R5, and R6, and capacitors C4 and C5 form a high-pass filter module 4. Operational amplifier U4, resistors R7 and R8, and MOSFETs M1 and M2 form a dynamic phase-shifting module 5. Operational amplifier U5, resistors R9, R... 10 R 11 R 12 Capacitor C7 forms a low-pass filter module 7; comparator U6 serves as a square wave shaping module 8; operational amplifier U7, resistor R 13 R 14 Amplitude control module 9 is formed; differential driver U8 and capacitor C8 form differential drive module 10.

[0036] The high-pass filter module 4 includes an input capacitor C4, which is connected to the output terminal V of the front-end amplifier module 3. sThe other end of the input capacitor C4 is connected to capacitor C5 and resistor R6. The other end of capacitor C5 is connected to the non-inverting input of operational amplifier U3, and the other end of resistor R6 is connected to the output of operational amplifier U3. One end of resistor R5 is connected to the non-inverting input of operational amplifier U3, and the other end is grounded. One end of resistor R3 is connected to the inverting input of operational amplifier U3, and the other end is grounded. One end of resistor R4 is connected to the inverting input of operational amplifier U3, and the other end is connected to the output of operational amplifier U3. Resistors R3 and R4 form the negative feedback network of operational amplifier U3.

[0037] The dynamic phase-shifting module 5 includes a capacitor C6. One end of capacitor C6 and resistor R7 are connected to the output of the high-pass filter module 4, i.e., the output of operational amplifier U3. The other ends of capacitor C6 and resistor R7 are connected to the non-inverting input and inverting input of operational amplifier U4, respectively. Resistor R8 is connected in parallel between the inverting input and output of operational amplifier U4, forming a negative feedback network of operational amplifier U4 together with resistor R7. MOSFETs M1 and M2 are connected in parallel. The gate of MOSFET M1 is connected to the non-inverting input of operational amplifier U4, and the gate of MOSFET M1 is connected to its own drain, forming a voltage-controlled variable resistor to control the voltage V. c The gate input of MOSFET M2 is connected to the common ground of MOSFETs M1 and M2.

[0038] The low-pass filter module 7 includes a resistor R9, which is connected to the output terminal of the dynamic phase shift module 5, i.e., the output terminal of the operational amplifier U4. The other end of the resistor R9 is connected to a resistor R 10 Capacitor C7, Resistor R 10 The other end is connected to the non-inverting input of operational amplifier U5, the other end of capacitor C7 is grounded, and resistor R... 11 Resistance R 12 One end is simultaneously connected to the inverting input of operational amplifier U5, and resistor R 11 The other end is grounded, and the resistor R 12 The other end is connected to the output of operational amplifier U5, and resistor R 11 and R 12 The negative feedback network that forms the operational amplifier U5.

[0039] The square wave shaping module 8 uses a comparator U6, and the input of the comparator U6 is connected to the output of the low-pass filter module 7, which is the output of the operational amplifier U5.

[0040] The amplitude control module 9 includes a resistor R. 13 resistance R 13 One end is connected to the output terminal of the square wave shaping module 8, i.e., the output terminal of comparator U6, and resistor R. 13 The other end and resistor R 14The resistor R is connected to the inverting input of operational amplifier U7. 14 The other end is connected to the output of operational amplifier U7, and the non-inverting input of operational amplifier U7 is grounded.

[0041] The differential drive module 10 includes a differential driver U8. The non-inverting input of the differential driver U8 is connected to the output of the amplitude control module 9, i.e., the output of the operational amplifier U7. The inverting input of the differential driver U8 is grounded. The non-inverting output of the differential driver U8 is connected to the driving terminal of the quartz beam resonator 1. The inverting output of the differential driver U8 is connected to capacitor C. s Capacitor C s The other end is connected to the output terminal 11 of the quartz beam resonator 1.

[0042] The front-end amplification module 3 detects the vibration signal of the quartz beam resonator 1 and converts it into a high-gain voltage output. The high-pass filter module 4 filters out the low-frequency unwanted signals and passes them to the dynamic phase shifter. After automatic phase modulation, the output is an oscillation signal with zero phase difference from the quartz beam resonator 1. The square wave shaping module uses a dedicated comparator, which can quickly and without distortion convert the sine wave signal into a square wave signal that can be directly processed by the digital system. Since the natural frequency of the quartz beam resonator 1 is much lower than the bandwidth of the control circuit, undersampling is performed during the square wave shaping process to modulate high-frequency noise higher than the natural frequency of the quartz beam resonator 1 into the vicinity of the carrier wave, reducing the system signal-to-noise ratio. A low-pass filter module 7 is inserted before the square wave shaping module 8 to limit the loop bandwidth, reduce noise aliasing in the next stage, and improve the stability and resolution of the accelerometer. The signal-to-noise ratio (SNR) of the quartz beam resonator 1 is proportional to its amplitude. However, excessive amplitude will cause the system to enter a nonlinear state, where its natural frequency is modulated by the amplitude, directly converting amplitude noise into frequency noise and reducing the linearity and stability of the accelerometer's scaling factor. The amplitude control module 9 ensures that the quartz beam resonator 1 achieves the highest SNR within its linear operating region. It allows for flexible and convenient adjustment of different quartz beam resonators 1 without any structural changes, significantly reducing production costs and unleashing the device's ideal performance. The non-inverting and inverting outputs of the differential drive module 10 drive the quartz beam resonator 1 and the compensation capacitor C, respectively. s The static capacitance and compensation capacitance C of the quartz beam resonator 1 s The generated output signals cancel each other out, retaining the vibration signal of the quartz resonator 1 and eliminating unwanted parasitic oscillations.

[0043] The high-pass filter module 4 and the low-pass filter module 7 can also be implemented by passive circuits or three or more active circuits.

[0044] The square wave shaping module 8 can also be implemented by an operational amplifier or a discrete MOS transistor.

[0045] like Figure 4 As shown, the automatic phase control module 6 consists of analog-to-digital converters U9 and U10, D flip-flops U11 and U12, AND gate U13, inverter U14, MOSFETs M3 and M4, low-pass filter 13, PID controller 14, and digital-to-analog converter U15. The D flip-flops U11 and U12, AND gate U13, inverter U14, and MOSFETs M3 and M4 are connected to form a phase-frequency detector (PFD). The automatic phase control module 6 is implemented using digital circuitry. The analog-to-digital converters U9 and U10 connect the drive terminal 12 of the differential drive module 10 and the output terminal V of the front-end amplifier module 3. s The analog signal is converted into a digital signal and enters the phase-frequency detector (PFD). When the signal at the drive terminal 12 passes the rising edge, the phase-frequency detector (PFD) outputs a high level. When port V... s When the signal passes through the rising edge, the phase-frequency detector (PFD) outputs a low level; a voltage signal proportional to the phase difference between the two input signals can be obtained through the low-pass filter 13. The PID controller 14 converts the output signal of the low-pass filter 13 into a control signal, which is then output as an analog signal V after passing through the digital-to-analog converter U15. c The voltage-controlled variable resistor composed of MOSFETs M1 and M2 in the dynamic phase-shifting module 5 controls the phase advance or lag of the control circuit due to the resistance change, ensuring that the oscillation frequency of the loop is always consistent with the natural frequency of the quartz resonator 1.

[0046] The automatic phase control module 6 can also be implemented using analog circuits.

[0047] The frequency-phase detector (PFD) mentioned above can also be a multiplication phase detector, an EXOR phase detector, a JK trigger-type phase detector, etc.

[0048] The control circuit in this embodiment can be implemented by combining discrete analog and digital circuit chips, or it can be implemented using application-specific integrated circuit (ASIC) technology.

Claims

1. A high-gain automatic phase modulation quartz beam accelerometer control circuit, comprising a feedthrough suppression module, characterized in that: The feedthrough suppression module and the quartz resonator are connected in parallel to form a parallel resonant unit. The output of the parallel resonant unit is connected to the input of the front-end amplification module. The output of the front-end amplification module is connected to the input of the high-pass filter module and the first input of the automatic phase control module. The output of the high-pass filter module is connected to the first input of the dynamic phase shift module. The second input of the dynamic phase shift module is connected to the output of the automatic phase control module. The output of the dynamic phase shift module is connected to the input of the low-pass filter module. The output of the low-pass filter module is connected to the input of the square wave shaping module. The output of the square wave shaping module is connected to the input of the amplitude control module. The output of the amplitude control module is connected to the input of the differential drive module. The output of the differential drive module is connected to the input of the feedthrough suppression module, the drive end of the quartz resonator, and the second input of the automatic phase control module. The automatic phase control module includes an analog-to-digital converter (ADC), a phase-frequency detector (PFD), a low-pass filter, a PID controller, and a digital-to-analog converter (DAC). The ADC is implemented using digital circuitry. The ADC converts the analog signals output from the differential drive module and the front-end amplifier module into digital signals, which then enter the PFD. The PFD is connected to the low-pass filter, which outputs a voltage signal proportional to the phase difference between the two input signals. The PID controller converts the output signal of the low-pass filter into a control signal, which, after passing through the DAC, outputs as the control signal for the voltage-controlled variable resistor in the dynamic phase-shifting module. Changes in resistance cause the phase of the control circuit to lead or lag, eliminating the deviation between the loop's oscillation frequency and the natural frequency of the quartz resonator.

2. The high-gain automatic phase modulation quartz beam accelerometer control circuit according to claim 1, characterized in that: The aforementioned front-end amplification module includes an operational amplifier U1, the inverting input of which is connected to the output of a quartz beam resonator, and a resistor. R 1 and capacitor C 1 is connected in parallel between the inverting input and output of operational amplifier U1; a capacitor is connected to the output of operational amplifier U1. C 2. One end, capacitor C 2. The other end is connected to the inverting input of operational amplifier U2; capacitor C 3 and resistance R 2 are connected in parallel at the inverting input and output of operational amplifier U2; operational amplifier U1, resistor R 1 and capacitor C 1. This forms the first-stage front-end interface circuit, consisting of operational amplifier U2 and capacitors. C 2. C 3 and resistance R 2. Form the second-stage amplifier circuit; The first-level front-end interface circuit is equivalent to an integrator, which uses a capacitor... C 1. Provides high gain, resistive R 1. A DC feedback path is provided for operational amplifier U1 to prevent output signal saturation caused by input bias voltage; the second-stage amplifier circuit acts as a differentiator, providing stable AC gain for the front-end amplifier module within the operating frequency range of the quartz beam resonator. The gain is determined by the capacitor. C 2 and resistance R The bandwidth is jointly determined by the capacitor. C 3. Decision; The aforementioned front-end amplification module has bandpass characteristics, and the gain within the passband is ( C 2 / C 1) R 2.

3. The high-gain automatic phase modulation quartz beam accelerometer control circuit according to claim 1, characterized in that: The aforementioned phase-frequency detector (PFD) is composed of a D flip-flop, an AND gate, an inverter, a PMOS, and an NMOS connected in sequence. The low-pass filter and PID controller are implemented using digital circuits or analog circuits.

4. The high-gain automatic phase modulation quartz beam accelerometer control circuit according to claim 1, characterized in that: The frequency-phase detector (PFD) mentioned above uses a multiplication phase detector, an EXOR phase detector, or a JK-triggered phase detector.

5. The high-gain automatic phase modulation quartz beam accelerometer control circuit according to claim 1, characterized in that: The high-pass filter module and low-pass filter module are implemented in a second-order active manner and can be replaced with passive filters or higher-order active filters.

6. The high-gain automatic phase modulation quartz beam accelerometer control circuit according to claim 1, characterized in that: The dynamic phase-shifting module consists of an active phase shifter and a voltage-controlled variable resistor, which is composed of two P-channel metal-oxide-semiconductor field-effect transistors (PMOS) connected in parallel.

7. The high-gain automatic phase modulation quartz beam accelerometer control circuit according to claim 1, characterized in that: The square wave shaping module is implemented using a comparator or an operational amplifier operating in an open loop.

8. The high-gain automatic phase modulation quartz beam accelerometer control circuit according to claim 1, characterized in that: The feedthrough suppression module is implemented using a compensation capacitor; the amplitude control module is implemented using a negative feedback operational amplifier; and the differential drive module is implemented using a differential driver.

9. The high-gain automatic phase modulation quartz beam accelerometer control circuit according to claim 1, characterized in that: The control circuit is composed of a mixture of analog and digital circuits, or is implemented using integrated circuit (ASIC) technology.

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