Interface circuit for capacitive mems sensor, quadrature error suppression method

Abstract

This disclosure provides an interface circuit for a capacitive MEMS sensor and a quadrature error suppression method. The quadrature error suppression method includes: acquiring a first-direction displacement from the capacitive MEMS sensor; providing a driving voltage to a driving electrode based on the first-direction displacement to cause the capacitive MEMS sensor to resonate along the first direction; acquiring a second-direction displacement from the capacitive MEMS sensor; amplifying and converting the second-direction displacement signal to obtain a detection signal containing a quadrature error component and an input angular velocity; performing in-phase quadrature demodulation on the detection signal; and obtaining an output signal characterizing the input angular velocity based on the demodulated quadrature component, in-phase component, and error elimination coefficient. The error elimination coefficient is obtained based on the changes in the in-phase component and quadrature component before and after an electrostatic force is applied to the torsion electrode. This application can obtain a more accurate error elimination coefficient, thereby improving the detection accuracy of the capacitive MEMS sensor.

Description

Technical Field

[0001] This disclosure relates to the field of sensing technology, and in particular to an interface circuit and a method for suppressing quadrature errors in a capacitive MEMS sensor. Background Technology

[0002] Capacitive sensors, with their high sensitivity and non-contact characteristics, are widely used in precision measurement, industrial inspection, and consumer electronics. Taking MEMS (Micro-Electro-Mechanical System) gyroscopes as an example, they offer advantages such as high integration, low cost, high precision, and the ability to be mass-produced and adjusted. The navigation calculations, platform stabilization, and attitude measurement functions of MEMS gyroscopes are widely used in the defense industry and smart devices.

[0003] A capacitive sensor contains a movable mass and measures the angular velocity along the detection axis using the Coriolis effect. When an input angular velocity exists along the detection axis, the Coriolis effect couples the energy along the driving axis to the sensing axis. By detecting the motion of the movable mass along the sensing axis, the input angular velocity can be obtained.

[0004] However, due to limitations in the manufacturing process of capacitive sensors, problems such as irregular comb teeth and asymmetrical support beams exist during actual production. This results in the drive shaft and detection shaft of the capacitive sensor not being completely perpendicular or not completely coincident with the designed elastic main shaft, thus generating significant mechanical coupling. When there is no angular velocity input, some of the motion in the drive mode (i.e., the zero-bias error) will also couple to the detection mode, affecting the accuracy of the detection signal to some extent. This, in turn, causes the zero-bias error and scale factor drift and instability of the capacitive sensor. Summary of the Invention

[0005] In view of the above problems, this disclosure provides an interface circuit and an orthogonal error suppression method for a capacitive MEMS sensor to improve the detection accuracy of the capacitive MEMS sensor.

[0006] According to a first aspect of this disclosure, a method for suppressing quadrature errors in a capacitive MEMS sensor is provided, wherein the capacitive MEMS sensor includes a mass block, a detection electrode, a driving electrode, and a torsion electrode, and the method for suppressing quadrature errors includes:

[0007] The capacitive MEMS sensor acquires a displacement in a first direction, and provides a driving voltage to the driving electrode based on the displacement in the first direction so that the capacitive MEMS sensor resonates along the first direction.

[0008] The second-direction displacement is acquired from the capacitive MEMS sensor, and the second-direction displacement signal is amplified and converted to obtain a detection signal, which includes orthogonal error components and input angular velocity.

[0009] The detected signal is demodulated in phase and quadrature. The output signal is obtained based on the demodulated quadrature component, in-phase component, and error elimination coefficient. The output signal represents the input angular velocity.

[0010] Specifically, the demodulated quadrature and in-phase components are obtained without applying electrostatic force to the torsion electrode, and the demodulated quadrature and in-phase components are obtained with applying electrostatic force to the torsion electrode. The error elimination coefficient is obtained based on the changes in the in-phase and quadrature components before and after the torsion electrode is subjected to electrostatic force.

[0011] Optionally, obtaining the error elimination coefficient includes:

[0012] Acquire at least two demodulated in-phase and quadrature components of the detection signal, with or without an input angular velocity, wherein at least one detection signal is acquired without applying an electrostatic force to the torsion electrode, and at least one detection signal is acquired with an electrostatic force applied to the torsion electrode; and

[0013] The error elimination coefficient is obtained based on the in-phase and quadrature components of the demodulated signals from at least two detection signals.

[0014] Optionally, the error elimination coefficient is obtained during the calibration or operation phase of the capacitive MEMS sensor.

[0015] Optionally, it includes: acquiring the first in-phase component and the first quadrature component of the demodulated first detection signal when no electrostatic force is applied to the torsion electrode and the input angular velocity is 0;

[0016] Under the condition that a first electrostatic force is applied to the torsion electrode and the input angular velocity is 0, the second in-phase component and the second quadrature component of the demodulated second detection signal are obtained; and

[0017] The error elimination coefficient is obtained based on the first in-phase component, the first quadrature component, the second in-phase component, and the second quadrature component.

[0018] Optionally, the error elimination coefficient is: ,in, The error elimination coefficient is... This is the first in-phase component. This is the first orthogonal component. This is the second in-phase component. This is the second orthogonal component.

[0019] Optionally, it includes: acquiring at least three in-phase and quadrature components of the demodulated detection signal at equal time intervals when an input angular velocity is present, wherein the change in the input angular velocity is consistent within the same time interval; and

[0020] The error elimination coefficient is obtained based on the in-phase and quadrature components of the demodulated detection signals from at least three tests.

[0021] Optionally, it includes: acquiring the third in-phase component and the third quadrature component of the demodulated third detection signal when no electrostatic force is applied to the torsion electrode and the input angular velocity is the first angular velocity;

[0022] When a second electrostatic force is applied to the torsion electrode and the input angular velocity is the second angular velocity, the fourth in-phase component and the fourth quadrature component of the demodulated fourth detection signal are obtained.

[0023] Under the condition that a second electrostatic force is applied to the torsion electrode and the input angular velocity is a third angular velocity, the fifth in-phase component and the fifth quadrature component of the demodulated fifth detection signal are obtained; and

[0024] The error elimination coefficient is obtained based on the third in-phase component, the third quadrature component, the fourth in-phase component, the fourth quadrature component, the fifth in-phase component, and the fifth quadrature component.

[0025] The difference between the second angular velocity and the first angular velocity is equal to the difference between the third angular velocity and the second angular velocity.

[0026] Optionally, the error elimination coefficient is: ,in, The error elimination coefficient is... The third in-phase component, The third orthogonal component, The fourth in-phase component, For the fourth orthogonal component, The fifth in-phase component, This is the fifth orthogonal component.

[0027] Optionally, the output signal is obtained based on the demodulated quadrature component, in-phase component, and error cancellation coefficient, including:

[0028]

[0029]

[0030]

[0031] in, The value of the output signal. The in-phase component of the detected signal. These are the orthogonal components of the detected signal. The error elimination coefficient is... The input angular velocity, To detect the modal displacement amplitude, This is the stiffness coupling coefficient caused by orthogonal error. To detect the orthogonal displacement amplitude of the mode.

[0032] Optionally, the electrostatic force is a differential signal, which can be a digital signal or an analog signal.

[0033] According to a second aspect of this disclosure, an interface circuit for a capacitive MEMS sensor is provided. The capacitive MEMS sensor includes a mass block, a detection electrode, a driving electrode, and a torsion electrode. The interface circuit includes:

[0034] The driving circuit acquires a first-direction displacement from the capacitive MEMS sensor and provides a driving voltage to the driving electrode according to the first-direction displacement so that the capacitive MEMS sensor resonates along the first direction.

[0035] The detection circuit acquires the second-direction displacement from the capacitive MEMS sensor, amplifies and converts the second-direction displacement signal to obtain a detection signal, which includes orthogonal error components and input angular velocity; and

[0036] The signal processing circuit performs in-phase quadrature demodulation on the detected signal, and obtains an output signal based on the demodulated quadrature component, in-phase component, and error cancellation coefficient. The output signal represents the input angular velocity.

[0037] The signal processing circuit also obtains the demodulated quadrature and in-phase components without applying electrostatic force to the torsion electrode, obtains the demodulated quadrature and in-phase components with applying electrostatic force to the torsion electrode, and obtains the error elimination coefficient based on the changes in the in-phase and quadrature components before and after the torsion electrode is subjected to electrostatic force.

[0038] Optionally, the driving circuit also provides in-phase demodulation parameters and quadrature demodulation parameters, and the signal processing circuit includes:

[0039] The demodulation unit performs in-phase demodulation on the detection signal according to the in-phase demodulation parameters to obtain the demodulated in-phase component, and performs quadrature demodulation on the detection signal according to the quadrature demodulation parameters to obtain the demodulated quadrature component.

[0040] An error elimination coefficient generating unit provides electrostatic force to the torsion electrode and generates an error elimination coefficient; and

[0041] The logic unit, connected to the demodulation unit and the error cancellation coefficient generation unit, obtains an output signal based on the demodulated quadrature component, in-phase component, and error cancellation coefficient. The output signal represents the input angular velocity.

[0042] The error elimination coefficient generation unit is connected to the demodulation unit to obtain the demodulated quadrature component and in-phase component when no electrostatic force is applied to the torsion electrode, and to obtain the demodulated quadrature component and in-phase component when an electrostatic force is applied to the torsion electrode. The error elimination coefficient is obtained based on the changes in the in-phase component and quadrature component before and after the electrostatic force is applied to the torsion electrode.

[0043] Optionally, the error elimination coefficient generating unit acquires at least two in-phase and quadrature components of the demodulated detection signals, whether or not an input angular velocity is present. At least one detection signal is acquired without applying electrostatic force to the torsion electrode, and at least one detection signal is acquired with electrostatic force applied to the torsion electrode. The error elimination coefficient is then obtained based on the in-phase and quadrature components corresponding to the demodulated detection signals.

[0044] Optionally, the signal processing circuit obtains the error elimination coefficient during the calibration or operation phase of the capacitive MEMS sensor.

[0045] Optionally, the error elimination coefficient generating unit acquires the first in-phase component and the first quadrature component of the demodulated first detection signal when no electrostatic force is applied to the torsion electrode and the input angular velocity is 0; acquires the second in-phase component and the second quadrature component of the demodulated second detection signal when the first electrostatic force is applied to the torsion electrode and the input angular velocity is 0; and obtains the error elimination coefficient based on the first in-phase component, the first quadrature component, the second in-phase component, and the second quadrature component.

[0046] Optionally, the error elimination coefficient is: ,in, The error elimination coefficient is... This is the first in-phase component. This is the first orthogonal component. This is the second in-phase component. This is the second orthogonal component.

[0047] Optionally, the error elimination coefficient generating unit further acquires at least three in-phase and quadrature components of the demodulated detection signal at equal time intervals when an input angular velocity is present, wherein the change in input angular velocity is consistent under the same time interval; and obtains the error elimination coefficient based on the at least three in-phase and quadrature components of the demodulated detection signal.

[0048] Optionally, the error elimination coefficient generating unit further acquires the third in-phase component and the third quadrature component of the demodulated third detection signal when no electrostatic force is applied to the torsion electrode and the input angular velocity is the first angular velocity; acquires the fourth in-phase component and the fourth quadrature component of the demodulated fourth detection signal when a second electrostatic force is applied to the torsion electrode and the input angular velocity is the second angular velocity; acquires the fifth in-phase component and the fifth quadrature component of the demodulated fifth detection signal when a second electrostatic force is applied to the torsion electrode and the input angular velocity is the third angular velocity; and obtains the error elimination coefficient based on the third in-phase component, the third quadrature component, the fourth in-phase component, the fourth quadrature component, the fifth in-phase component, and the fifth quadrature component, wherein the difference between the second angular velocity and the first angular velocity is equal to the difference between the third angular velocity and the second angular velocity.

[0049] Optionally, the error elimination coefficient is: ,in, The error elimination coefficient is... The third in-phase component, The third orthogonal component, The fourth in-phase component, For the fourth orthogonal component, The fifth in-phase component, This is the fifth orthogonal component.

[0050] Optionally, the signal processing circuit obtains the output signal based on the demodulated quadrature component, in-phase component, and error cancellation coefficient, including:

[0051]

[0052]

[0053] in, The value of the output signal. The in-phase component of the detected signal. These are the orthogonal components of the detected signal. The error elimination coefficient is... The input angular velocity, To detect the modal displacement amplitude, This is the stiffness coupling coefficient caused by orthogonal error. To detect the orthogonal displacement amplitude of the mode.

[0054] Optionally, the electrostatic force is a differential signal, which can be a digital signal or an analog signal.

[0055] The interface circuit and quadrature error suppression method of the capacitive MEMS sensor disclosed herein achieve real-time tracking of phase difference by adding a torsion electrode to the capacitive MEMS sensor and obtaining the error elimination coefficient based on the changes in the in-phase and quadrature components of the demodulated detection signal before and after the torsion electrode is subjected to electrostatic force. This eliminates the quadrature error components caused by process, temperature, stress changes and other non-ideal characteristics, thereby improving the output signal's ability to suppress quadrature errors.

[0056] Furthermore, this disclosure can obtain the error elimination coefficient during the calibration or operation phase of the capacitive MEMS sensor to take into account the impact of environmental changes on residual orthogonal errors, thereby improving the orthogonal error elimination effect. Attached Figure Description

[0057] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0058] Figure 1 A schematic diagram of a sensing system is shown.

[0059] Figure 2 This diagram illustrates the structure of a sensing system provided in an embodiment of this application.

[0060] Figure 3 This diagram illustrates a structural block diagram of a capacitive MEMS sensor provided in an embodiment of this application.

[0061] Figure 4 This diagram illustrates an ideal structure of a capacitive MEMS sensor provided in an embodiment of this application.

[0062] Figure 5 This diagram illustrates the structure of a capacitive MEMS sensor according to an embodiment of this application.

[0063] Figure 6 This diagram illustrates the principle of the demodulation unit in the interface circuit of a capacitive MEMS sensor according to an embodiment of this application.

[0064] Figure 7 This diagram illustrates an error elimination coefficient generation unit in the interface circuit of a capacitive MEMS sensor according to an embodiment of this application.

[0065] Figure 8 This diagram illustrates an error elimination coefficient generation unit in the interface circuit of another capacitive MEMS sensor provided in an embodiment of this application.

[0066] Figure 9 This diagram illustrates a flow chart of an orthogonal error suppression method for a capacitive MEMS sensor provided in an embodiment of this application. Detailed Implementation

[0067] Various embodiments of the invention will now be described in more detail with reference to the accompanying drawings. In the various drawings, the same elements are indicated by the same or similar reference numerals. For clarity, the various parts in the drawings are not drawn to scale.

[0068] Figure 1 A schematic diagram of a capacitive sensing system is shown.

[0069] like Figure 1 As shown, the sensing system 100 includes an angular velocity sensor 110 and an interface circuit 120.

[0070] The angular velocity sensor 110 includes at least a mass block 111, a drive capacitor 112 disposed along a drive axis (e.g., the x-axis), and a detection capacitor 113 disposed along a detection axis (e.g., the y-axis). The detection electrode is connected to the detection capacitor 113, and the drive electrode is connected to the drive capacitor 112.

[0071] Interface circuit 120 includes driving circuit 130 and detection circuit 140. Driving circuit 130 includes a first amplification unit 131, a phase-locked loop, and an automatic gain control unit 132, used to drive angular velocity sensor 110 to a resonant state, for example, constant frequency and constant amplitude oscillation. Detection circuit 140 mainly includes a second amplification unit 141, a demodulation unit 142, and an analog-to-digital converter 143, used to detect weak signals and digitally demodulate Coriolis signals.

[0072] In driving mode, the first amplification unit 131, phase-locked loop, and automatic gain control unit 132 in the driving circuit 130 provide driving voltage to the driving electrode in the angular velocity sensor 110 connected to the driving capacitor 112. This causes the angular velocity sensor 110 to operate in a resonant state in the drive shaft direction (e.g., the x-axis direction).

[0073] In the detection mode, the external input angular velocity (e.g., the angular velocity input in the z-axis direction) generates a Coriolis force along the direction of motion of the detection mode, thereby producing displacement on the detection axis (e.g., the y-axis direction). The detection circuit 140 reads the vibration displacement caused by the Coriolis force and then converts it into a detection signal (e.g., a voltage signal) that is proportional to the input angular velocity and easy to read.

[0074] However, due to limitations in the manufacturing process of capacitive sensors, problems such as irregular comb teeth and asymmetrical support beams exist in actual production and processing. This causes the drive shaft and detection shaft of the capacitive sensor to be not completely perpendicular or not completely coincident with the designed elastic main shaft, resulting in significant mechanical coupling. When there is no angular velocity input, the motion in the drive mode will also partially couple to the detection mode, affecting the output of the detection signal to a certain extent (i.e., zero bias error). This, in turn, causes zero bias error and scale factor drift and instability in the capacitive sensor. Among the factors causing output error, the drive displacement (drive displacement...) is the most significant. The displacement is along the x-axis. Due to manufacturing errors, the vibration displacement along the detection axis (i.e., the y-axis) in the detection mode will be affected. The orthogonal error that couples to the detection capacitor 113 and varies is the biggest factor that has an impact.

[0075] The typical detection circuit 140 amplifies the signal acquired by the detection electrodes and uses coherent demodulation technology to eliminate most of the quadrature errors to obtain the intermediate signal. and intermediate signals Analog-to-digital conversion yields a detection signal proportional to the input angular velocity. However, since a phase difference inevitably exists between the phase of the coherent demodulated signal and the phase of the quadrature error signal, the residual error still needs to be eliminated.

[0076] Existing technologies also employ the simultaneous demodulation of the in-phase and quadrature components of the signal, then subtract the product of the quadrature component and the phase difference from the in-phase signal to further eliminate quadrature errors. However, the phase difference between the quadrature signal and the demodulation clock is related to parameters such as resonant frequency and circuit delay, and is a quantity that varies with process technology, temperature, and stress. Existing technologies typically treat the phase difference between the quadrature signal and the demodulation clock as a fixed value or a temperature-dependent variable as a coefficient for eliminating quadrature errors. This means that quadrature error components caused by other non-ideal characteristics and stress variations cannot be effectively eliminated, affecting the accuracy of input angular velocity detection.

[0077] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0078] Capacitive MEMS sensors can be categorized into two types based on their operating mode: mode matching and mode splitting. They can also be classified into two types based on their detection principle: open-loop detection and closed-loop detection. Mode splitting and open-loop detection architectures offer advantages such as system simplicity, low power consumption, and high bandwidth, and are widely used in consumer gyroscopes.

[0079] The working principle of capacitive MEMS sensors is based on energy coupling and transfer between the driving mode and the detection mode. The sensing system includes a capacitive MEMS sensor (mechanical part) and an interface circuit (circuit part). In the driving mode, the capacitive MEMS sensor, under the action of the driving circuit in the interface circuit, acts like a resonator in the first direction (driving axis direction, e.g., the X direction) and operates in a resonant state. In the detection mode, the externally input angular velocity generates a Coriolis force along the direction of motion of the detection mode, thereby producing displacement in the second direction (detection axis direction, e.g., the Y direction). The detection circuit reads the vibration displacement caused by the Coriolis force and then converts it into a voltage signal that is proportional to the input angular velocity and easy to read through signal transformation.

[0080] Figure 2 This diagram illustrates the structure of a capacitive sensing system provided in an embodiment of this application. Figure 3 This diagram illustrates a structural block diagram of a capacitive sensor provided in an embodiment of this application. Figure 4 This diagram illustrates an ideal structure of a capacitive sensor provided in an embodiment of this application. Figure 5 This diagram illustrates the structure of a capacitive sensor provided in an embodiment of this application. Figure 6 This diagram illustrates the principle of the demodulation unit in the interface circuit of a capacitive sensor provided in an embodiment of this application. Figure 7 This diagram illustrates an error elimination coefficient generation unit in the interface circuit of a capacitive sensor provided in an embodiment of this application. Figure 8 This diagram illustrates an error elimination coefficient generation unit in the interface circuit of another capacitive sensor provided in an embodiment of this application. Figure 9 This diagram illustrates a flow chart of an orthogonal error suppression method for a capacitive MEMS sensor provided in an embodiment of this application.

[0081] like Figure 2 As shown, the sensing system 200 includes a capacitive MEMS sensor 210 and an interface circuit 220.

[0082] The capacitive MEMS sensor 210 is, for example, a MEMS linear vibration angular velocity sensor. The capacitive MEMS sensor 210 includes at least a mass block 111, a driving capacitor 112 disposed along a driving axis (e.g., the x-axis), a torsion electrode 214, and a detection capacitor 113 disposed along a detection axis (e.g., the y-axis). The detection electrode is connected to the detection capacitor 113, and the driving electrode is connected to the driving capacitor 112.

[0083] The interface circuit 220 includes a driving circuit 130, a detection circuit 240, and a signal processing circuit 250.

[0084] The drive circuit 130 acquires the first direction displacement x from the capacitive MEMS sensor 210. And according to the displacement x in the first direction Provide driving voltage to the driving electrode This causes the capacitive MEMS sensor 210 to resonate along a first direction. In an alternative embodiment, the displacement in the first direction can also be a differential signal acquired through a set of sensing capacitors.

[0085] The detection circuit 240 acquires the second-direction displacement y from the capacitive MEMS sensor 210. The second directional displacement signal is amplified and converted to obtain a detection signal Out0, which includes an orthogonal error component and the input angular velocity. In this embodiment, the second directional displacement is a differential signal acquired by a set of detection capacitors. In an alternative embodiment, the second directional displacement can also be a single signal acquired by a side detection capacitor.

[0086] The signal processing circuit 250 performs in-phase quadrature demodulation on the detection signal Out0, and then performs quadrature demodulation based on the demodulated quadrature components. , in-phase component The error elimination coefficient is used to obtain the output signal Output, which represents the input angular velocity. Further, the signal processing circuit 250 also obtains the demodulated quadrature and in-phase components without applying electrostatic force to the torsion electrode, obtains the demodulated quadrature and in-phase components with electrostatic force applied to the torsion electrode, and obtains the error elimination coefficient based on the changes in the in-phase and quadrature components before and after the electrostatic force is applied to the torsion electrode.

[0087] like Figure 3 As shown, the capacitive MEMS sensor 210 can be equivalently represented as a "spring-mass-damping" system. The x-axis (drive axis) represents the vibration direction of the drive mode, the y-axis (detection axis) represents the vibration direction of the detection mode, and the z-axis (sensing axis) represents the input direction of the external angular velocity. In the drive mode, the mass 111 of the capacitive MEMS sensor 210 resonates in the x-axis direction. When an angular velocity is input in the z-axis direction... At that time, the mass block 111 is subjected to the Coriolis force in the y direction, resulting in vibration displacement. The detection electrodes S+ and S- convert displacement changes into capacitance changes, which are then converted into digital signals by the detection circuit 240.

[0088] Based on the working principle of capacitive MEMS sensors, the following dynamic equation can be obtained: .

[0089] in, Let be the equivalent mass of mass block 111 in the driving mode. Let the mass block 111 be the equivalent mass in the detection mode. For Coriolis quality, Here, x is the input angular velocity, x is the driving displacement of the driving mode, and y is the vibration displacement of the detection mode. To drive the equivalent stiffness of the mode, For the equivalent damping of the driving mode, To detect the equivalent damping of the modes, The electrostatic driving force for driving the mode, To detect the feedback force of the modal, To drive the speed of the driving mode, To detect the vibration velocity of the modes, For driving mode acceleration, To detect the vibration acceleration of the modal.

[0090] To input the Coriolis force caused by the angular velocity on the drive shaft, - The Coriolis force caused by the input angular velocity on the detection axis. This is due to the electrostatic driving force under the driving mode. The Coriolis force on the drive shaft is much greater than the input angular velocity. Therefore, the Coriolis force in the driving mode can be ignored. Furthermore, in the detection mode under open-loop conditions... =0. Therefore, the above dynamic equation can be further simplified to:

[0091] .

[0092] Ideally, the capacitive MEMS sensor 210 is only affected by the Coriolis effect in the detection mode, thus producing a vibration displacement proportional to the Coriolis force. However, due to the presence of orthogonal errors in the micromechanical structure, the detection signal Out0 output by the detection circuit 240 contains an orthogonal error signal with a 90° phase difference from the Coriolis signal. Therefore, formula (4) is adjusted to the following:

[0093] (5).

[0094] in, - To input the Coriolis force caused by the angular velocity on the detection axis, - It is an elastic coupling force.

[0095] Due to limitations in the manufacturing process of capacitive sensors, capacitive MEMS sensors 210 exhibit various types of error coupling between modes. Among these, elastic coupling occurs because the elastic axis is not perfectly aligned with the driving and detection axes, causing the resonance of the driving mode to couple to the detection mode, resulting in an elastic coupling force. Compared to the Coriolis force introduced on the detection axis by the input angular velocity This cannot be ignored, as it directly affects the performance of the capacitive MEMS sensor 210.

[0096] Ideally, such as Figure 4 As shown. In the driving mode, without external angular velocity input, the detection frame is stationary, and the driving frame and mass block 111 move along the driving axis (e.g., the x-axis). When there is angular velocity input, the driving frame and the detection frame move along the driving axis (e.g., the x-axis) and the detection axis (e.g., the y-axis), respectively. The mass block 111 moves in an elliptical motion along its major and minor axes (which coincide with the driving axis and the detection axis, respectively).

[0097] In practical applications, such as Figure 5 As shown. Manufacturing errors cause a certain directional angle between the spring principal axis and the inertial principal axis of the capacitive MEMS sensor 210. This results in orthogonal motion, and the motion of mass block 111 is an elliptical motion in which the major and minor axes do not coincide with the drive axis and the detection axis.

[0098] The driving circuit 130 includes a first amplification unit 131, a phase-locked loop, and an automatic gain control unit 132, used to drive the capacitive MEMS sensor 210 to a resonant state, for example, a constant frequency and constant amplitude oscillation. The driving circuit 130 provides a driving voltage... The phase-locked loop in the drive circuit 130 and the phase-locked loop in the automatic gain control unit 132 provide stable frequency signals. The phase-locked loop in the drive circuit 130 and the automatic gain control unit in the automatic gain control unit 132 provide variable voltage. In the driving mode of the sensing system 200, the capacitive MEMS sensor 210 operates at a driving voltage. Under its influence, a driving displacement is generated in the x-axis direction. Furthermore, the drive circuit 130 also provides in-phase demodulation parameters. and orthogonal demodulation parameters .

[0099] The detection circuit 240 mainly includes a second amplification unit 141 and an analog-to-digital converter 143, used to obtain the detection signal and digitally demodulate the Coriolis signal. In the detection mode of the sensing system 200, when there is an angular velocity input in the z-axis direction, considering the effects of orthogonality error and the delay of the detection circuit 240, the vibration displacement of the detection mode... Including Coriolis displacement and orthogonal displacement ,Right now Vibration displacement under detection modes After amplification and analog-to-digital conversion by the second amplification unit 141 and the analog-to-digital converter 143, the detection signal Out0, which includes the quadrature error component and the input angular velocity, is obtained.

[0100] The signal processing circuit 250 includes a demodulation unit 251, an error elimination coefficient generation unit 252, and a logic unit 253.

[0101] The error elimination coefficient generation unit 252 provides an electrostatic force F to the torsion electrode and generates an error elimination coefficient. The electrostatic force is a differential signal, which can be a digital signal or an analog signal. Exemplarily, the differential signal provided by the error elimination coefficient generation unit 252 in this embodiment is a digital signal. In an alternative embodiment, the signal processing circuit 240 further includes a digital-to-analog converter unit to convert the differential signal provided by the error elimination coefficient generation unit 252 into an analog signal and provide it to the torsion electrode. Further, the error elimination coefficient generation unit 252 is connected to the demodulation unit 251, acquiring the demodulated quadrature and in-phase components when no electrostatic force is applied to the torsion electrode, and acquiring the demodulated quadrature and in-phase components when an electrostatic force is applied to the torsion electrode, and obtaining the error elimination coefficient based on the changes in the in-phase and quadrature components before and after the electrostatic force is applied to the torsion electrode.

[0102] Furthermore, the error elimination coefficient generation unit 252 in the signal processing circuit 250 obtains the error elimination coefficient during the calibration or operation phase of the capacitive sensing system. For example, the error elimination coefficient generation unit 252 can obtain the error elimination coefficient during the factory calibration of the sensing system 200, or during the overall calibration of the sensing system 200, or during use. The error elimination coefficient obtained above can take into account the impact of environmental changes on residual orthogonal errors, thus improving the orthogonal error suppression effect.

[0103] Demodulation unit 251 is connected to analog-to-digital converter 143 and phase-locked loop and automatic gain control unit 132, and is used to demodulate the detection signal Out0 to obtain quadrature components. and in-phase components Furthermore, the detection signal Out0 is demodulated in phase according to the in-phase demodulation parameters to obtain the demodulated in-phase component. And perform orthogonal demodulation on the detection signal Out0 according to the orthogonal demodulation parameters to obtain the demodulated orthogonal components. .

[0104] Logic unit 253 includes a multiplier U1 and an adder U2. Multiplier U1 is connected to demodulation unit 251 and error elimination coefficient generation unit 252 to obtain the quadrature components of the detection signal Out0. With error elimination coefficient The product of.

[0105] Adder U2 is connected to demodulation unit 251 and multiplier U1, and converts the quadrature component of detection signal Out0. With error elimination coefficient The product of the product and the in-phase component of the detection signal Out0 Summing is performed on the detection signal Out0 to suppress orthogonal errors and obtain the output signal Output (DC voltage signal) that characterizes the input angular velocity.

[0106] Furthermore, the value of the output signal Output satisfies the following formula:

[0107]

[0108]

[0109] in, The value of the output signal. To detect the in-phase component of the signal, To detect the orthogonal components of the signal, This is the error elimination coefficient. Input angular velocity, To detect the modal displacement amplitude, This is the stiffness coupling coefficient caused by orthogonal error. To detect the orthogonal displacement amplitude of the mode.

[0110] The output signal value and input angular velocity after calibration Proportional, and at this time the error elimination coefficient (total phase difference) The effect of ) on the output is a second-order small quantity.

[0111] Due to the presence of quadrature error in the capacitive MEMS sensor 210, the detection signal in the detection mode contains a quadrature error component with a 90° phase difference from the Coriolis signal. The signal processing circuit of this application performs in-phase quadrature demodulation on the detection signal to separate the input angular velocity and the quadrature error component. The residual quadrature error in the in-phase component is eliminated by subtracting the product of the quadrature component and the error elimination coefficient from the in-phase component. This error elimination coefficient takes into account the influence of environmental changes (process, temperature, stress changes, and other non-ideal characteristics) on the residual quadrature error, thus improving the effectiveness of quadrature error suppression.

[0112] like Figure 6 As shown, the demodulation unit 251 is implemented, for example, through an algorithm model, to demodulate the detection signal in phase and quadrature to obtain the corresponding in-phase and quadrature components.

[0113] Assuming the driving mode remains in resonance and the vibration frequency and amplitude are stable, the driving voltage... The driving displacement of the driving resonance. Drive speed in the drive direction under drive mode According to the Coriolis effect, the input angular velocity... Coriolis force caused - Based on the generation mechanism of orthogonal coupling, it can be known that the stiffness coupling force... - .

[0114] Considering the effects of orthogonality error and detection circuit delay, the vibration displacement under the detection mode is... Including Coriolis displacement and orthogonal displacement ,Right now .in,

[0115] .

[0116] .

[0117] .

[0118] in, To drive displacement amplitude, For driving frequency, Input angular velocity, To detect the natural resonant frequency under modal conditions, To detect the quality factor under modal conditions, Let the mass block 111 be the equivalent mass in the detection mode. This is the stiffness coupling coefficient caused by orthogonal error. To detect the output phase under different modes, To detect phase shift caused by circuit delay.

[0119] Vibration displacement of detection modes After quadrature demodulation, the output contains DC and second harmonics. Then, by using an LPF to filter out the high-frequency signal, the DC component can be obtained.

[0120] The in-phase component of the in-phase demodulation output is:

[0121] .

[0122] The quadrature components of the quadrature demodulation output are:

[0123] .

[0124] This application adds a pair of torsion electrodes to the mass block in a capacitive MEMS sensor 210, thereby applying a torsional electrostatic force to the mass block through the torsion electrodes F+ and F-. This electrostatic force causes a change in the stiffness coupling coefficient of the quadrature error coupled to the detection axis. Furthermore, by calculating the changes in the in-phase and quadrature outputs before and after the application of the electrostatic force to the torsion electrodes, a precise error elimination coefficient is obtained. .

[0125] Furthermore, the signal processing circuit 250 uses the error elimination coefficient obtained by the error elimination coefficient generation unit 252 to calculate the influence of environmental changes on residual orthogonal errors, so as to eliminate orthogonal error components caused by process, temperature, stress changes and other non-ideal characteristics, thereby improving the detection accuracy of the capacitive sensing system.

[0126] Furthermore, the signal processing circuit 250 acquires at least two in-phase and quadrature components of the demodulated detection signals, whether or not an input angular velocity is present. At least one detection signal is acquired without applying an electrostatic force to the torsion electrode. At least one detection signal is acquired with an electrostatic force applied to the torsion electrode. An error elimination coefficient is obtained based on the in-phase and quadrature components corresponding to the demodulated detection signals.

[0127] Furthermore, such as Figure 7 As shown, in one embodiment, the error elimination coefficient is obtained when the capacitive MEMS sensor 210 is stationary.

[0128] When no electrostatic force is applied to the torsional electrode and the input angular velocity is 0 (electrostatic force F=0), a first detection signal is obtained by the detection circuit 240. Then, the demodulation unit 251 in the signal processing circuit 250 performs in-phase quadrature demodulation on the first detection signal to obtain the first in-phase component of the first detection signal. and the first orthogonal component .

[0129] For example, assume that the stiffness coupling coefficient before the application of electrostatic force F is .

[0130] ,

[0131] .

[0132] When a first electrostatic force is applied to the torsional electrode and the input angular velocity is 0 (electrostatic force F=F1), a second detection signal is obtained by the detection circuit 240. Then, the demodulation unit 251 in the signal processing circuit 250 performs in-phase quadrature demodulation on the second detection signal to obtain the second in-phase component of the second detection signal. Second orthogonal component .

[0133] For example, the stiffness coupling coefficient after applying an electrostatic force F to the mass block is: .

[0134] ,

[0135] .

[0136] In this embodiment, the input angular velocity A value of 0 indicates that the input acceleration is zero.

[0137] For example, the error elimination coefficient generation unit 252 includes an adder and a divider to perform the following calculation:

[0138] ,in, This is the error elimination coefficient. The first in-phase component, The first orthogonal component, The second in-phase component, The second orthogonal component, To detect the orthogonal displacement amplitude of the mode, The stiffness coupling coefficient is the result of orthogonality error when no electrostatic force is applied to the torsional electrode and the input angular velocity is 0. The stiffness coupling coefficient is the result of orthogonal error when a first electrostatic force is applied to the torsional electrode and the input angular velocity is 0.

[0139] In other words, in this embodiment, by calculating the changes in in-phase and quadrature outputs after applying electrostatic force through the torsion electrode, a more accurate error elimination coefficient can be obtained. After the calculation is complete, you can choose to remove the electrostatic force F or retain it.

[0140] The error elimination coefficient acquisition method provided in this embodiment can be performed during factory calibration, during the whole-machine calibration stage after board installation, or during use. Then, it is obtained through calculation. As coefficients in the correction algorithm, to account for the impact of environmental changes on... The impact of this calculation is taken into account, which improves the effectiveness of orthogonal error suppression. The orthogonal error suppression method provided in this embodiment requires the capacitive MEMS sensor 210 to remain stationary to avoid the influence of the input angular velocity on the correction accuracy.

[0141] In another embodiment, the error cancellation coefficient is obtained while the capacitive MEMS sensor 210 is operating. The signal processing circuit 250 also acquires at least three demodulated in-phase and quadrature components of the detection signal at equal time intervals, wherein the change in input angular velocity is consistent across the same time intervals; and obtains the error cancellation coefficient based on the corresponding in-phase and quadrature components of the demodulated detection signal at least three times.

[0142] For example, such as Figure 8 As shown. Under the condition that no electrostatic force is applied to the torsion electrode and the input angular velocity is the first angular velocity (electrostatic force F=0, input angular velocity is...),... The detection circuit 240 obtains a third detection signal. Then, the demodulation unit 251 in the signal processing circuit 250 performs in-phase quadrature demodulation on the third detection signal to obtain the third in-phase component of the third detection signal. and the third orthogonal component .

[0143] For example, when the input angular velocity is Without applying an electrostatic force F to the mass block through the torsion electrodes F+ and F-, the stiffness coupling coefficient is: .

[0144] ,

[0145] .

[0146] go through The time interval, when the input angular velocity is When an electrostatic force F2 is applied to the mass block through torsion electrodes F+ and F- (electrostatic force F=F2, input angular velocity is...), the mass block is... The fourth detection signal is obtained through the detection circuit 240. Then, the demodulation unit 251 in the signal processing circuit 250 performs in-phase quadrature demodulation on the fourth detection signal to obtain the fourth in-phase component of the fourth detection signal. and the fourth orthogonal component .

[0147] For example, when the input angular velocity is When the electrostatic force F2 applied to the mass block by the torsion electrodes F+ and F- is greater than F1, the stiffness coupling coefficient is: .

[0148] ,

[0149] .

[0150] After that The time interval, when the input angular velocity is When an electrostatic force F2 is applied to the mass block through torsion electrodes F+ and F- (electrostatic force F=F2, input angular velocity is...), the mass block is... The fifth detection signal is obtained through the detection circuit 240. Then, the demodulation unit 251 in the signal processing circuit 250 performs in-phase quadrature demodulation on the fifth detection signal to obtain the fifth in-phase component of the fifth detection signal. and the fifth orthogonal component .

[0151] For example, when the input angular velocity is When an electrostatic force F2 is applied to the mass block through torsion electrodes F+ and F-, the stiffness coupling coefficient is: .

[0152] ,

[0153] .

[0154] It should be noted that, within a short period of time, the change in the input angular velocity of the capacitive sensor 210 can be approximated as a linear change, i.e.: .

[0155] For example, the error elimination coefficient generation unit 352 includes an adder and a divider to perform the following calculation: ,in, This is the error elimination coefficient. The third in-phase component, It is the third orthogonal component. It is the fourth in-phase component. It is the fourth orthogonal component. This is the fifth in-phase component. It is the fifth orthogonal component.

[0156] This application also provides a method for suppressing orthogonal errors in a capacitive sensing system, such as... Figure 9 As shown, it includes the following steps:

[0157] Step S410: Acquire a first-direction displacement from the capacitive MEMS sensor, and provide a driving voltage to the driving electrode according to the first-direction displacement so that the capacitive MEMS sensor resonates along the first direction.

[0158] Step S420: Acquire the second-direction displacement from the capacitive MEMS sensor, amplify and convert the second-direction displacement signal to obtain a detection signal, the detection signal including orthogonal error components and input angular velocity.

[0159] Step S430: Perform in-phase quadrature demodulation on the detected signal, and obtain an output signal based on the demodulated quadrature component, in-phase component, and error elimination coefficient. The output signal represents the input angular velocity. Specifically, the demodulated quadrature component and in-phase component are obtained without applying electrostatic force to the torsion electrode, and the demodulated quadrature component and in-phase component are obtained with applying electrostatic force to the torsion electrode. The error elimination coefficient is obtained based on the changes in the in-phase component and quadrature component before and after applying electrostatic force to the torsion electrode.

[0160] Further, obtaining the error elimination coefficient includes: acquiring at least two in-phase and quadrature components of the demodulated detection signals under conditions of the presence or absence of an input angular velocity, wherein at least one detection signal is acquired without applying an electrostatic force to the torsion electrode, and at least one detection signal is acquired with an electrostatic force applied to the torsion electrode; and obtaining the error elimination coefficient based on the in-phase and quadrature components of the demodulated detection signals.

[0161] Furthermore, the error elimination coefficient is obtained during the calibration or operation phase of the capacitive MEMS sensor.

[0162] Further, it includes: acquiring the first in-phase component and the first quadrature component of the demodulated first detection signal when no electrostatic force is applied to the torsion electrode and the input angular velocity is 0; acquiring the second in-phase component and the second quadrature component of the demodulated second detection signal when the first electrostatic force is applied to the torsion electrode and the input angular velocity is 0; and obtaining the error elimination coefficient based on the first in-phase component, the first quadrature component, the second in-phase component, and the second quadrature component.

[0163] Furthermore, the error elimination coefficient is: ,in, This is the error elimination coefficient. The first in-phase component, The first orthogonal component, The second in-phase component, It is the second orthogonal component.

[0164] Further, it includes: obtaining at least three in-phase and quadrature components of the demodulated detection signal at equal time intervals when an input angular velocity is present, wherein the change in the input angular velocity is consistent under the same time interval; and obtaining the error elimination coefficient based on the at least three in-phase and quadrature components of the demodulated detection signal.

[0165] Further, the method includes: acquiring a third in-phase component and a third quadrature component after demodulating a third detection signal when no electrostatic force is applied to the torsion electrode and the input angular velocity is a first angular velocity; acquiring a fourth in-phase component and a fourth quadrature component after demodulating a fourth detection signal when a second electrostatic force is applied to the torsion electrode and the input angular velocity is a second angular velocity; acquiring a fifth in-phase component and a fifth quadrature component after demodulating a fifth detection signal when a second electrostatic force is applied to the torsion electrode and the input angular velocity is a third angular velocity; and obtaining the error elimination coefficient based on the third in-phase component, the third quadrature component, the fourth in-phase component, the fourth quadrature component, the fifth in-phase component, and the fifth quadrature component, wherein the difference between the second angular velocity and the first angular velocity is equal to the difference between the third angular velocity and the second angular velocity.

[0166] Furthermore, the error elimination coefficient is: ,in, This is the error elimination coefficient. The third in-phase component, It is the third orthogonal component. It is the fourth in-phase component. It is the fourth orthogonal component. This is the fifth in-phase component. It is the fifth orthogonal component.

[0167] Furthermore, the output signal obtained based on the demodulated quadrature components, in-phase components, and error cancellation coefficients includes:

[0168]

[0169]

[0170]

[0171] in, The value of the output signal. To detect the in-phase component of the signal, To detect the orthogonal components of the signal, This is the error elimination coefficient. Input angular velocity, To detect the modal displacement amplitude, This is the stiffness coupling coefficient caused by orthogonal error. To detect the orthogonal displacement amplitude of the mode.

[0172] Furthermore, the electrostatic force is a differential signal, which can be a digital signal or an analog signal.

[0173] The interface circuit and quadrature error suppression method of the capacitive MEMS sensor disclosed herein achieve real-time tracking of phase difference by adding a torsion electrode to the capacitive MEMS sensor and obtaining the error elimination coefficient based on the changes in the in-phase and quadrature components of the demodulated detection signal before and after the torsion electrode is subjected to electrostatic force. This eliminates the quadrature error components caused by process, temperature, stress changes and other non-ideal characteristics, thereby improving the output signal's ability to suppress quadrature errors.

[0174] Furthermore, this disclosure can obtain the error elimination coefficient during the calibration or operation phase of the capacitive MEMS sensor to take into account the impact of environmental changes on residual orthogonal errors, thereby improving the orthogonal error elimination effect.

[0175] As described above, these embodiments of the present disclosure do not exhaustively cover all details, nor do they limit the disclosure to the specific embodiments described. Clearly, many modifications and variations can be made based on the above description. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the present disclosure, thereby enabling those skilled in the art to make good use of the present disclosure and modifications based on it. This disclosure is limited only by the claims and their full scope and equivalents.

Claims

1. A method for suppressing orthogonal errors in a capacitive MEMS sensor, wherein, The capacitive MEMS sensor includes a mass block, a detection electrode, a driving electrode, and a torsion electrode. The orthogonal error suppression method includes: The capacitive MEMS sensor acquires a displacement in a first direction, and provides a driving voltage to the driving electrode based on the displacement in the first direction so that the capacitive MEMS sensor resonates along the first direction. The second-direction displacement is acquired from the capacitive MEMS sensor, and the second-direction displacement signal is amplified and converted to obtain a detection signal, which includes orthogonal error components and input angular velocity. The detected signal is demodulated in phase and quadrature. The output signal is obtained based on the demodulated quadrature component, in-phase component, and error elimination coefficient. The output signal represents the input angular velocity. Specifically, the demodulated quadrature and in-phase components are obtained without applying electrostatic force to the torsion electrode, and the demodulated quadrature and in-phase components are obtained with applying electrostatic force to the torsion electrode. The error elimination coefficient is obtained based on the changes in the in-phase and quadrature components before and after the torsion electrode is subjected to electrostatic force.

2. The orthogonal error suppression method according to claim 1, wherein, Obtaining the error elimination coefficient includes: Acquire at least two demodulated in-phase and quadrature components of the detection signal, with or without an input angular velocity, wherein at least one detection signal is acquired without applying an electrostatic force to the torsion electrode, and at least one detection signal is acquired with an electrostatic force applied to the torsion electrode; and The error elimination coefficient is obtained based on the in-phase and quadrature components of the demodulated signals from at least two detection signals.

3. The orthogonal error suppression method according to claim 1, wherein, The error elimination coefficient is obtained during the calibration or operation phase of the capacitive MEMS sensor.

4. The orthogonal error suppression method according to claim 2, wherein, include: The first in-phase component and the first quadrature component of the demodulated first detection signal are obtained when no electrostatic force is applied to the torsion electrode and the input angular velocity is 0. When a first electrostatic force is applied to the torsion electrode and the input angular velocity is 0, the second in-phase component and the second quadrature component of the demodulated second detection signal are obtained. as well as The error elimination coefficient is obtained based on the first in-phase component, the first quadrature component, the second in-phase component, and the second quadrature component.

5. The orthogonal error suppression method according to claim 4, wherein, The error elimination coefficient is: ,in, The error elimination coefficient is... This is the first in-phase component. This is the first orthogonal component. This is the second in-phase component. This is the second orthogonal component.

6. The orthogonal error suppression method according to claim 2, wherein, include: In the presence of an input angular velocity, at least three in-phase and quadrature components of the demodulated detection signal are obtained at equal time intervals, wherein the change in the input angular velocity is consistent under the same time interval. as well as The error elimination coefficient is obtained based on the in-phase and quadrature components of the demodulated detection signals from at least three tests.

7. The orthogonal error suppression method according to claim 6, wherein, include: The third in-phase component and the third quadrature component of the demodulated third detection signal are obtained without applying electrostatic force to the torsion electrode and with the input angular velocity being the first angular velocity. When a second electrostatic force is applied to the torsion electrode and the input angular velocity is the second angular velocity, the fourth in-phase component and the fourth quadrature component of the demodulated fourth detection signal are obtained. When a second electrostatic force is applied to the torsion electrode and the input angular velocity is a third angular velocity, the fifth in-phase component and the fifth quadrature component of the demodulated fifth detection signal are obtained. as well as The error elimination coefficient is obtained based on the third in-phase component, the third quadrature component, the fourth in-phase component, the fourth quadrature component, the fifth in-phase component, and the fifth quadrature component. The difference between the second angular velocity and the first angular velocity is equal to the difference between the third angular velocity and the second angular velocity.

8. The orthogonal error suppression method according to claim 7, wherein, The error elimination coefficient is: ,in, The error elimination coefficient is... The third in-phase component, The third orthogonal component, The fourth in-phase component, For the fourth orthogonal component, The fifth in-phase component, This is the fifth orthogonal component.

9. The orthogonal error suppression method according to claim 1, wherein, The output signal obtained from the demodulated quadrature component, in-phase component, and error cancellation coefficient includes: in, The value of the output signal. The in-phase component of the detected signal. These are the orthogonal components of the detected signal. The error elimination coefficient is... The input angular velocity, To detect the modal displacement amplitude, This is the stiffness coupling coefficient caused by orthogonal error. To detect the orthogonal displacement amplitude of the mode.

10. The orthogonal error suppression method according to claim 1, wherein, The electrostatic force is a differential signal, which can be a digital signal or an analog signal.

11. An interface circuit for a capacitive MEMS sensor, the capacitive MEMS sensor comprising a mass block, a detection electrode, a driving electrode, and a torsion electrode, wherein, The interface circuit includes: The driving circuit acquires a first-direction displacement from the capacitive MEMS sensor and provides a driving voltage to the driving electrode according to the first-direction displacement so that the capacitive MEMS sensor resonates along the first direction. The detection circuit acquires the second-direction displacement from the capacitive MEMS sensor, amplifies and converts the second-direction displacement signal to obtain a detection signal, which includes orthogonal error components and input angular velocity; and The signal processing circuit performs in-phase quadrature demodulation on the detected signal, and obtains an output signal based on the demodulated quadrature component, in-phase component, and error cancellation coefficient. The output signal represents the input angular velocity. The signal processing circuit also obtains the demodulated quadrature and in-phase components without applying electrostatic force to the torsion electrode, obtains the demodulated quadrature and in-phase components with applying electrostatic force to the torsion electrode, and obtains the error elimination coefficient based on the changes in the in-phase and quadrature components before and after the torsion electrode is subjected to electrostatic force.

12. The interface circuit according to claim 11, wherein, The driving circuit also provides in-phase demodulation parameters and quadrature demodulation parameters, and the signal processing circuit includes: The demodulation unit performs in-phase demodulation on the detection signal according to the in-phase demodulation parameters to obtain the demodulated in-phase component, and performs quadrature demodulation on the detection signal according to the quadrature demodulation parameters to obtain the demodulated quadrature component. An error elimination coefficient generating unit provides electrostatic force to the torsion electrode and generates an error elimination coefficient; and The logic unit, connected to the demodulation unit and the error cancellation coefficient generation unit, obtains an output signal based on the demodulated quadrature component, in-phase component, and error cancellation coefficient. The output signal represents the input angular velocity. The error elimination coefficient generation unit is connected to the demodulation unit to obtain the demodulated quadrature component and in-phase component when no electrostatic force is applied to the torsion electrode, and to obtain the demodulated quadrature component and in-phase component when an electrostatic force is applied to the torsion electrode. The error elimination coefficient is obtained based on the changes in the in-phase component and quadrature component before and after the electrostatic force is applied to the torsion electrode.

13. The interface circuit according to claim 12, wherein, The error elimination coefficient generation unit acquires at least two in-phase and quadrature components of the demodulated detection signals, whether or not an input angular velocity is present. At least one detection signal is acquired when no electrostatic force is applied to the torsion electrode, and at least one detection signal is acquired when an electrostatic force is applied to the torsion electrode. The unit also obtains the error elimination coefficient based on the in-phase and quadrature components corresponding to the demodulated detection signals.

14. The interface circuit according to claim 11, wherein, The signal processing circuit obtains the error elimination coefficient during the calibration or operation phase of the capacitive MEMS sensor.

15. The interface circuit according to claim 13, wherein, The error elimination coefficient generation unit acquires the first in-phase component and the first quadrature component of the demodulated first detection signal when no electrostatic force is applied to the torsion electrode and the input angular velocity is 0; acquires the second in-phase component and the second quadrature component of the demodulated second detection signal when the first electrostatic force is applied to the torsion electrode and the input angular velocity is 0; and obtains the error elimination coefficient based on the first in-phase component, the first quadrature component, the second in-phase component, and the second quadrature component.

16. The interface circuit according to claim 15, wherein, The error elimination coefficient is: ,in, The error elimination coefficient is... This is the first in-phase component. This is the first orthogonal component. This is the second in-phase component. This is the second orthogonal component.

17. The interface circuit according to claim 13, wherein, The error elimination coefficient generation unit also acquires at least three in-phase and quadrature components of the demodulated detection signal at equal time intervals when an input angular velocity is present, wherein the change in input angular velocity is consistent under the same time interval; and obtains the error elimination coefficient based on the at least three in-phase and quadrature components of the demodulated detection signal.

18. The interface circuit according to claim 17, wherein, The error elimination coefficient generating unit also acquires the third in-phase component and the third quadrature component of the demodulated third detection signal when no electrostatic force is applied to the torsion electrode and the input angular velocity is the first angular velocity; acquires the fourth in-phase component and the fourth quadrature component of the demodulated fourth detection signal when a second electrostatic force is applied to the torsion electrode and the input angular velocity is the second angular velocity; acquires the fifth in-phase component and the fifth quadrature component of the demodulated fifth detection signal when a second electrostatic force is applied to the torsion electrode and the input angular velocity is the third angular velocity; and obtains the error elimination coefficient based on the third in-phase component, the third quadrature component, the fourth in-phase component, the fourth quadrature component, the fifth in-phase component, and the fifth quadrature component, wherein the difference between the second angular velocity and the first angular velocity is equal to the difference between the third angular velocity and the second angular velocity.

19. The interface circuit according to claim 18, wherein, The error elimination coefficient is: ,in, The error elimination coefficient is... The third in-phase component, The third orthogonal component, The fourth in-phase component, For the fourth orthogonal component, The fifth in-phase component, This is the fifth orthogonal component.

20. The interface circuit according to claim 11, wherein, The signal processing circuit obtains the output signal based on the demodulated quadrature component, in-phase component, and error cancellation coefficient, including: in, The value of the output signal. The in-phase component of the detected signal. These are the orthogonal components of the detected signal. The error elimination coefficient is... The input angular velocity, To detect the modal displacement amplitude, This is the stiffness coupling coefficient caused by orthogonal error. To detect the orthogonal displacement amplitude of the mode.

21. The interface circuit according to claim 11, wherein, The electrostatic force is a differential signal, which can be a digital signal or an analog signal.

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