CN114993278A

CN114993278A - MEMS gyroscope open loop reading circuit

Info

Publication number: CN114993278A
Application number: CN202210600938.1A
Authority: CN
Inventors: 山永启; 熊坤; 张潭; 徐浩谋; 陈方
Original assignee: Sichuan Weizhu Technology Co ltd
Current assignee: Sichuan Weizhu Technology Co ltd
Priority date: 2022-05-30
Filing date: 2022-05-30
Publication date: 2022-09-02

Abstract

The invention discloses an open loop reading circuit of an MEMS gyroscope, which comprises a driving loop, an orthogonal compensation and detection channel, a digital processing system and a power management module, wherein the driving loop is connected with the orthogonal compensation and detection channel; the MEMS gyroscope sensitive structure is electrically connected with a driving loop, and the driving loop is respectively electrically connected with the orthogonal compensation and detection path and the digital processing system; the MEMS gyroscope sensitive structure is electrically connected with an orthogonal compensation and detection channel, and the orthogonal compensation and detection channel is respectively electrically connected with the driving channel and the digital processing system; a power management module configured to power the drive loop, the quadrature compensation and detection path, and the digital processing system. The invention can configure the register to match different gyroscope sensitive structures, thereby improving the adaptation range of the reading circuit.

Description

MEMS gyroscope open loop reading circuit

Technical Field

The invention belongs to the technical field of micro-mechanical gyroscopes, and particularly relates to an open-loop readout circuit of an MEMS gyroscope.

Background

The operating mechanism of a micro-mechanical (MEMS) gyroscope is based on the Goldcell force effect, a driving electrostatic force is applied to a gyroscope driving mode, so that a mass block is subjected to constant amplitude vibration in a driving direction, when an external angular velocity is input, the mass block is caused to move in a detection direction, and a reading circuit picks up the movement amount in the detection direction, so that the angular velocity measurement is realized. A typical gyroscope sensitive structure is shown in fig. 1, at present, most of the gyroscope sensitive structures in various units and institutions are still in a development stage, and in order to adapt to different gyroscope sensitive structures, a reading circuit needs to be customized according to corresponding structure parameters. Meanwhile, a process deviation can be introduced into a sensitive structure of the gyroscope during processing, for example, zero deviation is introduced into detection and driving of capacitance value deviation of upper and lower differential capacitors, for example, incomplete verticality and rigidity asymmetry are detected and driven, and an orthogonal signal is introduced into damping coupling.

Disclosure of Invention

The present invention is directed to solving the above-mentioned problems, and to providing an open-loop readout circuit for a MEMS gyroscope to solve or improve the above-mentioned problems.

In order to achieve the purpose, the invention adopts the technical scheme that:

an open loop readout circuit of an MEMS gyroscope comprises a driving loop, an orthogonal compensation and detection path, a digital processing system and a power management module;

the MEMS gyroscope sensitive structure is electrically connected with a driving loop, the driving loop is respectively electrically connected with the orthogonal compensation and detection path and the digital processing system, and the driving loop is configured to drive displacement to start vibration in the direction of a driving shaft and stabilize the vibration amplitude at a set value;

the MEMS gyroscope sensitive structure is electrically connected with the orthogonal compensation and detection passage, the orthogonal compensation and detection passage is respectively electrically connected with the driving passage and the digital processing system, and the orthogonal compensation and detection passage is configured to perform orthogonal compensation on the MEMS gyroscope sensitive structure;

a power management module configured to power the drive loop, the quadrature compensation and detection path, and the digital processing system.

Further, the drive loop comprises:

the voltage input end of the driving capacitor voltage conversion circuit DC2V is connected with the driving detection end 2 of the MEMS gyroscope sensitive structure; and

the output end of the driving loop high-voltage control circuit DHVD is connected with the driving end 4 of the sensitive structure end of the MEMS gyroscope; and

a phase-locked loop frequency multiplier circuit PLL; and the mass block end of the MEMS gyroscope is connected with a mass block carrier signal STR output by a PLL frequency doubling circuit PLL.

Further, the drive loop further comprises: the driving circuit comprises a driving band-pass filter circuit DPGA, a driving loop amplitude control circuit DCTL, a voltage control gain circuit DVGA and a comparator circuit CMP;

the output of the driving band-pass filter circuit DPGA is respectively connected with the input of the driving loop amplitude control circuit DCTL and the input of the comparator circuit CMP; a signal output end 7 of the driving capacitor voltage conversion circuit DC2V is connected with the input ends of the driving band-pass filter circuit DPGA and the adder ADD, and a self-calibration output end 9 of the DC2V is connected with the digital processing module DPM;

the output of the driving loop amplitude control circuit DCTL is connected with the input of the voltage control gain circuit DVGA;

the output of the voltage control gain circuit DVGA meets the input of the DHVD circuit of the high-voltage control of the driving loop;

the output of the comparator circuit CMP is connected to the input of the phase locked loop frequency multiplier circuit PLL.

Further, the phase-locked loop frequency multiplier circuit PLL performs frequency locking according to the output signal of the comparator, and outputs an in-phase demodulation signal CK00 and a 90-degree phase difference demodulation signal CKN 90; the demodulation signal CK00 and the demodulation signal CKN90 are connected with the input of the angular velocity and orthogonal signal demodulation DEM circuit;

the in-phase demodulation signal CK00 is also connected with the input of a quadrature compensation integral control circuit QPIC and used for rigidity compensation quadrature demodulation;

and a mass block carrier signal STR generated by a phase-locked loop frequency multiplication circuit PLL is connected with a mass block end 5 of the MEMS gyroscope sensitive structure.

Further, the quadrature compensation and detection path includes:

the detection capacitor voltage conversion circuit SC2V is connected with the voltage input end of the MEMS gyroscope sensitive structure detection end 3 which is connected with the voltage input end of the detection capacitor voltage conversion circuit SC 2V; the self-calibration output end 10 of the SC2V is connected with a digital processing module DPM;

and the orthogonal compensation high-voltage control circuit QHVD is connected with the orthogonal rigidity compensation end 1 of the MEMS gyroscope sensitive structure.

Further, the quadrature compensation and detection path further comprises: the device comprises an adder ADD, a detection band-pass filter circuit SPGA, an orthogonal compensation integral control circuit QPIC and an angular velocity and orthogonal signal demodulation circuit DEM;

a signal output end 7 of the driving capacitor voltage conversion circuit DC2V and a signal output end 8 of the detection capacitor voltage conversion circuit SC2V are both connected with an input end of the adder ADD; the addition result output end of the adder ADD is connected with the input of the detection band-pass filter circuit SPGA;

the output of the detection band-pass filter circuit SPGA is connected with the input of the quadrature compensation integral control circuit QPIC and the input of the angular velocity and quadrature signal demodulation circuit DEM;

the output of the quadrature compensation integral control circuit QPIC is connected to the input of the quadrature compensation high voltage control circuit QHVD and the input of the adder ADD.

Further, the quadrature compensation and detection path further comprises: a low-pass filter circuit SLPF and an angular velocity and quadrature signal quantization circuit SADC;

the output end of the angular velocity and orthogonal signal demodulation circuit DEM is connected with the input end of the low-pass filter circuit SLPF;

the output end of the low-pass filtering SLPF circuit is connected with the input end of the angular velocity and orthogonal signal quantization circuit SADC, and meanwhile, the output end of the low-pass filtering SLPF circuit is used as the output of the analog angular velocity and orthogonal signal.

Further, the digital processing system comprises a temperature sensor quantification (TADC), a nonvolatile memory (NVP) and a Digital Processing Module (DPM);

the digital processing module DPM is connected with a self-calibration output end 9 of the driving capacitor voltage conversion circuit DC2V and a self-calibration output end 10 of the detection capacitor voltage conversion circuit SC 2V;

voltage signals output by the temperature sensor VTSEN are quantized by a temperature sensor quantization circuit TADC and then are accessed to a digital processing module DPM for temperature compensation;

the DPM system built-in filter bank configures system output bandwidth through a nonvolatile memory NVP.

Further, a reference current bias temperature sensor REF circuit is included that generates a low temperature drift and a reference voltage supply to drive the loop amplitude control circuit DCTL.

Further, a charge pump generating circuit CPP for generating an output voltage as a high voltage power supply, a drive loop high voltage control circuit DHVD, and a quadrature compensation high voltage control circuit QHVD are included.

The open-loop reading circuit of the MEMS gyroscope provided by the invention has the following beneficial effects:

1. the invention can configure the register to match different gyroscope sensitive structures, thereby improving the adaptation range of the reading circuit.

2. The invention adopts a charge injection method and a rigidity compensation method to carry out orthogonal compensation on a sensitive structure of the gyroscope, the charge injection method adopts register configuration and closed-loop control to compensate orthogonal signals, the rigidity compensation method adopts a register configuration orthogonal compensation high-voltage control circuit to adjust the gain of an electrostatic force to offset the orthogonal force of rigidity coupling, and simultaneously, the register can be configured to simultaneously complete the compensation of the orthogonal signals by the charge injection method and the rigidity compensation method, and after the compensation of the orthogonality by the charge injection method and the rigidity compensation method, the angular speed output temperature characteristic and the zero offset stability can be greatly improved.

3. The invention can configure analog angular speed output and digital angular speed output through the register, thereby being convenient for users to use.

4. The embedded nonvolatile memory can realize self calibration of a matching capacitor and zero offset, compensation of an angular velocity zero offset temperature coefficient, compensation of a scale factor temperature coefficient, calibration of a scale factor, configuration of system bandwidth and the like by combining a digital processing system, can conveniently debug and calibrate a sensitive structure of a gyroscope, and improves the yield of the whole gyroscope.

Drawings

Fig. 1 is a schematic diagram of the internal structure of the MEMS gyroscope structure.

FIG. 2 is a schematic diagram of an embodiment of an open-loop readout circuit of a MEMS gyroscope.

Fig. 3 is a schematic diagram of an embodiment of a capacitance-to-voltage conversion circuit.

Fig. 4 is a schematic diagram of an embodiment of an angular velocity and quadrature signal demodulation circuit.

Wherein, the reference numbers in fig. 1 are:

1-driving comb teeth; 2-drive detection; 3, detecting comb teeth; 4-an elastic beam; 5-driving the support beam; 6, detecting the support beam; 7-a mass block; 8-anchor point.

The circuit corresponding to the letter in fig. 2 is:

DC 2V-driving capacitance voltage conversion circuit, DGPA-driving band-pass filter circuit, DCTL-driving loop amplitude control circuit, DVGA-voltage control gain circuit, DHVD-driving loop high-voltage control circuit, CMP-comparator circuit, PLL-phase locked loop frequency doubling circuit, SC 2V-detecting capacitance voltage conversion circuit, ADD-adder, SPGA-detecting band-pass filter circuit, DEM-angular velocity and quadrature signal demodulation circuit, SLPF-low pass filter circuit, SADC-angular velocity and quadrature signal quantization circuit, QPIC-quadrature compensation integration control circuit, QHVD-quadrature compensation high-voltage control circuit, VTSEN-temperature sensor, TADC-temperature sensor quantization, NVP-nonvolatile memory, DPM-digital processing module, REF-reference voltage and bias current generation circuit, and, POR-power-on reset circuit, LDO-digital power voltage and analog reference voltage generating circuit, CPP-charge pump generating circuit.

In the circuit of fig. 3: 1-differential operational amplifier, 2-analog multiplier, 3-comparator;

in the circuit of fig. 4: 1-differential operational amplifier, 2-alternative selector, 3-inverter and 4-buffer.

Detailed Description

The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined in the appended claims, and all matters produced by the invention using the inventive concept are protected.

According to an embodiment of the present application, referring to fig. 2, the MEMS gyroscope open-loop readout circuit of the present solution includes a driving loop, a quadrature compensation and detection path, a digital processing system, and a power management module.

A drive loop configured to start the drive displacement in the drive shaft direction and stabilize the vibration amplitude at a set value; specifically, the MEMS gyroscope sensitive structure is electrically connected with a driving loop, and the driving loop is respectively electrically connected with the orthogonal compensation and detection path and the digital processing system.

An orthogonal compensation and detection path configured to orthogonally compensate the MEMS gyroscope sensitive structure;

specifically, the MEMS gyroscope sensitive structure is electrically connected with an orthogonal compensation and detection channel, and the orthogonal compensation and detection channel is respectively electrically connected with a driving channel and a digital processing system.

The further technical scheme of the driving loop of the embodiment is as follows:

the driving loop comprises a driving capacitor voltage conversion circuit DC2V, a driving band-pass filter circuit DPGA, a driving loop amplitude control circuit DCTL, a voltage control gain circuit DVGA, a driving loop high-voltage control circuit DHVD, a comparator circuit CMP and a phase-locked loop frequency doubling circuit PLL.

The specific connection relationship of the circuit is as follows:

the drive detection end 2 of the MEMS gyroscope sensitive structure is connected with the voltage input end of the drive capacitor voltage conversion circuit DC 2V; the driving end 4 of the MEMS gyroscope sensitive structure is connected with the output of the driving loop high-voltage control circuit DHVD; and the mass block end of the MEMS gyroscope is connected with a mass block carrier signal STR output by a PLL frequency doubling circuit PLL.

In a driving loop, a driving capacitor voltage conversion circuit DC2V processes a signal at a driving detection end of a gyroscope sensitive structure, a signal output end 7 of the driving capacitor voltage conversion circuit DC2V is connected with the input of a driving band-pass filter circuit DPGA and an adder ADD, and a self-calibration output end 9 of DC2V is connected with a digital processing module DPM; the output of the driving band-pass filter circuit DPGA is connected with the input of the driving loop amplitude control circuit DCTL, and is simultaneously connected with the input of the comparator circuit CMP; the output of the driving loop amplitude control circuit DCTL is connected with the input of the voltage control gain circuit DVGA; the output of the voltage control gain circuit DVGA is connected with the input of the drive loop high-voltage control DHVD circuit; the output of the comparator circuit CMP is connected to the input of the phase-locked loop frequency multiplier circuit PLL.

The specific application of the driving loop of the embodiment is as follows:

the PLL frequency multiplier circuit PLL carries out frequency locking according to the output signal of the comparator, the output comprises an in-phase demodulation signal CK00 and a 90-degree phase difference demodulation signal CKN90, the two demodulation signals are connected with the input of the angular velocity and quadrature signal demodulation DEM circuit and used for angular velocity and quadrature signal demodulation, and the in-phase demodulation signal CK00 is further connected with the input of the quadrature compensation integral control circuit QPIC and used for rigidity compensation quadrature demodulation. The generated mass block carrier signal STR is connected to a mass block end 5 of the MEMS gyroscope sensitive structure and is used for providing a carrier signal for a mass block of the sensitive structure, a phase-locked loop frequency multiplier circuit PLL generates a carrier signal VTR signal with a phase opposite to that of the STR and is connected with matching capacitors of a driving capacitor voltage conversion circuit DC2V and a detection capacitor voltage conversion circuit SC2V, the matching capacitors and the capacitance of the gyroscope sensitive structure form a full-bridge structure together, the capacitance of the gyroscope sensitive structure causes jump of an input common mode point to be counteracted by jump in the opposite direction of the matching capacitors, so that the voltages of upper detection electrodes and lower detection electrodes of the two capacitance voltage conversion circuits are kept stable, and the VTR signal is simultaneously connected to a zero-bias compensation capacitor and used for compensating mismatch of capacitance of the gyroscope sensitive structure.

The driving capacitance-voltage conversion circuit has the function of converting capacitance change on the driving detection end 2 of the MEMS gyroscope sensitive structure into differential voltage for output; the function of the driving band-pass filter circuit DPGA is to filter out clutter signals outside the frequency band of interest.

The driving loop amplitude control circuit DCTL limits the amplitude of the output signal of the driving band-pass filter circuit DPGA within a set value; the voltage control gain circuit DVGA is used for providing variable gain in a driving oscillation starting stage and has the function of adjusting the gain according to the oscillation amplitude of an input signal, the gain is larger when the oscillation amplitude is smaller, the gain is gradually reduced when the oscillation amplitude is gradually increased, and the gain is kept unchanged when the oscillation amplitude reaches a set value.

The driving loop high-voltage control circuit DHVD converts the output low-voltage signal of the voltage control gain circuit DVGA into a high-voltage signal, and the driving loop provides adjustable gain amplification and high-voltage preloading to generate electrostatic force for starting vibration of the gyroscope sensitive structure.

The driving loop is used for enabling the driving displacement to start vibration in the direction of the driving shaft and enabling the vibration amplitude to be stabilized at a set value. The comparator circuit CMP and the phase-locked loop frequency multiplication circuit PLL complete the picking up and locking of the driving resonant frequency of the sensitive structure of the gyroscope, CK00 which is output by the phase-locked loop frequency multiplication circuit PLL and has the same phase with the driving resonant frequency is used for quadrature demodulation, CKN90 which has the driving resonant frequency difference of 90 DEG is used for angular velocity demodulation, a mass block carrier signal STR, a matching capacitor carrier signal VTR which drives the capacitor voltage conversion circuit DC2V and the detection capacitor voltage conversion circuit SC2V are generated, and working frequency signals of the angular velocity and quadrature signal quantization circuit SADC, the temperature sensor quantization module TADC and the digital processing module DPM are generated.

The circuit functions and specific circuit implementation modes of the band-pass filter circuit DGPA, the driving loop amplitude control circuit DCTL, the voltage control gain circuit DVGA and the driving loop high-voltage control circuit DHVD belong to the prior art in the field, and are not described herein again.

The further technical scheme of the orthogonal compensation and detection path of the embodiment is as follows:

the orthogonal compensation and detection path comprises a detection capacitance voltage conversion circuit SC2V, an adder ADD, a detection band-pass filter circuit SGPA, an orthogonal compensation integral control circuit QPIC, an orthogonal compensation high-voltage control circuit QHVD, an angular velocity and orthogonal signal demodulation circuit DEM, a low-pass filter circuit SLPF and an angular velocity and orthogonal signal quantization circuit SADC.

The connection relationship of each circuit structure in the quadrature compensation and detection path in this embodiment is:

the detection end 3 of the MEMS gyroscope sensitive structure is connected with the voltage input end of the detection capacitor voltage conversion circuit SC 2V; and the orthogonal rigidity compensation end 1 of the MEMS gyroscope sensitive structure is connected with the output end of the orthogonal compensation high-voltage control circuit QHVD.

A signal output end 7 of the driving capacitor voltage conversion circuit DC2V and a signal output end 8 of the detection capacitor voltage conversion circuit SC2V are connected with the input end of the adder ADD; the self-calibration output end 10 of the SC2V is connected with the digital processing module DPM; the output end of the addition result of the adder ADD is connected with the input end of the detection band-pass filter circuit SPGA; the detection band-pass filter circuit SPGA outputs and is connected with the input of a quadrature compensation integral control circuit QPIC, and is simultaneously connected with the input of an angular velocity and quadrature signal demodulation circuit DEM; the output of the quadrature compensation integration control circuit QPIC is connected to the input of the quadrature compensation high voltage control circuit QHVD and the input of the adder ADD.

The output end of the angular velocity and orthogonal signal demodulation circuit DEM is connected with the input end of the low-pass filter circuit SLPF; the output end of the low-pass filtering SLPF circuit is connected with the input end of the angular velocity and orthogonal signal quantization circuit SADC, and meanwhile, the output end of the low-pass filtering SLPF circuit is also used as the output of the analog angular velocity and orthogonal signal, so that the use by a user is facilitated.

The specific application of each circuit structure in the quadrature compensation and detection path in this embodiment is as follows:

the function of the detection capacitance voltage conversion circuit SC2V is to convert the capacitance change on the detection end 2 of the MEMS gyroscope sensitive structure into differential voltage output.

One embodiment of the driving and detecting capacitor-voltage converting circuit is shown in fig. 3, where Cm is a base capacitor of a gyroscope sensing structure, C0 is a matching capacitor corresponding to Cm, and Cc is a zero-offset compensation capacitor. Cm, Cb and Cc form a capacitance bridge; the input of the differential operational amplifier is used as the input end of the capacitor voltage conversion circuit, Cf is an amplification feedback capacitor, the output of the differential operational amplifier is connected with the input of the comparator, and the output of the comparator is connected with the DPM, so that self-calibration of the matching capacitor and the zero-offset compensation capacitor is realized.

The adder ADD ADDs output signals of the driving capacitor voltage converting circuit DC2V, the detection capacitor voltage converting circuit SC2V, and the quadrature compensation integration control circuit QPIC, outputs the result to the detection band pass filter circuit SPGA, and outputs the result to the angular velocity and quadrature demodulation circuit DEM and the quadrature compensation integration control circuit QPIC after band pass filtering.

The quadrature compensation integral control circuit QPIC picks up a quadrature amplitude value and sends the quadrature amplitude value to the quadrature compensation high-voltage control circuit QHVD and the adder ADD for quadrature compensation, the quadrature compensation high-voltage control circuit QHVD has the functions of generating a compensation signal through an integral signal output by the quadrature compensation integral control circuit QPIC and outputting the compensation signal to a rigidity compensation end of a sensitive structure of the MEMS gyroscope, and the gain of the quadrature compensation high-voltage control circuit QHVD is configured to adjust electrostatic force so as to offset the orthogonal force of rigidity coupling, so that the rigidity compensation of quadrature signals is realized.

The angular velocity and orthogonal signal demodulation circuit DEM is used for receiving an in-phase demodulation signal CK00 for orthogonal demodulation, receiving a 90-degree phase difference demodulation signal CKN90 for angular velocity demodulation, filtering the demodulated signal through a low-pass filter circuit SLPF, inputting the filtered signal into an angular velocity and orthogonal signal quantization circuit SADC, converting the signal into a digital signal bitstrim by the angular velocity and orthogonal signal quantization circuit SADC, and inputting the digital signal bitstrim into a digital processing module DPM to complete a subsequent digital function algorithm.

The specific circuit implementation of the angular velocity and quadrature signal demodulation circuit DEM and the quadrature compensation integration control circuit QPIC is the prior art in the field.

For example, as shown in fig. 4, a typical implementation of the circuit of the angular velocity and quadrature signal demodulation circuit DEM is that an input signal is differentially amplified by a differential operational amplifier 1 and then output, an in-phase demodulation signal CK00 and a 90-degree phase difference demodulation signal CKN90 are used as control signals to control quadrature demodulation or angular velocity demodulation, and a feedback resistor Rf in fig. 4 implements a feedback function.

When the demodulation mode pin QEMOD input signal is at a high level, the alternative selector 2 selects the in-phase demodulation signal CK00, and the angular velocity and quadrature signal demodulation circuit DEM receives the in-phase demodulation signal CK00 for quadrature demodulation; when the demodulation mode pin QEMOD is low, the alternative selector 2 selects the 90-degree phase difference demodulation signal CKN90, the angular velocity and quadrature signal demodulation circuit DEM receives the 90-degree phase difference demodulation signal CKN90 for angular velocity demodulation, CKP and CKN in fig. 4 are internal control signals that are mutually inverted, and the output signals of the selector pass through an in-phase buffer stage and an inverted buffer stage formed by a buffer 4 and an inverter 3, respectively.

The orthogonal error may be caused by displacement coupling or rigidity coupling, the displacement coupling can be equivalently regarded as the projection of the driving displacement directly to the detection displacement, and the orthogonal signal caused by the coupling still has a 90-degree phase shift with the driving displacement after passing through the detection capacitor voltage conversion circuit SC 2V; the rigidity coupling is mainly caused by the coupling rigidity of the driving axial detection shaft, and the rigidity coupling generates phase shift after passing through the detection resonant cavity

After CV detection, the phase shift of the driving displacement is still 90 DEG with the Cogowski force

。

When the quadrature error is displacement coupling, the quadrature compensation adopts a charge injection method, firstly an RGBUS register is configured for the adder ADD through a digital processing module DPM to offset most of the quadrature error, and then the residual quadrature error is offset through quadrature compensation integral control circuit QPIC closed-loop control.

When the quadrature error is rigidity coupling, the RGBUS register is configured by the DPM to adjust the gain of the quadrature compensation high-voltage control circuit QHVD, so that the electrostatic force counteracts the orthogonal force of the rigidity coupling; if the quadrature error of the sensitive structure of the gyroscope simultaneously contains displacement coupling and rigidity coupling, an RGBUS register is configured to simultaneously complete compensation of quadrature signals by a charge injection method and a rigidity compensation method.

After the orthogonal compensation is carried out by a charge injection method and a rigidity compensation method, the angular speed output temperature characteristic and the zero offset stability of the system can be greatly improved. The selection enabling and specific parameters of the two orthogonal compensation methods can be flexibly configured through the NVP and the DPM.

The digital processing module DPM can realize the self-calibration of the matching capacitor C0 and the zero offset compensation Cc by processing the self-calibration output signal of the driving loop capacitor voltage conversion circuit and the self-calibration output signal of the detection loop capacitor voltage conversion circuit.

The digital processing system of the embodiment further has the technical scheme that:

the digital processing system comprises a temperature sensor quantification TADC, a nonvolatile memory NVP and a digital processing module DPM.

The digital processing system of this embodiment combines a driving loop, an orthogonal compensation and detection path, a power management module, and other circuits, and the implemented application is as follows:

the digital processing module DPM receives self-calibration output signals CLBO _ D and CLBO _ S of a self-calibration output end 9 of the driving capacitor voltage conversion circuit DC2V and a self-calibration output end 10 of the detection capacitor voltage conversion circuit SC2V, a calibration comparator in the capacitor voltage conversion circuit compares the sizes of a gyroscope sensitive structure capacitor and a matching capacitor, picks up zero offset of the gyroscope sensitive structure capacitor, outputs the zero offset to the digital processing module DPM to calculate configuration register values needed by the matching capacitor and the zero offset compensation capacitor, and then completes adjustment self-calibration of the matching capacitor and the zero offset compensation capacitor through REGBUS bus feedback; and the DPM receives the angular velocity and bitstrim output by the orthogonal signal quantization circuit SADC, and performs extraction filtering, temperature compensation, scale factor calibration, system bandwidth configuration and the like.

The reference current bias temperature sensor REF circuit generates low temperature drift and high-precision reference voltage to be supplied to the driving loop amplitude control circuit DCTL, and a voltage signal output by the temperature sensor VTSEN is quantized by the temperature sensor quantization circuit TADC and then is accessed to the digital processing module DPM for temperature compensation.

The charge pump generating circuit CPP is used to generate a higher output voltage as a high voltage power supply, driving the loop high voltage control circuit DHVD and the quadrature compensation high voltage control circuit QHVD. The power-on reset circuit POR is used for generating a power-on reset signal and enabling a circuit system after power-on.

The non-volatile memory NVP and the digital processing module DPM generate RGBUS (REGISTER BUS) REGISTERs for storing parameters, and the REGISTERs are connected with the driving loop amplitude control circuit DCTL, the charge pump generating circuit CPP, the driving loop high-voltage control circuit DHVD, the orthogonal compensation high-voltage control circuit QHVD, the phase-locked loop frequency doubling circuit PLL and the like, so that flexible configuration of circuit parameters is realized.

The NVP and DPM can carry out angular speed output zero offset temperature coefficient calibration, zero offset compensation and scale factor calibration; the digital processing module DPM system built-in filter bank can also configure the system output bandwidth through a nonvolatile memory NVP; the digital processing module DPM may have built-in digital communication interfaces such as I2C, PSI, RS _458, etc., selectable by the non-volatile memory NVP configuration.

According to the parameters of the gyroscope sensitive structures of different users, the nonvolatile memory NVP and the digital processing module DPM are used for configuring the matching capacitor to match the gyroscope sensitive structures, and the adaptation range of the reading circuit to the gyroscope sensitive structures is widened.

The driving loop amplitude control circuit DCTL can be configured through a nonvolatile memory NVP and a digital processing module DPM, so that the parameter requirements of different user sensitive structures are met, and the adaptation range of the readout circuit to the gyroscope sensitive structure is widened.

The output of the angular speed signal analog quantity or digital quantity can be selected through the NVP and the DPM, so that the use by a user is facilitated. When the analog quantity is output, digital parts such as an ADC (analog to digital converter) can be closed through the register, so that the power consumption of the whole device is reduced.

The output voltage of the charge pump generating circuit CPP is flexibly configured through the NVP of the nonvolatile memory and the DPM, the gains of the DHVD of the loop high-voltage control circuit and the QHVD of the quadrature compensation high-voltage control circuit are driven, and the adaptation range of the readout circuit to a gyroscope sensitive structure is expanded.

According to the resonant frequency of the gyroscope sensitive structure of different users, the locking frequency of the PLL frequency multiplier circuit PLL can be flexibly configured through the nonvolatile memory NVP and the digital processing module DPM, and the adaptation range of the readout circuit to the gyroscope sensitive structure is expanded.

The driving band-pass filter circuit DPGA, the detection band-pass filter circuit SPGA and the phase-locked loop frequency multiplier circuit PLL are internally provided with a phase compensation circuit, and the relative phase shift of a driving signal and a detection signal is configured by combining the non-volatile memory NVP and the digital processing module DPM, so that the accuracy of quadrature compensation and angular speed demodulation phase is improved.

A communication interface is selected through a nonvolatile memory NVP and a digital processing module DPM, and the communication interface is compatible with SPI, I2C, RS _458 and the like, so that a user can conveniently use the communication interface according to the interface of the user; the non-volatile memory NVP comprises a one-time programmable memory OTP and a multi-time erasable memory MTP.

The readout circuit has strong adaptability, can be matched with gyroscope sensitive structures of different users, and eliminates orthogonal signals to ensure the performance and yield of devices.

While the embodiments of the invention have been described in detail in connection with the accompanying drawings, it is not intended to limit the scope of the invention. Various modifications and changes may be made by those skilled in the art without inventive step within the scope of the appended claims.

Claims

1. An open-loop readout circuit of a MEMS gyroscope, comprising: the system comprises a driving loop, an orthogonal compensation and detection path, a digital processing system and a power management module;

the MEMS gyroscope sensitive structure is electrically connected with a driving loop, the driving loop is respectively electrically connected with the orthogonal compensation and detection path and the digital processing system, and the driving loop is configured to start the driving displacement in the direction of a driving shaft and stabilize the vibration amplitude at a set value;

the MEMS gyroscope sensitive structure is electrically connected with an orthogonal compensation and detection passage, the orthogonal compensation and detection passage is respectively electrically connected with the driving passage and the digital processing system, and the orthogonal compensation and detection passage is configured to perform orthogonal compensation on the MEMS gyroscope sensitive structure;

2. The MEMS gyroscope open loop readout circuit of claim 1, wherein the drive loop comprises:

a phase-locked loop frequency multiplier circuit PLL; and the mass block end of the MEMS gyroscope is connected with a mass block carrier signal STR output by a PLL frequency multiplier circuit PLL.

3. The MEMS gyroscope open loop readout circuit of claim 2, wherein the drive loop further comprises: the drive circuit comprises a drive band-pass filter circuit DPGA, a drive loop amplitude control circuit DCTL, a voltage control gain circuit DVGA and a comparator circuit CMP;

the output of the driving band-pass filter circuit DPGA is respectively connected with the input of the driving loop amplitude control circuit DCTL and the input of the comparator circuit CMP; the signal output end 7 of the driving capacitor voltage conversion circuit DC2V is connected with the input ends of a driving band-pass filter circuit DPGA and an adder ADD, and the self-calibration output end 9 of the DC2V is connected with a digital processing module DPM;

the output of the voltage control gain circuit DVGA meets the input of the drive loop high-voltage control DHVD circuit;

4. The MEMS gyroscope open loop readout circuit of claim 3, wherein the phase locked loop frequency multiplier circuit PLL performs frequency locking based on the comparator output signal, the output comprising an in-phase demodulation signal CK00 and a 90 degree phase difference demodulation signal CKN 90; the demodulation signal CK00 and the demodulation signal CKN90 are connected with the input of the angular velocity and orthogonal signal demodulation DEM circuit;

the in-phase demodulation signal CK00 is also connected with the input of a quadrature compensation integral control circuit QPIC and is used for rigidity compensation quadrature demodulation;

and a mass block carrier signal STR generated by the phase-locked loop frequency multiplication circuit PLL is connected with a mass block end 5 of the MEMS gyroscope sensitive structure.

5. The MEMS gyroscope open loop readout circuit of claim 4, wherein the quadrature compensation and detection path comprises:

the detection capacitor voltage conversion circuit SC2V is connected with the voltage input end of the MEMS gyroscope sensitive structure detection end 3 which is connected with the voltage input end of the detection capacitor voltage conversion circuit SC 2V; the self-calibration output end 10 of the SC2V is connected with the digital processing module DPM;

and the quadrature compensation high-voltage control circuit QHVD is connected with the quadrature stiffness compensation end 1 of the MEMS gyroscope sensitive structure.

6. The MEMS gyroscope open loop readout circuit of claim 5, wherein the quadrature compensation and detection path further comprises: the device comprises an adder ADD, a detection band-pass filter circuit SPGA, an orthogonal compensation integral control circuit QPIC and an angular velocity and orthogonal signal demodulation circuit DEM;

the output of the quadrature compensation integration control circuit QPIC is connected to the input of the quadrature compensation high voltage control circuit QHVD and the input of the adder ADD.

7. The MEMS gyroscope open loop readout circuit of claim 6, wherein the quadrature compensation and detection path further comprises: a low-pass filter circuit SLPF and an angular velocity and quadrature signal quantization circuit SADC;

8. The MEMS gyroscope open loop readout circuit of claim 7, wherein the digital processing system comprises a temperature sensor quantization TADC, a non-volatile memory NVP, and a digital processing module DPM;

a voltage signal output by the temperature sensor VTSEN is quantized by a temperature sensor quantization circuit TADC and then is accessed to a digital processing module DPM for temperature compensation;

9. The MEMS gyroscope open loop readout circuit of claim 8, wherein: also included is a reference current bias temperature sensor REF circuit that generates a low temperature drift and a reference voltage supply to the drive loop amplitude control circuit DCTL.

10. The MEMS gyroscope open loop readout circuit of claim 9, wherein: also included is a charge pump generating circuit CPP for generating an output voltage as a high voltage power supply, a drive loop high voltage control circuit DHVD and a quadrature compensation high voltage control circuit QHVD.