CN111426310A - A gyro sensor module and its detection method - Google Patents

Abstract

The invention proposes a gyro sensor module and a detection method thereof, including a gyro sensor, a driving circuit and an induction circuit; the driving circuit is used to drive the gyro sensor: a feedback circuit is generated inside, so that the mass body of the gyro sensor is at a specified resonance Resonance is generated on the frequency; the induction circuit is used to detect the movement displacement and capacitance of the mass body and determine the angular velocity; the drive circuit applies power to the gyro sensor module through the drive electrode and the drive induction electrode; the induction circuit and The drive circuits all include at least one capacitance detection circuit. For the output value of the gyro sensor, the gyro sensor module that can measure the device movement detection value can also be measured without using a signal amplifier that changes the noise characteristics. The gyro sensor module is on the capacitance detection circuit. A fully differential current converter is included, which can operate at low current and high frequency, thus improving sensing efficiency and accuracy.

Description

A gyro sensor module and its detection method

technical field

The invention relates to the field of gyro sensors, in particular to a gyro sensor module and a detection method thereof.

Background technique

In recent years, a variety of sensors that can measure movement have been mounted on mobile communication devices developed. At this time, a gyro sensor measures information about the rotational force exerted by an object, and is a sensor that measures angular velocity. At present, a large number of researches have been conducted to output the slight change of the gyro sensor during the movement, and to detect the accurate movement of the device through this output value. Patent document US2007-0163815 provides a differential capacitive sensor interface circuit with an input common mode control circuit---the common mode control circuit 32, which is characterized in that, for the interface circuit input of the detection circuit, the first and second detection inputs are connected 7a, 7b, and connect the sense amplifier 12 and the first and second sense inputs 7a, 7b which are related to the capacitance unbalance (ΔCs) of the drive capacitance sensor-1 and provide the output signal (Vo), and control the first and second Detecting the common mode power on the inputs 7a and 7b, in this way, the value of the gyro sensor is amplified by the amplifier, which is convenient for the movement of the detection device. However, after the signal is amplified, the noise characteristic is deteriorated. Therefore, a precision device for improving noise quality is required. .

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the present invention provides a gyro sensor module, including a gyro sensor, a drive circuit and an induction circuit;

The drive circuit is used to drive the gyro sensor: a feedback circuit is generated inside, so that the mass body of the gyro sensor resonates at the specified resonance frequency;

The induction circuit is used to detect the displacement and capacitance of the mass body and determine the angular velocity;

The drive circuit applies power to the gyro sensor module through the drive electrode and the drive induction electrode; the induction circuit measures the angular velocity with the gyro sensor module through the induction electrode;

Both the sensing circuit and the driving circuit include at least one capacitance detection circuit.

Preferably, the capacitance detection circuit includes a charge-to-voltage conversion circuit or/and a band-pass filter.

Preferably, the charge-to-voltage conversion circuit includes a current converter or/and a modulator or/and an integrator.

Preferably, the current converter is a fully differential current converter.

Preferably, the drive circuit further comprises a comparator connected to the charge-voltage conversion circuit and a phase-locked loop, the phase-locked loop can compensate for the AC signal just generated thereon.

A measurement method of a gyro sensor module circuit, the drive circuit internally generates a feedback loop, and based on the applied power, the mass body of the gyro sensor resonates at a specified resonant frequency, and the induction circuit detects the impact on the mass body through a capacitance detection circuit. Move displacement, detect capacitance, and determine angular velocity;

The capacitance detection circuit detects the sine wave signal through the current converter, and outputs the sine wave current signal corresponding to the capacitance change;

The modulator modulates the sine wave signal output by the current converter, and integrates the modulated sine wave signal through the integrator to generate a sine voltage signal;

The integrator will accumulate and integrate the input sine and current signals, which can increase the output voltage. The sine wave voltage signal output by the integrator is in the state of noise or white signal elimination through the accumulation and integration;

The bandpass filter control controls the compensation of the sine wave voltage signal output by the integrator.

Preferably, the resonance of the mass body on the gyro sensor is generated by a cosine wave of a specified period transmitted by the driving circuit. For the situation where a rotational force is applied to the mass body, the displacement of the resonance frequency is detected in the form of the cosine wave bearing the rotational force. And the change of capacitance, at this time, the size of the cosine wave is represented by the size of the rotational force.

Preferably, the drive circuit uses a phase-locked loop to process the frequency components of the output signal through a charge-to-voltage conversion circuit or/and a comparator, and can apply a positive feedback signal based on the phase-locked loop to the mass body to resonate.

Preferably, the capacitance and/or capacitance change of the cosine wave generated by the driving circuit on the mass body is detected by the capacitance detection circuit, and the capacitance detection circuit of the induction circuit synchronizes the detection value of the driving circuit.

Preferably, the phase locking loop (33) can compensate the resonance frequency change detected on the mass body under a certain temperature and time and the phase delay occurring on the gyro sensor module circuit for the gyro sensor module, and provide a certain resonance frequency on the circuit. required clock at the frequency. .

The gyro sensor module proposed by the present invention has the following beneficial effects: for the output value of the gyro sensor, the gyro sensor module can also measure the device movement detection value without using a signal amplifier that changes noise characteristics. The work of eliminating the input capacitance at the output of the gyro sensor is the same or similar, but because the gain is not large, the undistorted current signal can be detected even if the capacitance is not eliminated. In addition, the gyro sensor module includes a fully differential current converter on the capacitance detection circuit, which can work at a low current and a high frequency, thus improving the sensing efficiency and accuracy.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments.

Fig. 1 is the module schematic diagram of the present invention;

Fig. 2 is the component block diagram of the present invention;

Fig. 3 is the output curve diagram of the charge-voltage variation circuit of the present invention with bias;

4 is a block diagram of the detailed structural elements of the capacitance detection circuit of the present invention;

5 is a graph showing the output of the integrator before eliminating the bias of the integrator in the capacitance detection circuit of the present invention;

Fig. 6 is the output curve diagram of the common mode feedback loop integrator in the capacitance detection circuit of the present invention

Among them, 100, gyro sensor module; 10, gyro sensor; 101, capacitance detection circuit; 30, drive circuit; 50, induction circuit; 201, charge-voltage conversion circuit; 203, band-pass filter; 31, comparator; 33, Phase fixed loop; 301, current converter; 303, modulator; 305, integrator.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

As shown in FIG. 3, a gyro sensor module includes a gyro sensor 10, a driving circuit 30 and a sensing circuit 50; the Coriolis effect is based on the Coriolis force generated by the mass, velocity and acceleration of an object. The gyro sensor module 100 includes a drive circuit 30 for driving the gyro sensor module 100 in order to generate the Coriolis force and a sensing circuit 50 for measuring the angular velocity output in the gyro sensor 10 and each circuit includes at least one electrode that performs an electrical function , the drive circuit includes drive electrodes (DRV_P, DRV_N) for applying power on the gyro sensor (10) and drive induction electrodes (DRVS_P, DRVS_N) for resonance displacement and measurement frequency, and the induction circuit includes a gyro sensor (10) for measuring angular velocity Sensing electrodes (SEN_P, SEN_N) dl); the sensing circuit 50 measures the angular velocity with the gyro sensor module 100 through the sensing electrodes. The drive circuit 30 is used to drive the gyro sensor 10: a feedback circuit is generated inside, so that the mass body of the gyro sensor 10 resonates at a specified resonance frequency;

Preferably, the capacitance detection circuit 101 includes a charge-to-voltage conversion circuit 201 or/and a band-pass filter 203, and the charge-to-voltage conversion circuit 201 includes a current converter 301 or/and a modulator 303 or/and an integrator 305. and/or refer to at least one, the current converter 301 is a fully differential current converter 301 . The drive circuit 30 also includes a comparator connected to the charge-to-voltage conversion circuit 201 and a phase-locked loop, which can compensate for the AC signal just generated thereon.

The capacitance detection circuit 101 uses the amount of current corresponding to the amount of capacitance change to determine the detection value, so a large voltage difference does not occur, and therefore, the signal value can be increased by increasing the frequency. The capacitance detection circuit 101 provides the voltage signal of the mass movement detection value based on the current signal, which has less influence on noise than the induction operation of detecting the voltage value, and improves the signal processing efficiency. The capacitance detection circuit 101 generates a common mode feedback loop that inputs the output value of the bandpass filter 203 into the integrator 305. Therefore, the compensation generated in the integrator 305 can be eliminated, and the output range of the integrator 305 can be set to be larger, The induction circuit 50 has the same or similar structure as the capacitance detection circuit 101 and can output a sine wave voltage signal that cancels the compensation.

The gyro sensor module 100 and its components include electronics connected to at least one processor. At this time, the functions and/or actions are performed by at least one processor included on the electronic device.

Specifically, its measurement method is:

The drive circuit 30 internally generates a feedback loop, and based on the applied power, the mass body of the gyro sensor 10 resonates at a specified resonance frequency, the induction circuit 50 detects the displacement of the mass body through the capacitance detection circuit 101, and detects the capacitance, and determine the angular velocity;

Among them, the capacitance detection circuit 101 detects the sine wave signal through the current converter 301, and outputs the sine wave current signal corresponding to the change of capacitance; the resonance of the mass body on the gyro sensor 10 is generated by the specified period cosine wave transmitted by the driving circuit 30. For When a rotational force is applied to the mass body, the displacement of the resonance frequency and the change of the capacitance are detected in the form of a cosine wave supported by the rotational force. At this time, the magnitude of the cosine wave is represented by the magnitude of the rotational force. Among them, the resonance is through: the drive circuit 30 uses the phase-locked loop to process the frequency components of the output signal through the charge-voltage conversion circuit 201 or/and the comparator, and the positive feedback signal based on the phase-locked loop can be applied to the mass body. resonate. For the gyro sensor module 100, the phase locked loop can compensate the resonance frequency change detected on the mass body under a certain temperature and time and the phase delay occurring on the circuit of the gyro sensor module 100. clock.

The detection of capacitance is to detect the capacitance and/or capacitance change of the cosine wave generated by the driving circuit 30 on the mass body through the capacitance detection circuit 101, and the capacitance detection circuit 101 of the sensing circuit 50 synchronizes the detection value of the driving circuit 30 to detect the mass body. When the capacitance changes, the driving circuit 30 or the sensing circuit 50 may adopt at least one charge-to-voltage conversion circuit 201 . At this time, the capacitance change through the mass body is very small, and the gain can be amplified in order to obtain a signal within the detectable range.

The modulator 303 modulates the sine wave signal output by the above-mentioned current converter, and integrates the modulated sine wave signal through the integrator 305 to generate a sine voltage signal;

The integrator 305 accumulates and integrates the input sine and current signals, which can increase the output voltage, and the sine wave voltage signal output on the integrator 305 is in a state of noise or white signal elimination through the accumulation and integration;

Bandpass filter 203 controls the compensation of the sine wave voltage signal output by integrator 305 . Specifically, as shown in FIG. 5 , before the compensation of the integrator 305 is controlled, the sine wave voltage signal output by the integrator 305 outputs a voltage signal with a part of the peak value removed from the sine wave voltage signal. For example, the output signal of the integrator 305 outputs a part of the highest value in the positive voltage signal, eg, a value (1-1, 1-3) greater than the drain voltage (VDD) and the lowest value in the positive voltage signal, eg, cancels The positive voltage signal and the negative voltage signal less than the source voltage (VSS) value (3-1, 3-3), through the band-pass filter 203 output the alternating current (AC) signal of the power of the integrator 305, that is, the output power is distorted. Sine wave voltage signal.

In contrast, the capacitance detection circuit 101 uses the output value of the band-pass filter 203 to control the distortion of the output value of the integrator 305 . Bandpass filter 203 passes a bandwidth of 10 kHz to 60 kHz and has a resonant frequency with a bandwidth of 30 kHz.

As shown in FIG. 4 , the capacitance detection circuit 101 feeds back the voltage signal output from the bandpass filter 203 to the integrator 305 .

The output value of the bandpass filter 203 is then input to the integrator 305 to generate a common mode feedback loop. At this time, when working for the first time, the output of the integrator 305 of the capacitance detection circuit 101 may be greatly distorted based on the compensation of the input current, but the band-pass filter 203 can make the output of the integrator 305 within VDD/2 DC ( It operates in the DC) range and outputs the alternating current (AC) signal of the integrator 305.

That is, after the first operation, the reverse output of the bandpass filter 203 is fed back as the input value of the integrator 305, so that the output signal of the integrator 305 operates within the range of VDD/2, as shown in FIG. 6 .

In order to improve the sensitivity of the gyro sensor 10, the capacitance detection circuit 101 detects the positive current output on the positive edge of the output terminal and the negative current output on the negative edge (negative edge) through the output of the chopping circuit. Therefore, noise having a 1/f pattern can be eliminated.

The gyro sensor module 100 outputs the integrator 305 power (sinusoidal current voltage signal) that cancels the compensation at the integrator 305 through the bandpass filter 203 .

According to the above content, the capacitance detection circuit 101 of the gyro sensor module 100 adopts the current converter 301 at the output end of the gyro sensor 10 .

Compared with the circuit using the charge amplifier, the capacitance detection circuit 101 has the same or similar operation of eliminating the input capacitance at the output end of the gyro sensor 10, but because the gain is not large, it can detect the undistorted current signal even if the capacitance is not eliminated. In addition, according to various embodiments, the gyro sensor module 100 includes a fully differential current converter 301 on the capacitance detection circuit 101 , which can operate at a low current and a high frequency, thereby improving sensing efficiency and accuracy.

Various modifications to the embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. a gyro sensor module, is characterized in that, comprises gyro sensor, drive circuit and induction circuit; The drive circuit is used to drive the gyro sensor: a feedback circuit is generated inside, so that the mass body of the gyro sensor resonates at the specified resonance frequency; The induction circuit is used to detect the displacement and capacitance of the mass body and determine the angular velocity; The drive circuit applies power to the gyro sensor module through the drive electrode and the drive induction electrode; the induction circuit measures the angular velocity with the gyro sensor module through the induction electrode; Both the sensing circuit and the driving circuit include at least one capacitance detection circuit. 2 . The gyro sensor module according to claim 1 , wherein the capacitance detection circuit comprises a charge-to-voltage conversion circuit or/and a band-pass filter. 3 . 3 . The gyro sensor module according to claim 2 , wherein the charge-to-voltage conversion circuit comprises a current converter or/and a modulator or/and an integrator. 4 . 4. The gyro sensor module according to claim 3, wherein the current converter is a fully differential current converter. 5 . The gyro sensor module circuit according to claim 1 , wherein the driving circuit further comprises a comparator connected with the charge-voltage conversion circuit and a phase-locked loop, the phase-locked loop can compensate for the generated AC signal. 6. A measurement method for a gyro sensor module circuit, characterized in that the drive circuit internally generates a feedback loop, and based on the applied power, the mass body of the gyro sensor resonates at a specified resonant frequency, and the induction circuit detects by capacitance The circuit detects the displacement of the mass body, detects the capacitance, and determines the angular velocity; The capacitance detection circuit detects the sine wave signal through the current converter, and outputs the sine wave current signal corresponding to the capacitance change; The modulator modulates the sine wave signal output by the current converter, and integrates the modulated sine wave signal through the integrator to generate a sine voltage signal; The integrator will accumulate and integrate the input sine and current signals, which can increase the output voltage. The sine wave voltage signal output by the integrator is in the state of noise or white signal elimination through the accumulation and integration; The bandpass filter control controls the compensation of the sine wave voltage signal output by the integrator. 7. The gyro sensor module circuit according to claim 6 is characterized in that, on the gyro sensor, the resonance of the mass body is generated by a specified period cosine wave transmitted by the drive circuit, and for the situation where a rotational force is applied on the mass body, The displacement of the resonance frequency and the change of capacitance are detected according to the form of the cosine wave supported by the rotational force. At this time, the size of the cosine wave is represented by the magnitude of the rotational force. 8. The gyro sensor module circuit according to claim 6, wherein the driving circuit adopts a phase-locked loop to process the output signal frequency components through a charge-voltage conversion circuit or/and a comparator, and can be based on a phase-locked The positive feedback signal of the loop is applied to the mass to resonate. 9 . The gyro sensor module circuit according to claim 6 , wherein the capacitance and/or capacitance change of the cosine wave generated by the driving circuit on the mass body is detected by the capacitance detection circuit, and the capacitance detection circuit of the induction circuit is driven synchronously. 10 . The detection value of the circuit. 10. gyro sensor module circuit according to claim 8, is characterized in that, phase lock loop (33) can compensate the resonant frequency change detected on mass body under certain temperature, time for gyro sensor module and in gyro sensor module The phase delay that occurs on the circuit provides the clock required at a certain resonant frequency on the circuit.

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