阅读说明：本技术 微型陀螺仪接口电路 (Micro gyroscope interface circuit ) 是由 张卫平 刘敏茜 谷留涛 王子杰 于 2021-07-22 设计创作，主要内容包括：本发明提供了一种微型陀螺仪接口电路,差分驱动模块的输入端连接网络分析仪,差分驱动模块的第一输出端连接第一反相馈通取消模块的输入端,差分驱动模块的第二输出端连接第二反相馈通取消模块的输入端；第一反相馈通取消模块的输出端连接差分检测模块的第一输入端,第二反相馈通取消模块的输出端连接差分检测模块的第二输入端；差分检测模块的输出端连接滤波器的输入端,滤波器的输出端连接驱动器的输入端,驱动器的输出端连接网络分析仪。本发明无需制备两个高度对称的MEMS谐振器,实现了馈通信号的自消除,在不降低驱动力的情况下将馈通信号完全取消,可以大幅提升测量信号的稳定性与准确度。(The invention provides a micro gyroscope interface circuit, wherein the input end of a differential driving module is connected with a network analyzer, the first output end of the differential driving module is connected with the input end of a first reverse-phase feed-through cancelling module, and the second output end of the differential driving module is connected with the input end of a second reverse-phase feed-through cancelling module; the output end of the first reverse-phase feed-through cancellation module is connected with the first input end of the differential detection module, and the output end of the second reverse-phase feed-through cancellation module is connected with the second input end of the differential detection module; the output end of the differential detection module is connected with the input end of the filter, the output end of the filter is connected with the input end of the driver, and the output end of the driver is connected with the network analyzer. According to the invention, two MEMS resonators with high symmetry are not required to be prepared, self elimination of feed-through signals is realized, the feed-through signals are completely cancelled under the condition of not reducing the driving force, and the stability and accuracy of the measurement signals can be greatly improved.)

1. The micro gyroscope interface circuit is characterized by comprising a differential driving module (1), a differential detection module (2), a first reversed-phase feed-through cancellation module (3), a second reversed-phase feed-through cancellation module (4), a filter (11) and a driver (12);

the input end of the differential driving module (1) is connected with a network analyzer, the first output end of the differential driving module (1) is connected with the input end of the first inverted feedthrough cancellation module (3), and the second output end of the differential driving module (1) is connected with the input end of the second inverted feedthrough cancellation module (4);

the output end of the first inverted feed-through cancellation module (3) is connected with the first input end of the differential detection module (2), and the output end of the second inverted feed-through cancellation module (4) is connected with the second input end of the differential detection module (2);

the output end of the differential detection module (2) is connected with the input end of the filter (11), the output end of the filter (11) is connected with the input end of the driver (12), and the output end of the driver (12) is connected with the network analyzer.

2. The micro-gyroscope interface circuit according to claim 1, characterized in that the differential drive module (1) comprises a low-pass filter (5) and a single-ended to differential circuit (6);

the input end of the low-pass filter (5) is used as the input end of the differential driving module (1), and the output end of the low-pass filter (5) is connected with the input end of the single-ended-to-differential circuit (6);

and a first output end of the single-end to differential circuit (6) is used as a first output end of the differential driving module (1), and a second output end of the single-end to differential circuit (6) is used as a second output end of the differential driving module (1).

3. The microgyroscope interface circuit according to claim 1, characterized in that the differential detection module (2) comprises a first transimpedance amplifier (201), a second transimpedance amplifier (202), a third transimpedance amplifier (203), a fourth transimpedance amplifier (204) and a third inverting amplifier (9);

the input end of the first transimpedance amplifier (201) is used as the first input end of the differential detection module (2), and the output end of the first transimpedance amplifier (201) is connected with the input end of the second transimpedance amplifier (202);

the output end of the second transimpedance amplifier (202) is connected with the negative phase input end of the third inverting amplifier (9);

the input end of the third transimpedance amplifier (203) is used as the second input end of the differential detection module (2), and the output end of the third transimpedance amplifier (203) is connected with the input end of the fourth transimpedance amplifier (204);

the output end of the fourth transimpedance amplifier (204) is connected with the non-inverting input end of the third inverting amplifier (9);

and the output end of the third inverting amplifier (9) is used as the output end of the differential detection module (2).

4. The microgyroscope interface circuit as claimed in claim 3, characterized in that the first transimpedance amplifier (201) comprises a third capacitance C3, a fourth resistance RL4 and a fourth inverting amplifier (10);

the negative phase input end of the fourth inverting amplifier (10) is used as the first input end of the differential detection module (2), and the negative phase input end of the fourth inverting amplifier (10) is respectively connected with one end of the third capacitor C3 and one end of the fourth resistor RL 4;

the other end of the third capacitor C3 and the other end of the fourth resistor RL4 are both connected with the output end of the fourth inverting amplifier (10);

the non-inverting input end of the fourth inverting amplifier (10) is grounded.

5. The micro gyroscope interface circuit according to claim 3, further comprising a third resistor RL3, wherein one end of the third resistor RL3 is connected to the negative input terminal of the third inverting amplifier (9), and the other end of the third resistor RL3 is connected to the output terminal of the third inverting amplifier (9).

6. The microgyroscope interface circuit as claimed in claim 3, further comprising a fourth capacitor C4 and a fifth resistor RL 5;

the output end of the first transimpedance amplifier (201) is connected with one end of the fourth capacitor C4, the other end of the fourth capacitor C4 is connected with one end of the fifth resistor RL5, and the other end of the fifth resistor RL5 is connected with the input end of the second transimpedance amplifier (202).

7. The microgyroscope interface circuit as claimed in claim 1, characterized in that the first inverting feedthrough cancellation block (3) comprises a first resistor RL1, a first adjustable resistor R1 and a first inverting amplifier (7);

one end of the first resistor RL1 is used as the input end of the first inverted feed-through cancellation module (3), and the other end of the first resistor RL1 is respectively connected with one end of the first adjustable resistor R1 and the negative phase input end of the first inverted amplifier (7);

the other end of the first adjustable resistor R1 is connected with the output end of the first inverting amplifier (7);

the non-inverting input end of the first inverting amplifier (7) is grounded, and the output end of the first inverting amplifier (7) is used as the output end of the first inverting feed-through cancellation module (3).

8. The micro gyroscope interface circuit according to claim 7, further comprising a first capacitor C1, wherein one end of the first capacitor C1 is connected to the output terminal of the first inverting amplifier (7), and the other end of the first capacitor C1 is used as the output terminal of the first inverting feed-through cancellation module (3).

9. The microgyroscope interface circuit as claimed in claim 1, characterized in that the second inverting feedthrough cancellation block (4) comprises a second resistor RL2, a second adjustable resistor R2 and a second inverting amplifier (8);

one end of the second resistor RL2 is used as the input end of the second inverted feed-through cancellation module (4), and the other end of the second resistor RL2 is respectively connected with one end of the second adjustable resistor R2 and the negative phase input end of the second inverted amplifier (8);

the other end of the second adjustable resistor R2 is connected with the output end of the second inverting amplifier (8);

the non-inverting input end of the second inverting amplifier (8) is grounded, and the output end of the second inverting amplifier (8) is used as the output end of the second inverting feed-through cancellation module (4).

10. The micro-gyroscope interface circuit according to claim 9, further comprising a second capacitor C2, wherein one end of the second capacitor C2 is connected to the output terminal of the second inverting amplifier (8), and the other end of the second capacitor C2 is used as the output terminal of the second inverting feed-through cancellation module (4).

Technical Field

The invention relates to the technical field of micro-electro-mechanical systems, in particular to a micro-gyroscope interface circuit, and particularly relates to a fully-differential gyroscope interface circuit combined with an inverted feedthrough elimination circuit.

Background

The gyroscope is an inertial device capable of detecting the angle or angular velocity of a carrier, and plays a very important role in the fields of attitude control, navigation positioning and the like. With the development of national defense science and technology and the aviation and aerospace industries, the requirements of the inertial navigation system on the gyroscope are also developed in the direction of low cost, small volume, high precision, multi-axis detection, high reliability and adaptability to various severe environments. Thus, the importance of MEMS micro-gyroscopes is self evident.

For the measurement and control field of micro-gyroscopes, the direct coupling interference between input signals and output signals, which is generated due to parasitic effects, especially parasitic capacitance, is called feed-through effect. When the micro gyroscope is tested, the coupling interference enables the micro gyroscope to have output with the same frequency as an input signal under the condition of no oscillation, so that the test result of the micro gyroscope is interfered. Under the effect of feed-through capacitance, there can be great direct coupling between input drive signal and the output detection signal, this can lead to little gyroscope to have a great zero offset, and the amplitude-frequency and the phase-frequency curve of drive mode can distort, produces a parallel resonance peak, leads to there being certain deviation between resonant frequency and the Q value that the test obtained and its actual value to can't reflect the true performance of device, when this kind of deviation is too big, little gyroscope will can't test. Therefore, a new micro gyroscope feed-through cancellation method is urgently needed to be provided, so that the above influence factors are avoided or reduced, and the detection sensitivity and accuracy are improved.

Patent document CN104821800A discloses a MEMS piezoelectric resonator for reducing the influence of feed-through capacitance, which includes a differential input/output structure and two MEMS piezoelectric resonance units; the MEMS piezoelectric resonance unit is characterized in that a cavity is etched on the silicon substrate and the silicon dioxide insulating layer at the position corresponding to the vibrating block and the supporting beam in one of the two MEMS piezoelectric resonance units, and the cavity is not formed in the other one of the two MEMS piezoelectric resonance units. However, the patent document requires two highly symmetrical MEMS resonators to generate equal feed-through current amount, the process is complicated, and the symmetry of the micro gyroscope cannot reach an ideal state due to errors in the process, structure, environment and the like, and the effect of the method depends heavily on the symmetry of the device, and cannot achieve the effect of completely canceling feed-through when the symmetry is poor.

Disclosure of Invention

In view of the defects in the prior art, the present invention provides a micro gyroscope interface circuit.

The invention provides a micro gyroscope interface circuit, which comprises a differential driving module, a differential detection module, a first reversed-phase feed-through cancellation module, a second reversed-phase feed-through cancellation module, a filter and a driver, wherein the differential driving module is used for driving a first signal to be fed back to the first reversed-phase feed-through cancellation module;

the input end of the differential driving module is connected with a network analyzer, the first output end of the differential driving module is connected with the input end of the first inverted feedthrough cancellation module, and the second output end of the differential driving module is connected with the input end of the second inverted feedthrough cancellation module;

the output end of the first reverse-phase feed-through cancellation module is connected with the first input end of the differential detection module, and the output end of the second reverse-phase feed-through cancellation module is connected with the second input end of the differential detection module;

the output end of the differential detection module is connected with the input end of the filter, the output end of the filter is connected with the input end of the driver, and the output end of the driver is connected with the network analyzer.

Preferably, the differential driving module comprises a low-pass filter and a single-end-to-differential circuit;

the input end of the low-pass filter is used as the input end of the differential driving module, and the output end of the low-pass filter is connected with the input end of the single-ended-to-differential circuit;

a first output end of the single-end to differential circuit is used as a first output end of the differential driving module, and a second output end of the single-end to differential circuit is used as a second output end of the differential driving module.

Preferably, the differential detection module includes a first transimpedance amplifier, a second transimpedance amplifier, a third transimpedance amplifier, and a fourth transimpedance amplifier;

the input end of the first transimpedance amplifier is used as the first input end of the differential detection module, and the output end of the first transimpedance amplifier is connected with the input end of the second transimpedance amplifier;

the output end of the second transimpedance amplifier is connected with the negative phase input end of the third inverting amplifier;

the input end of the third transimpedance amplifier is used as the second input end of the differential detection module, and the output end of the third transimpedance amplifier is connected with the input end of the fourth transimpedance amplifier;

the output end of the fourth transimpedance amplifier is connected with the non-inverting input end of the third inverting amplifier;

and the output end of the third inverting amplifier is used as the output end of the differential detection module.

Preferably, the first transimpedance amplifier comprises a third capacitor C3, a fourth resistor RL4 and a fourth inverting amplifier;

a negative phase input end of the fourth inverting amplifier is used as a first input end of the differential detection module, and the negative phase input end of the fourth inverting amplifier is respectively connected with one end of the third capacitor and one end of the fourth resistor RL 4;

the other end of the third capacitor and the other end of the fourth resistor RL4 are both connected with the output end of the fourth inverting amplifier;

and the non-inverting input end of the fourth inverting amplifier is grounded.

Preferably, the inverter further comprises a third resistor RL3, one end of the third resistor RL3 is connected to the negative phase input end of the third inverting amplifier, and the other end of the third resistor RL3 is connected to the output end of the third inverting amplifier.

Preferably, the capacitor further comprises a fourth capacitor C4 and a fifth resistor RL 5;

the output end of the first transimpedance amplifier is connected with one end of the fourth capacitor C4, the other end of the fourth capacitor C4 is connected with one end of the fifth resistor RL5, and the other end of the fifth resistor RL5 is connected with the input end of the second transimpedance amplifier.

Preferably, the first inverting feedthrough cancellation module comprises a first resistor RL1, a first adjustable resistor R1 and a first inverting amplifier;

one end of the first resistor RL1 is used as an input end of the first inverting feed-through cancellation module, and the other end of the first resistor RL1 is respectively connected with one end of the first adjustable resistor R1 and a negative phase input end of the first inverting amplifier;

the other end of the first adjustable resistor R1 is connected with the output end of the first inverting amplifier;

the non-inverting input end of the first inverting amplifier is grounded, and the output end of the first inverting amplifier is used as the output end of the first inverting feed-through cancellation module.

Preferably, the electronic device further comprises a first capacitor C1, one end of the first capacitor C1 is connected to the output terminal of the first inverting amplifier, and the other end of the first capacitor C1 is used as the output terminal of the first inverting feed-through cancellation module.

Preferably, the second inverting feedthrough cancellation module comprises a second resistor RL2, a second adjustable resistor R2 and a second inverting amplifier;

one end of the second resistor RL2 is used as the input end of the second inverting feed-through cancellation module, and the other end of the second resistor RL2 is respectively connected with one end of the second adjustable resistor R2 and the negative phase input end of the second inverting amplifier;

the other end of the second adjustable resistor R2 is connected with the output end of the second inverting amplifier;

the non-inverting input end of the second inverting amplifier is grounded, and the output end of the second inverting amplifier is used as the output end of the second inverting feed-through cancellation module.

Preferably, the electronic device further comprises a second capacitor C2, one end of the second capacitor C2 is connected to the output terminal of the second inverting amplifier, and the other end of the second capacitor C2 is used as the output terminal of the second inverting feed-through cancellation module.

Compared with the prior art, the invention has the following beneficial effects:

1. the pre-low-pass filter can smooth the stepped waveform output by the DAC, and reduces the influence of higher harmonics on signals;

2. the invention realizes differential drive and differential detection on the circuit level for the amplitude of a single resonator, and the structure not only can enhance the strength of a detection signal, but also can achieve the effect of reducing feed-through capacitance signal interference between a drive electrode and a detection electrode without preparing two highly symmetrical MEMS resonators;

3. the fully differential structure design of the invention also makes the frequency component of the output signal more single, and makes the detection of the output signal and the design of the closed-loop control circuit easier;

4. the reverse phase feed-through elimination circuit designed by the invention does not depend on the symmetry of devices, has adjustable cancellation effect, is suitable for micro gyroscopes with different parameters, can completely eliminate feed-through by combining with a fully differential circuit, and greatly improves the stability and accuracy of measurement signals.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic diagram of a micro gyroscope interface circuit of the present invention;

FIG. 2 is a schematic diagram of an inverted feedthrough cancellation circuit according to an embodiment of the invention.

The figure shows schematically:

differential drive module 1 low-pass filter 5

Differential detection module 2 single-end-to-differential circuit 6

First transimpedance amplifier 201 first inverting amplifier 7

Second transimpedance Amplifier 202 second inverting Amplifier 8

Third transimpedance Amplifier 203 the third inverting Amplifier 9

Fourth transimpedance Amplifier 204 fourth inverting Amplifier 10

First inverted feedthrough cancellation block 3 filter 11

Second inverted feedthrough cancellation module 4 driver 12

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.

As shown in FIG. 1, the micro gyroscope interface circuit provided by the present invention includes a differential driving module 1, a differential detecting module 2, a first inverted feedthrough cancellation module 3, a second inverted feedthrough cancellation module 4, a filter 11 and a driver 12, wherein an input terminal of the differential driving module 1 is connected to a network analyzer, a first output terminal of the differential driving module 1 is connected to an input terminal of the first inverted feedthrough cancellation module 3, a second output terminal of the differential driving module 1 is connected to an input terminal of the second inverted feedthrough cancellation module 4, an output terminal of the first inverted feedthrough cancellation module 3 is connected to a first input terminal of the differential detecting module 2, an output terminal of the second inverted feedthrough cancellation module 4 is connected to a second input terminal of the differential detecting module 2, an output terminal of the differential detecting module 2 is connected to an input terminal of the filter 11, an output terminal of the filter 11 is connected to an input terminal of the driver 12, the output of the driver 12 is connected to a network analyzer.

The differential driving module 1 comprises a low-pass filter 5 and a single-end to differential circuit 6, an input end of the low-pass filter 5 is used as an input end of the differential driving module 1, an output end of the low-pass filter 5 is connected with an input end of the single-end to differential circuit 6, a first output end of the single-end to differential circuit 6 is used as a first output end of the differential driving module 1, and a second output end of the single-end to differential circuit 6 is used as a second output end of the differential driving module 1. The differential detection module 2 includes a first transimpedance amplifier 201, a second transimpedance amplifier 202, a third transimpedance amplifier 203, and a fourth transimpedance amplifier 204, an input end of the first transimpedance amplifier 201 serves as a first input end of the differential detection module 2, an output end of the first transimpedance amplifier 201 is connected to an input end of the second transimpedance amplifier 202, an output end of the second transimpedance amplifier 202 is connected to a negative phase input end of a third inverting amplifier 9, an input end of the third transimpedance amplifier 203 serves as a second input end of the differential detection module 2, an output end of the third transimpedance amplifier 203 is connected to an input end of the fourth transimpedance amplifier 204, an output end of the fourth transimpedance amplifier 204 is connected to a positive phase input end of the third inverting amplifier 9, and an output end of the third inverting amplifier 9 serves as an output end of the differential detection module 2.

The first transimpedance amplifier 201 includes a third capacitor C3, a fourth resistor RL4 and a fourth inverting amplifier 10, a negative phase input terminal of the fourth inverting amplifier 10 is used as a first input terminal of the differential detection module 2, a negative phase input terminal of the fourth inverting amplifier 10 is respectively connected to one end of the third capacitor C3 and one end of the fourth resistor RL4, the other end of the third capacitor C3 and the other end of the fourth resistor RL4 are both connected to an output terminal of the fourth inverting amplifier 10, and a positive phase input terminal of the fourth inverting amplifier 10 is grounded. In a preferred embodiment, the first transimpedance amplifier 201 includes a third capacitor C3, a fourth resistor RL4, and the fourth inverting amplifier 10, which have the same circuit structure, and the output terminals of the first transimpedance amplifier and the fourth inverting amplifier are connected in sequence with the capacitors and the resistors.

The amplifier further comprises a third resistor RL3, one end of the third resistor RL3 is connected with the negative phase input end of the third inverting amplifier 9, the other end of the third resistor RL3 is connected with the output end of the third inverting amplifier 9, the amplifier further comprises a fourth capacitor C4 and a fifth resistor RL5, the output end of the first transimpedance amplifier 201 is connected with one end of the fourth capacitor C4, the other end of the fourth capacitor C4 is connected with one end of the fifth resistor RL5, and the other end of the fifth resistor RL5 is connected with the input end of the second transimpedance amplifier 202.

The first inverting feed-through cancellation module 3 comprises a first resistor RL1, a first adjustable resistor R1 and a first inverting amplifier 7, wherein one end of the first resistor RL1 serves as an input end of the first inverting feed-through cancellation module 3, the other end of the first resistor RL1 is respectively connected with one end of the first adjustable resistor R1 and a negative phase input end of the first inverting amplifier 7, the other end of the first adjustable resistor R1 is connected with an output end of the first inverting amplifier 7, a positive phase input end of the first inverting amplifier 7 is grounded, and an output end of the first inverting amplifier 7 serves as an output end of the first inverting feed-through cancellation module 3. The first capacitor C1 is further included, one end of the first capacitor C1 is connected to the output terminal of the first inverting amplifier 7, and the other end of the first capacitor C1 is used as the output terminal of the first inverting feed-through cancellation module 3.

The second inverting feed-through cancellation module 4 includes a second resistor RL2, a second adjustable resistor R2, and a second inverting amplifier 8, wherein one end of the second resistor RL2 serves as an input terminal of the second inverting feed-through cancellation module 4, the other end of the second resistor RL2 is respectively connected to one end of the second adjustable resistor R2 and a negative-phase input terminal of the second inverting amplifier 8, the other end of the second adjustable resistor R2 is connected to an output terminal of the second inverting amplifier 8, a positive-phase input terminal of the second inverting amplifier 8 is grounded, and an output terminal of the second inverting amplifier 8 serves as an output terminal of the second inverting feed-through cancellation module 4. And the second capacitor C2 is also included, one end of the second capacitor C2 is connected with the output end of the second inverting amplifier 8, and the other end of the second capacitor C2 is used as the output end of the second inverting feed-through cancellation module 4.

Example 1：

A fully-differential micro-gyroscope interface circuit incorporating an inverted feedthrough cancellation circuit, comprising: the differential drive structure, the differential detection structure, the two inverted feed-through cancellation structures, the filter and the ADC driver; wherein:

the driving signal is converted into a balanced differential signal through a differential driving structure and used for driving the micro gyroscope, a differential detection structure is used for detecting the differential signal generated by the micro gyroscope and subtracting the signals of the differential signal, two reverse feed-through cancellation structures are respectively connected between two groups of driving electrodes and detection electrodes, the error caused by asymmetry of a differential circuit is adjusted, and the feed-through signal is completely eliminated; the signal is passed through band-pass filter to eliminate clutter, and is finally passed through ADC driver and is outputted to subsequent digital signal processing module.

The signal input end of the differential driving structure adopts a low-pass filter, so that the stepped waveform formed by the DAC can be smoothed, and the influence of high-order noise on the signal is eliminated. The differential driving structure adopts a single-end-to-differential circuit structure and optimized parameters, so that the symmetry of differential output is improved. The differential detection circuit adopts a trans-impedance amplifier to convert a capacitance signal of the micro gyroscope into a voltage signal, and adopts an instrument amplifier structure to subtract the differential signal, so that common-mode errors and feed-through signals are eliminated, and the common-mode rejection ratio and the signal-to-noise ratio are improved. The inverted feed-through cancellation circuit inverts the driving voltage by using an inverting amplifier with adjustable amplification factor and then connects a compensation capacitor used for matching the feed-through capacitor in series.

Example 2:

as shown in fig. 1, in the fully differential micro-gyroscope interface circuit combined with the inverted feedthrough cancellation circuit in the first embodiment of the present invention, a driving signal is converted into a balanced differential signal through a differential driving structure for driving the micro-gyroscope, a differential detection structure detects the differential signal generated by the micro-gyroscope and performs signal subtraction on the differential signal, two inverted feedthrough cancellation structures are respectively connected between two sets of driving electrodes and detection electrodes, and an error caused by asymmetry of the differential circuit is adjusted to completely cancel the feedthrough signal; the signal is passed through the filter to eliminate clutter, and finally passed through ADC driver and output to follow-up digital signal processing module.

In this example, the signal input end of the differential driving structure adopts a low-pass filter, and the stepped waveform formed by the DAC due to the bit limitation is smoothed, so that the influence of high-order clutter on the signal can be eliminated.

In this example, the differential driving structure adopts a single-ended to differential circuit structure and adopts optimized parameters, so that the symmetry of differential output is improved. The generated differential driving signal is loaded on a differential driving electrode of the micro gyroscope, the signal can be simultaneously fed through to a differential detection electrode and feed-through current is generated, and the generated feed-through current can be mutually counteracted on the detection electrode due to the good signal symmetry of the single-ended-to-differential circuit, so that the feed-through current is reduced.

In the embodiment, the differential detection circuit adopts the transimpedance amplifier to convert a capacitance signal of the micro gyroscope into a voltage signal, the instrumentation amplifier is adopted to subtract the differential detection signal and amplify the signal, and simultaneously, the rest feed-through signals on the differential detection electrode are subtracted to offset the signals.

In the embodiment, the reverse-phase feed-through cancellation circuit adopts a reverse-phase amplifier with adjustable amplification factor to perform reverse phase on the driving voltage, and then is connected in series with a compensation capacitor for matching the feed-through capacitor; schematic diagram of reverse feed-through cancellation circuit as shown in fig. 2, series RLC oscillator circuit represents an equivalent circuit model of micro-gyroscope, C connected in parallel therewith_tRepresenting a feed-through capacitor. The inverting amplifier with adjustable amplification factor is connected to a compensation capacitor C for matching the feed-through capacitor after inverting the driving voltage_tcThe generated current and the feed-through current have opposite phases and equal amplitudes, and the feed-through cancellation is realized by adding the generated current and the feed-through current.

According to the schematic diagram, the current value I output by the detection electrode during resonance is calculated:

in the formula I_mRepresenting the micro-gyroscope movement current, I_tRepresenting the feed-through current, I_tcIndicating feed-through cancellation current, v_acIs the drive signal applied to the drive electrode and s is the complex frequency. To be offset by feed-through currents, i.e. I_t＝I_tcThe method comprises the following steps:

set up R₂Is a variable resistor, the resistance of which is adjusted, in combination with a fully differential circuit, in principle completely eliminating the feedthrough. And finally, high-frequency and low-frequency noises outside the passband width are filtered by a band-pass filter, so that the signal-to-noise ratio of the circuit is improved. And the output end ADC driver outputs the output end ADC driver to a subsequent digital signal processing module.

The invention adopts a fully differential structure and an inverted feed-through cancellation structure to eliminate feed-through between an input electrode and an output electrode, compared with an interface circuit in the prior art, two MEMS resonators with high symmetry do not need to be prepared, self-elimination of feed-through signals is realized, the inverted feed-through cancellation structure compensates errors caused by symmetry in the fully differential circuit structure, the feed-through signals can be completely cancelled under the condition of not reducing driving force, and the stability and accuracy of measurement signals can be greatly improved.

Those skilled in the art will appreciate that, in addition to implementing the system and its various devices, modules, units provided by the present invention as pure computer readable program code, the system and its various devices, modules, units provided by the present invention can be fully implemented by logically programming method steps in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers and the like. Therefore, the system and various devices, modules and units thereof provided by the invention can be regarded as a hardware component, and the devices, modules and units included in the system for realizing various functions can also be regarded as structures in the hardware component; means, modules, units for performing the various functions may also be regarded as structures within both software modules and hardware components for performing the method.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.