Quadrature error closed-loop compensating circuit for vibrating type silicon micromechanical gyroscope

Abstract

The invention discloses a quadrature error closed-loop compensating circuit for a vibrating type silicon micromechanical gyroscope. A gyroscope detection signal enters a synchronous demodulation circuit by diving into two parts after being amplified and filtered: one part of gyroscope detection signal is demodulated through reference signals generated by a phase-locked loop, and after low-pass filtering is performed, an angular velocity signal is obtained; the other part of the gyroscope detection signal is demodulated through the reference signals, which is subjected to phase displacement for 90 degrees, and generated by the phase-locked loop, after low-pass filtering is performed, the voltage amplitude of quadrature error signals in the detection signal is extracted out, and a feedback control voltage is obtained through an integrating circuit; the feedback control voltage passes through a single-double switching circuit and is modulated to the driving frequency through a driving detection capacitance so as to generate a feedback current to compensate quadrature displacement current in the detection shaft direction, and then quadrature error amount in the detection signal is eliminated and finally, the pure angular velocity is obtained. According to the invention, the quadrature error amount in an angular velocity detection loop is eliminated by using the feedback current to compensate the quadrature displacement current in the detection shaft direction of the micromechanical gyroscope, and high-precision closed-loop compensating for the quadrature error of the vibrating type silicon micromechanical gyroscope is achieved.

Description

technical field [0001] The invention relates to a silicon micromachine gyroscope quadrature error elimination circuit, which belongs to the technical field of analog integrated circuits. Background technique [0002] In actual production, due to the imperfection of the micro-machining technology for processing micro-mechanical gyroscopes, errors will be brought to micro-gyroscopes, mainly including coupling errors caused by mismatching of driving capacitors, and orthogonality caused by non-perpendicular driving and detection axes. Errors, etc. Among them, the quadrature error is the main error source of the micromachined gyroscope signal detection. It has the same frequency as the angular velocity envelope signal and a phase difference of 90 degrees. It is difficult to filter it out for general operational amplifiers or filters, and its magnitude It will directly affect the zero output and temperature drift of the gyroscope. Therefore, in order to improve the performance of...

AI Technical Summary

Problems solved by technology

However, due to the precision limitation of the phase shifting circuit in the existing analog integrated circuit and the influence of the output drift of the electronic components in the circuit, the phase shifting angle usually changes

Therefore, when using the traditional synchronous demodulation method, there is still a large amount of quadrature error residual in the output result

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