Design Of Low Noise Interface Circuit Of Micro Disk Resonator Gyroscope

With the advantages of high symmetry and high reliability,the micro disk resonator gyroscope(DRG)is one of the most promising fields for the development of high-performance micro gyroscopes.As the first step of micro gyroscope signal detection,the interface circuit’s performance will directly affect the measurement accuracy of micro gyroscope,so it is necessary to study the circuit noise and anti-interference performance,and design an appropriate interface circuit for micro gyroscope.This paper is based on the self-developed capacitive detection DRG in the laboratory,and completes the design and implementation of its interface circuit.The main tasks are as follows:Firstly,the structural advantages and working principle of DRG are introduced,and then the conversion relationship between mechanical parameters and electrical parameters is explained in detail through dynamic analysis.The working mode and main performance parameters are determined by finite element simulation,and electrical modeling and simulation analysis are completed based on these parameters.Based on theoretical analysis and modeling,the generation principle and influence of feed-through effect on DRG prepared by SOI tablets were studied.In addition,various feed-through cancellation schemes are analyzed and compared.The reverse phase cancellation method and the difference method are respectively applied to drive and sense modes to suppress the feed-through.The results show that the scheme can effectively eliminate the influence of signal feed on capacitance detection,and the resonance peak height can be increased by about 25 times.Then,based on the principle of micro-capacitance detection,the different structures of the weak signal readout circuit are introduced and compared,the performance parameters of the DRG are used to determine the design index,and the noise calculation and simulation are carried out for the cross resistance amplifier,the charge amplifier and their optimized structures.Combined with the DRG theoretical model,the structure and parameters of the readout circuit were determined,and the power spectral density of the output voltage noise was measured to be less than 178 n V/√Hz,and the optimal capacitive resolution was up to 0.001 a F/√Hz.Finally,on the basis of calculation,simulation analysis and test,the overall structure of the interface circuit was designed,and the device selection and printed circuit board(PCB)design were carried out to realize the complete interface circuit.The interface circuit designed in this paper was used to test the performance of DRG,and the resonant frequency was59.7k Hz and the Q value was 12710.