Modeling Of Distribution Parameters Of Silicon Micro - Gyro Interface And Optimization Design Of Measurement And Control Circuit

Silicon microgyroscope is a kind of inertial sensors based on Coriolis Effect combining MEMS(Micro-electro-mechanical System). It can adapt to harsh environmental conditions and has a series of advantages such as, low power consumption, small size, light weight and strong anti-overload.Compared with foreign countries, domestic gyroscope’s scale factor, bias stability and circuit need to be improved. Therefore, this paper aims to optimize the circuit and improve the performance of silicon micro-gyroscope. The main contents are expressed as follows:First of all, based on the operating principle and internal structure, the equivalent model with RLC is established. The distribution parameters of gyroscope’s interface are analyzed and measured for the precise model. The system level model in Cadence contains gyro’s structure, distribution parameters and signal conditioning. With the simulation results, distribution parameters’effect on circuit is analyzed.Secondly, the driving circuit is analyzed and its model is establishes based on discrete devices in Cadence. With the system level simulation results, the optimization design is proposes:using the new interface circuit to replace the original and using auto-zero amplifier AD8629 to replace the traditional amplifier AD8642. Theory analysis and experiment results indicate that new interface’s noise spectral density within operating band is reduced to 36% of the original and AD8629’s 1/f noise is lower than AD8642’s.Thirdly, the sense and demodulation circuit is analyzed and their model is establishes based on discrete devices in Cadence. With the system level simulation results, the optimization design is proposes:using the new interface circuit to replace the original and using switch phase sensitive demodulation to replace the multiplication demodulation. It turns out that SNR, scale factor and bias stability are improved by the optimization design.Finally, we did a lot experiments to verify gyroscope’s equivalent model and the optimization design. It turns out that the relative error between Vds, Vac, bias and scale factor’s simulation and experimental results is less than 7%. With the improved circuit, gyroscope’s scale factor increases from 0.0057V/°/s to 0.0302V /°/s and the bias stability is impoved from 57.198°/hr to 7.638°/hr.