A method to reduce harmonic distortion of MEMS accelerometer

摘要

This paper recommends a method to reduce harmonic distortion of MEMS accelerometer. The fifth-order MEMS accelerometer interface circuit designed in this work used the Cascade-of-Integrators, Feedforward modulation structure. This paper analyzes and calculates the main sources of HD, the unstable problem brought by the vacuum encapsulation sensitive structure. The use of front-phase compensation and the increase in loop forward gain helps ensure the system's stability as well as reduce the system harmonic distortion. Simulink is used to get the simulation results. After harmonic optimization, the third harmonic reached -141.83 dB, the Signal-to-Noise-and-Distortion-Ratio rose to 118.1 dB, the noise density is under 200 ng/Hz(1/2), the effective number of bits rose up to 19.33 bits.