硅微振梁式加速度计的温度检测及闭环控制

Abstract

To measure the chip-level temperature and to achieve close-loop control for a Micro-ElectroMechanical(MEMS)resonant accelerometer system,this paper investigates non-inertial parts of the system,proposes a method to measure the temperature of the MEMS structure and optimizes the parameters in the close-loop control.Different from the traditional method that using a temperature from a temperature control cover as the conference,this paper proposes design methods of MEMS structures,processing technology and circuits,and achieves the temperature compensation by measuring the MEMS structure temperature directly to improve the temperature measuring accuracy.Furthermore,a diode pre-circuit is applied to detection of the variation of the tiny capacity instead of the transimpedance amplifier and transconductance amplifier,which reduces the requirement for high-performance components from pA to nA magnitudes.Based on the analysis in the time domain,analytical so-lution of diode pre-circuit is proposed to optimize the parameters and to guarantee the linear relationship between input and output.Moreover,a second-order optimal mode is applied to control of the settling time of the post-circuit.Experiment shows that after compensation on temperature,the MEMS resonant accelerometer has the performance of bias stability of 52.0μg,scale factor stability of 16.0×10-6,resolution of 34.9μg.The result indicates that the proposed theories can satisfy the requirements of high-performance MEMS resonant accelerometer systems.