Using pseudo electrostatic spring constant to improve the resolution of micro-machined accelerometer

作者：Xiong, Xingyin^*; Cong, Ning; Li, Zongwei; Han, Kedu

来源：Sensors and Actuators A: Physical , 2017, 265: 187-192.

DOI：10.1016/j.sna.2017.08.041

• Pseudo spring constant
• Closed-loop accelerometer
• Electrostatic force-feedback
• Sigma-delta modulator

High-resolution accelerometers have commonly used an electrostatic force-feedback sigma-delta closed loop. In order to improve the resolution of the accelerometers, high-order noise shaping filters has been used. However, it is difficult to trade off between the stability and the noise shaping ability to design high order sigma-delta closed-loop, especially with the high-Q acceleration sensors. In this paper, a pseudo electrostatic spring constant is proposed based on the electrostatic force-feedback sigma-delta closed loop accelerometer. It uses to adjust the resonant frequency of the system transfer function to achieve a lower noise level.in the signal band, and this adjustment is outside the closed-loop without influence on the stability of the closed-loop system. The concept of the pseudo electrostatic spring constant, the system analysis and simulation are presented. The integrated measurement system is implemented on the PCB. The system noise floor can achieve about 160 ngi.s/Hz after the adjustment by using the optimal pseudo electrostatic spring constant. The experimental results confirm the theoretical analysis and simulation results.

• 出版日期2017-10-1
• 单位中国科学院大学; 中国科学院地质与地球物理研究所; 中国科学院地质与地球物理研究所兰州油气资源研究中心