System-level simulation and implementation for a high Q capacitive accelerometer with PD feedback compensation

Abstract

Based on the challenge of high-Q capacitive accelerometer, the analysis of the structure and the dynamic response of an all-silicon sandwich accelerometer are conducted. An analog closed-loop interface circuit based on proportional-differential feedback compensation is designed and simulated by SIMULINK/SIMSCAPE in order to stabilize the sensor and increase the closed-loop damping. Based on the design, a printed circuit board level circuit and an ASIC circuit are made for the test. Simulation and measurement are provided to support the design. Measurement results show that the circuit effectively improves the dynamic response time of the system. The accelerometer with ASIC circuit has the scale factor of 0.9976 V/g and the second order non-linearity of −400 ppm g/g 2 in the range of ±1 g, the average noise floor is 2 μg/√Hz (0–200 Hz).