高动态范围闭环电容式加速度计接口电路设计

o improve the dynamic range of accelerometers, a continuous-time based fully differential closed-loop accelerometer interface circuit is proposed in this paper. The circuit adopts chopper stabilization technique to suppress flicker noise to obtain lower noise floor, and achieves larger output swing by class AB type closed-loop output stage. The closed-loop accelerometer interface circuit is also designed to compensate the stability of the closed-loop by introducing a PID (proportional-integral-derivative) frequency compensation circuit, which shortens the response time of the closed-loop interface circuit and reduces the static error to improve the stabHigh dynamic range closed-loop capacitive accelerometer interface circuit designility of the closed-loop. The interface circuit is designed and implemented using SMIC 180nm BCD process. The simulation results show that the closed-loop system has a bandwidth of 250Hz, a range of ±25g, an output dynamic range of about 126dB in the frequency range of 1~250Hz, and a nonlinearity of about 0.092%.