Design of charge amplifier for the accelerometer

In this paper, the detection circuit chose continuous time detection principle. The acceleration signal through the mechanical module transform to capacitance change. Then the signal through the sensitive charge amplifier, in-phase amplifier, synchronous demodulation circuit and low pass filter transform to a output voltage signal which is linear relationship with the acceleration signal. And the output signals through the PI controller feedback to the in-phase end of sensitive charge amplifier which realize closed-loop testing, so that the signal detection circuit has good dynamic response characteristics and eliminate static error at the same time.