A low power and low noise CMOS chopper amplifier for use in capacitive type accelerometer

摘要

This paper presents a low power, low-g and low noise accelerometer. By using chopper topology, an integrated low pass filter and zero and hold (ZOH) low pass filter, the low noise and low power are achieved. The integrated low-pass filter eliminates the chopping ripple voltage caused by the demodulation. The ZOH low pass filter provides a nulling function at chopping frequency to notch the residual voltage from the first modulator and amplifying gain to achieve greater sensor sensitivity. The circuit achieves a ±6 g dynamic range, and the simulated noise is 75 μg/rtHz with a current consumption of 11 μA.