JSSC 2013第1期Other0.18μm

A Interface for MEMS Accelerometers Using Electrostatic Spring Constant Modulati

提出一种基于力反馈闭环的MEMS加速度计接口，通过静电弹簧常数调制降低寄生电容不对称引起的偏移。

0.18μm CMOS, 3V供电, 3.1mW功耗, 220μg/√Hz噪声密度, 200Hz信号带宽

MEMS加速度计力反馈闭环静电弹簧调制偏移消除CMOS接口电路

▸采用力反馈闭环设计降低偏移及其漂移

▸通过静电调制弹簧常数实现偏移补偿

▸集成偏移消除环路显著提升精度

Abstract

This paper presents a closed-loop accelerometer inter- face based on a force-feedback loop. The interface reduces the offset, and its drift, arising from asymmetry in the parasitic capaci- tances of the bondwires connecting the CMOS interface IC and the MEMS sensor element. This is achieved by modulating the spring c o n s t a n to ft h es e n s o re l e c t r o s t a tically and continuously measuring and nulling the offset via an offse t cancellation loop. In a bondwire deformation experiment,