微型加速计全差分Σ-Δ接口IC

A fully-differential Sigma-delta interface IC for micro-accelerometer

主要描述一种加速度感应系统全差分Σ-ΔCMOS接口IC。电容传感器接口由一个前端可配置开关电容(SC)电荷放大器和一个末端,一阶SCΣ-Δ调制器组成。本设计采用开关双采样技术(CDS)来消减低频噪声,能有效地隔离高性能Σ-Δ调制器和MEMS传感器。采用0.35μm CMOS技术,在3.3 V电源环境下能够理想工作。仿真结果显示该设计能达到0.55 V/g的精度。

Presents a fully-differential Sigma-delta CMOS interface IC for an acceleration sensing system.The Capacitive sensor interface is composed of a front-end programmable Switched Capacitor（SC） charge amplifier that converts the acceleration signal to voltage,and a back-end first-order SC Sigma-delta modulator.Two stages of correlated-double-sampling（CDS） scheme were used in the charge amplifier to cut down the low frequency noise.This architecture decouples the MEMS sensor from the optimized-performance Sigma-delta modulator.This work is designed and implemented in a 0.35μm CMOS technology with 3.3V supply voltage.Simulation results show sensitivity of 0.55V/g is achieved in the range of ＋1g.