Design of High-SNR CMOS Interface Circuit for Micro-Machined Gyroscope

Abstract

A CMOS integrated interface circuit for micro-machined gyroscope containing a novel front-end and 6th-order Sigma-delta modulator is presented in this paper. To reduce the noise coming from the sensor and circuit, the front-end is accomplished by a switched-capacitor architecture, which constructed by a high-gain fully-differential amplifier and improved by chopper-stabilization technique, and work under a designed charging and sampling logic scheme. A cascade 6th-order Sigma-Delta modulator is designed to get high resolution, reduce quantized error and suppress the instability brought by high-order modulator. With the cascade structure and 16-bit resolution 32 OSR, the modulator outputs 3-bits digital stream. The whole circuit is designed with AMS technique and 3.3V power consumption. The simulation result presents that the interface circuit performs a appointed under a low-noise design specification in signal band, and the SNR of the circuit achieves remarkable value of 106dB.