a novel fully-differential switched capacitor chopper stabilized cascade sigma-delta modulator for mems gyroscope
This paper presents a novel design for a fully-differential switched capacitor (SC) Sigma-Delta modulator (SDM). The structure is unconditional stable based on 1-1-1 multi-stage noise shaping (MASH). A new integrator is embedded in each modulator separately. Chopper stabilization (CHS) method is used for eliminating 1/ f noise and DC offset of the OTA. This work is fabricated in a 0.35?m CMOS technology with 3.3 V supply voltage. The circuit is capable of handling signals with 56kHz bandwidth and amplitudes ranging from microvolts to hundreds of millivolts with a Dynamic Rang (DR) over 100dB. The modulator can do well for temperature processing and low frequency angle velocity signal transformation in micro-electro mechanical system (MEMS) gyroscope. The design of circuit is based on a top-down CAD methodology which combines simulation and statistical optimization at different levels of the interface hierarchy. Simulation results show 18-bit with a sampling rate of 14.336 MSamples/sec for temperature sensing control, drive mode and sense mode loop.
chs sc mems gyroscope sdm mash