A Mode-Matching ¿¿ Closed-Loop Vibratory-Gyroscope Readout Interface with a 0.004°/s/¿Hz Noise Floor over a 50Hz Band

Abstract

A mode-matching DeltaSigma closed-loop vibratory-gyroscope readout interface fabricated in a 0.35 mum CMOS process is presented. This paper describes the architecture and circuits used to exploit mode matching effectively to attain order-of-magnitude noise and power dissipation reductions over state-of-the-art implementations without sacrificing other aspects of system performance. As micromachined vibratory gyroscopes push to lower noise floors, mode matching is necessary to moderate interface power dissipation. Our design overcomes these limitations by using force feedback to achieve a stable scale factor, a well defined phase relationship, and a bandwidth well in excess of 50Hz, commensurate with the requirements of automotive and consumer applications.