An interface ASIC of quartz vibratory gyroscope with 0.8°/hour root Allan variance

Abstract

This paper analyzed the factor of bias drift of quartz vibratory gyroscope, proposed the method of improving bias stability of quartz vibratory gyroscope and designed an interface ASIC of quartz vibratory gyroscope. The bias instability is generated by characteristic of noise in the detecting circuit and the quantity of the driving single in the exciting circuit. We propose a sine-wave exciting circuit which has lower phase noise than the traditional exciting approach. An operational amplifier with low noise and offset voltage temperature coefficient is designed to decrease the bias instability. The interface ASIC integrated on a 5×4.4 mm2 chip with 0.5 μm CMOS process has 40mW power supply, 18nV/Hz1/2 equivalent input noise density, and 0.8°/hour root Allan variance.