A closed-loop self-excited drive circuit for quartz gyroscope

In order to satisfy the requirement of high performance, miniaturization and integration for quartz gyroscope, design of the application-specific integrated circuit (ASIC) interface chip is the trend. In this paper, it is derived that a square wave drive mode is the tradeoff of system performance and complexity based on the analysis of electrical and mechanical characteristics of the element. A closed-loop self-excited drive circuit is designed based on the above conclusion. This circuit together with the quartz element comprise the closed-loop that achieves the self-excited oscillation, and an automatic gain control module maintains the stability of the vibration amplitude. The closed-loop self-excited drive circuit is realized in a 0.5 μm CMOS process. The test results show that the designed circuit accomplishes a drive signal with stable amplitude and frequency, with the amplitude stability of 0.01%. The performance of the quartz gyroscope integrated with this circuit can satisfy the tactical requirement.