A Novel Closed-loop Drive Circuit for the Micromechined Gyroscope

The closed-loop drive circuit is widely used in high performance micromachined gyroscopes. Most of the closed-loop drive circuit includes an AGC module in order to control the amplitude of the output signal. But the AGC circuit may restrict the linear operational range of the whole circuit and limit the amplitude of the output signal, so that deteriorates sensitivity and stability of the gyroscope system. Based on the investigation of the equivalent model of the closed-loop drive system, a novel closed-loop drive circuit is presented. A comparator is applied instead of the AGC circuit, which overcomes the disadvantages of limited linear operational range and limited output signal amplitude.