Analysis And Design For Low Harmonic Distortion Driving Circuit Of Quartz Gyroscope

With the development of micro-electronics, miniaturization and integration are becoming major trends of systems, which promote the progress of MEMS. As one of the most important part of MEMS, micro-gyroscopes are used to measure the angular velocity of inertial systems. They have the advantages of small size, high reliability and so on. In view of widely use in military and civil affairs, micro-gyroscope becomes a research focus. However, most of the researches in this filed are still in experiment statue recently. As the most important part of micro-gyroscope, interface circuit’s performance has great effect on the system. Nowadays most of interface circuits are realized by discrete device. In order to decrease cost and size, it’s necessary to realize them by integrated circuit technology. The driving part of the interface circuit is the basic of system. Based on above, a driving circuit for micro-gyroscope will be designed.In this paper, firstly, an equivalent model of the driving mode is built by combing the operation principle with the kinetic equations of micro-gyroscope. The model establishes the foundation of the subsequent design. Then, the harmonic distortion’s effect on interface circuit is analyzed in the term of phase noise and stability of output. The next, a closed-loop driving circuit is designed in system-level and circuit-level by comparing different design methods of circuit items. After that, optimization method is been used to improve the performance of driving circuit. Finally, the layout of driving circuit is designed and relevant parasitic parameters are extracted. The simulation results of circuit-level and layout-level are compared to check up their consistency.The driving circuit is realized by CSMC 0.5μm process. When the driving circuit turns into stable statue, parameters of the driving signal are as follows. The frequency is 118259 Hz. The peak-to-peak value is 5.64 V. The jitter of frequency is 4Hz, so the degree of instability is 0.036%. After that, the THD of driving signal is 0.8%, and the THD of sensing signal is 0.245%. Those satisfy the requirements of this issue.