Electromagnetic Capacitive Vibration-driven Micro-mechanical Gyro Interface Circuit

Name: Fu Shengrong (Microelectronics and Solid State Electronics) Directed by Prof. Yuelin WangCompared to traditional gyroscope, micro-gyroscope takes the advantage of MEMS technology and makes it possible to decrease the cost and size in several magnitudes. So it is hoped to have many applications in many fields. In this dissertation, we focused on the research of interface circuit for the vibratory gyroscope, which is driven by e electromagnetic forces and detected by capacitance.First, based on theoretical analysis, we gave the solution for the dynamic equations and got the implication for the design of interface circuit. Then we introduced the theory about electromagnetic force and capacitive detection. At last we derived its equivalent electrical analogue, which would give us much help to understand the working of the gyroscope and design the interface circuit.Second, we researched the driving-circuit and related theory. Two kinds of driving technology as forcing-driving and self-excited oscillation driving were presented. We concentrated on the self-excited oscillation technology and began with the theoretical analysis, after we put forward the scheme of the circuit, with the help of simulation tools as Spice, we implemented the circuit in form of PCB. The test result confirmed our scheme.Third, we gave the detailed analysis and simulations of a type of C-V convert ASIC. After that, we researched another key technology in the detecting-circuit: demodulation. Based on these results, we designed the detecting-circuit and implemented it in PCB form. The testing result proved that the circuit worked well in a large range of input signal with the output of 0. 5mV/?s. The advice for further work is also given.The theoretical study and experiment result is a good start for the further work.