Design Of Single-loop Fourth Order Digital Closed-loop Readout Circuit For Silicon Micro-gyroscope

With the rapid development of microelectronics technology and the rapidly growing popularity of digital circuits, it makes electronic devices developing towards the direction of miniaturization and digital. After gyroscope’s miniaturization, it has many advantages, as small size, light weight, low cost, can be mass production and so on, and plays an important role in everyday life, its role in the military is of great significance. With the advances in technology, requirements for the gyro’performance becomes higher. The work that further making gyro digital in order to improve the performance becomes very important. View of this situation, a new digital readout interface circuit base on Sigma-Delta modulator for micro-mechanical gyro is researched in this paper.Using of mathematical methods established an equivalent electrical model of micro-gyroscope readout mode. Analysis of the system input carrier which can get the composition of the carrier can be as a basis of follow-up simulation.A micro-machined gyroscope readout system based on Sigma-Delta Modulator technology was built by using the Matlab Simulink. Its functional verification and simulation obtained SNR80.2dB, the effective13.2bits having a good readout function. Then, using the Cadence software and CMOS0.5-micron process to circuit-level design and simulate system circuit module, and finally simulate the overall readout circuit, the SNR is78.25dB, effective12.7bits. It is similar to the system-level simulation’s result and finished its design.From theory and simulation, the feasibility of micro-machined gyroscope digital readout circuit based on Sigma-Delta Modulator technology is verified. It provides the basis and bedding for micro-machined gyroscope digital process. To further enhance the performance of the micro-machined gyroscope, it made a good theoretical research and practical work, playing an important role.