Analysis and design of Gyro-drive mode loop with amplitude control

This paper presents the system architecture of a primary mode oscillation loop of a MEMS GYRO interface. The loop is designed using an all digital PLL acting as a frequency selective gain element in the positive feedback oscillation loop. An amplitude control negative feedback loop is implemented to maintain the stability of oscillation amplitude and consequently the output reading scale factor. A new methodology for modelling the Gyro sensing element in the context of the amplitude loop is presented. System analysis based on this model is presented and verified by simulation.