Stability Analysis of Switched-capacitor Closed-loop Micro-accelerometers

This paper presents in-depth research into the system stability of switched-capacitor closed-loop micro- accelerometers. Universal method of dynamic characteristic analysis on such type of micro-accelerometer is imposed. Critical influencing factors of system stability are investigated, including the quality factor of the sensor, the force feedback delay, and the parameters of the electronic compensator. The theory is further confirmed with the design and fabrication of a prototype interface circuit in a commercial 0.35 m CMOS process. Experiment results show that elaborately-designed electronic compensator is very significant for ensuring system stability, while the measured stability border of the system matches well with the theoretic result.