New Stability Method of a Multirate Controller for a Three-Axis High- $Q$ MEMS Accelerometer With Simultaneous Electrostatic Damping

Over the past years, cutting-edge advances in electronics and microfabrication have allowed the integration of multiple sensors within integrated analog and digital circuits to design microelectromechanical systems. The multiple sensor integration or sensor fusion enables both cost and surface reduction, while maintaining high performances. This paper presents a new control system for an underdamped three-axis accelerometer, which allows the co-integration in the same cavity with a threeaxis Coriolis gyroscope to design a six degrees-of-freedom combo sensor. The accelerometer analog front end consumes 300 μA from a 1.6V power supply and is able to reach its steady state in 800 μs compared with a 400ms open loop and no damping configuration. The transducer control is implemented using a simultaneous multirate electrostatic damping method. To conclude on the closed-loop system stability, an innovative approach based on the multirate signal processing theory has been developed.