Active Shock/Vibes Rejection in FM MEMS Accelerometers

Abstract

The work presents a novel system formed by a frequency-modulated microelectromechanical system (MEMS) accelerometer and an associated circuit which sustains the anti-phase resonant mode of the MEMS and at the same time operates an active damping of the in-phase, acceleration-sensitive, mode. Within (500x500) µm2, at noise levels in the 50 µg/√Hz range, the system recovers from large (>100 g) shocks in less than 3 ms, which is about 20 times less than in absence of active damping compensation. Additionally, it stands vibrations sweeping around the sensing mode frequency without noticeable effects.