Feedthrough Compensation for Force-Feedback Controlled Piezoelectric MEMS Microphones

Electrical feedthrough describes the parasitic coupling of the control signal on the sensor output in a closed-loop control system and might lead to instabilities. For the case of a piezoelectric MEMS microphone featuring a fully clamped corrugated membrane and a sophisticated electrode design we derive and validate an equivalent circuit model of the whole electro-mechanical system, which enables to identify potential solutions for feedback compensation to set-up a stable control scheme. We show that by combining dedicated design of the transducer as well as of the control scheme stable control can be achieved.