A MEMS microphone interface with force-balancing and charge-control

This paper presents a low-power CMOS interface for a MEMS capacitive sensor. The interface has embedded force-balancing capability which improves the linearity of the readout for higher sound pressures. The interface also features a bias-charge control functionality to enhance the sensitivity of the microphone. The interface employs boot-strapped preamplifier for active parasitic capacitance compensation, followed by a 3rd-order sigma-delta modulator. The interface is designed in 0.35um CMOS technology and its brief simulation results in Cadence-Spectre are presented.