A linear capacitive sensor interface circuit with single-ended to differential output capability

In this paper we present a concept for single-ended to differential capacitive sensor interface circuit suitable for implementation in CMOS. The interface circuit converts the capacitance change of a single sensor capacitor into a differential output voltage. The main advantages of the proposed circuit are high linearity, immunity from parasitic capacitances of the sensor capacitor, and sensitivity to the capacitance change rather than the absolute capacitance.