A CMOS integrated circuit design of charge-sharing scheme for a capacitive fingerprint sensor

Abstract

In this paper, a CMOS integrated detection circuit for capacitive type fingerprint sensor signal processing is described. We designed a detection circuit of charge-sharing sensing scheme. The proposed detection circuit increases the voltage difference between a ridge and valley. The test chip is composed of $160{\times}192$ array sensing cells (12 by $12.7{\;}mm^{2}$). The chip was fabricated on a 0.35 m standard CMOS process. Measured difference voltage between a ridge and valley was 0.95 V.