A CMOS readout circuit for LTPS-TFT capacitive fingerprint sensor

In this paper, a CMOS readout circuit for capacitive fingerprint sensor fabricated by using low temperature polycrystalline silicon thin-film transistor (LTPS-TFT) process is presented. Based on capacitive fingerprint sensing, the readout circuit grabs the induced capacitance by the finger directly touched on the sensor chip. An experimental readout chip is designed for sensor array size of 30 x 30, and implemented by using a standard CMOS process. A prototype PCB is used to integrate the readout chip and sensor chip to achieve a fingerprint acquisition system.