A 15.5x-gain 0.29-mm2 CMOS readout circuit for 1.5-Mpixel 60-fps CMOS image sensor

Abstract

An analog signal processing (ASP) circuit used for CMOS image sensor (CIS) readout is presented. The proposed ASP mainly includes a two-stage programmable gain amplifier (PGA), a sample-and-hold amplifier (SHA) merged by a pipelined analog–digital converter (ADC), and a digital-analog converter (DAC). Compared with conventional readout architecture, the proposed can provide finer gain, level shifting as well as offset calibrating function. A 1.5-Mpixel 60-fps CIS with the ASP is fabricated in a 0.13 μm 1P4M CMOS mixed signal process. The experiment results indicate the sensor can normally capture images without missing code. Moreover, the measured maximum gain error of the PGA is 1.6%, and the power dissipation is 16.5 mW for single ASP.