Pixel Sharing Based Design of High Signal-to-Noise Ratio Mixed Domain Time Delay Integration Complementary Metal Oxide Semiconductor Image Sensor

With the progress of science and technology, people have higher and higher performance requirements for image sensors. Enhancing SNR (Signal-to-Noise Ratio) has become one of the important issues in optimizing the performance of image sensors nowadays. A mixed-domain accumulation technique based on pixel-sharing TDI (Time Delay Integration) CMOS (Complementary Metal Oxide Semiconductor) image sensor was proposed in this paper. By adopting a signal accumulation technique combining two levels of charge-domain accumulation with low-noise pixel-sharing and eight levels of analog-domain accumulation for suppressing parasitics, sixteen levels of accumulation was realized. The design of the mixed-domain TDI CMOS image sensor is fabricated in the 55-nm CMOS technology with sixteen levels of accumulation and a 58.82 kHz line frequency. The SNR of 16-stage accumulation can be improved by 21.96dB after simulation verification.