An Improved Design of Key Analog Circuits in CMOS Image Sensor

CMOS image sensors transmit images by photoelectric conversion and consist of several key analog circuits. We discuss the structure and the overall operating principles of typical CMOS image sensor, and conduct analysis of the key analog circuits function. We carry out the discussion of the theoretical and mathematical principles of those circuits and then we design certain improved key analog circuits on the base of the SMIC 0.5μm 2P3M CMOS craft, such as the pixel cell array circuit, the correlated sampling circuit as well as the Bandgap reference circuit. Our improved designs have improved characteristics such as high output swings, high temperature stability and relatively low room occupation.