The approach to rail-to-rail CMOS active pixel sensor for portable applications

We have proposed an innovative structure of low-voltage rail-to-rail CMOS Active Pixel Sensor (APS), which can work at 1.2 V supply voltage with relative high dynamic range and signal to noise ratio. It is a suitable alternative for the conventional active pixel in portable applications. Compared with the conventional pixel, it surpasses the bottleneck of the voltage limitation and makes the signal voltage as large as possible. We also implement the photodiode type rail-to-rail CMOS active pixel in commercially available 0.25 /spl mu/m CMOS technology, with a fill factor of 30% and pixel size of 12 /spl mu/m/spl times/10 /spl mu/m.