A high-speed 512 x 512 CMOS image sensor with column-parallel cyclic ADC's and a global electronic shutter is developed. The fully differential cyclic ADC achieves the highest resolution of 12b in the 3500frames/s CMOS image sensor. The proposed pixel uses a charge amplifier in each pixel to enhance the sensitivity and sample-and-hold circuits for global electronic shuttering. The measured signal dynamic range is 60dB, and the sensitivity is as high as 19.9V/lx-s. The sensitivity is two times higher than that of the high-speed image sensor which claims high sensitivity.
|Equivalent circuit of high-sensitivity pixel.
|Schematic of amplifier shared 2-stage cyclic ADC with noise canceller.