CMOS pixel-level ADC with change detection

Yu M. Chi, Udayan Mallik, Edward Choi, Matthew A. Clapp, G. Gauwenberghs, Ralph Etienne-Cummings

Abstract: An array of 90 /spl times/ 90 active pixel sensors (APS) that performs both in-pixel temporal intensity change detection and analog-to-digital conversion is presented. The 6-T 3-C 25/spl mu/m /spl times/ 25/spl mu/m pixel fabricated on a 0.5/spl mu/m 3M2P CMOS process provides a digital output of light intensity via an integrated single slope ADC. Using the programmable threshold of the pixel level comparator, the imager acquires two exposure levels of a scene simultaneously for increased dynamic range. The imager is intended for surveillance network applications requiring low cost, power efficient sensors remotely operating over bandwidth constrained networks.