An Event-Detection High Dynamic Range CMOS Image Sensor

Abstract—A novel CMOS image sensor is proposed to overcome the analog design limitations in Active Pixel Sensors- APS and large area overcome in Digital Pixel Sensors- DPS for use in bio-medical applications. The design includes a pixel level event generation mechanism by using a binary search technique. A ramp voltage generated by a combined block of 10-bit counter and DAC Digital to Analog Converter is compared with the pixel integrated voltage at each clock cycle at the same time allowing a fixed exposure time interval. The proposed design arrives to a total pixel array area of 1505.62µm × 4566µm for a pixel array size of 160(H) × 120(V). The photo-active area in each pixel is considered as the N-well area in a p+/n-well/p-sub type photo-transistor corresponding to a size of 11.24µm×10.76µm. The overall pixel array reaches a fill factor of %34. I