Wide Dynamic Range CMOS Image Sensor with Dual Mode Operation

摘要

This paper presents a wide dynamic range complementary metal oxide semiconductor (CMOS) image sensor (CIS) using column capacitors and feedback structure. The prototype sensor is designed and fabricated by using 0.18um standard CMOS technology. This sensor is operated under dual mode scheme; an active pixel sensor (APS) mode for normal light condition and a passive pixel sensor (PPS) mode for high light condition. For checking the light conditions, a node capacitance controlled by the reference voltage is added in every column line. By utilizing the proper sensing mode depending on the light conditions, the dynamic range can be adjusted with a linear response. By using the proposed structure, it is possible to store more electric charge, which results in a wider dynamic range. The simulation and measurement results demonstrate the feature of wide dynamic range (WDR).