An Over 140 dB Dynamic Range CMOS Image Sensor Combined DCG and Logarithmic Response

A dynamic range enhancement pixel architecture based on a standard CMOS image sensor (CIS) process with a pinned photodiode (PPD) is proposed, combining dual conversion gain (DCG) and logarithmic response. Due to a unique charge compensation mechanism of the proposed pixel, in a single exposure, three images are captured with the same integration time, related to different incident light levels. As a result, an over 140 dB dynamic range image is able to be obtained by merging these images. Photo response measurements show the image sensor exhibits over 92 dB linear dynamic range and more than 51 dB logarithmic dynamic range, without signal-to-noise ratio (SNR) performance degradation under low light conditions.