A Single-Transistor Active Pixel CMOS Image Sensor Architecture

A single-transistor CMOS active pixel image sensor (1 T CMOS APS) architecture is proposed. By switching the photosensing pinned diode, resetting and selecting can be achieved by diode pull-up and capacitive coupling pull-down of the source follower. Thus, the reset and selected transistors can be removed. In addition, the reset and selected signal lines can be shared to reduce the metal signal line, leading to a very high fill factor. The pixel design and operation principles are discussed in detail. The functionality of the proposed 1 T CMOS APS architecture has been experimentally verified using a fabricated chip in a standard 0.35 µm CMOS AMIS technology.