Low power CMOS image sensors employing adaptive bulk biasing control (AB2C) approach

A low power CMOS image sensor employing adaptive bulk biasing control (AB2C) approach is presented. The AB2C is a novel method that utilizes self adaptive biasing of the sensor array and digital periphery and allows sensor power reduction and image performance improvement. The presented AB2C technique can be easily implemented in a standard twin well or triple well CMOS technology. Both rolling shutter and global shutter imagers were examined using the AB2C, showing increased sensor output voltage swing, reduced in-pixel leakage currents, increased shutter efficiency and significant improvement in power dissipation of the scanning circuitry. A detailed description and analysis of the AB2C method is presented. Various image sensors employing AB2C have been implemented in a standard 0.18mum CMOS technology available through MOSIS and are operated via a 1.8V supply. Imagers operation is discussed and simulation results are reported.