High fill factor CMOS APS sensor with extended output range

A new active pixel sensor (APS) circuit architecture with increased signal range is proposed. This feature contributes to improvement of the dynamic range of the imager, since it is effectively a way to increase the full well capacity, which is reduced as pixel pitch decreases. The proposed solution does not degrade the fill factor, and can be applied to most existing CMOS APS pixels. The new readout topology is described and experimental results for a 64 × 64 3T photodiode pixel array are given.