Wide dynamic range CMOS active pixel sensor using a feedback structure

In this work, we propose a wide dynamic range CMOS active pixel sensor (APS) using a feedback structure. The proposed APS uses one additional MOSFET in comparison with a conventional 3-transistor APS. Although the size of pixel is slightly larger than that of conventional 3-transistor APS, extension of the dynamic range is much easier than conventional methods by using a feedback structure. The proposed APS has advantages to allow improvements in both the dynamic range and the sensitivity without process modification. The dynamic range of the proposed APS is expected to be greater than 130 dB. The proposed APS is being fabricated by using 0.18 μm standard CMOS technology.