A Four-Transistor Capacitive Feedback Reset Active Pixel and Its Reset Noise Reduction Capability

A new CMOS active pixel with reset noise reduction capability using capacitive feedback reset (CFR) is proposed. The CFR pixel with capacitive feedback consists of a photodiode, four MOS transistors, a feedback capacitor and a buffer capacitor. It can be fabricated in standard CMOS process, thus yielding a low noise pixel without additional process steps. It has been confirmed with a fabricated pixel structure that the reset noise is reduced to 0.39 times the reset noise level of the conventional photodiode active pixel configuration.

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