Reset noise reduction through column-level feedback reset in CMOS image sensors

A low reset noise CMOS image sensor (CIS) based on column-level feedback reset is proposed. A feedback loop was formed through an amplifier and a switch. A prototype CMOS image sensor was developed with a 0.18 μm CIS process. Through matching the noise bandwidth and the bandwidth of the amplifier, with the falling time period of the reset impulse 6 μs, experimental results show the reset noise level can experience up to 25 dB reduction. The proposed CMOS image sensor meets the demand of applications in high speed security surveillance systems, especially in low illumination. (semiconductor integrated circuits)