Black-sun noise immune correlated double sampling scheme for CMOS image sensors

초록

This paper presents a black-sun immune correlated double sampling (CDS) scheme for high-quality imaging. Based on an analysis of signal characteristics in strong light conditions, a clamping circuit-based signal difference generator is proposed to accurately present the bright light information. The proposed scheme eliminates the black-sun noise with simple circuitry to improve the A/D conversion efficiency. Moreover, it can be is reversible to the conventional algorithm so that it still preserves the structural advantages of the existing CMOS image sensor (CIS) structure. A prototype CIS with a column-parallel 11-bit single-slope (SS) analog-to-digital converter (ADC) was fabricated in a 0.11-mu m 1P4M CIS process with a 2.9-mu m pixel pitch.

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