A CMOS Image Sensor with Self-Reset Circuit in Active Pixel

Abstract

The desire characters for image sensor are high dynamic range and high capture speed. CMOS image sensors benefit from technology scaling by reducing pixel size, increasing resolution. The ability to reproduce a high-quality image depends strongly on the image sensor light sensitivity. Pixel design is a key part of image sensor design. A sensor with higher dynamic can detect a wider range of scene illumination and can produce images with greater detail. This paper discusses the design, layout and simulation results of a high dynamic range CMOS activepixel. Each pixel block consists of a phototransistor and 14 MOS transistors. Using self-reset, the scheme can extend dynamic range at the high end. The image data output is generated from the ADC output and the reset counter output. The sensor is designed with a 0.35μm CMOS technology and the fill-fact is 30%. Keywords-CMOS; image sensor; dynamic range; signal-tonoise ratio