TWO-STAGE A/D CONVERTER AN IMAGE SENSOR USING THE SAME

摘要

In the conventional CMOS image sensor, an A/D converter performing A/D conversion at a high speed arranges A/D converter elements in columns so as to operate in parallel and has a low resolution in the order of 9 bits. The present invention provides an image sensor A/D converter which performs a part of the A/D conversion function by using a column noise cancel circuit and performing amplification simultaneously with this, thereby obtaining a high signal noise ratio (SNR) and realizing a an A/D converter of a high resolution together with the A/D conversion section after this.