Column analog-to-digital converter for CMOS sensor

摘要

A system and method is disclosed for an imaging device and/or an analog to digital converter which converts an analog input signal to a digital data signal using a comparator which compares the analog input signal to a first ramped reference signal to determine an operating point and then uses the same comparator to compare the analog input signal to a second ramped reference signal multiple times about the determined operating point.

主权项

1. An imaging device, comprising:
a first digital to analog converter to provide a first reference signal to a comparator, a second digital to analog converter to provide a second reference signal to said comparator, and a first pixel in a pixel array to provide a pixel output signal to said comparator; said comparator comprising an output terminal operatively connected to a first input terminal of a first counter and a first input terminal of a second counter; said first counter comprising a second input terminal to receive a first clock count signal, a third input terminal to receive a first control signal, and a output terminal operatively connected to a memory device; and said second counter comprising a second input terminal to receive a second clock count signal, a third input terminal to receive a second control signal, and a output terminal operatively connected to said memory device, wherein the comparator is configured to compare the pixel output signal to the second reference signal that is configured to ramp plural through a coarse conversion operating level.