Analog-to-digital conversion circuit using comparator and counter, photoelectric conversion apparatus using comparator and counter, and photoelectric conversion system using comparator and counter

Abstract

An analog-to-digital conversion circuit includes a comparator circuit configured to perform processing of comparison between an analog signal and a ramp signal, and a counter configured to perform count processing in parallel with the comparison processing by the comparator circuit. The analog-to-digital conversion circuit acquires digital data, which is a count value corresponding to the comparison processing, and subjects the analog signal to analog-to-digital conversion. A period from the start to the end of the analog-to-digital conversion of the one analog signal includes a first period and a second period following the first period. The first and the second periods are switched based on an output of the counter. The count processing is performed at a high speed during the first period and performed at a low speed during the second period.