Photoelectric conversion device and imaging system

A photoelectric conversion device comprising:

• a plurality of pixels arranged to form a plurality of columns, each of the plurality of pixels outputting a pixel signal in accordance with an incident light;
• a plurality of output lines each provided to a corresponding one of the plurality of columns, each of the plurality of output lines being connected to pixels on a corresponding column;
• a plurality of signal holding units each provided to a corresponding one of the plurality of output lines and each configured to hold the pixel signal;
• an analog-to-digital (AD) conversion unit that converts the pixel signal from an analog signal to a digital signal;
• a first switch circuit provided between the plurality of output lines and the plurality of signal holding units, the first switch circuit including a switch configured to control electrical connections between adjacent output lines;
• and
• a second switch circuit provided between the plurality of signal holding units and the AD conversion unit,
• wherein the first switch circuit is configured to connect one of the plurality of output lines to the plurality of signal holding units individually so as to hold one pixel signal output from one of the plurality of pixels in each of the plurality of signal holding units in different sampling periods,
• wherein the second switch circuit is configured to switch connection between the plurality of signal holding units and the AD conversion unit, and
• wherein pixel signals held in the plurality of signal holding units are averaged and output.