An electronic circuit includes a unit pixel, a first clamp circuit, and a second clamp circuit. The unit pixel outputs a voltage having an output voltage level at a first output voltage level in a first time interval and at a second output voltage level in a second time interval different from the first time interval. The first clamp circuit is configured to clamp the output voltage level from the unit pixel to a first voltage level responsive to the first output voltage level being not greater than the first voltage level in the first time interval. The second clamp circuit is configured to clamp the output voltage level from the unit pixel to a second voltage level responsive to the second output voltage level being not greater than the second voltage level in the second time interval.