Patent ID: 8477220

Claim:
A solid state image pickup device comprising: a pixel unit that includes a plurality of pixels arranged in the form of a matrix, each of the plurality of pixels generating a pixel signal, the pixel signal being output from a plurality of pixel signal output lines arranged to correspond to a column of the plurality of pixels; a pulse delay unit that includes a plurality of delay elements connected in a ring form, each of the plurality of delay elements including a power supply terminal that is connected to one of the plurality of pixel signal output lines, one of the plurality of delay elements including an input terminal that receives a pulse, each of the plurality of delay elements transferring the pulse with a delay time corresponding to the pixel signal; a stop control unit that outputs a stop signal when a predetermined time elapses after the pulse delay unit receives the pulse; a stop signal delay unit that outputs a delay stop signal delayed from the stop signal; a lower bit latch unit that latches output signals of the plurality of delay elements when receiving the delay stop signal; a counter unit that counts a circulation number of the pulse based on an output signal of one of the plurality of delay elements; a first upper bit latch unit that latches at least a least significant bit of an output signal of the counter unit when receiving the delay stop signal; a second upper bit latch unit that latches the output signal of the counter unit when receiving the delay stop signal; and a correcting unit that compares an output signal of the first upper bit latch unit with an output signal of the second upper bit latch unit, and corrects a count value, which is a count result of the counter unit, based on a comparison result and an output signal of the lower bit latch unit.