Patent attributes
A solid state image pickup element includes a pixel unit having a plurality of pixels for photoelectric conversion disposed in a matrix shape and a pixel signal read circuit for reading pixel signals in the unit of a plurality of pixels from the pixel unit. The pixel signal read circuit includes a plurality of comparators disposed in correspondence with a pixel column layout for performing comparison judgment between a read signal potential and a reference voltage and outputting a judgment signal and a plurality of counters each for counting a comparison time of a corresponding one of the comparators, an operation being controlled by an output from a corresponding one of the comparators. The comparators include a first amplifier for performing a comparison operation between the reference voltage and the read signal potential and inverting an output at a predetermined comparison point, a second amplifier for forming a current path when an output of the first amplifier is inverted, to output an output of the first amplifier by gain up, and a current control circuit for shutting the current path of the second amplifier when an output level of the second amplifier exceeds a predetermined threshold level.
