SEMICONDUCTOR INTEGRATED CIRCUIT

摘要

PROBLEM TO BE SOLVED: To precisely compare two pieces of picture data with simple circuit constitution and to reduce the cost by providing a comparison circuit comparing two input voltages and making output voltage to be minimum when both voltages are equal. SOLUTION: Picture data outputted in a photoelectric conversion circuit 2 is alternately stored in first and second memories 3 and 4 by alternately inputting write enable signals to input terminals W1 and W2 from outside. A comparison circuit 5 compares data stored in the first memory 3 with data stored in the second memory 4 and outputs the compared result. As for the comparison circuit 5, the comparison circuit where output voltage becomes maximum or minimum only when two inputted voltages are equal and two pieces of picture data obtained in the photoelectric conversion circuit 2 are precisely compared with simple circuit constitution is provided. The comparison circuit 5 can be introduced to the picture element of a picture sensor and the cost can be reduced.