PULSE WIDTH ADJUSTING CIRCUIT

PROBLEM TO BE SOLVED: To correct the waveform distortion of a light signal due to the rise delay of the light signal with simple constitution by applying a variable comparison reference voltage to a buffer amplifier and adjusting the pulse width when an input signal having its signal waveform rise and fall slanted by using a filter circuit is shaped through the buffer amplifier. SOLUTION: The input signal is inputted to an input terminal 11A of a filter circuit 11 to obtain an output 11B whose digital signal waveform rise and fall are slanted, and the output is inputted to the uninverted input terminal 12A of a buffer amplifier circuit 12. The buffer amplifier circuit 12 outputs a reference voltage 12C which is internally compensated according to a driving power source, so the voltage divided by it through resistances R12 to R14 is inputted as the comparison reference voltage to the inverted input terminal 12B. The uninverted and inverted outputs 12D and 12E of the buffer amplifier 12 are inputted to the uninverted and inverted input terminals 13A and 13B of a light emitting element driving circuit 13 to drive a light emitting element 14.