DRIVING CIRCUIT OF LASER DIODE, AND SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To provide a laser diode driving circuit that makes a waveform of a driving current to be supplied to a laser diode close to a square wave without providing an extra waveform correction circuit.SOLUTION: The driving circuit of the laser diode includes a diving current supply circuit 11 to supply a current pulse ILD to the laser diode LD1, and a damping circuit 12 connected to the laser diode LD1 in parallel to suppress overshoot and undershoot of the current pulse ILD. The damping circuit 12 is constructed by connecting a resistor element R11 with a capacitor element in series. The capacitor element is constructed by connecting a plurality of series circuits consisting of capacitors C and switches SW in parallel. Thus, the overshoot and undershoot of the current pulse ILD are suppressed by adjusting a time constant of the damping circuit 12.