Patent ID: 7120180

Claim:
A laser diode driving circuit comprising an integrated circuit for driving a laser diode, a capacitor disposed in the vicinity of the integrated circuit and a board on which the integrated circuit and the capacitor are mounted, the integrated circuit comprising a switching element for generating a driving signal for driving the laser diode, a high voltage power supply terminal and a low voltage power supply terminal for feeding a power supply voltage to the switching element and a driving signal output terminal for outputting a driving signal generated by the switching element to outside, the high voltage power supply terminal, the low voltage power supply terminal and the driving signal output terminal being disposed in line on one side of the integrated circuit, the board comprising a high voltage conductive section adapted for feeding a high voltage to the high voltage power supply terminal or connected to a ground level, a low voltage conductive section adapted for feeding a low voltage to the low voltage power supply terminal or connected to a ground level and a driving signal transmitting conductive section for connecting the driving signal output terminal and the laser diode and transmitting a driving signal to the laser diode, and the capacitor being connected to the high voltage power supply terminal at one terminal thereof and connected to the low voltage power supply terminal at the other terminal thereof, and being disposed so that a distance between itself and the high voltage power supply terminal, the low voltage power supply terminal and the driving signal output terminal is equal to or shorter than 10 mm.