US Patent 7646989 Light emitting element driving device

A light emitting element driving device of the present invention comprises at least one light emitting element and a power supply device for generating a driving current of the light emitting element. The power supply device has a step-up type DC-DC converter circuit. The step-up type DC-DC converter circuit has a soft-start function for gradually increasing the driving current at a rise of the driving current in generation of the driving current. Thus can be provided a light emitting element driving device which is capable of suppressing an inrush current to be generated at turn-on of the main power supply of the power supply device.