Patent ID: 7482765
Filing Date: 2009-01-27
Classification: H05B,Y02B

Abstract:
1. A lighting control apparatus of a vehicle-purpose lighting device comprising: a plurality of semiconductor light sources connected in parallel to each other and employed as a load; a switching regulator for applying an input voltage from a power supply to the respective semiconductor light sources; a plurality of series regulators which are connected in series to the respective semiconductor light sources; and protection control means for performing a protection control operation with respect to the respective series regulators in response to an abnormal condition caused by a disconnection as to each of the semiconductor light sources, or by a disconnection as to a circuit coupled to each of the semiconductor light sources; wherein each of the series regulators is implemented by a current detecting element for detecting a current of each of the semiconductor light sources, a switch element connected in series to each of the semiconductor light sources, and respective comparators for comparing a current detected by the current detecting element with a defined value and for controlling ON/OFF operations of the switch element in response to a comparison result; and wherein the switching regulator controls an output voltage in response to a comparison result of any of said comparators; and wherein, when the detected current of each of the current detecting elements is lowered so that a comparison result of the comparator becomes abnormal, each of the protection control means turns OFF the switch element and maintains the OFF operation of the switch element.