Patent ID: 7755295

Claim:
A head lamp device for a vehicle including a DC power source, a diode array having a plurality of series-connected light emitting diodes and a current control circuit that supplies driving current to said diode array, wherein said current control circuit comprises: means for supplying driving current to said diode array; means for measuring a voltage drop of each of a plurality of sections of said light emitting diodes; means for comparing the voltage drop of each of said plurality of sections of light emitting diodes with the voltage drop of each of said plurality of sections of said light emitting diodes; means for judging a short-circuiting at any of said plurality of sections of said light emitting diodes based on the comparison by said comparing means; and means for displaying an alarm when said judging means judges that there is a short-circuiting; wherein said supplying means comprises a current measuring circuit that measures current supplied to said diode array, a DC-DC converter for converting voltage of said DC power source to a voltage suitable to said diode array; and a feedback control circuit, connected between said current measuring circuit and said DC-DC converter, for controlling driving current supplied to said diode array according to current measured by said current measuring circuit; and said feedback control circuit increases the driving current when said judging means judges that there is a short-circuiting.