Patent ID: 7635952

Claim:
A lighting controller for a lighting device for a vehicle comprising: a current supply control unit for receiving a supply of an electric power from a power source and controlling a supply of a current to a semiconductor light source; a forward voltage detecting unit for detecting values of a forward voltage of the semiconductor light source; an initial value storing unit for storing as an initial value a detected value from the forward voltage detecting unit that is obtained when the semiconductor light source is initially turned on; an updated value storing unit for storing a latest detected value of detected values from the forward voltage detecting unit as an updated value; a first deciding unit for comparing a first abnormality deciding value set from the initial value with a detected value from the forward voltage detecting unit to decide whether or not an abnormality depending on a change of the forward voltage of the semiconductor light source is present; and a second deciding unit for setting a second abnormality deciding value having a condition different from that of the first abnormality deciding value in accordance with the updated value stored in the updated value storing unit and comparing the set second abnormality deciding value with a detected value from the forward voltage detecting unit to decide whether or not an abnormality depending on a change of the forward voltage of the semiconductor light source is present.