DISCHARGE LAMP LIGHTING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a small size lighting device with a low cost whose circuit structure is simplified without requiring installation of special circuit having a function of protecting circuits or preventing electric shock incidents and which quickly stops output voltage generation even in the case an a.c. output terminal is earthed to the ground. SOLUTION: This apparatus is provided with a DC/DC conversion circuit 1, a DC/AC conversion circuit 2 to convert d.c. output into a.c. voltage at low frequency and to supply the a.c. voltage to a discharge lamp LP and an ignitor circuit 3 to start a discharge lamp LP. In this case, a protection circuit to stop the circuit output in the case the output voltage of the DC/DC conversion circuit 1 is continuously lower than a standard value for a prescribed duration T1 or longer is installed and the prescribed duration T1 is set to be shorter than the half period T2 of the low frequency of the DC/AC conversion circuit 2.