ELECTRODELESS DISCHARGE LAMP LIGHTING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an electrodeless discharge lamp lighting device having a no-load protection circuit capable of restraining stress of a lighting circuit at the time of no load even at the time of a high ambient temperature, and capable of facilitating start of an electrodeless discharge lamp even at the time of a low ambient temperature. SOLUTION: This device has a high frequency electric power source circuit for converting a direct current into a high frequency output, an induction coil 5 supplied with the high frequency voltage of the power source circuit, an electrodeless discharge lamp 6 arranged proximately to the induction coil 5, and a protection circuit 8 for detecting abnormality of a load comprising at least the induction coil 5 and the discharge lamp 6 to intermittently oscillate the high frequency electric power source circuit at the time of the abnormality. An intermittent oscillation condition therein is changed in response to an ambient temperature.