Discharge lamp driving circuit provided with discharge detecting pattern

摘要

In a discharge lamp driving circuit comprising: a transformer having one end of a discharge lamp connected to one end of the secondary side thereof; a current-voltage converting circuit provided at the other end of the discharge lamp and functioning to convert a lamp current to a voltage; and a lamp current controlling pattern provided at the other end of the discharge lamp, there is provided a discharge detecting pattern at a grounding end of the secondary side of the transformer so as to be located close to and in parallel with the lamp current controlling pattern, whereby a voltage induced in the discharge detecting pattern is detected, and the supply of electric power to the secondary side of the transformer is stopped. Thus, the discharge lamp driving circuit is deactivated when a discharge occurs at the wiring at the secondary side of the high-voltage transformer.