Dielectric barrier discharge lamp lighting apparatus and method of detecting the number of normally lighting dielectric barrier discharge lamps

摘要

A dielectric barrier discharge lamp lighting apparatus includes twenty-four dielectric barrier discharge lamps, and a ballast circuit for lighting the twenty-four dielectric barrier discharge lamps which includes a DC power supply, an inverter circuit, a step-up transformer, and a lighting lamp number detecting circuit. The lighting lamp number detecting circuit detects the number of normally lighting dielectric barrier discharge lamps based on a first peek appearing right after polarity change of an approximate rectangular wave provided from the step-up transformer. When the detected number is less than a predetermined value, the operation of the ballast circuit is controlled to be stopped.