Piezoelectric transformer driving circuit and cold cathode tube illuminating device using the same

摘要

A piezo electric transformer driving circuit and a cold cathode tube illuminating device comprising a series circuit including a switch circuit, a coil and a switching transistor and being connected successively in the named order between a power source line and a ground; a piezo electric transformer of which primary side electrode is connected to a juncture of the coil and the switching transistor; and a drive halting circuit which geneates a first control signal for turning OFF the switching circuit and further generates a second control signal for halting a switching operation of the switching transistor after a predetermined period from the generation of the first control signal, wherein the predetermined period is at least one turned ON interval of the switching transistor and through the switching operation of the switching transistor a high voltage is generated at a secondary side of the piezo electric transformer.