Method and unit for driving piezoelectric transformer used for controlling luminance of cold-cathode tube

摘要

A method and unit for driving a small high-efficiency piezoelectric transformer allowing a cold-cathode tube to have stable luminance by detecting only an active current flowing in the cold-cathode tube based on a phase difference between an output current and voltage of the piezoelectric transformer, removing a reactive current caused by stray capacitance formed between the cold-cathode tube and a reflector, and accurately controlling driving of the piezoelectric transformer so that a constant active current is detected.