Detection and regulation of CCFL current and open-lamp voltage while keeping floating condition of the lamp

Abstract

A new simple balanced circuitry using four printed circuit board trace capacitors effectively detects the cold-cathode fluorescent lamp current and the transformer voltage of the inverter without grounding either side of the lamp. The inverter employing this circuit is free from the problems caused by grounding one side of the lamp, and it provides a stable and wide dimming control as well as an open-lamp voltage regulation with a better efficacy.