Patent ID: 7545369
Filing Date: 2009-06-09
Classification: G09G,H05B

Abstract:
1. A method of operating a resonant full bridge cold cathode fluorescent light (CCFL) controller controlling first through fourth transistors controlling current through a series connection of a capacitor and a primary of a transformer, the series connection having first and second leads coupled to a connection between the first and second transistors and coupled to a connection between the third and fourth transistors, respectively, the CCFL coupled across a secondary of the transformer, comprising: turning on the first and fourth transistors to couple the series connection between first and second power supplies with a first polarity; turning off the first transistor responsive to a pulse width modulator output, the pulse width modulator being responsive to current through the CCFL, and turning on the second transistor; when the current through the series connection is within a predetermined range of zero, initiating a time delay; at the end of the time delay, turning off the fourth transistor and turning on the third transistor.