Light modulation method and apparatus for cold cathode fluorescent lamps

摘要

A method and apparatus for modulating light of CCFLs that couples frequency alteration and pulse width modulation (PWM) approaches to change output voltage and current of a piezoelectric transformer to modulate the luminosity of a CCFL. The invention includes a PWM controller to alter operation cycle and a frequency control IC to change resonant frequency that drives the piezoelectric transformer at different operation cycles thereby to modulate the luminosity of the CCFL and improve the life span of the piezoelectric transformer.