Variable inductive power supply arrangement for cold cathode fluorescent lamps

A plurality of cold cathode fluorescent lamps (CCFLs) for a backlight of a display device are connected, each in series with a respective variable inductance, in parallel to an AC supply from a power converter. Each variable inductor comprises a first inductor in series with the CCFL, a second induc...

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Bibliographic Details
Main Author ORR RAYMOND K
Format Patent
LanguageEnglish
Published 25.05.2010
Subjects
CONTROLLING
PHYSICS
REGULATING
SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
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Summary:A plurality of cold cathode fluorescent lamps (CCFLs) for a backlight of a display device are connected, each in series with a respective variable inductance, in parallel to an AC supply from a power converter. Each variable inductor comprises a first inductor in series with the CCFL, a second inductor inductively coupled to the first inductor, and an AC switch for selectively shorting the second inductor. A capacitor in parallel with the first inductor forms a resonant circuit tuned to the AC supply frequency when the switch is open. Each switch is opened and closed with a controlled duty cycle to provide individual control of an average current of each CCFL.
Bibliography:Application Number: US20070945699