Abstract
A low frequency architecture is proposed for driving parallel cold cathode
fluorescent lamps (CCFLs) in large screen liquid crystal display (LCD) TV
backlighting applications. Key to the architecture is a proposed capacitive
coupling approach for aiding lamp ignition. A dc voltage is applied to the
lamp electrodes while an ac voltage is applied to an external plate for capacitive coupling.
The result is reliable, simultaneous ignition of parallel lamps with a required
applied dc voltage near the lamp steady-state operating voltage. The complete
system architecture includes a single high voltage converter, a pulse lamp
ignition circuit, current control circuits and a single backlight controller.
The topology is capable of driving a large number of parallel lamps with independent
lamp current regulation, while avoiding ac coupling losses in steady-state
operation and achieving significant reduction in reactive
components when compared to typical high frequency ac ballast designs. Experimental
results are presented for a system of four parallel 250 mm length lamps, demonstrating
simultaneous parallel lamp ignition and dc current regulation.
© 2009 IEEE
PDF Article
More Like This
Cited By
You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.
Contact your librarian or system administrator
or
Login to access Optica Member Subscription