Premium
26.1: Low‐Frequency Square‐Wave Drive for Large Screen LCD‐TV Backlighting Systems
Author(s) -
Doshi Montu,
Zane Regan,
Azcondo Francisco J.
Publication year - 2006
Publication title -
sid symposium digest of technical papers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.351
H-Index - 44
eISSN - 2168-0159
pISSN - 0097-966X
DOI - 10.1889/1.2433201
Subject(s) - backlight , ignition system , fluorescent lamp , square wave , electrical engineering , voltage , liquid crystal display , gas discharge lamp , capacitive sensing , cold cathode , spark (programming language) , controller (irrigation) , materials science , optics , engineering , cathode , optoelectronics , computer science , physics , aerospace engineering , agronomy , biology , programming language
Abstract This paper presents a low‐frequency square‐wave drive, consisting of a single high voltage converter, an ac lamp ignition circuit, current control devices and a single backlight controller, capable of driving an arbitrary number of parallel cold cathode fluorescent lamps (CCFLs) with independent accurate lamp current regulation. Key to the architecture is a proposed capacitive coupling approach for ac lamp ignition that results in reliable, simultaneous ignition of parallel lamps with a maximum ignition voltage near the normal lamp operating voltage. A brief summary of the lamp model and behavior is presented to explain the findings during the capacitive ignition and low‐frequency operation. Experimental results are presented demonstrating parallel lamp ignition and current regulation for four, 250 mm CCFLs.