For a back-light module with multiple cold cathode fluorescent lamps (CCFLs) in mid-size or large size liquid crystal displays, a balance scheme must be included to have approximately equal currents among the lamps and hence to output equal brightness. In this thesis, a half-bridge inverter is adopted to drive multiple step-up transformers with the same turn ratio, in which the primary windings of the transformers are connected in series whereas the second windings drive CCFLs in parallel. Due to the series connection of the transformer sets, the current going through the primary windings is identical, so that the lamp currents from second windings tend to be equal.
A driver circuit with the proposed scheme is designed for 8 U-type cold cathode fluorescent lamps in a 32-inch backlight module. The simulation and experimental results demonstrate the effectiveness of the balance scheme, even for the lamps operating at low current.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0911107-065757 |
| Date | 11 September 2007 |
| Creators | Huang, Chao-ming |
| Contributors | Hung-Liang Cheng, Chin-Sien Moo, Ming-Tang Chen |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0911107-065757 |
| Rights | off_campus_withheld, Copyright information available at source archive |
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