具零電壓全橋諧振式多燈管全橋諧振式多燈管 冷陰極燈管驅動電路之設計與應用

由於隨著技術研發在不斷地提昇，但是當液晶面板的尺寸越來越大，其所使用的冷陰極螢光燈管（Cold Cathode Fluorescent Lamp, CCFL）的長度也越來越長，且使用的數目也越來越多，這時候的產品成本就成為企業能否延續其生命的主要因素。本篇論文中，我們以具零電壓全橋諧振式轉換器驅動電路具架構上簡單，體積小，不需另外加元件，仍然可以用寄生元件及諧振零電壓切換技術，降低開關元件切換的損失，不是讓寄生元件去減損電路的性能，利用相移控制達成，開關元件具零電壓(ZVS)切換特性，主要是用變壓器次級側洩漏電感，激磁電感，功率開關元件(MOSFET或IGBT)與其諧振電容產生諧振，以實現增加效率及可靠度。最後，藉著OZ Micr公司所設計的OZ9938控制IC，來完成使用於19”液晶顯示器，藉助外部光源達到顯示效果，光源則是以冷陰極螢光燈管為主。冷陰極螢光燈管的驅動電路泛稱為換流器，藉著換流器電路的硬體架構，讓讀者了解到，在諧振換流器為主來提供給液晶面板的背光模組(Backlight Unit, BLU)上的應用。

關鍵字

諧振式轉換器；變壓器；冷陰極螢光燈管；換流器；背光模組

並列摘要

As technology developed rapidly, the size of the TFT-LCD panel grow larger and larger. Thus, the Cold Cathode Fluorescent Lamp (CCFL) contained became longer in length, and more in number. A low product cost solution has become a crucial issue for lifetime enterprise. The purpose of this paper is to use the full-bridge phase-shift quasi-resonant converter that allows zero voltage turn-on of switches. While retaining the merits of simple circuit and small size, it uses the parasitic components to resonate. Therefore, additional resonant components are not required. Moreover, the switching loss is reduced by the use of the zero voltage switching (ZVS) resonant technique. It uses phase-shift control to achieve the result. The transistor has the characteristic of zero voltage switching, using a transformer. A main combination of parasitic components, which includes the Metal Oxide Semiconductor Field Effect Transistor (MOSEFT) and second leakage inductance of the Isolation transformer, produces a resonant action and reduces drain-source voltage prior to turn-on. Moreover, it achieved high efficiency and increased Mean Time Between failure (MTBF). Finally, the OZ9938 controller IC manufactured by OZ Micr corp. is adopted in this thesis for use in 19” TFT-LCD with CCFLs from external light source, for the driver circuit of CCFL same as inverter, and introduced hardware aspects of the structure, so that readers understand quasi-resonant converter to the TFT-LCD of backlight unit application.

並列關鍵字

Quasi-resonant Converter ； Transformer ； (Cold Cathode Fluorescent Lamp CCFL) ； inverter ； (Backlight Unit BLU)

參考文獻

[1]. E. Deng S. Cuk, “Negative incremental impedance and stability of fluorescent lamps,” in proc. of IEEE APEC’97, 1997, pp. 1050-1056.

[2]. C. G. Kim, K. C. Lee, and B. H. Cho, “Modeling of CCFL using lamp delay and stability analysis of backlight inverter for large size LCD TV,” in proc. of IEEE

[4]. M. Gulko and S. Ben-Yaakov, “Current sourcing push pull parallel resonance inverter (CS-PPRI): theory and application as a discharge lamp driver,” IEEE Trans.Ind. Electronics, Volume: 41, Issue: 3, June 1994, pp. 285 - 291

[6]. Joel A. Donahue, P. E. and Milan M. Jovanovic, “The LCC Inverter as a cold cathode Fluorescent Lamp Driver”, Applied Power Electronics Conference and Exposition, 1994. APEC '94. Conference Proceedings 1994. Ninth Annual, 13-17,

[8]. J.M.Alonso, C. Blanco, E.Lopez, A.J. Calleja, M. Rico, ”Analysis, design, and optimization of the LCC resonant inverter as a high-intensity discharge lamp ballast,” Power Electronics, IEEE Transactions on, Vol. 13,no. 3, May 1998,P: 573 – 585.

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具零電壓全橋諧振式多燈管全橋諧振式多燈管冷陰極燈管驅動電路之設計與應用

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