應用於白光LED驅動之限流脈波頻率調變升壓型轉換器

隨著手持式消費性電子產品的快速成長，故面積小、高效率、低成本的白色發光二極體(Light-emitting diodes, LEDs)驅動電路開發，將有助於提高此類產品競爭力，因此，對於電源轉換電路設計者而言，改善電路的防護機能與提高電源轉換效率已經成為一個相當重要的研究主題。　　本文主要針對白光LEDs驅動電路進行改良，並可區分為三方面；首先，對於全負載區域問題，本文所使用的限流脈波頻率調變(Current limited pulse frequency modulation)控制架構，將可較傳統脈波寬度調變(Pulse width modulation)有較佳之轉換效率，並且因使用較少元件而可縮小控制架構面積，因此，能有效的延長可攜式電子產品電池操作時間及減少硬體空間。　　其次，本文針對白光LEDs驅動電路之保護功能提升方法，提出可實現積體化與減少功率損耗之電晶體電流檢測(Current sense FET)電路；另外，針對LEDs出現斷路及開機突波電流問題，提出過電壓保護(Over voltage protection)電路與軟啟動(Soft start)電路，以分別防止驅動電路因過電壓與突波電流而毀損。　　最後，有別於傳統功率積體電路以脈波訊號直接驅動方式，本文提出以前置驅動器(Pre-driver)電路對功率開關之切換控制，因此能增加脈波訊號能力，並達到降低功率電晶體之導通損失與交換損失，進而提升轉換效率。

關鍵字

白光LED驅動

並列摘要

With rapid growth of portable consumer electronics, white light-emitting diodes (LEDs) driving circuits which develop the advantages of small size, high efficiency, and low cost will help to improve competition of such products. Thus, to upgrade protection functions and conversion efficiency of driving circuits has become a crucial subject for power integrated circuit designers. 　　This research aims to improve white light LEDs driving circuits and include three sections. Firstly, about the issue of full loading, the current limited pulse frequency modulation employed in this paper achieves better conversion efficiency than the conventional pulse width modulation, and reduces the control circuit size with fewer components. Consequently, this method can effectively prolong portable electronic products’ battery life and eliminate space of devices. 　　Second, this research proposes current sense FET circuits which can implement integrated design and reduce power loss to improve protection functions of white light LEDs driving circuits. Furthermore, to cope with broken circuits of LEDs and rush currents of driving circuits while power is on, this paper uses over voltage protection and soft start circuits to prevent driving circuits from damage because of over-voltage and rush currents. 　　Finally, different from the conventional power integrated circuits using pulse signals to drive directly, this research presents a study on pre-driver circuits to control power switchs that can improve the capability of pulse signals, reduce the conduction loss and switching loss, and raise the conversion efficiency.

並列關鍵字

White Light LEDs Driving

參考文獻

[22] L. G. Vermaas, C. R. De Mori, R. L. Moreno, A. M. Pereira, R. E. Charry, “A Bandgap Voltage Reference Using Digital CMOS Process,” IEEE International Symposium on Circuits and Systems, vol. 2, pp. 303-306, 1998.

[2] K. Toshihiko, N. Masao, “Integrated System of White LED Visible-Light Communication and Power-Line Communication,” IEEE Trans. Consumer Electronics, vol. 49, issue 1, pp. 71-79, 2003.

[4] B. Sahu, G. A. Rincon-Mora, “A Low Voltage, Dynamic, Noninverting, Synchronous Buck-Boost Converter for Portable Applications,” IEEE Trans Power Electronics, vol. 19, issue 2, pp. 443 - 452, 2004.

[5] B. Sahu, G. A. Rincon-Mora, “System-Level Requirement of DC-DC Converter for Dynamic Power Supplies of Power Amplifiers,” IEEE ASIC Proceedings, Asia-Pacific Conference, pp. 149 - 152, 2002.

[8] W. H. Daniel, "Introduction to Power Electronics", Prentice Hall, pp.211 - 226, 1998.

國際替代計量

應用於白光LED驅動之限流脈波頻率調變升壓型轉換器

全文下載

主題瀏覽