降壓轉換器的低電壓與零電壓切換控制

本論文主要針對降壓轉換器，提出操作於連續/非連續之臨界模式的低電壓切換與零電壓切換之積體化電路控制技術。此技術可自動補償電路延遲，並在低汲源電壓/零汲源電壓的狀態時，將功率電晶體導通，不需任何複雜計算時間的電路，也不需任何外部輔助元件。本論文提出之控制電路，也可應用於其他電源轉換器上，如昇壓、昇－降壓、及返馳式轉換器。本論文內容包含控制分析、電路組成、及輸入電壓5V、輸出電壓各為1.8V、3.3V的實驗結果；實驗結果顯示具低電壓切換/零電壓切換技術之降壓轉換器，比傳統降壓轉換器具更高的轉換效率，尤其是在高切換頻率的時候（1.8V為1.35MHz，3.3V為3.6MHz的切換頻率），其轉換效率比傳統硬切換技術之降壓轉換器高（約各為9%與11%）。在本論文低電壓/零電壓技術中，也針對所使用之取樣/儲存電容，設計一更新儲存電壓的電路，其內容包含動作原理與模擬波形。最後，本論文也提出降壓轉換器同步整流電晶體的控制電路，內容同樣也囊括了動作原理與模擬波形。

關鍵字

零電壓切換；低電壓切換；臨界電流模式；諧振；效率

並列摘要

A new integrated circuit approach for Lowest-Voltage-Switching and ZVS control is presented for PWM buck converters under DCM/CCM boundary mode. This proposed technique compensates control circuit delay and hence turns on the power MOS at the exact instant of lowest/zero drain-to-source voltage. No complicated timing calculation circuits or additional external components are required. This proposed integrated Lowest-Voltage-Switching and ZVS control can be applied to other DC-DC converters as well. Circuit analysis, implementation and the die photo are shown. Experimental results for an example circuit with VIN of 5V and VOUT of 1.8V and 3.3V reveal that buck converters with the presented Lowest-Voltage-Switching and ZVS technique have higher efficiency than conventional ones, especially at higher frequencies. At about 1.35MHz and 3.6MHz operation, the measured conversion efficiency of the PWM buck converter under DCM/CCM boundary mode with the proposed Lowest-Voltage-Switching and ZVS approach is 9% and 11% higher, respectively. Also, the replenishing scheme for the holding capacitor in sample and hold circuit is designed and simulated. Its operation is analyzed and simulation results are illustrated. Furthermore, buck converter with synchronous rectifier and its related ZVS gating control is presented. Analysis and simulation results are conducted and shown.

並列關鍵字

ZVS ； LVS ； boundary mode ； resonance ； efficiency

參考文獻

[1] W. J. Lee, S. W. Choi, C. E. Kim, G. W. Moon, “A new PWM-controlled quasi-resonant converter for a high efficiency PDP sustaining power module,” IEEE Trans. Power Electronics, Vol. 23, pp. 1782-1790, July 2008.

[2] S. Arulselvi, C. Subashini, G. Uma, “A new push-pull zero voltage switching quasi-resonant converter: topology, analysis and experimentation,” IEEE INDICON, 2005, pp. 482-486.

[3] R. J. Wai, C. Y. Lin, L. W. Liu, R. Y. Duan, “Voltage-clamped forward quasi-resonant converter with soft switching and reduced switch stress,“ Proc. IEE Electric Power Applications, Vol. 152, pp. 558-564, May 2005.

[4] W. A. Tabisz, P. Gradzki, F. C. Lee, “Zero-voltage-switched quasi-resonant buck and flyback converter – experimental results at 10 MHz,” IEEE Trans. Power Electronics, Vol. 4, pp.194-204, Apr. 1989.

[5] W. A. Tabisz, F. C. Lee, “Zero-voltage-switching multi-resonant technique – A novel approach to improve performance of high-frequency quasi-resonant converters,” in IEEE Power Electronics Specialists Conf., 1988, pp. 9-17

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降壓轉換器的低電壓與零電壓切換控制

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