具有降相最佳化之變頻同步整流 VRM 研製

Study and Design of a Variable Frequency Synchronous Rectified VRM with Phase Reduction Optimization

王瑞乾(Jui-Chien Wang)

指導教授 ： 歐勝源

國立臺北科技大學/電資學院/電機工程系研究所/碩士(2011年)

https://doi.org/10.6841/NTUT.2011.00066

摘要

本論文提出一種新型最佳化自動降相技術並結合切換頻率調變控制技術，適用於主機板上的同步整流降壓型轉換器。此種新型控制技術乃是當負載變輕時，降低總工作相數並提高切換頻率，而負載變重時，則提高總工作相數並降低切換頻率。藉由此新型控制技術可改善當負載變輕時，降低總工作相數而導致輸出電壓漣波增加的問題，並能提升輕載時的轉換效率。因應於輸出電壓漣波能控制在規範內，在本新型控制技術中必需設定一負載電流之臨界點，當負載高於此電流之臨界點時，不再降低切換頻率，藉由所提電路切換至定頻模式控制。最後，本論文研製一具八相同步整流降壓型轉換器，相較於傳統8相定頻切換控制技術，本文所提之新型控制技術其效率最高可改善30%。

關鍵字

切換頻率調變 ； 多相同步整流 ； 自動化降相 ； 輸出電壓漣波減少

並列摘要

This thesis proposes a novel control method that combines automatic phase reduction with switching frequency modulation and applies to the synchronous rectified buck converter on motherboards. The proposed novel control method decreases phases and increases switching frequency in light loads, on the contrary, increases phases and decreases switching frequency in heavy load. Due to the proposed novel control method, it can further improve output voltage ripple with phase reduction and increase the efficiency in light loads. To match the required output voltage specifications, a load current threshold is predetermined and the switching frequency is fixed as the load current is higher than the threshold. Finally, this paper implements an eight-phase synchronous rectified buck converter, compared to conventional constant frequency techniques, the efficiency can be increased up to 30% for eight-phase one under the proposed novel control method.

並列關鍵字

Switching frequency modulation ； Multiphase synchronous rectification ； Automatic phase reduction ； Output voltage ripple reduction

參考文獻

[1] Y. Ren, K. Yao and F. C. Lee, “Analysis of the power delivery path from the 12 V VR to the microprocessor,” in Proc. IEEE Applied Power Electron. Conference and Exposition, 2004, pp.285 – 291, .

[2] S. K. Mishra and K. D. T Ngo, “Dynamic Response Optimization of the Synthetic Ripple Modulator for a PointofLoad Converter with Adaptive Voltage Positioning,” in Proc. IEEE Compatibility and Power Electron., 2009, pp.402 – 405, USA.

[4] A. Barrado, A. Lazaro, R. Vazquez, V. Salas and E. Olias, “The Fast Response Double Buck DC–DC Converter (FRDB): Operation and Output Filter Influence,” IEEE Trans. Power Electron., vol.20, pp.1261 – 1270, 2005.

[5] M. Lee, C. Dan, K. Huang, C. W. Liu and T. Ben, “Modeling and Design for a Novel Adaptive Voltage Positioning (AVP) Scheme for Multiphase VRMs,” IEEE Trans. Power Electron., vol.23, pp.1733 – 1742, 2008.

[6] P. J. Liu, H. J. Chiu, Y. K. Lo and Y. J. E. Chen, “A Fast Transient Recovery Module for DC–DC Converters,” IEEE Trans. Ind. Electron., vol.56, pp.2522 – 2529, 2009.