應用於直流-直流轉換器之雙相數位脈寬調變控制器

摘要當CMOS製程技術不斷地提升，更多的電晶體能夠整合於一單晶片中。因為一些大型數位電路如ASIC與處理器消耗很大的功率，往往需要複雜的功率控制機制降低功率消耗。由於頻繁地由睡眠模式切換至正常工作模式，於是供應這些大型數位電路的電源便產生巨大的電流變動。因此，一個能驅動大電流與提供穩壓功能的切換式直流-直流轉換器便成為供應這些大型數位電路電源不可缺少的電路。一個雙相切換式直流-直流轉換器相對於單相切換式直流-直流轉換器而言，不但能提供更大的電流，還降低輸出電壓的漣波。但是存在於兩組功率級之間的些微差異會造成彼此的電流產生不平衡的狀況，使得系統的可靠度降低。因此必須加上電流平衡機制來改善這個問題。目前商用的雙相切換式直流-直流轉換器的控制方式幾乎全是類比控制系統。然而類比控制器不但容易受到製程漂移與雜訊的影響，也較沒有設計的彈性。一個可程式化，數位控制的雙相切換式直流-直流轉換器將會在論文中討論。採用單一電流迴路與單一電壓回路的架構來簡化迴路的複雜度。並透過電壓迴路幫助電流迴路校準兩組功率級之間電流差異。這個控制器由0.35微米CMOS製程實現，基本的功能已由實驗結果得到驗證。此外，由於切換式穩壓器會產生電磁干擾的問題，因此需要外部濾波器來濾除電磁干擾，在本論文中，我們基於雙相脈寬調變器的架構下衍生出頻率調變控制機制來減輕電磁干擾。這個頻率調變控制器由0.35微米CMOS製程實現，其降低電磁干擾的功能已由實驗驗證。

關鍵字

數位脈寬調變控制器；直流-直流轉換器

並列摘要

Abstract Due to rapid development of CMOS technologies, more and more transistors can be fabricated on a single chip. Since these large digital circuits such as the processors and ASICs need the large power consumption, the complicated power control technique must be adopted to reduce power consumption. There is a large current step in the voltage supply sources of ASICs and processors because of frequently switching from the sleep mode to the hot-run mode. Consequently, a switching DC-DC converter with large current driving ability and tight voltage regulation is inevitable for the voltage supply sources of ASICs or processors. A dual-phase switching DC-DC converter has larger current driving ability than a single-phase one. Besides, the output voltage ripple can be reduced in the dual-phase architecture. However, the mismatch of two power stages in dual-phase architecture will produce current sharing between them, and system reliability decreases. Hence, the current balancing technique has to be used to improve this phenomenon. Commercial solutions for dual-phase switching DC-DC converters are almost realized by analog circuits. However, the analog control scheme is sensitive to the process variation and noise, and has low design flexibility. In this thesis, a programmable, dual-phase digital PWM DC-DC converter will be introduced. A simple current balancing approach is used to simplified loop complexity. There are only one current loop and an inherent voltage loop to calibrate difference current level between two power stages to minimize the system complexity. This controller has been realized by 0.35um CMOS process, and the functionalities of this circuit have been verified by the measurement results. Moreover, because a switching regulator will generate electronic magnetic interference (EMI), it is necessary to add external EMI filters to alleviate this phenomenon. In this thesis, we present a frequency-modulation mechanism based on a dual-phase digital PWM to alleviate the problem of EMI. This frequency-modulation controller has been fabricated by 0.35um CMOS process, and the function of EMI reduction has been verified by the experimental results.

並列關鍵字

Digital PWM Controllers ； DC-DC Converters

參考文獻

[1] G.-Y. Wei and M. Horowitz, “A fully digital, energy-efficient, adaptive power-supply regulator,” IEEE J. of Solid-State Circuits, Vol 34, No.4, pp.520-528, April 1999.

[2] A. Peterchev, J. W. Xiao, and S. Sanders, “Architecture and IC implementation of a digital VRM controller,” IEEE Trans. Power Elec., no. 1,pp. 356–364, Jan. 2003.

[3] B. J. Patella, A. Prodic, A. Zirger, and D. Maksimovic, “High-frequency digital controller IC for dc/dc converters,” in Proc. IEEE Apply Power Electron. Conf., vol 1, pp. 374-380, 2002.

[4] A. P. Dancy and A. P. Chandrakasan, “Ultra low power control circuits for PWM converters,” in Proc. IEEE Power Electron. Spec. Conf., vol. 1, pp. 21-27, 1997.

[5] B. Razavi, “Principles of Data Conversion System Design”, Wiley-Interscience, 1995.

國際替代計量

應用於直流-直流轉換器之雙相數位脈寬調變控制器

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