本論文以數位控制實現適應性電壓準位(Adaptive Voltage Positioning, AVP)模式之切換式降壓型直流-直流轉換器。AVP模式在相同的輸出規格下相較於傳統模式可減少約一半的輸出電容值，大幅節省元件成本及電路面積。此外AVP模式具有電阻性輸出阻抗之特性，藉由調整電流量測參數(Ri)使其與輸出電容等效串聯阻抗(Rc)匹配，如此則能達到最佳化的暫態響應。實際上，Rc隨著電路元件以及操作環境改變並非一個定值，因此如何根據系統狀態自動調整Ri值便相當重要。相較於類比控制，數位控制由撰寫程式碼實現，能實現自動調控之演算法並與數位控制器整合。另外，傳統數位電流控制法取得電感電流的方法通常使用霍爾元件(Hall Sensor)搭配類比-數位轉換器(Analog to Digital Converter)，此兩者將耗費大量元件成本及面積。因此本論文採用自動電流估測之演算法，藉由數位控制器內部已知參數推導出電感電流值。
在電路實現上，本研究以PCB板實現12V轉1.2V的切換式降壓型直流-直流轉換器，搭配FPGA實現其數位控制器架構並整合上述兩種演算法。模擬與實驗結果顯示數位控制AVP模組能根據系統狀態自動調整控制器參數並達到最佳化輸出電壓響應。

A digitally controlled Buck converter for adaptive voltage positioning (AVP) scheme is proposed in this thesis. Compare to the traditional Buck converter, AVP scheme can reduce almost half numbers of the output capacitor for the same design specification and thus save more cost and circuit area. In addition, AVP scheme can perform optimal fast transient response if the resistive output impedance could be achieved by tuning the current sensing parameter (Ri) to be equal to the value of the output capacitor equivalent series resistor (Rc). Practically, Rc value is not constant and would varies with circuit components and operating environment. Therefore, an auto-tuning algorithm is beneficial to tuning the Ri value in accordance with the operating status. Compare to the analog control approach, digital control is programmable, which enables a possibility of integrating the auto-tuning algorithm into the controller. Furthermore, Hall Sensor as well as the analog to digital converter(ADC) are the traditional way to obtain the inductor current for digital current control. Both of two components seize most of cost and circuit area. This research also adopts a self-tuning inductor current estimator. The estimator uses the available circuit parameters to derive the inductor current by a current sensing algorithm.
The whole digital controller with two algorithms is realized by a FPGA board for the implementation of a PCB-layout 12V-to-1.2V switching Buck converter. Simulated and experimental results show that the digitally controlled AVP scheme is able to automatically tune the parameters of the controller for giving out optimal output voltage response.

1. Intel, Voltage Regulator Module (VRM) and Enterprise Voltage Regulator-Down (EVRD) 11.1 Design Guidelines. Doc.321736-002, Intel Corporation, Sep. 2009.
2. Qahouq, J.A.A. and V. Arikatla, Power Converter With Digital Sensorless Adaptive Voltage Positioning Control Scheme. IEEE Trans. Power Electronics., vol. 58, pp. 4105-4116, Sep. 2011.
3. Mishra, S.K., Design-Oriented Analysis of Modern Active Droop-Controlled Power Supplies. IEEE Trans. Power Electronics., vol. 56, pp. 3704-3708, Sep. 2009.
4. Julu, S., Z. Jinghai, X. Ming, and F.C. Lee, A Novel Input-Side Current Sensing Method to Achieve AVP for Future VRs. IEEE Trans. Power Electronics., vol. 21, pp. 1235-1242, Sep. 2006.
5. Yu-Cheng, L., C. Ching-Jan, C. Dan, and B. Wang, A Ripple-Based Constant On-Time Control With Virtual Inductor Current and Offset Cancellation for DC Power Converters. IEEE Trans. Power Electronics., vol. 27, pp. 4301-4310, Oct. 2012.
6. Shangzhi, P. and P.K. Jain, A New Digital Adaptive Voltage Positioning Technique with Dynamically Varying Voltage and Current References. IEEE Trans. Power Electronics., vol. 24, pp. 2612-2624, Nov. 2009.
7. Kaiwei, Y., X. Ming, M. Yu, and F.C. Lee, Design considerations for VRM transient response based on the output impedance. IEEE Trans. Power Electronics., vol. 18, pp. 1270-1277, Nov. 2003.
8. Lee, M., C. Dan, K. Huang, L. Chih-Wen, and T. Ben, Modeling and Design for a Novel Adaptive Voltage Positioning (AVP) Scheme for Multiphase VRMs. IEEE Trans. Power Electronics., vol. 23, pp. 1733-1742, July. 2008.
9. Eirea, G. and S.R. Sanders, Adaptive Output Current FeedforwardControl in VR Applications. IEEE Trans. Power Electronics., vol. 23, pp. 1880-1887, July. 2008.
10. Han-Hsiang, H., H. Chun-Yu, L. Jie-Yu, and C. Ke-Horng, Adaptive Droop Resistance Technique for Adaptive Voltage Positioning in Boost DC-DC Converters. IEEE Trans. Power Electronics., vol. 26, pp. 1920-1932, July.2011.
11. Saggini, S., M. Ghioni, and A. Geraci, An innovative digital control architecture for low-Voltage, high-current DC-DC converters with tight voltage regulation. IEEE Trans. Power Electronics., vol. 19, pp. 210-218, Jan. 2004.
12. Lukic, x, Z., S.S. Ahsanuzzaman, Z. Zhenyu, Prodic, and A. ele, Sensorless Self-Tuning Digital CPM Controller With Multiple Parameter Estimation and Thermal Stress Equalization. IEEE Trans. Power Electronics., vol. 26, pp. 3948-3963, Dec. 2011.
13. Kisun, L., F.C. Lee, W. Jia, and X. Ming, Analysis and Design of Adaptive Bus Voltage Positioning System for Two-Stage Voltage Regulators. IEEE Trans. Power Electronics., vol. 24, pp. 2735-2745, Dec. 2009.
14. Ching-Jan, C., C. Dan, H. Chun-Shih, M. Lee, and E.K.L. Tseng, Modeling and Design Considerations of a Novel High-Gain Peak Current Control Scheme to Achieve Adaptive Voltage Positioning (AVP) for DC Power Converters. IEEE Trans. Power Electronics., vol. 24, pp. 2942-2950, Dec. 2009.
15. Eirea, G. and S.R. Sanders, High Precision Load Current Sensing Using On-Line Calibration of Trace Resistance. IEEE Trans. Power Electronics., vol. 23, pp. 907-914, March 2008.
16. Yao, K., K. Lee, M. Xu, and F.C. Lee. Optimal design of the active droop control method for the transient response. in IEEE APEC.
17. Yao, K., Y. Ren, J. Sun, K. Lee, M. Xu, J. Zhou, and F.C. Lee. Adaptive voltage position design for voltage regulators. in IEEE APEC.
18. 黃晉益, 以數位控制實現之AVP模式切換式降壓型直流-直流轉換器. 國立成功大學電機工程學系電機研究所碩士論文, 2010.
19. 盧美如, 具AVP數位控制模式錯相電源轉換器之研製. 國立成功大學電機工程學系電機研究所碩士論文, 2011.
20. Patella, B.J., A. Prodic, A. Zirger, and D. Maksimovic, High-frequency digital PWM controller IC for DC-DC converters. IEEE Trans. Power Electronics., vol. 18, pp. 438-446, Jan. 2003.
21. Peng, H., A. Prodic, E. Alarcon, and D. Maksimovic, Modeling of Quantization Effects in Digitally Controlled DC-DC Converters. IEEE Trans. Power Electronics., vol. 22, pp. 208-215, Jan. 2007.
22. Peterchev, A.V., X. Jinwen, and S.R. Sanders, Architecture and IC implementation of a digital VRM controller. IEEE Trans. Power Electronics., vol. 18, pp. 356-364, Jan. 2003.
23. Peterchev, A.V. and S.R. Sanders, Quantization resolution and limit cycling in digitally controlled PWM converters. IEEE Trans. Power Electronics., vol. 18, pp. 301-308, Jan. 2003.
24. Corradini, L., P. Mattavelli, W. Stefanutti, and S. Saggini, Simplified Model Reference-Based Autotuningfor Digitally Controlled SMPS. IEEE Trans. Power Electronics., vol. 23, pp. 1956-1963, July. 2008.
25. Miao, B., R. Zane, and D. Maksimovic, System identification of power converters with digital control through cross-correlation methods. IEEE Trans. Power Electronics., vol. 20, pp. 1093-1099, Sep. 2005.
26. Shirazi, M., R. Zane, and D. Maksimovic, An Autotuning Digital Controller for DC-DC Power Converters Based on Online Frequency-Response Measurement. IEEE Trans. Power Electronics., vol. 24, pp. 2578-2588, Nov. 2009.
27. Stefanutti, W., P. Mattavelli, S. Saggini, and M. Ghioni, Autotuning of Digitally Controlled DC-DC Converters Based on Relay Feedback. IEEE Trans. Power Electronics., vol. 22, pp. 199-207, Jan. 2007.
28. Zhao, Z. and A. Prodic, Limit-Cycle Oscillations Based Auto-Tuning System for Digitally Controlled DC-DC Power Supplies. IEEE Trans. Power Electronics., vol. 22, pp. 2211-2222, Nov. 2007.
29. Zhenyu, Z., S.M. Ahsanuzzaman, and A. Prodic. ESR Zero Estimation and Auto-compensation in Digitally Controlled Buck Converters. in IEEE APEC.
30. Lukic, Z., Z. Zhenyu, S.M. Ahsanuzzaman, and A. Prodic. Self-tuning digital current estimator for low-power switching converters. in IEEE APEC.
31. Dallago, E., M. Passoni, and G. Sassone, Lossless current sensing in low-voltage high-current DC/DC modular supplies. IEEE Trans. Industrial Electronics, vol. 47, pp. 1249-1252, Dec. 2000.
32. Saggini, S., D. Zambotti, E. Bertelli, and M. Ghioni, Digital Autotuning System for Inductor Current Sensing in Voltage Regulation Module Applications. IEEE Trans. Power Electronics., vol. 23, pp. 2500-2506, Sep. 2008.
33. Simon-Muela, A., S. Petibon, C. Alonso, and J.L. Chaptal, Practical Implementation of a High-Frequency Current-Sense Technique for VRM. IEEE Trans. Industrial Electronics, vol. 55, pp. 3221-3230, Sep. 2008.
34. Yan, D., X. Ming, and F.C. Lee. DCR Current Sensing Method for Achieving Adaptive Voltage Positioning(AVP) in Voltage Regulators with Coupled Inductors. in IEEE PESC.
35. Ying, Q., H. Liu, and C. Xiyou, Digital Average Current-Mode Control of PWM DC-DC Converters Without Current Sensors. IEEE Trans. Power Electronics., vol. 57, pp. 1670-1677, May. 2010.
36. Kaiwei, Y., R. Yuancheng, and F.C. Lee, Critical bandwidth for the load transient response of voltage regulator modules. IEEE Trans. Power Electronics., vol. 19, pp. 1454-1461, Nov. 2004.
37. Pit-Leong, W., F.C. Lee, X. Peng, and Y. Kaiwei, Critical inductance in voltage regulator modules. IEEE Trans. Power Electronics., vol. 17, pp. 485-492, July. 2002.
38. Corradini, L., P. Mattavelli, E. Tedeschi, and D. Trevisan, High-Bandwidth Multisampled Digitally Controlled DC-DC Converters Using Ripple Compensation. IEEE Trans. Industrial Electronics, vol. 55, pp. 1501-1508, April. 2008.
39. Guang, F., E. Meyer, and L. Yan-Fei, A New Digital Control Algorithm to Achieve Optimal Dynamic Performance in DC-to-DC Converters. IEEE Trans. Power Electronics., vol. 22, pp. 1489-1498, July. 2007.
40. Haitao, H., V. Yousefzadeh, and D. Maksimovic, Nonuniform A/D Quantization for ImprovedDynamic Responses of Digitally ControlledDC-DC Converters. IEEE Trans. Power Electronics., vol. 23, pp. 1998-2005, July. 2008.