臺灣大學: 電機工程學研究所陳德玉陳永任Chen, Yung-JenYung-JenChen2013-03-272018-07-062013-03-272018-07-062012http://ntur.lib.ntu.edu.tw//handle/246246/253931穩壓器(Voltage Regulator)目前已被廣泛使用在許多電腦相關產品上，來提供能量給中央處理器(CPU)。提升轉換器在重載情況下的轉換效率一直是過去設計的重點所在。直到近幾年，考慮到許多直流轉直流電壓轉換器大多時間是運作在輕載或是待機的狀態，在現今電腦產品大量應用的時代，輕載時的能量損失加總起來就變得非常可觀。 為了解決上述的挑戰，固定導通時間的控制方法近幾年來工業界受到高度的重視。固定導通時間的控制架可以提升輕載時的轉換效率，同時又保持重載時原本的效率。有許多的電路架構都可以使用固定導通時間的控制方法，而本論文主要探討固定導通時間電流模式的控制架構，並應用在降壓型直流電源轉換器上，同時有著適應性電壓定位的功能。其中，電流模式可以達到相電流平衡的優點，而適應性電壓定位則是為了符合INTEL與節能的規範。 本篇論文中主要探討電路回授的穩定性與達成固定輸出阻抗，固定輸出阻抗為達到應性電壓定為功能的主要考量。電路的小訊號模型將藉由描述函數(Describing-function) 來推導，過程雖然較複雜，但是卻是了解固定導通時間電流模式控制之特性所不可或缺的。模擬與實驗的結果將呈現在本篇論文中，並且與其他固定導通時間之電路架構也會做個比較。Voltage regulators have been widely used in many computer applications for powering the central processing units (CPU). Converter efficiency has always been a design priority but most emphasis had been placed on the efficiency under the heavy-load conditions until recent years. Considering the fact that most of the DC converters are operating under light-load or standby conditions most of the time, the total energy loss is significant especially considering the number of computers used today. To meet the challenges described above, constant on-time (COT) control scheme has received much attention by industry recently. COT control scheme features improved light-load efficiency while preserving heavy-load efficiency. There are various of constant on-time control schemes. The focus of the present thesis is on the current-mode COT scheme (COTCM) applied to a buck converter with adaptive voltage positioning (AVP) feature. Current mode control is considered because it features inherent channel current balancing. AVP is considered because that’s the feature imposed by computer chip maker INTEL Corp. for the purpose of energy saving. In this thesis, the focus of investigation is on the circuit feedback stability and the converter output impedance which is an important consideration to achieve AVP function. A small-signal model is developed based on describing-function approach which is complicated but necessary to uncover the inherent nature of this control scheme. Experimental results will be shown. A comparison with other COT control schemes will also be given.4576515 bytesapplication/pdfen-US穩壓器適應性電壓定位固定導通時間控制電流模式輸出阻抗描述函數穩定度條件Voltage Regulator (VR)Adaptive Voltage Position (AVP)Constant on-time controlCurrent mode controlOutput impedanceDescribing FunctionStability criteriathesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/253931/1/ntu-101-R99921019-1.pdf