高效率20MHz切換頻率電流模式降壓電源轉換器設計

Design of a High-Efficiency 20MHz Switching Frequency Current-Mode Buck Converter

王世賢(Shih-Sian Wang)

指導教授 ： 劉萬榮

共同指導教授 ： 林嘉洤(Jia-Chuan Lin)

國立臺北大學/電機資訊學院/電機工程研究所/碩士(2013年)

摘要

可攜式電子産品的應用上，提高轉換較率和縮小體積是不斷追求進步的目標。為了降低電源轉換器所需的體積，以提高切換頻率的方式大幅降低外接被動元件的尺寸。然而，對於傳統電壓控制模式之電源轉換器並不適合操作於高頻切換，因為使用到的控制電路頻寬被限制住，換句話說，由於控制電路頻寬不足會造成不正確的操作且無法跟上系統的操作頻率。為了確保電壓轉換器可以在高頻率切換下操作，電流脈波寬度調變控制將在本論文採用。

雖然以提高切換頻率降低外部元件尺寸，但提高切換頻率相對的會造成切換損失的增加，因此本論文提出多組切換開關控制，在不同負載下啟用不同數量的Power MOSFET，因此可以在不同負載情況下將切換損失最佳化，以提升整體轉換效率。由於使用了電流模式脈波控制，減少了外部補償元件使得操作電路更為簡單，且控制訊號全都轉為電流訊號讓各個子電路之間的傳遞更加快速。而得到更好的輸入電壓節率與負載調節率也是使用電流模式脈波控制的優點之一。

本篇論文實現了『高效率 20 MHz 切換頻率電流模式降壓電源轉換器設計』，且以台灣積體電路製造股份有限公司點三五微米互補式金氧製程來實現，輸入電壓從2.7伏特到4.2伏特，系統特色為可使用較小的外部被動元件且可得到較快的暫穩響應，其中電感大小只需200nH、輸出電容值只需5uF，非常適於可攜式電子産品之電源管理。

關鍵字

轉換器 ； 電流模式 ； 高頻切換 ； 脈波寬度調變 ； 多開關控制

並列摘要

In the applications of portable electronics products, high efficiency, and on-chip integration is highly desired. Relatively small size, less component counts will reduce the power consumption thus it helps to improve the switching frequency. However, the conventional voltage control mode is not suitable for high frequency operation, because the bandwidth is limited. When the control circuit has a limited bandwidth, improper operation of the system may occur. In order to ensure that the voltage converter can be operated at high frequency, a switching current pulse width modulation is proposed in this paper.
Reducing component size of the system will result to increase in switching frequency, and this increases switching loses as well. In this thesis, the power MOSFET is tested at a switch control mode in different loading conditions. At different loading conditions switching losses is examined and optimized to improve the overall conversion efficiency. A current-mode pulse-width control is used to reduce external compensation components to make the system simpler and making the control signal transmission faster; these improves the conversion rate and load regulation of the system.

This paper presents a High efficiency 20 MHz switching frequency current mode step-down power converter design and implemented in Taiwan Semiconductor Manufacturing Company using a 0.35-micron CMOS process. The input voltage ranges from 2.7 volts to 4.2 volts. The system is optimized by using smaller external passive components. With inductor size of 200nH, the system exhibit a faster response and more stable. The output capacitor is 5uF, in which it is ideal for portable electronic product power management application.

並列關鍵字

converte ； current-mode ； high frequency switching ； pulse width modulation ； multi-switch control

參考文獻

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