臺灣博碩士論文加值系統

本論文設計一個直流同步降壓型轉換器，並且採用40V的雙載子電晶體製程來模擬。整個電路主要使用的是電壓模式的PWM直流電壓轉換器操作電壓在+4.3V到20V之間。模擬的結果顯示內部振盪器的震盪頻率為200 kHz。藉由底端N-MOSFET的RDS (ON)，我們可以建立一個電流限制的保護機制。柔性啟動功能可以保護開機瞬間，因為突波的大電流所造成的損壞。過熱保護機制可以在溫度超過攝氏150度時，保護整個系統。

A DC-DC synchronous buck converter with soft start has been designed and simulated with 40V bipolar process. The overall circuit is designed based on a voltage-mode PWM controlled converter. The input voltage range is from +4.3V to +20V. Simulation results show that this converter with on-chip current sensor can operate at 200 kHz. The current limit is implemented by sensing the voltage drop across the bottom N-MOSFET RDS (ON). The soft start function is used to prevent large inrush currents upon power-up. The internal thermal protection circuit can protect the system when the temperatures exceed 150°C.

TABLE OF CONTENTS
ABSTRACT i
摘要 ii
LIST OF FIGURES v
LIST OF TABLES vii
CHAPTER 1 INTRODUCTION 1
1.1 Motivation and Research Methods 1
1.2 The Thesis Organization 3
CHAPTER 2 THE STEP-DOWN SYSTEM 4
2.1 Principle of Step-down System 4
2.2 Synchronous Step-down Converter 8
2.3 Stable Compensation of Buck Step-down Network 9
CHAPTER 3 SYSTEM BLOCKS AND CIRCUIT 17
3.1 Error Amplifier 19
3.2 GAP 25
3.2.1 The concept of bandgap reference circuit 27
3.2.2 Bandgap 29
3.2.3 IPAT (Inversely proportional to absolute temperature) 31
3.2.4 TSD (Thermal shut down) 33
3.3 UVLO (Under Voltage Lock Out) 34
3.4 OSC (Oscillator) 40
3.5 CS (Current Sensing) 44
3.6 SS (Soft Start) 47
3.7 PWM 50
3.8 DRV (Driver) 53
CHAPTER 4 THE SYSTEM APPLICATION AND SIMULATION 56
4.1 Application Circuits 56
4.2 Compensation Network 57
4.3 Simulation Result 59
4.4 Chip Layout 64
CHAPTER 5 CONCLUSIONS 67
REFERENCES 68

[1] 蔣忠誠,類比IC電路設計入門, 全華科技圖書股份有限公司, 1985.
[2] B. Razavi, Design of analog CMOS integrated circuit, John Wiley & Sons, 2002.
[3] A. B. Grebene, Bipolar and MOS analog integrated circuit design, John Wieley & Sons. Inc, 1984.
[4] C. F. Lee and P. K. T. Mok, “A monolithic current-mode CMOS DC–DC converter with on-chip current-sensing technique,” IEEE J. of solid-state circuits, vol. 39, no. 1, Jan. 2004.
[5] 江炫樟,Power Electronics電力電子學,全華科技圖書股份有限公司,1991
[6] 梁適安,交換式電源供給器之理論與實務設計,全華科技圖書股份有限公司,1984.
[7] M. Darwish, “Advanced power devices for DC-DC conversion,” in proc Microelectronics int. conf, May 2004.
[8] M. Darwish, “Next-generation semiconductors for DC-to-DC converters,” in proc Bipolar/BiCMOS Circuits and Technology meeting, pp. 5 -21, Sept. 2003.
[9] Sipex, “Selecting Appropriate Compensation: Type-II or Type-III Application Note #ANP18”.
[10] Semtech, “Synchronous Voltage-Mode Controller for Distributed Power-Supply Applications”, 2004.
[11] M. Qiao, P. Parto and R. Amirani,” Application Note AN-1043”, International Rectifier, Oct. 2002.
[12] 徐康禹,“Current Mode Bandgap Voltage Reference,＂逢甲大學, 電機工程研究所, 碩士論文,民國90年.
[13] M. Green, K. Hayatleh, B. L. Hart and F. J. Lidgey,” PTAT direct current converter for bias circuit applications,” Electronics Letters, Vol 42, pp.530 – 531, Apr. 2006.
[14] A. Hastings, The art of analog layout, Prentice Hall, 2001.