對切換式電源供應器來說，在輕載或無載時的能量損耗是一個相當重要的議題。為了降低待機模式的能量損失，許多國際組織如能源之星及歐盟執委會已經對電源供應器制定各級的能量消耗標準。降低切換式電源供應器的能量損失，最有效的方法是降低切換頻率。因此，在輕載時，切換式穩壓器所使用的脈寬調變控制器必須具備有頻率調變的功能。在本論文中，藉由非導通時間調變的概念，設計一個具省電模式電路的脈寬調變控制晶片。此省電模式將會依據負載的減少，適度降低切換頻率以減少切換損失。為了達到更好的效能，前沿遮蔽消隱、軟啟動、斜率補償以及過電壓保護等功能，亦將整合於所提出的晶片中。本晶片是使用0.35μm 2P4M 3.3V/5V 混合訊號互補式金氧半製程來製作。

The energy consumption at light-load or no-load conditions is a very important issue in switching power supply design. In order to lower the energy losses at the standby mode, many international organizations like ENERGY STAR and the European Commission (EC) have stipulated various criteria of energy consumption for external power supplies. To decrease the power consumption of a switching power supply, the most effective approach is to lower the switching frequency. Hence, the pulse width modulation (PWM) controller used in a switching regulator must be capable of frequency modulation at the light-load condition. In this thesis, by the concept of off-time modulation, the green mode circuit is designed in this proposed PWM controller. The reduction in switching frequency and switching losses will be in proportion to the load decrease at light-load condition. For the purpose of better performance, the functions such as leading edge blanking (LEB), soft start, slope compensation, and over voltage protection (OVP) are also integrated into the proposed chip. This chip is fabricated by 0.35μm 2P4M 3.3V/5V Mixed Signal CMOS Process.

[1] R. W. Erickson, and D. Maksimovic, Fundamental of Power Electronics, 2nd ed., Boston, MA: Kluwer Academic, 2001.
[2] N. Mohan, T. M. Undeland, and W. P. Robbins, Power Electronics: Converters, Applications and Design, 3rd ed., New York: John Wiley & Sons, 2003.
[3] A. I. Pressman, Switching Power Supply Design, 2nd ed., New York: McGraw-Hill, 1998.
[4] Energy Star, “Energy star program requirements for external power supplies,” version 1.1, March 2006.
[5] European Commission, “External power supplies code of conduct,” version 2, Nov. 24, 2004.
[6] “Source resistance: the efficiency killer in DC-DC converter circuits,” Maxim Inc., Application Note AN3166, Apr. 06, 2004.
[7] R. Mammano, “Switching power supply topology voltage mode vs. current mode,” Texas Instruments Inc., Design Note DN-62, June 27, 1994.
[8] R. B. Ridley, “Current mode or voltage mode?,” Switching Power Magazine, Oct. 2000.
[9] I. M. Gottlieb, Power Supplies Switching Regulators, Inverters, and Converters, 2nd ed., New York: McGraw-Hill, 1994.
[10] K. H. Billings, “Switchmode Power Supply Handbook,” 2nd ed., New York: McGraw-Hill, 1999.
[11] H. D. Venable, “Current mode control,” Venable Instruments Inc., Technical Paper TP-05.
[12] “Modeling, analysis, and compensation of the current-mode converter,” Texas Instruments Inc., Application Note U-97, 1999.
[13] “NCP1230 Low-standby power high performance PWM controller,” rev. 8, ON Semiconductor Corp., Nov. 2006.
[14] “LD7575 Green-mode PWM controller with high-voltage start-up circuit,” rev. 3, Leadtrend Technology Corp., July 2006.
[15] “SG6848 Low-cost green-mode PWM controller for flyback converters,” version 1.3, System General Inc., Jan. 27, 2006.
[16] M. Brown, Power Supply Cookbook, 2nd ed., Boston, MA: Newnes, 2001.
[17] M. Brown, Practical Switching Power Supply Design, San Diego: Academic Press, 1990.
[18] M. Oloughlin, “Bootstrap circuit for green mode applications,” Texas Instruments Inc., Application Report SLUA-373, Jan. 2006.
[19] H. S. Choi, and D. Y. Huh, “Techniques to minimize power consumption of SMPS in standby mode,” in Power Electronics Specialists Conference 36th, Recife, Brazil, June 2005, pp. 2817-2822.
[20] M. Rayabhari, “Cutting stand-by power,” Power Engineer, Apr. 2003.
[21] T. Yang, “PWM controller having off-time modulation for power converter,” U.S. patent 6545882, Aug. 2001, System General Inc.
[22] D. Johns, and K. Martin, Analog Integrated Circuit Design, New York: John Wiley & Sons, 1997.
[23] R. Gregorain, Introduction to CMOS OP-Amps and Comparators, New York: John Wiley & Sons, 1999.
[24] B. Razavi, Design of Analog CMOS Integrated Circuits, New York: McGraw-Hill, 2001.
[25] K. N. Leung, and K. T. Mok, “A sub-1-V 15-ppm/°C CMOS bandgap voltage reference without requiring low threshold voltage device,” IEEE J. Solid-State Circuits, vol. 37, no. 4, pp. 526-529, Apr. 2002.
[26] K. N. Leung, and K. T. Mok, “Design considerations of recent advanced low-voltage low-temperature-coefficient CMOS bandgap voltage reference,” IEEE Custom Integrated Circuits Conference, Orlando, Florida, USA, pp. 635-642, Oct. 2004.
[27] “Technical review of low dropout voltage regulator operation and performance,” Texas Instruments Inc., Application Report SLVA-072, Aug. 1999.
[28] S. K. Lau, K. N. Leung, and P. K. T. Mok, “Analysis of low-dropout regulator topologies for low-voltage regulation,” IEEE Conference on Electron Devices and Solid-State Circuits, pp. 379-382, Dec 2003.

[29] “UCC3813 Low power economy BiCMOS current mode pwm,” Texas Instruments Inc., Datasheet SLUS-161A, Jan. 2005.
[30] “UCC 3800/1/2/3/4/5 BiCMOS current mode control ICs,” Texas Instruments Inc., Application Note U-133A, 1999.
[31] R. S. Sandige, Digital Design Essentials, New Jersey: Prentice-Hall, 2001.