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http://dx.doi.org/10.5573/ieie.2015.52.3.059

Improving the Light-Load Efficiency of a LDO-Embedded DC-DC Buck Converter Using a Size Control Method of the Power-Transistor  

Kim, Hyojoong (Department of Electronic Engineering, Soongsil University)
Wee, Jaekyung (Department of Electronic Engineering, Soongsil University)
Song, Inchae (Department of Electronic Engineering, Soongsil University)
Publication Information
Journal of the Institute of Electronics and Information Engineers / v.52, no.3, 2015 , pp. 59-66 More about this Journal
Abstract
In this paper, we propose a method of improving the light-load efficiency of DC-DC buck converter using 4bit SAR-ADC (Successive Approximation ADC) for a LDO or a power transistor size selection technique. The proposed circuit selects power transistor sizes depending on load current so that improves the light-load efficiency of the DC-DC buck converter. For this, we select the power transistor size with a cross point of the switching loss and the conduction loss. Also, when the IC operates in standby mode or sleep mode, a LDO mode is selected for improving the efficiency. The proposed circuit selects power transistor sizes(X1, X2, X4, X8) with 4 bits and its efficiency is higher about the maximum of 25% at the light-load than that of a single transistor size. Input voltage and output voltage are 5V and 3.3V for maximum load currents of 500mA.
Keywords
DC-DC Buck Converter; Power Transistor Sizes; Light-Load Efficiency;
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Times Cited By KSCI : 1  (Citation Analysis)
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1 Ahn, Y.; Jeon, I.; Roh, J., "A Multiphase Buck Converter With a Rotating Phase-Shedding Scheme For Efficient Light-Load Control," Solid-State Circuits, IEEE Journal of, vol.49, no.11, pp.2673,2683, Nov. 2014.   DOI   ScienceOn
2 Wei Yan; Wenhong Li; Ran Liu, "A Noise-Shaped Buck DC-DC Converter With Improved Light-Load Efficiency and Fast Transient Response," Power Electronics, IEEE Transactions on , vol.26, no.12, pp.3908,3924, Dec. 2011.   DOI   ScienceOn
3 Alghamdi, M.K.; Hamoui, A.A., "A Spurious Free Switching Buck Converter Achieving Enhanced Light-Load Efficiency by Using a ${\Delta}{\Sigma}$-Modulator Controller With a Scalable Sampling Frequency," Solid-State Circuits, IEEE Journal of , vol.47, no.4, pp.841,851, April 2012   DOI   ScienceOn
4 Gandhimathi, C., "DC-DC converter with improved light load efficiency and transient response," Communications and Signal Processing (ICCSP), 2013 International Conference on, vol., no., pp.176,180, 3-5 April 2013.
5 Chu-Hsiang Chia; Pui-Sun Lei; Chang, R.C.-H., "A high-efficiency PWM DC-DC buck converter with a novel DCM control under light-load," Circuits and Systems (ISCAS), 2011 IEEE International Symposium on, vol., no., pp.237,240, 15-18 May 2011.
6 Chu-Hsiang Chia; Pui-Sun Lei; Chang, R.C.-H., "A high-speed converter with light-load improvement circuit and transient detector," Circuits and Systems (ISCAS), 2012 IEEE International Symposium on, vol., no., pp.456,459, 20-23 May 2012.
7 Xiaohan Gong; Jinhua Ni; Zhiliang Hong; Liu, B., "An 80% peak efficiency, 0.84mW sleep power consumption, fully-integrated DC-DC converter with buck/LDO mode control," Custom Integrated Circuits Conference (CICC), 2011 IEEE , vol., no., pp.1,4, 19-21 Sept. 2011.
8 Mary, N.J.M.S.; Maity, A.; Patra, A., "Light Load Efficiency Improvement in High Frequency DC-DC Buck Converter Using Dynamic Width Segmentation of Power MOSFET," VLSI Design and 2014 13th International Conference on Embedded Systems, 2014 27th International Conference on, vol., no., pp.563,568, 5-9 Jan. 2014.
9 Musunuri, S.; Chapman, P.L., "Optimization of CMOS Transistors for Low Power DC-DC Converters," Power Electronics Specialists Conference, 2005. PESC '05. IEEE 36th , vol., no., pp.2151,2157, 16-16 June 2005
10 Baei, M.; Moschopoulos, G., "An investigation into the use of active snubbers to improve light-load converter efficiency," Telecommunications Energy Conference (INTELEC), 2011 IEEE 33rd International, vol., no., pp.1,7, 9-13 Oct. 2011.
11 Microchip Technology, Datasheet of AN1471, 2012.
12 Chi Yat Leung; Mok, P.K.T.; Ka Nang Leung; Chan, M., "An integrated CMOS current-sensing circuit for low-Voltage current-mode buck regulator," Circuits and Systems II: Express Briefs, IEEE Transactions on, vol.52, no.7, pp.394,397, July 2005.   DOI
13 Ji-Hoon Lim, Jae-Kyung Wee, Inchae Song "A Low Area and High Efficiency SMPS with a PWM Generator Based on a Pseudo Relaxation-Oscillating Technique," Journal of The Institute of Electronics Engineers of Korea Vol. 50, NO. 10, October 2013
14 Kui Ma; Fa-shun Yang; Jie-xing Lin; Xing-hua Fu, "A segmented output strategy for improving efficiency of DC-DC converter," Electronics, Communications and Control (ICECC), 2011 International Conference on, vol., no., pp.670,672, 9-11 Sept. 2011.