Improvement of power-conversion efficiency at light-load using a variable-duty burst mode

Abstract

This paper proposes a new burst-mode driving method to increase the power-conversion efficiency (PCE) of a power supply at light load. The burst mode minimizes the power consumption by stopping the converter operation when load is light. The proposed method changes the off-period of the converter according to the load to achieve optimized efficiency across the entire load range. The PCE at 6% load was measured as 83.6% and 85.1% for 75-W flyback and LLC Half-bridge converters, repectively, when applying the proposed burst mode; these values were 8% and 16.5% higher respectively than those for the converters without it. Index Terms-Light load efficiency, power-conversion, dc-dc converter.Kyungmin Lee received the B.. His current research interests include the design of drive circuits for display devices and the modeling and characterization of semiconductor devices..

Efficient and Zero Net Energy-Ready Plug Loads

“…Past works have proposed numerous standby solutions for many applications. Of these solutions, the most relevant to this paper are burst mode (Lo, Yen, and Lin 2008;Lee et al 2013;B.-C. Kim, Park, and Moon 2011;Huh et al 2004), sleep transistors (Jiang, Marek-Sadowska, and Nassif 2005;Shi and Howard 2006;Long and He 2004;Fallah and Pedram 2005;Fukuoka et al 2013Fukuoka et al , 2012Chao and Harrison 2008), optical wake-up (Kang et al 2011;Serikawa 2015a, 2015b), and wake-up radio (Demirkol, Ersoy, and Onur 2009;Magno et al 2014;Umeda and Otaka 2007;Gamm et al 2010;Oller et al 2013). As shown in Figure 4, these solutions contribute to the growing standby reduction portfolio.…”

“…Burst mode is a control method for switching power converters that was developed in the early 2000s to address standby consumption (Lo, Yen, and Lin 2008;Lee et al 2013;B.-C. Kim, Park, and Moon 2011;Huh, Kim, and others 2004). Lightly loaded power converters are generally inefficient because of losses in switching and control that are constant regardless of the output power.…”

A Novel Analysis Method and Corresponding Voltage Regulation Strategy for LLC Resonant Converter

“…Although it is easy to achieve, regarding the output voltage as a criterion of judging light load is not accurate. [14] adopted the output current saw tooth wave comparative intermittent control, which reduced noise, but did not limit the output voltage, which may cause overvoltage. [15] proposed an optimal efficiency intermittent control, while the fluctuation of output voltage cannot be limited.…”

Burst FM Control of LLC Resonant Converter with Multiplier for High Efficiency and Low Ripple in TWT Power Supply

“…Although the methods in the above literature can avoid the high frequency of resonant converter under light load, the efficiency is still very low in the case of extremely light load because of the circulating current. Many researchers have explored burst control methods [6][7][8][9][10][11][12][13][14][15][16][17][18][19]. In the burst control mode, the normal FM control is adopted during burst-on and the switches are completely closed during burst-off to prevent switching or conduction losses.…”

“…In Refs. [6][7][8][9][10][11][12][13][14][15][16][17], burst mode control methods were applied in the LLC converter to increase the efficiency at light load. In Ref.…”