A novel winding-coupled buck converter for high-frequency, high-step-down DC-DC conversion

This paper analyzes the fundamental limitations of the buck converter for high-frequency, high-step-down dc-dc conversion. Further modification with additional coupled windings in the buck converter yields a novel topology, which significantly improves the efficiency without compromising the transient response. An integrated magnetic structure is proposed for these windings so that the same magnetic cores used in the buck converter can be used here as well. Furthermore, it is easy to implement a lossless clamp circuit to limit the device voltage stress and to recover inductor leakage energy. This new topology is applied for a 12V-to-1.5V/25A voltage regulator module (VRM) design. At a switching frequency of 2MHz, over 80% full-load efficiency is achieved, which is 8% higher than that of the conventional buck converter.

[1]  J. Drobnik,et al.  PC platform power distribution system-past application, today's challenge and future direction , 1999, 21st International Telecommunications Energy Conference. INTELEC '99 (Cat. No.99CH37007).

[2]  Fred C. Lee,et al.  Investigation of candidate VRM topologies for future microprocessors [voltage regulator modules] , 1998, APEC '98 Thirteenth Annual Applied Power Electronics Conference and Exposition.

[3]  S. Ben-Yaakov,et al.  A SPICE compatible model of tapped-inductor PWM converters , 1994, Proceedings of 1994 IEEE Applied Power Electronics Conference and Exposition - ASPEC'94.

[4]  B. H. Cho,et al.  Analysis and interpretation of loop gains of multiloop-controlled switching regulators (power supply circuits) , 1988 .

[5]  Peng Xu,et al.  Comparison of three topology candidates for 12 V VRM , 2001, APEC 2001. Sixteenth Annual IEEE Applied Power Electronics Conference and Exposition (Cat. No.01CH37181).

[6]  Yu Meng,et al.  Tapped-inductor buck converters with a lossless clamp circuit , 2002, APEC. Seventeenth Annual IEEE Applied Power Electronics Conference and Exposition (Cat. No.02CH37335).

[7]  Peng Xu,et al.  The active-clamp couple-buck converter-a novel high efficiency voltage regulator modules , 2001, APEC 2001. Sixteenth Annual IEEE Applied Power Electronics Conference and Exposition (Cat. No.01CH37181).

[8]  Peng Xu,et al.  Static and dynamic modeling of the active clamp coupled-buck converter , 2001, 2001 IEEE 32nd Annual Power Electronics Specialists Conference (IEEE Cat. No.01CH37230).

[9]  J. Sebastián,et al.  Static and dynamic modeling of tapped-inductor dc-to-dc converters , 1987, IEEE Power Electronics Specialists Conference.

[10]  Fred C. Lee,et al.  Design considerations for VRM transient response based on the output impedance , 2003 .