Tapped-inductor buck converter for high-step-down DC-DC conversion

• Published in: IEEE transactions on power electronics Vol. 20; no. 4; pp. 775 - 780
• Main Authors: Kaiwei Yao, Mao Ye, Ming Xu, Lee, F.C.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-07-2005; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Buck converters; Circuit topology; Circuits; Clamps; Conversion; Electric currents; Electric potential; Electrical engineering. Electrical power engineering; Exact sciences and technology; High-step-down dc-dc converter; Inductance; Inductors; Leakage; lossless clamp circuit; Low voltage; Magnetic separation; Power electronics, power supplies; Power supply; Pulse width modulation; Spikes; Switches; Switching; tapped inductor; Transformers; Voltage; Performance evaluation; Waveform; Lossless circuit; lossless clamp circuit; Power electronics; Leakage flux; Experimental study; Inductor; DC-DC power convertors; Step down convertor; Experimental result; tapped inductor; High-step-down dc-dc converter
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2005.850920

The narrow duty cycle in the buck converter limits its application for high-step-down dc-dc conversion. With a simple structure, the tapped-inductor buck converter shows promise for extending the duty cycle. However, the leakage inductance causes a huge turn-off voltage spike across the top switch. Also, the gate drive for the top switch is not simple due to its floating source connection. This paper solves all these problems by modifying the tapped-inductor structure. A simple lossless clamp circuit can effectively clamp the switch turn-off voltage spike and totally recover the leakage energy. Experimental results for 12V-to-1.5V and 48V-to-6V dc-dc conversions show significant improvements in efficiency.