High-speed switching of the power transistor in a DC-DC converter with current feedback and core saturation

To reduce the size and weight of a switching dc‐dc converter, it is effective to increase its switching frequency. This requires the reduction of the switching time and switching loss. This paper introduces a dc‐dc converter with a short turn‐off time and a high efficiency at a switching frequency u...

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Bibliographic Details
Published inElectronics & communications in Japan. Part 2, Electronics Vol. 69; no. 7; pp. 60 - 68
Main Authors Harada, Koosuke, Sakamoto, Hiroshi, Shoyama, Masahito
Format Journal Article
LanguageEnglish
Published New York Wiley Subscription Services, Inc., A Wiley Company 1986
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Summary:To reduce the size and weight of a switching dc‐dc converter, it is effective to increase its switching frequency. This requires the reduction of the switching time and switching loss. This paper introduces a dc‐dc converter with a short turn‐off time and a high efficiency at a switching frequency up to the order of megahertz. This is achieved by using a bipolar transistor with current feedback and core saturation. The turn‐off mechanism was analyzed by using an equivalent circuit. The turn‐off time was found to be considerably shortened by the quick discharge of the excess carrier in the base region. This is due to the formation of an LC circuit consisting of the saturated inductance of the current feedback transformer which magnetically saturates during the turn‐off period, and the base‐emitter capacitance of the switching transistor. This phenomenon can be used widely for high‐speed and high current switchings.
Bibliography:ark:/67375/WNG-4Z9DLL43-9
ArticleID:ECJB4420690707
istex:768F86FA39FD122A2D6AC9E4A286877F09635D23
Koosuke Harada graduated from the Electrical Dept. Faculty of Engineering, Kyushu University, in 1953. Received his Doctorate at the same university in 1958, and in 1960 was appointed Associate Professor. Engaged in research on power supply systems for electronic instruments, magnetic sensors, biomagnetics, and reliability engineering. IEEE Fellow.
Hiroshi Sakamoto graduated from the Dept. of Electronics, Faculty of Engineering, Kumamoto Technological College. Appointed technical assistant, Electronics, Faculty of Engineering, Kyushu University, in 1968. Engaged in research on applications of nonlinear magnetics and power supply systems for electronic instruments. Member of Inst. Television, Japan.
Masahito Shoyama graduated from the Electrical Dept., Faculty of Engineering, Kyushu University, in 1981; and obtained M.E. in 1983. Presently, graduate student in Doctor's program of the same university. Engaged in research on switching regulators.
ISSN:8756-663X
1520-6432
DOI:10.1002/ecjb.4420690707