| 摘要 |
PROBLEM TO BE SOLVED: To reduce total loss of a synchronous rectifier being connected with an AC voltage source as a commercial power supply without increasing the chip size of a main switching element. SOLUTION: The MOSFET (11) of a unipolar element as a main switching element is constituted of a wide band gap semiconductor. Parasitic diode (15) in the MOSFET (11) is used as a circulation diode. An element composed of a wide band gap semiconductor has an on-resistance lower than that of an element composed of an Si semiconductor. Switching speed of the MOSFET (11) is set to twice or more the switching speed of the main switching element composed of an Si semiconductor. Switching speed of the parasitic diode in the MOSFET (11) is also set to twice or more the switching speed of the parasitic diode in the MOSFET composed of an Si semiconductor. COPYRIGHT: (C)2008,JPO&INPIT
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