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Patent Searching and Data


Title:
SNUBBER CIRCUIT
Document Type and Number:
Japanese Patent JP3451419
Kind Code:
B2
Abstract:

PROBLEM TO BE SOLVED: To suppress surge voltage and reduce a switching loss, by controlling a circuit so that, when a main switch is turned on, a synchronous rectifying switch may be turned off, and when the main switch is turned off, discharge current may be caused to flow in a capacitor for snubber and, after a specified delay time, the synchronous rectifying switch may be turned off.
SOLUTION: By means of a control circuit 1, a synchronous rectifying switch SW2 is turned off when a main switch SW1 is turned on and, when the main switch SW1 is turned off, discharge current is caused to flow in a capacitor C3 for snubber and, after current is caused to flow in a diode D2 using a delay circuit, the synchronous rectifying switch SW2 is turned off in a zero voltage state. By this method, a switching operation can be conducted in a zero voltage state, thereby reducing a switching loss and absorbing surge voltage by the capacitor C3 for snubber.


Inventors:
Sato, Toshimitsu
Shimizu, Hisao
Application Number:
JP1997000203209
Publication Date:
September 29, 2003
Filing Date:
July 29, 1997
Export Citation:
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Assignee:
FUJITSU DENSO LTD
International Classes:
H02M3/155; H02M1/08; H02M3/28; (IPC1-7): H02M3/28; H02M1/08; H02M3/155; H02M3/28
Attorney, Agent or Firm:
眞鍋 潔 (外3名)