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Patent Searching and Data

Document Type and Number:
Japanese Patent JP3861871
Kind Code:

PROBLEM TO BE SOLVED: To obtain a small, high efficiency and low noise switching power supply in which zero voltage switching of a switch is realized while reducing the size of a transformer.
SOLUTION: The switching power supply comprises a series circuit of the primary winding 5a of a transformer T and a main switch Q1 connected across a DC power supply Vdc1, a circuit for rectifying and smoothing a voltage being outputted to the secondary winding 5b when the Q1 is turned on, a series circuit of an auxiliary switch Q2 and a clamp capacitor C1 connected across the 5a, a series circuit of diode Dx1 and a snubber capacitor Cx connected across the Q1, a series circuit of an auxiliary winding 5x and diode Dx2 connected between the joint of Dx1, Cx and the joint of Q2, C1, and a control circuit 10 for turning the Q1 and Q2 on/off alternately wherein the charges of the Cx are discharged to the C1 through the 5x when the Q1 is turned on and gradient of voltage rise of the Q1 is relaxed by charging the Cx when the Q1 is turned off.

Tsuruya Mamoru
Application Number:
Publication Date:
December 27, 2006
Filing Date:
November 26, 2003
Export Citation:
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Sanken Electric Co., Ltd.
International Classes:
H01F27/28; H02M3/28; H01F27/24; H01F27/38; H01F30/00; H01F38/08; H02M3/335; (IPC1-7): H02M3/28; H01F27/24; H01F27/28; H01F30/00
Domestic Patent References:
Attorney, Agent or Firm:
Hidekazu Miyoshi
Iwa Saki Kokuni
Kawamata Sumio
Masakazu Ito
Shunichi Takahashi
Toshio Takamatsu