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Title:
STEP-DOWN CIRCUIT AND STEP-DOWN CONVERTER
Document Type and Number:
WIPO Patent Application WO/2018/154988
Kind Code:
A1
Abstract:
This step-down circuit is provided with: an input terminal; a step-down part; and an output terminal. The step-down part has a choke coil and a switching element. The choke coil is provided with a powder magnetic core that contains soft magnetic powders, and a coil that is arranged around the powder magnetic core. When µr0 denotes the initial relative magnetic permeability, and µr denotes a relative magnetic permeability at a magnetic field of 10000 A/m, µr0 is 30-80, and the reduction rate of µr with respect to µr0 is 40% or less. When ΔB denotes the change amount of the magnetic flux density of the powder magnetic core with respect to a ripple component of a current flowing through the choke coil when the switching element is turned ON/OFF, and B denotes a magnetic flux density with respect to the DC component of the current flowing through the choke coil, the ratio of ΔB to B is 30% or less, and B is 0.4 T or more.

Inventors:
ZHENG, Xiaoguang (1-3, Shimaya 1-chome, Konohana-ku, Osaka-sh, Osaka 24, 〒5540024, JP)
MASUDA, Shigeki (1-3, Shimaya 1-chome, Konohana-ku, Osaka-sh, Osaka 24, 〒5540024, JP)
KUSAWAKE, Kazushi (1-3, Shimaya 1-chome, Konohana-ku, Osaka-sh, Osaka 24, 〒5540024, JP)
Application Number:
JP2018/000428
Publication Date:
August 30, 2018
Filing Date:
January 11, 2018
Export Citation:
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Assignee:
SUMITOMO ELECTRIC INDUSTRIES, LTD. (5-33, Kitahama 4-chome Chuo-ku, Osaka-sh, Osaka 41, 〒5410041, JP)
International Classes:
H02M3/155; H01F27/255; H01F37/00
Domestic Patent References:
WO2012111153A12012-08-23
WO2009139368A12009-11-19
Foreign References:
JP2007129045A2007-05-24
Attorney, Agent or Firm:
SUNCREST PATENT AND TRADEMARK ATTORNEYS (1-11, Sakaemachidori 4-chome Chuo-ku, Kobe-sh, Hyogo 23, 〒6500023, JP)
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