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Title:
DC POWER SUPPLY
Document Type and Number:
Japanese Patent JP2002171692
Kind Code:
A
Abstract:

To improve overall power conversion efficiency of a power supply and also save its space at a low cost.

In a power supply which has an AC/DC converter 1, a DC/DC converter 2, and a DC converter to change the output current of a battery 4 into an ac voltage to connect it to the AC/DC converter output terminal, a control circuit 100 is provided to monitor a charging control level and a load distributing level. When it is lower than the charging control level it gives a charging instruction to a UPS control which control the DC converter and a current instruction to the PFC control which controls the AC/DC converter, but when it is over the charging control level and lower than the load distributing level, it stops only the charging instruction, further when it is over the load distributing level it gives a current instruction to the UPS control and the PFC control. When the load 5 is larger than predetermined, the AC/DC converter and the DC converter supply power in parallel, and in case of an ac input failure, the DC converter supplies power to back up.


Inventors:
TOKUNAGA KIICHI
ONDA KENICHI
ONAKA TAKESHI
MASUYAMA SATORU
SAGA RYOHEI
HAYASHI KATSUNORI
Application Number:
JP2000371207A
Publication Date:
June 14, 2002
Filing Date:
December 06, 2000
Export Citation:
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Assignee:
HITACHI LTD
HITACHI COMP PERIPHERALS CO
HITACHI TOBU SEMICONDUCTOR LTD
International Classes:
H02M1/00; H02M1/42; H02J9/06; H02M7/12; (IPC1-7): H02J9/06; H02M7/12
Domestic Patent References:
JP2000116029A2000-04-21
JP2000209778A2000-07-28
JPH04304160A1992-10-27
JPH0667767A1994-03-11
JPH08129436A1996-05-21
JPH08171436A1996-07-02
JPH09322433A1997-12-12
JP2001054239A2001-02-23
JP2001095175A2001-04-06
JP2001507199A2001-05-29
Foreign References:
US5781422A1998-07-14
US5982645A1999-11-09
US6037756A2000-03-14
WO1998028832A11998-07-02
US5631814A1997-05-20
Attorney, Agent or Firm:
Shigeru Sasaoka (1 person outside)



 
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