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Patent Searching and Data


Title:
POWER SUPPLY DEVICE, EMISSION CONTROL DEVICE AND DISPLAY DEVICE
Document Type and Number:
WIPO Patent Application WO/2007/094194
Kind Code:
A1
Abstract:
A power supply device is provided with a charge pump circuit (54), which generates a desired output voltage (Vo) from an input voltage (Vi) and supplies a load (LED) with the output voltage, by periodically turning on/off a plurality of charge transfer switches (Q1-Q4) corresponding to clock signals (c1, c2) and by charging/discharging a charge accumulating capacitor (C1); an output current detecting circuit (57) for detecting an output current (Io) (reference current (Im) in Fig. 1) to the load; and a clock signal control means (frequency converting circuit (52) in Fig. 1) for variably controlling the frequency of the clock signals (c1, c2) based on the detection results of the output current (Io). Thus, the power efficiency is improved corresponding to the level of the load.

Inventors:
IMANAKA YOSHINORI (JP)
Application Number:
PCT/JP2007/051961
Publication Date:
August 23, 2007
Filing Date:
February 06, 2007
Export Citation:
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Assignee:
ROHM CO LTD (JP)
IMANAKA YOSHINORI (JP)
International Classes:
H02M3/07
Foreign References:
JP2002238243A2002-08-23
JP2003199329A2003-07-11
JP2005261102A2005-09-22
JP2003219314A2003-07-31
JP2006014581A2006-01-12
Attorney, Agent or Firm:
SANO, Shizuo et al. (2-6 Tenmabashi-Kyomachi, Chuo-Ku, Osaka-Sh, Osaka 32, JP)
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