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Patent Searching and Data


Title:
A charge circuit and a method for controlling the same
Document Type and Number:
Japanese Patent JP6004772
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To achieve low power consumption and high efficiency charging.SOLUTION: A current control MOSFET (14) and current detection resistor (16) are serially connected to a primary side of a flyback transformer (12). A MOSFET (20) is connected to the resistor (16) in parallel. A charge control circuit (18) turns on the MOSFET (14) while the MOSFET (20) is in an off state, before starting charging. The charge control circuit (18) clocks a time that elapses before a primary-side current reaches a predetermined value after a voltage drop of the resistor (16) at this point; and holds it in a memory (44). In order to charge a capacitor (24), the charge control circuit (18) turns on the MOSFET (20) and performs switching control of the MOSFET (14) according to an on time based on the time that is stored in the memory (44).

Inventors:
Koyama
Application Number:
JP2012138941A
Publication Date:
October 12, 2016
Filing Date:
June 20, 2012
Export Citation:
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Assignee:
Canon Inc
International Classes:
G03B15/05; G03B15/02; G03B15/03; H04N5/225
Domestic Patent References:
JP2010057214A
JP2008172909A
JP2002333653A
JP2007068368A
JP2000314909A
JP11113252A
JP2007012768A
Foreign References:
US6219493
US5932938
Attorney, Agent or Firm:
Tsuneo Tanaka