Title:
STARTING CIRCUIT AND POWER SUPPLY CIRCUIT
Document Type and Number:
Japanese Patent JP2018042464
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a starting circuit that can reliably and moderately start a power supply circuit without rapid variation of output voltage of the power supply circuit when the power supply circuit is started.SOLUTION: When a power supply circuit is started, slope-shaped terminal voltage VCS generated by charging a capacitor CS for soft start with current of a constant current circuit IS is supplied to an error amplifier EA as target voltage at the starting time. Variation of the terminal voltage VCS is monitored by a detection circuit DET, and the detection circuit DET stops output of a PWM pulse VPWM2 of a logic circuit LC until the terminal voltage VCS which is equal to zero volt at the starting time reaches a predetermined threshold value. At the same time, the detection circuit DET stops a function of an error amplifier EA. Only in the case where the terminal voltage VCS reaches the predetermined threshold value and outputs the PWM pulse VPWM2, the function of the error amplifier EA is enabled. Start control is started on the basis of difference between the terminal voltage VCS and a feedback signal at that time, so that the output voltage does not sharply rise up.SELECTED DRAWING: Figure 1
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Inventors:
SUGAWARA SATOSHI
Application Number:
JP2017241278A
Publication Date:
March 15, 2018
Filing Date:
December 18, 2017
Export Citation:
Assignee:
FUJI ELECTRIC CO LTD
International Classes:
H02M3/155
Domestic Patent References:
| JP2004215356A | 2004-07-29 | |||
| JP2007028783A | 2007-02-01 | |||
| JP2011244677A | 2011-12-01 | |||
| JP2004173386A | 2004-06-17 | |||
| JP2012114987A | 2012-06-14 |
Attorney, Agent or Firm:
Takeshi Hattori