| 摘要 |
PROBLEM TO BE SOLVED: To reduce a rush current at a voltage reset time even when a temporary voltage drop occurs at an input power source voltage. SOLUTION: A capacitor 27 is gradually charged by a constant-current circuit 38 at a voltage VB applying time, and an operational amplifier 36 controls an output voltage Vo based on a detected voltage Va and the terminal voltage Vc of a capacitor 27. If the output voltage Vo (detected voltage Va) is lowered when the voltage VB is temporarily lowered so that Vd>Va is satisfied, a diode 44 is turned on to lower the terminal voltage Vc. When the voltage VB is reset to a normal voltage, the voltage Vc starts gradually increasing from the voltage which is once lowered according to the drop of the detected voltage Vs, and hence soft starting is effectively functioned. COPYRIGHT: (C)2004,JPO
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