| 摘要 |
PROBLEM TO BE SOLVED: To provide a soft start circuit in which the circuitry can be protected when a power supply is started by preventing inrush current, and the output voltage can be stabilized. SOLUTION: The soft start circuit generating a reference voltage required for controlling the output voltage of a power supply comprises a circuit 101 for charging a capacitor when the power supply is started, a circuit 102 for comparing the charging voltage of the capacitor with a reference voltage VRF2 which is relatively lower than its reference voltage and outputting a signal when the charging voltage reaches the second reference voltage VRF2, and a controlcircuit 105 for taking out the charging voltage of the capacitor as the reference voltage of the power supply over a period from the start until a signal is outputted from the comparison circuit 102, and switches that reference voltage to a reference voltage VRF1 when a signal is outputted from the comparison circuit 102 and taking it as its reference voltage. COPYRIGHT: (C)2007,JPO&INPIT
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