| 摘要 |
PROBLEM TO BE SOLVED: To provide an LED driving power supply device that controls the brightness of an LED by using an input of a dimming control signal to a shut-down terminal, and that avoids the deterioration of power efficiency caused by the frequent generation of a rush current, and to provide a semiconductor integrated circuit for driving a power supply. SOLUTION: In a DC power supply device which is constituted so that the operation of an internal circuit including an error amplifier (11) and a control signal generation circuit (12) is stopped when a prescribed external terminal (the shut-down terminal) is set at first potential (grounding potential) or second potential (power-supply voltage), there is arranged an operation circuit (13) which outputs a voltage corresponding to an input of the external terminal, an output of the operation circuit varied based on the input voltage is fed to the error amplifier when the input voltage of the external terminal is lower or higher than prescribed potential (Vdet), and a prescribed reference voltage (Vref1) is fed to the error amplifier when the input voltage is higher or lower than the prescribed potential. COPYRIGHT: (C)2009,JPO&INPIT
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