| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply voltage step-down circuit that is improved in the return response of an internal power supply voltage outputted from an output terminal when the voltage step-down circuit is shifted from an inactive state to an active state. SOLUTION: This power supply voltage step-down circuit comprises an input terminal connected to an external voltage source, the output terminal for outputting an internal voltage lower than an external voltage, a transistor P10 connected between the output terminal and the external voltage source, and switching elements P20 and N10 connected in series between the output terminal and a reference voltage source GND, a comparator having a first input part, a second input part, and an output part connected to the gate of P10, a constant voltage source for supplying a constant voltage to the first input part, a feedback circuit for returning a voltage depending on the internal voltage from a node between P20 and N10 to the second input part, a set voltage source for supplying an arbitrarily set voltage to the second input part, a switching element SW interposed between the set voltage source and the second input part, and a control signal sending source for controlling P20, N10 and SW. COPYRIGHT: (C)2006,JPO&NCIPI
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