| 摘要 |
PROBLEM TO BE SOLVED: To provide a stable voltage regulator in which an output voltage is not beyond the range of a specific voltage even in an area where load current amounts are small without allowing idle currents to always flow. SOLUTION: A voltage regulator 100 is composed of a reference voltage generating circuit 10, an error amplifier circuit 12, an output transistor Q1, voltage-dividing resistances R1 and R2 serially connected with the output transistor Q1, an idle current control circuit 16 connected in parallel with those voltage- dividing resistances, and an outside control terminal 18 for controlling the idle current control circuit. The idle current control circuit 16 is composed of a resistance R3 and an NMOSFET MN1. The MN1 is switched by the outside control terminal, and when output currents IQ1 are small, currents Ii are increased, and as the result, the output currents IQ1 are increased, and the output resistance value of the output transistor Q1 is decreased. Thus, the output voltage can be stably supplied within the range of a specific voltage by the voltage regulator 100.
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