| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply circuit, an overcurrent protection circuit therefor and an electronic apparatus, for improving the stability of circuit operation with improved responsiveness in overcurrent protection. SOLUTION: The power supply circuit includes an output transistor, having a source connected to a supply voltage, and outputting an output voltage from the drain; an error amplifier, operated by the supply voltage as a power source, for outputting a signal based on a potential difference between the output voltage and a reference voltage; a buffer transistor, having a gate connected to the output of the error amplifier, and a source connected to the supply voltage via a constant current source and connected to the gate of the output transistor; a current detection transistor having the gate and the source respectively connected in common to the output transistor; and an overcurrent protection circuit for controlling the output current of the output transistor, by limiting the drain current of the buffer transistor when the drain current of the current detection transistor increases. COPYRIGHT: (C)2009,JPO&INPIT
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