Step-down circuit for reducing an external supply voltage

摘要

A step-down circuit according to the present invention for reducing external supply voltage to be supplied from the outside to supply it to the internal circuit is provided with a diode circuit for reducing the external supply voltage by desired voltage to output it as the internal supply voltage, a pull-down transistor for pulling down the internal supply voltage to be outputted from the diode circuit when the external supply voltage drops, and a controlling circuit for controlling the operation of the pull-down transistor.