A reference voltage generating circuit generates reference voltage and outputs
the thus generated reference voltage from an output terminal thereof. A voltage
generating circuit lowers external power supply voltage according to the reference
voltage supplied from the reference voltage generating circuit to output internal
power supply voltage from an output terminal thereof. A transistor has a current
path connected between a terminal to which the external power supply voltage is
supplied and the output terminal of the voltage generating circuit or between the
terminal to which the external power supply voltage is supplied and the output
terminal of the reference voltage generating circuit and a gate supplied with constant
voltage and has negative threshold voltage.
