A reference voltage generating circuit with ultra-low power consumption,
which includes: a constant current circuit part generating a first
constant current from a supply voltage; a current mirror circuit part
mirroring the constant current and supplying a second constant current; a
voltage control circuit part receiving the second constant current and
generating a first reference voltage by using substrate transistors
driven by a PTAT (Proportional To Absolute Temperature) voltage and MOS
transistors driven by a CTAT (Complementary To Absolute Temperature)
voltage; and an output circuit part amplifying an output voltage from the
voltage control circuit part to generate second to fourth reference
voltages, and feeding back at least one of the second to fourth reference
voltages to the voltage control circuit part so that the magnitude of an
output voltage is adjusted. The reference voltage generating circuit is
able to stably output four reference voltages, independently of changes
in supply voltage, process, temperature, and other factors.