A CMOS reference voltage circuit, preferably formed on a semiconductor integrated
circuit, and outputting a reference voltage having a temperature-independent characteristic,
comprises first and second diode-connected transistors (or diodes), respectively
grounded and driven with two constant currents bearing a constant current ratio
to each other, and a unit for amplifying a differential voltage of output voltages
from the first and second transistors by a preset factor and for summing the amplified
differential voltage to an output voltage of the first or second transistor. The
amplifying and summing unit is formed by two OTAs 11, 12 and a current mirror
circuit 13. The first OTA 11 is fed with the differential voltage
and the second OTA 12 has a reverse phase input terminal fed with an output
voltage from the first or second transistor and a forward phase input terminal
connected to its output terminal and driven with a current proportional to an output
current of the first OTA 11, with an output terminal voltage of the second
OTA 12 being used as an output voltage.
