Appeal No. 1998-0992
Application 08/706,978
1. A circuit for generating a temperature
stable reference voltage, said circuit comprising:
a first circuit comprising a first bipolar
transistor, and connected to provide as output a
first voltage equivalent to a constant fraction,
which is less than unity, of the base-emitter
voltage of said first bipolar transistor;
an operational amplifier, configured as a
noninverting buffer, and operatively connected to
receive said first voltage and to produce a control
voltage equal to the sum of said first voltage and a
predefined and controlled intrinsic offset voltage
and a predefined and controlled intrinsic offset
voltage of a differential input pair of transistors
of said operational amplifier and said temperature
stabilized reference voltage, which is proportional
to said control voltage, a first one of said
differential input pair of transistors having an
emitter area different from a second one of said
differential input pair of transistors; and
said operational amplifier having a feedback loop
for controlling a bias current forced through said
input pair of transistors.
6. A method for generating a small reference
voltage without thermal drift, comprising the steps
of:
(a) generating a first voltage which is a pre-
established fraction of a base-emitter junction
voltage of a bipolar transistor;
(b) deriving a ªVbe voltage, which corresponds
to the difference between Vbe voltages of two
transistors with different current densities, and
(c) producing a voltage proportional to the sum
of said ªVbe and said first voltage to produce an
output signal.
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