Hi again,
Some of the other posts reminded me of another way
Use a few diodes in series as a voltage reference (maybe >2.5v).
Use a thermistor and measure the temperature using the diode voltage reference
even though it will be off.
Using both measurements, calculate the real voltage of the diode and
include that in whatever actual measurements you have to make.
To calibrate this scheme, run the diode and thermistor at room temperature,
measure the voltage and the thermistor and record. Turn up the temperature
by 10 degrees C and measure both again and record. You may have to
do a third time if you need better accuracy.
What will happen is the diode voltage will change and so will the thermistor,
with the diode reacting to temperature mostly and the thermistor will vary
both because of temperature AND voltage so it should be possible to calculate
the true voltage on the diode knowing these two pieces of information because
for any given temperature the thermistor will still read the same resistance,
just a different divider voltage than when the source voltage is constant. In effect,
it will be like a thermistor squared
If you need help with the equations just yell.
It is also possible with this scheme to allow the reference voltage to vary widely,
and measure the voltage of a single diode, then do the calculation for what
the reference voltage is based on the measured voltage of the diode and of
the thermistor (in a voltage divider circuit).
It was also common practice a long while back to temperature compensate a circuit
with a thermistor. In this way it may be possible to compensate the diode(s) with
a thermistor, but it's not that easy to do.