I've a problem, caused by a bad design (not mine). Now I'm looking for a solution that does not involve HW redesign.
I'm using one channel of the QG8 ADC module to read the voltage from a temperature sensor (a LM20 from National). The problem is that the QG8 Vdd is connected directly to a 3V battery. So when the battery voltage drops, it drops the Vdd, the Vddad and of course the Vhref. So the range of the AD shrinks and I read different values even if the temperature does not change.
The question is: there is a (sw) way to solve this? I think that the internal bandgap reference can have a major role in this, but I don't see how...
Thanks for any hint.