DANMAS@aol.com wrote:
> Which brings us back to Tom's statement about solid state regulators. As Tom
> said, there will be no temperature compensation with these, unless they were
> deliberately designed for it. I don't know if any of the units commercially
> available have this compensation or not. Does anyone on the list know?
Yes, they are temperature compensated. The accuracy of the temperature
compensation is usually on the data sheet, and most all are plenty good
for a fuel gauge situation.
They actually have to be temperature compensated, because they
operate over a wide range. We only think of say -30 to 50 celsius
because that's the range we survive. However, the solid state
regulators themselves generate a lot of heat as they drop
voltage, so their operating temperature is often much
higher.
Proper heatsinking helps, but it's not unusual to have
them run uncomfortably hot to the touch and still be working
fine and within spec on the output.
Usually it's a simple circuit. The temperature effects
of the transistors in question are determined mathematically
from their IC geometry, and then a circuit is created that
has the exact opposite effect with temperature so the two
keep each other in check. Automated circuit design tools
make this often point and click.
--
Trevor Boicey
Ottawa, Canada
tboicey@brit.ca
http://www.brit.ca/~tboicey/
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