Expo conv. heater (tomg et al.)

[Martin Czech]

> The recent thread on heated expo converters correctly discussed some of the
> drawback:  increased leakage current, permanent change in tranny
> characteristics if heated too high, mechanical stress, possible decreased
> reliability.  Ok, how about an alternative: cool it instead.  You can get
> Peltier junction coolers from many sources of surplus components pretty
> cheap, just monitor Vbe and drive the Peltier in a closed loop (don't
> forget to invert the gain stage, so you still have negative feedback).  The
> reduced temperature will greatly reduce transistor leakage current,
> reliability shouldn't be affected, and who cares if it gets too cold
> (unless ice forms).  One drawback, the Peltier sucks a lot of current.
>  Terry Michaels

	
If you provide a good regulator circuit and isolation, you won't destroy any
trannys. esp. important for start up. 
My motto: better know leakage at constant temperature, as unknow leakage
at varying temperature, the later can't be compensated.

The cooler approach has one big disadvantage: it's not on chip.
The you can take an MAT0x with external heater as well.


m.c.
(waiting for the Norwegian blizzards to come)