The application is an auto power (cigarette lighter) power outlet plug=20
containing a 3.3 VDC switching regulator to power a handheld GPS. The=20
regulator is a:
http://www.dimensionengineering.com/products/de-sw033
which fits nicely in the plug housing. Initial testing using a 12 VDC=20
bench supply was good, but when powered from 13.7 volt car battery,=20
overheat caused the thermal protection to drop things out until it could=20
cool down.

The regulator has a  78XX pin out and a nice little aluminum heat sink.=20
My first thought is to fill the housing cavity (1" dia.) with an epoxy=20
or silicone with a bond breaker to the aluminum heat sink. After cure=20
use a heat sink compound where the bond breaker was for good heat=20
transfer. For the filler I'm thinking JBweld, but open to suggestions.=20
Something with a good heat conduction. Would need to be something=20
readily available. I do have a thin epoxy that I could add a filler, and=20
have fine ground milled glass filler for it.


Any thoughts appreciated. :)
--=20
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