RE: [TCML] IGBT paralleling

["Brian" <brianv@xxxxxxxx>]

 Dave,
 That is what I meant, and did say stay under the spec max ratings and it
should work. Even running them over the max spec on short duty cycles can be
ok. I am not sure where this Headroom thing came from and how it got decided
that needs to be filled because it don't. But Like I said I might have
missed something somewhere. The Handling voltage I was talking about was
nothing more than Max rated voltage of the device and nothing more, what
ever the absolute MAX is on the spec that is what I was talking about. Sorry
for the confusion.

Brian

I'mve no idea what a 'handling voltage' spec is.
In my training there is max voltage, or standoff voltage.
or withstand voltage spec.  This is the voltage the
device is specced to NOT breakdown under, when 'off',
(The actual voltage for any given specimen will be higher,
 a bit, but don't plan on it....).  This means that same
 spec is more or less the max the device will 'handle' in
 ESD as it is 'handled' during assembly, etc.

I can think of no reason why the applied voltage
'needs' to 'fill' this rating: the device should be
quite happy anywhere under the rating.  BUT: Higher
ratings cost more dollars (euro's, whatever...).  In that
sense of the full voltage rating is not being 'used'
then money is being wasted.  Or.  The resulting design
is more rugged/reliable.  Its a design tradeoff...

One thing I've not seen mentioned (did I miss it?):

Paralleling 'things', especially active devices, can be
 tricky.  Most notably, the devices may not QUITE match:
   'identical parts aren't': Frumps law of design...

Paralleling power devices can result in Not Equal 'sharing'
of currents.  Either forced sharing, or conscious
allowance is in order...
 best
New dwp:     dave_p@xxxxxxxxxxx

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