RE: [TCML] IGBT paralleling

["McCauley, Daniel H" <daniel.h.mccauley@xxxxxxxx>]

Scott,

The electric ratings may be the same or similar, but you also have to compare the mechanical ratings -  in particular the thermal ratings.  This would be junction-to-case thermal impedances etc...  The expensive IGBTs that are commonly used in DRSSTCs are usually ISOBLOC type packages which excellent thermal impedances.  Compare this vs. a TO-247 package of the same die.

And when comparing a TO-247 package to an ISOBLOC, keep in mind that you STILL NEED to add a thermal insulator between the TO-247 and heatsink, which just makes the thermal impedance even worse.  The ISOBLOC (or SOT-227) doesn't require a thermal interface other a small smidgeon of thermal grease or a graphite pad.

Dan
http://www.easternvoltageresearch.com
DRSSTC, SSTC, Flyback, Plasma Speaker Kits




-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of Scott Bogard
Sent: Friday, July 09, 2010 9:52 PM
To: Tesla Coil Mailing List
Subject: EXTERNAL: [TCML] IGBT paralleling

Greetings all,
	So, after a bit of researching I've noticed there are IGBTs on Newark with exactly the same ratings as some of the SSTC approved IGBTs, but at 1/10th the price.  What makes these others so special that they are better, and if it is just a matter of peak current ratings, since IGBTs are gate driven, can we just parallel a few to get the required pulse current rating?  I ask because I've not heard of anybody doing this, then again I've only begun to research SSTC a little bit ago.  Just musing.

Scott Bogard.
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