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Old 04-07-2011, 05:56 PM   #4607 (permalink)
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Originally Posted by jyanof View Post
... have all 3 bus bars coming out the same end (wouldn't fit otherwise). This could indicate a few things:

-the current may have an easier path through some components, but it's not significant enough to have an effect
-the heat spreader performs adequately enough to distribute the heat and keep the diodes from entering thermal runaway
-there's not enough time on the controller for any problems related to this to surface
I'm guessing that it's a combination of 1+2, combined with the controller not pushing the limits of the components.

The single heat spreader bar might also be the savior here.

MOSFETs spread the load because they get worse when hotter, pushing the current (and heat generation) into the cooler devices. Diodes do the opposite, making them more difficult to parallel. But if you combine the two on a single heat spreader, the MOSFETs will heat up the cool spots and help the load balanced across the diodes.
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