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Using a feedback controller without SMPS Current Foldback

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PWRDesigner

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I am replacing the feedback controller in a forward converter due to obsolescence.

https://www.onsemi.com/PowerSolutions/product.do?id=MC33341

https://www.onsemi.com/PowerSolutions/product.do?id=NCS1002

The MC33341D has gone obsolete and I am looking to replace it with the NCS1002-D. However, I have noticed that the MC33341D appears to have an internal foldback currrent limit during lab testing that is not specified in the datasheet. The NCS1002-D does not appear to have this. I am using a seperate transformer winding and voltage regulator for the supply of this control chip that stays at 5V, even under short circuit condition. My max output current is ~2.9 amps (30V output) under full load. With the MC33341D, this folds back to around 2.2 amps (.1V output) under short circuit but the NCS1002-D stays at 2.9 amps (.1V output). Is running the power supply in this short circuit condition at 2.9 amps any harder on the switching controller than at full load? Can my switching converter run into thermal problems at short circuit but not at full load? The research I have done on foldback current limiting seems to indicate that it is mostly only beneficial in linear converters.


Any help would be appreciated, the previous designer made some strange design decisions and left no notes as to why things were done as they are.
Thanks!
 

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