Multiphase boost issue

[bowman1710]

Hi guys,

I am currently modifying the following development board from the initial 10-16V in to 36V 10A it was designed to do to 18-36V in to 50V 4A. The board is linked below:

**broken link removed**

I have made the following changes

Changed to only 3 phase channels
10uH for inductors
50V output with 18-36V Vin at 4A (so changed the feedback Vout sense Vin sense etc)

I have already done tests on with that all working no problem. The 60V MOSFETS seem a bit to close with ringing etc so I wanted to change the MOSFETS (attached). But now I changed to these then either the rectifying MOSFET blows or both on one phase. Any ideas why this is happening?

View attachment TPH1400ANH_datasheet_en_20140217 (1).pdf

 

[BradtheRad]

You probably are aware it's important to keep a load attached at all times. With no load, output can soar to a high voltage, and you have the possibility of destroying components.

Going with your specs, I ran my simulation of a triple-interleaved boost converter. It may or may not be similar to your converter's topology. Anyway this screenshot shows waveforms you might expect.

 

[bowman1710]

You probably are aware it's important to keep a load attached at all times. With no load, output can soar to a high voltage, and you have the possibility of destroying components.

Yes I am aware but with the feedback the output should be regulated it will just be a higher level of ringing seen on the MOSFET, I have kept the load the same for when I changed the MOSFETS it worked before so it must have something to do with these MOSFETS I am using but I couldn't see why they would blow. The ratings seem adequate for the job and the dead time programmed for the drivers shouldn't need changing (unless there is something i'm missing)