UCC28950: UCC28950 SR FET rating selection question

Wei-Hao Chen (TW-FAE)

Part Number: UCC28950
Other Parts Discussed in Thread: PMP6712

Hi support team champs:

My customer is designing a 1800W 400VDC to 115V DC/DC converter based on UCC28950. They are using full-bridge SR rectification configuration but wishes to reduce the rating for the SR FETs, which they add the active buck snubber circuit like PMP6712 or as shown below:

In such condition, can they chose 250V FET for their application? The X'FMR turns ratio is 2.5:1 for Np:Ns.

(400V/2.5=160V + 75V spike)

Thank you.

Best Regards,

Wei-Hao

over 7 years ago

0 Peter Meaney over 7 years ago

TI__Mastermind 31580 points

Hi Wei-Hao,

I don't have any experience of the active snubbers but the customer can try and see how well the system performs and then change the devices to a higher voltage if required.

Regards

Peter

0 Wei-Hao Chen (TW-FAE) over 7 years ago in reply to Peter Meaney

TI__Expert 3260 points

Hi Peter,

Can you please check with the designer of PMP6712 to see how this circuit works?
Customer has no experience on this active buck snubber and looking for our advises.

Thank you.

Best Regards,
Wei-Hao

0 Peter Meaney over 7 years ago in reply to Wei-Hao Chen (TW-FAE)

TI__Mastermind 31580 points

Hi Wei-Hao

I checked the designers name and he is no longer listed so I think he has left TI. The active snubber is similar to the active clamp and I found some good slides on this here.

I Hope this helps.

Regards

Peter

0 Wei-Hao Chen (TW-FAE) over 7 years ago in reply to Peter Meaney

TI__Expert 3260 points

Hi Peter,

Understood, thank you so much for find the material for us.

Many Thanks.

Best Regards,
Wei-Hao

Power management

Power management forum

UCC28950: UCC28950 SR FET rating selection question