UCC28780EVM-002: UCC28780 HV MOSFET damage issue

Lawrence He

Part Number: UCC28780

Dear,

our client reference design TIDA-01622 relayout new power board ,But find the IC HV start up 600v MOSFET was damage and output cannot load.

ACF 65W Type-C.pdf

HV damage part: infineon BSS126

DC147V output 20V Vsw pluse 4

Channl 1 FB Channl2 VSW

but If yellow highlight CS pin change connect to GND, the power board was can work.

If any suggestion, Please advise me.

Thanks,

Best regards,

Lawrence.

over 5 years ago

0 Kuan Wei Chen (Kevin Chen) over 5 years ago

TI__Genius 9710 points

Dear Lawrence,

Thanks for promoting TI's solution to your customer.
It might related the layout issue, cause too high di/dt on the HV MOSFET.
I will discuss with senior AE and get back to you soon

Best Regards
Kevin

0 Kuan Wei Chen (Kevin Chen) over 5 years ago in reply to Kuan Wei Chen (Kevin Chen)

TI__Genius 9710 points

Dear Lawrence,

Sorry for take such a long time to figure out your issue.
Can you help me to change RP38 from 4.7 to 5000ohm?
It might be high side isolator mis-turn on your high side GaN, which cause high di/dt to damage your HV MOSFET's Vgs.

I check the UCC28780EVM002 design.
They put 4.99kohm to mitigate the mis-turn on issue on high side GaN

I hope this can fix it.

Best Regards
Kevin

Power management

Power management forum

UCC28780EVM-002: UCC28780 HV MOSFET damage issue