UCC256303: UCC256303

daniel pruna

Part Number: UCC256303
Other Parts Discussed in Thread: UCC25600

Dear Mike,

I found one issue which might be responsable for the problem I am facing. I have noticed that UCC256303 gets some information from the HS point i.e. adaptive dead time control. As per my schematic, HS is conected to ground since the UCC256303 doesn't drive the power MOSFETs directly but trough a dedicated HB Mosfet driver. (LLC_FET_H, LLC_FET_Low beeing the driver inputs)

Could the grounding of HS pin be a problem?

over 6 years ago

0 Hong Huang over 6 years ago

TI__Guru 73825 points

Mike will reply to you.

0 Mike O' over 6 years ago in reply to Hong Huang

TI__Guru* 86266 points

Sure.

0 Mike O' over 6 years ago

TI__Guru* 86266 points

Hello Daniel,

The HS pin needs to be connected the switch node for proper opperation. Based on the dv/dt of the switch node it will adjuat the dead time to achieve ZVS. If this is grounded the UCC256303 will no opperate.

Regards,

Mike

0 daniel pruna over 6 years ago in reply to Mike O'

Prodigy 65 points

Hello Mike,

Thank you for your quick reply. It seems that I have to change my design.
I guess there is no way to use the UCC25630x family in combination with an external driver as I wanted.

Daniel.

0 Mike O' over 6 years ago in reply to daniel pruna

TI__Guru* 86266 points

Hello Daniel,

If you really want to use seperate drivers you might consider using a UCC25600 LCC controller. Less pins and you will have to program the minimum switching frequency and dead time to achieve ZVS.

Regards,

Mike

Power management

Power management forum

UCC256303: UCC256303