UCC21520: How to provide VDDA/VDDB when VSS is negative

Joaquin Casanova

Part Number: UCC21520

For this IC, can I use a negative VSS? If so, is VDD in reference to this negative rail? Do I need an isolated supply for VDDA/VDDB?

over 7 years ago

0 Mamadou Diallo over 7 years ago

TI__Genius 13445 points

Hi Joaquin,

My name is Mamadou Diallo, I am an applications engineer and I will be working to help address your questions.

For the first part of your question, yes you can use negative VSS for this IC. Please refer to figure 35, 36 and 37 of UCC21520's datasheet for examples and considerations on using negative VSS.

As far as VDDA/VDDB, you do not need an isolated supply for this driver.

If you have further questions, please let us know!

Best regards,

-Mamadou

0 Don Dapkus over 7 years ago in reply to Mamadou Diallo

TI__Guru**** 189401 points

Hi Joaquin,

I was auditing some threads, and noticed you haven't clicked the Green button to let us know this solved your issue.

If it did, please click that button for us, if not, let us know how we can help.

0 Joaquin Casanova over 7 years ago in reply to Mamadou Diallo

Prodigy 20 points

Actually, I found I did need an isolated supply for both. Otherwise it easily exceeds the chip's max vdd/vss limits.

0 Don Dapkus over 7 years ago in reply to Joaquin Casanova

TI__Guru**** 189401 points

Hi Joaquin,

Great! Thanks for letting us know.

Let us know if you have further questions.

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UCC21520: How to provide VDDA/VDDB when VSS is negative