TINA/Spice/UCC21520: Isolated Grounds

Anthony Watson

Part Number: UCC21520
Other Parts Discussed in Thread: TINA-TI,

Tool/software: TINA-TI or Spice Models

Hi,

I'm working with a UCC21520 Transient Model, and I need to confirm if TI's TINA software supports isolated grounds. The circuit needs at least 3 grounds that aren't connected together.

I've built the schematic using 3 unconnected grounds, each labeled with a unique Jumper name, but does that mean the grounds aren't connected within the simulation? I tried editing the ground label but when I do that and reopen the schematic (after saving) the ground label is blank again.

Sorry, first post here, so I apologize if this doesn't make much sense.

over 6 years ago

0 Mateo Begue over 6 years ago

TI__Intellectual 2805 points

Hello Anthony,

I have contacted the appropriate group and they should respond to you soon.

regards,
Mateo

0 Nikhil Gupta (Product Folder Models) over 6 years ago in reply to Mateo Begue

TI__Mastermind 39210 points

Hi Anthony,

From an electrical sim point of view, they are all node 0, hence would recommend connecting the same GND symbol to each GND node. Ofcourse in the actual application these are different grounds, but it does not matter form spice perspective.

0 Anthony Watson over 6 years ago in reply to Nikhil Gupta (Product Folder Models)

Prodigy 50 points

Thanks Nikhil,

So this TINA simulation should still run properly, even if all the grounds are connected together? I know in the actual implementation certain grounds need to be isolated from each other.

Thanks!

0 Nikhil Gupta (Product Folder Models) over 6 years ago in reply to Anthony Watson

TI__Mastermind 39210 points

Yes, TINA-TI should work fine if you short all grounds. TINA-TI (and any spice simulator for that matter) does not differentiate isolation. It only cares about electrical connections.

I would recommend not naming the GND pins since these are global and naming them can confuse some simulators (I know that sometimes, PSpice has an issue when you rename GND nets)

0 Anthony Watson over 6 years ago in reply to Nikhil Gupta (Product Folder Models)

Prodigy 50 points

Thanks for the prompt reply Nikhil!

So looking at the 2nd picture in my initial post, you don't recommend naming that ground point like I did with the jumper? (I named it DGND).

I was unable to name the ground point by double-clicking it and changing the Label; it wouldn't save when I reopened the schematic:

0 Nikhil Gupta (Product Folder Models) over 6 years ago in reply to Anthony Watson

TI__Mastermind 39210 points

You don't have to name it. When you instantiate the GND pin, just leave it as the default. Where ever you are using GND (any kind) on your schematic, just use this default GND symbol (without making any changes)

Power management

Power management forum

TINA/Spice/UCC21520: Isolated Grounds