UCC28950: UCC28950 Spice Model

lev nemets1

Intellectual 475 points

Part Number: UCC28950

Hello Colin,

Did you have a chance to solve my problem?

Thanks

over 4 years ago

0 Yunsheng Qu over 4 years ago

TI__Genius 9790 points

Hi, There

Colin has left TI.

Could you list your question here?

0 lev nemets1 over 4 years ago in reply to Yunsheng Qu

Intellectual 475 points

Hello Yunsheng,

Thank you for replay.

I am trying to simulate PSFB based on UCC28950. According to datasheet, if VADEL = 1.8 , VTABSET can be programmed between 29 ns and 155 ns. In my simulation I set RAHI=8.25k and RA=4.64k. RAHI is connected to VREF. RAB and RCD are 13k (minimum value according to datasheet) but delay between outputs A and B is 270ns. To reduce this delay I need to reduce RAB and RCD to 7k (but this is restricted by datasheet). In this case the delay drops to 125ns. Could you, please, explain this. I use unencrypted UCC28950 model, provided by TI. Simulator - Simetrix (not SIMPLIS!!) which is general SPICE simulator.

After some exchange of emails with Colin (and Mike) he realised that there is a problem in UCC28950 spice model (see attached file) and promised to find solution.

You can also see this issue :

https://e2e.ti.com/support/power-management/f/196/p/917984/3404722

Let me know if you need more information.

I hope you could help because this is very important for us as we going to use this controller in not typical application but for low voltage input converter (10-16V) and the behavior of PSFB is a bit different compare with typical 300-400V application and correct simulation can help to avoid costly mistakes.

Regards

Lev5611.8802.UCC28950.xlsx (9) [Resolved] UCC28950_ Simulation and...wer management - TI E2E support forums.pdf (9) [Resolved] UCC28950_ Simulation and...wer management - TI E2E support forums.pdf