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UCC28730: Webench simulation error

Danilo A.
Mastermind 25655 points
Part Number: UCC28730
Other Parts Discussed in Thread: UCC28950

Hi Team,

Our customer is trying to simulate the UCC28730 in Webench but encountered an error. Please see the details of the issue below.

I'm trying to take 575VDC nominal and step it to 50VDC 20A, preferably with a switching circuit.

I should let you know the input voltage could occasionally reach as high as 750V.

I was looking at the UCC28730, and it appears we could use that in our application.  I would draw the HV pin to the input voltage via a 39k ohm resistor, so there would be plenty of current to drive two 330-V zener diodes in series, limiting the voltage at the HV pin to 660.
 
Webench allows me to enter up to 2000V as input for this chip, yet I keep getting the “Design cannot be created!  Your preferred device does not work with the inputs you selected.” error when entering my range from 575-750V.  What do you think about this possibility?
 
Specifically, I am working off of the Simplified Application on page 21 of the data sheet.

Regards,

Danilo

  • 0
    TI__Mastermind 22245 points

    Hi Danilo,

    Thank you for the query on UCC28730.

    Webench has its limitations and it cannot be scaled for any power range. I would recommend using the design tool calculator / PSPICE model to design your circuit from the following link to start from:

    https://www.ti.com/product/UCC28730#design-tools-simulation

    If I read correctly, your output is 50V/20A and this too much for a flyback converter. So you are better off using a phase shifted full bridge (UCC28950/51) or LLC converter (UCC25640x) series of devices for this application (voltage / power level) for better performance.

    Regards,

    Harish