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UCC28180: 48Vac Input

Vladislav Mokluza
Prodigy 10 points
Part Number: UCC28180

Tool/software:

Hello TI team,

I am searching for PFC for 48V AC input. 

I did not find any input voltage limitations in datasheet, but WeBench shows that Input Vac is 85V.

Could you clarify is it possible to use input voltages less that 85Vac (e.g. 48Vac)? And which factors limit using of low input voltages?

Thanks in advance. 

  • +1
    TI__Mastermind 49960 points

    Hi Vladislav,

    The UVLO on the controller is such that it will work as long as VCC is greater than 12.1V. 

    I will get the model fixed on WEBENCH so it can simulate down to 24VAC.

    I hope this answers your question.

  • 0 in reply to JCHK
    Prodigy 10 points

    Hi JCHK,

    Thanks for answer.

    By the way, what about output voltage? WeBench has limits 130 to 400 V.

    Is it possible to work with output voltage 48V and input voltage 48VAC?

  • +1 in reply to Vladislav Mokluza
    TI__Mastermind 49960 points

    Hi Vladislav,

    Unfortunately no. With an 48V AC input the peak voltage would be 48*Sqrt(2) or 67.88V. This peak voltage would pass right through the rectification diode. 

    To regulate 48VDC from a 48VAC input, you might want to look at a buck-boost solution. Or depending on your power level follow the PFC with a 2nd power stage to regulate the 48V.

    I hope this answers your question.

  • 0 in reply to JCHK
    Prodigy 10 points

    Thanks a lot. Your question helped me.

    The main thing which I wanted to clarify that is it possible to work with voltages lower than in WeBench.

    Do you know any reference designs with PFC with a 2nd power stage?

  • 0 in reply to Vladislav Mokluza
    TI__Mastermind 49960 points

    Hi Vladislav,

    We have a lot of reference designs where a PFC is followed by a flyback, LLC, or Phase-shifted full-bridge. It really depends on the power level you would like to support. 

    Normally for <150W a flyback will be the most cost effective solution.

    for 150W-1kW and LLC could be a good option

    for 500W on up a phase-sifted full-bridge could work,