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UCC28515: Operating the UCC28515 with an AC input having 400Hz frequency

Mark Pearson
Genius 12705 points
Part Number: UCC28515

My Customer is using the UCC28515 in an AC-DC power supply.  It is intended for use at 60Hz, but it accidentally got designed into a 400Hz application, and while it runs OK if fails conducted EMC testing.

In the application information of the data sheet there is some equations for calculating values for the loops, and there is a reference schematic on page 23 – which I assume is for 60Hz.

Is there is a reference design for the UCC28515 with an AC input at 400Hz? or a spreadsheet calculator to assist with design?

It does NOT have to still run at 50/60Hz. (If it can, great – but it doesn’t have to)

Specs of the power supply are in the attached Excel File.

UCC28515 based Power System.xlsx

  • 0
    TI__Mastermind 31580 points
    Hi Mark,

    There are no calculators for the UCC28515 however I don't think the EMC issue is related to the loop component values. The EMC issue will be more centered on the EMI filter design to reduce common mode and differential mode noise generated by the power stages. Can you post the conducted EMC ploats?

    Thanks

    Peter
  • 0 in reply to Peter Meaney
    TI__Genius 12705 points

    Attached are a couple of plots from the testing.  One time domain and one frequency domain.  

    These plots are taken at the input to the supply under test.  The frequency plot is actually derived from a current probe, since that is the test method for MIL-461.

    Let us know if the there are any comments.  

    We are basically going through the app note portion of the data sheet and widening loop bandwidths to improve emissions.

  • 0 in reply to Mark Pearson
    TI__Expert 3095 points
    Hi Mark,
    Peter has asked me to assist with this issue.
    The current waveform looks like it contains a significant third harmonic component of the supply frequency.
    Is it possible to share part of your schematic?
    It would also be useful to see the VAOUT voltage waveform to see how much twice Line frequency ripple it contains.
    Thanks
    Joe Leisten
  • 0 in reply to Joe Leisten
    TI__Genius 12705 points
    Joe, I cannot supply you with the Schematic - but I will see if I can supply the VAOUT information.