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UCC28881: Power Dissipation of IC

Anand Meharwade
Expert 1090 points
Part Number: UCC28881

Hello,

I am able to arrive at the power dissipation of the calculated in the tool Webench Power desgner.

I also referred to one of the thread in the forum which explains about Power dissipation calculation

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1006641/ucc28881-how-to-calculate-power-dissipation-and-junction-temp-for-ucc28881?tisearch=e2e-sitesearch&keymatch=UCC28881#

In this thread, the mathcad file considers Ipp = 440mA which the Ilimit of the IC. But as per the Ipp = (Vout/Vinmax) x ((Vinmax-Vout) / (L x f ) I get 251mA, also why did f = 62kHz is considered in the calculation.

May I know what the formulae use the Webench tool to arrive at these design values.

Thanks in advance.

Regards,

Anand M

  • 0
    TI__Guru* 85946 points

    Hello,

    The 62 kHz was used to calculate switching loss.   The resulting calculation at the end of the thread should be correct for the estimate.

    If you are able to calculate the estimate in the Webench tool.  I would think that the calculations are the same.

    Your calculation is not for primary current but average current.

    Regards,