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UCC28221 calculation

mahesh jalgaonkar
Prodigy 170 points
Other Parts Discussed in Thread: UCC28221

Hello Sir,

As I discuss earlier in forum I want to design 5V/120Amp SMPS with ucc28221 IC.

I need designing tool for this. 

I have read its 200W design document but its not showing what will be the current flow into each transformer.

Which worries me.

I found one mathcad tool. But I dont know mathcad so i cant use that also.

If there is any spreadsheet made by you people please share it, I need it very much.

Or any other material with details design procedure.(including Primary RMS current, secondary RMS current, Wire guage, o/p inductor current,)

Thanks

Mahesh.

  • 0
    TI__Expert 3200 points
    Hi Mahesh,

    There is no spreadsheet design calculator. There is another design document that should help you www.ti.com/.../slua312.pdf that the Mathcad design tool file references. As I look through this reference and the Mathcad tool, it implies that we worked with a magnetics vendor which we do as well today at times so use this design material to calculate the key parameters then work with your magnetic supplier for final magnetics.
  • 0 in reply to Brian Johnson96
    Prodigy 170 points

    Thank you sir for replying me.

    Then my question is will both transformer will be of  120A each.

    Because datasheet says they will share current so will it be 60A each or other. 

    Because I need to fix gauge of wire and there is no explanation for this I have calculated Current but will that be 1/2 for each transformer.

    If both tx have will have 120A then transformer will be bulky and size will be hign.

  • 0 in reply to mahesh jalgaonkar
    TI__Expert 3200 points

    Hi Mahesh,

    The two-phase interleaved forward is two forward converters operating 180 degrees out of phase.  So each phase is half the load current.  To size the magnetic wire however, it is half the DC load current plus your ripple current that you assumed when sizing the inductance.  In the slua312 document, section 2.2 assumes the ripple current to be 60% of the maximum load current and you will see the DC current is Pout/(Vout*2).