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UCC256304: configurable output

Gaurav Gothoskar
Prodigy 100 points
Part Number: UCC256304
Other Parts Discussed in Thread: PMP, UCC256403,

I am looking at the PMP21863 application note which is configured for a 48V output.

I want to change the output to 57VDC. can I just change the resistor divider at the reference point? teh application note design is for 48V and 11A for a total power of 528W. I am looking at a 500W output at 57V.

Do you think this can be done? also can i get one of teh boards used in this design?

Thanks.

  • 0
    TI__Guru 74935 points

    Hello,

    Your inquiry is under review.

    Regards,

  • 0 in reply to Mike O'
    TI__Guru 74935 points

    Hello,

    Is the only thing in the design that is changing is the output voltage?

    Is your input power requirements remaining the same?

    Regards,

  • 0 in reply to Mike O'
    Prodigy 100 points

    input requirements are the same. Max input is 400V (typical is 370VDC).

    1. Can the Renco transformer be the same for a 57V output?

    2. Can I buy this evaluation board from T.I or some other distributor to try this design?

    Thanks. 

  • 0 in reply to Gaurav Gothoskar
    TI__Guru 74935 points

    Hello,

    The PMP reference designs are not available for purchase.  However, the  PMP reference designs have Gerber files, schematic and BOMs so engineers can have a PCB made and build the reference design.

    57 V is higher than the 48V.  You might need to change the output rectifiers and capacitors to high voltage rated devices.  These components should be rated for the same or greater peak currents and RMS currents.

    The only other thing that could be off is the transformer turns ratio.  It is generally set to (Vin/2)/Vout.  I was looking for the PMP21863 and could not find it on the TI web sight.  Is that reference design number correct?  If you have the transformer part number you should be able to see is this design will work or the transformer turns ratio needs to be changed.

    Regards,

  • 0 in reply to Mike O'
    Prodigy 100 points

    Attaching both the application note for the reference design and the Renco transformer spec. please review and comment. Thanks. Test Report.pdfRenco Transformer.pdf

  • 0 in reply to Gaurav Gothoskar
    TI__Guru 74935 points

    Hello,

    I received your inquiry and it is under review.

    Regards,

  • 0 in reply to Mike O'
    TI__Guru 74935 points

    Hello,

    I see that you are using the UCC256304 for a new design.  These devices are not recommended for new designs.  I would recommend that you switch over to the UCC256403. 

    The following link will bring you to an excel design tool that goes through the step by step design process.  There is a section on selecting the transformers Lm, Lr and turns ratio. You can use this tool to if the transformer will work for your design  If the transformer is within 5% of these values it should work for your design.

    https://www.ti.com/tool/download/SLUC675

    Regards,