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PMP21479: component change suggestion for the PMP21479 schematic to work with DC input from 300Vdc to 450Vdc

Randy Chen
Intellectual 1740 points
Part Number: PMP21479

Hi,

Customer would like to check the operation and behavior of this EVM board with DC input range from 300Vdc to 450Vdc for the server power aux application. Do you have any component change suggestion for the PMP21479 schematic to work with DC input from 300Vdc to 450Vdc and let this aux board operation normally? For example, change the C1 and C2 to the ones with 450Vdc rated cap. Don’t need to spend too much effort on efficiency improvement for this dc input range so far. Or do you have other aux EVM board suggestion for this dc input range operation? Thank you.

Best regards,

Randy

  • 0
    TI__Intellectual 2835 points

    Hi Randy,

    For this design, the input capacitors will obviously need to be rated for 450V.  If you have a fixed output voltage, the two-winding primary bias structure is not needed.  The voltage stress on the FETs (Q1, Q2 and Q7 will need to be checked at 450Vinput.  Also, since your minimum input is 300V, you could use a higher resistance (lower COSS) FET for Q2. This might help with efficiency and power loss at 400-450V input.

    Also check out PMP23146, which is specifically designed for server aux, but not 450Vin.  We don't have very many designs created for 450Vin.

    thanks,

    Brian