• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 40 subscribers
  • Views 228 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

PMP21867: 150W negative-to-positive solution

Ben Kuo
Expert 6915 points
Part Number: PMP21867
Other Parts Discussed in Thread: LM5122, PMP7979

Dear Team,

Do you have reference design for -48V to 12Vout/ 10A application?

I have find PMP21867, but it's 1000W solution with 4 phase.

If you have suitable solution, please share with us. Thanks.

Regards,

Ben

  • 0
    TI__Intellectual 1235 points

    Hi Ben,

    I don't find another design that matches your requirements, however, any boost converter can be configured as a negative-to-positive buck-boost. Take a look at PMP7979 which used the LM5122. For your power level you could use a single phase. To reconfigure for inverting buck-boost:

    1. GND ---> -VIN

    2. VIN --> GND

    3. VOUT remains the same but returns to the new GND, not -VIN

    Since the control circuit is now referenced to -VIN, you will need to add the transistor level shift for feedback control of the output voltage. This is shown on sheet 2 of PMP21867 schematic.

    Please note that the controller sees |-VIN|+|VOUT| which in this case is 48V+12V=60V. The LM5122 is rated for 65V, so this only leaves 5V of margin.

    Best Regards,

    Bob Sheehan

    Power Design Services