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LM5050-1: could you please help share the priority setting methods?

Frank Xiao
Genius 12055 points
Part Number: LM5050-1

Hi team,

could you please help check whether the requirements below  can be achieved by LM5050-1?

Two 12V input, A and B.

B is the first priority, if A has power, B has power. B will be on.

If A has power , B doesn't have power. A will be on.

could you please help share the priority setting methods?

Thanks.

     

  • 0
    TI__Genius 16305 points
    Hi Frank,

    Thanks for posting the question, we are looking into this.

    Could you let us know more about the power supply variation between two supply:

    A scenario where both supply has power but Supply A lower than supply B.
    In this case, do you still want to choose supply A?

    Let us know the range of supply used.

    Regards,
    Kari.
  • 0 in reply to Karikalan Selvaraj
    TI__Genius 12055 points
    HI Kari,

    you can consider A and B voltages are the same. Thanks.
  • 0 in reply to Karikalan Selvaraj
    TI__Genius 12055 points

    Hi Kari,

    do you have some update? Thanks.

  • 0 in reply to Frank Xiao
    TI__Genius 16305 points
    Hi Frank,

    When both the voltages are same, then priority can be assigned to Supply "A" by controlling the "OFF" pin of Supply "B" using a resistor ladder from Supply "A".

    So when Supply "A" is present and above UVLO, then it turns off the ORing IC of Supply "B".
    Diode of ORing supply "B" will block reverse current when "A" is higher than "B".
    And supply "A" has to go at-least one diode drop below "B" for diode "B" to start conducting.
    Resistor divider from "A" to control OFF pin of "B" can be chosen based on OFF pin threshold and "A" UVLO threshold.

    This way when Supply "A" is present, it will always power the load (with supply "B" off and not conducting).
    When supply "A" falls below UVLO, OFF pin is pulled down below its threshold and turns on the MOSFET of "B".
    Supply "B" will continue to power until, "A" comes back to power above its UVLO.


    Regards,
    Kari.