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TPS2378: Can TPS2378 get a power input from PoE Injector which does not negotiate?

Nicky Lim
Genius 3195 points
Part Number: TPS2378
Other Parts Discussed in Thread: TPS2376

Hello,

Can TPS2378 get a power input from PoE Injector which does not negotiate?

If it can get power input from Injector, Could you provide reference schematic or application note?

If cannot get, Could you recommend other PD device which can get injector input and external adapter input?

Regards,

Nicky

  • 0
    TI__Intellectual 1005 points

    Hi Nicky, 

    Yes. You can get power from a PoE injector. The FET inside the PoE PD will turn on whenever the input voltage exceeds the UVLO, which is 38.1V for TPS2378. 

    You don't need to add any additional circuits or components to enable this. Just use the application diagram as is.

    -Artem  

  • 0 in reply to Artem Rogachev
    Genius 3195 points
    Hi Artem,

    TPS2378 has been applied as an Adaptor priority circuit.
    And, Injector supply power through pin 4, 5, 7, 8 without Negotiation.
    When connect this injector to TPS2378 circuit, TPS2378 output is 7Vdc.
    We confirmed that 2-event nego is omitted and 7V is maintained.
    48V & GND are directly connected to bridge diode of input side.

    For TPS2376, if 48V directly supplied without nego, ouput is maintained 48V by UVLO divided resistors.
    But for TPS2378, if 48V directly supplied without nego, output is 7V.

    Could you let me know why this kind of voltage drop is occurred with TPS2378?
    And how can I can fix this problem?

    Regards,
    Nicky
  • 0 in reply to Nicky Lim
    TI__Mastermind 41770 points
    Hi Nicky,

    I am closing this thread as we are discussing this in the latest newer thread. Thanks!