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TPS23861: can i power 2 802.3af devices sharing the same gigabit ethernet connection

Mark Ishikawa
Prodigy 50 points
Part Number: TPS23861

I have an application where I need to power the router and a camera that share the same gigabit ethernet connection.  Is it possible to power both devices?  How do I isolate the devices from the Ti 802.3 chip power?

Thanls

  • 0
    TI__Genius 9230 points
    Hi Mark,

    Could you give some more clarity to you question? Are you asking about a PD into a PSE passing through one of the devices or is the IP camera & router connected on the board level (using the same PoE PD circuitry)?

    Best,
    Tom A.
  • 0 in reply to Thomas Amlee
    Prodigy 50 points

    Hi,

    I’m trying to power 2 devices of the ethernet connection.   Router on one side and Camera on the other.    Same physical ethernet  so Power Supply in the middle powering both ends.   Does this make sense?  

    I also have one other connectivity question   I'm planning on using the attached ethernet jack with PoE magnetics embedded.  Can you please let me know the proper pins to connect to the TI PoE Power Supply chip?

    Thanks

    MarkLPJ0012GDNL.pdf

  • 0 in reply to Mark Ishikawa
    Prodigy 50 points

    7824.LPJ0012GDNL.pdfsorry wrong eithernet connector.  this is a gigabit which is my choice.  Thanks

  • 0
    TI__Intellectual 1695 points

    Hi Mark,

    How many PSE channels and PD controllers do you want to use?

    If the total power of router and IPC is within type1, it is possible to use a single PSE channel and a single PD plus flyback controller with two different outputs which can also realize isolation from PSE side.

    If the power is larger, you can use two PSE channels with two PD controller including two flyback controller to supply power independently for routers and IPC.

    Thank you.

    Best Regards

    Jack Chen

  • 0 in reply to Jack CCY
    Prodigy 50 points

    Gig_RJ45_Magnetics.pdfThanks for the info.  So if I understand this correctly I can use 2 channels of the TPS23861 chip  one for thr Router and one for the IPC  and I can have PoE+ for each device?   My plan is to use 2 channels one for each device.  Do I need to provide any isolation between the data  conductors between the RJ45 with built in magnetics?

    Can you help me with the wiring to my Ethernet jack which has built in magnetics.    I am attaching a schematic of the connector.  I'm not quite sure which pins to connect to the output of the TI TPS23861 chip.   I know the chip suplys ( + & - ).  Do I connect all of the +'s and -'s to the 2 pins of the chip.  I see that on the data pins on the PCB board side are clear, do I apply my +48v (supply) to the VC+ and VC- or is that the output from the TI chip?    and what do I connect the MDCTL1-4 pins to?  

    Thanks for all the help

  • 0 in reply to Mark Ishikawa
    TI__Intellectual 1695 points
    Hi Mark,

    You can use two channels of PSE to implement up to class 4 which is not PoE+, just type2 PD. One channel is for IPC and one channel is for router. Both channels can go through one Ethernet wire. Pay attention to the power limit of every channel. If you want a high power PoE which is non-standard, you have to use two channels for one port.
    And you don't need to provide isolation because the RJ45 you mentioned has already had the data transformer.
    For correct connection, you can follow our TPS23861EVM, the link is as below:
    www.ti.com/.../sluuay8d.pdf
    And the MDCTL1-4 can be floated.

    Thank you so much.
    Best Regards
    Jack Chen