• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 63 subscribers
  • Views 72 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

TPS23753: Need help me check the schematic

Luke Chiang
Intellectual 270 points
Part Number: TPS23753

Tool/software:

Could you please help me take a look at this picture? Is there any problem. We found that the standard POE power supply equipment is connected here, but there is no output.

My first time using this chip, my previous experience tells me that the handshake may not have passed.

Please help me review this schematic and provide some possible reasons for the lack of output.

  • 0
    TI__Mastermind 37071 points

    Hi Luke,

    Thanks for reaching out!

    Due to the tasks accumulation after international labor day in May, we need longer time to response E2E. Please allow 2-6 business days for us to reply your question. Sorry for the delay and thanks for the patience!

    Best regards,

    Diang

  • 0 in reply to Diang Xing
    TI__Mastermind 37071 points

    Hi Luke,

    It looks strange that PR78 & PR36, PR12 & PR45 are grouped together. PoE normally Alt-A is PR12 & PR36 as a group, Alt-B is PR45 & PR78 as a group.  You may try to correct the pairs combination.

    Besides, can you capture the waveform at C75? Want to see if you can get a waveform like below (10V/div) 

    Best regards,

    Diang

  • 0 in reply to Diang Xing
    Intellectual 270 points

    This is an integrated Ethernet connector, not a discrete schematic diagram.  It is a schematic diagram describing the internal connections.  The Ethernet connector contains an isolation transformer and a rectifier inside.  This Ethernet connector is fine and normal.

    C75，The test waveforms are as follows (1V/div).

    The maximum voltage is only 0.5V

    Besides, the TI transformer did not adopt the one officially recommended by TI. I'm not sure if there will be any problems.

  • 0 in reply to Luke Chiang
    TI__Mastermind 37071 points

    Hi Luke,

    I am currently in timebank and will back on Wednesday. Sorry a delay on the replay and thanks for your patience!

    Best regards,

    Diang 

  • 0 in reply to Diang Xing
    TI__Mastermind 37071 points

    HI Luke,

    Based on the waveform, the detection could already have an issue. I would recommend you to double check if PR12 & PR36 is grouped, PR45 & PR78 is grouped. If PR78 & PR36, PR12 & PR45 are grouped as the circuit showing, the PoE won't work.

    The transformer winding bias looks ok to me.

    Best regards,

    Diang