• State Resolved
  • Locked Locked
  • Replies 8 replies
  • Answers 1 answer
  • Subscribers 65 subscribers
  • Views 482 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.

What is the optimal devices for 802.3af PSE and PD?

K. Sasaki14
Guru 10200 points
Other Parts Discussed in Thread: TPS23861, TPS23751, TPS23753A, PMP9175, TPS2384

What is the optimal devices for 802.3af PSE and PD?
Port number is 1 or 2.
It is best that PD device include DCDC controller. And output voltage is 3.8V or 3.3V or 5V.

On your web products list, old devices have been deleted from list.
So optimal devices are TPS23861 for PSE and TPS23751 for PD?

Best Regards,
Kohei Sasaki

  • 0
    TI__Genius 9230 points
    Hi Kohei,

    For PSE, we recommend our single port reference design: www.ti.com/.../TIDA-00465

    Do you have additional design requirements for your PD? (type, output power, topology, efficiency, etc) I can recommend designs.

    Regards,
    Tom Amlee
    PoE PD Apps Engineer
  • 0 in reply to Thomas Amlee
    Guru 10200 points

    Tom-san,

    Thank you for your reply.
    About PSE, is it OK that we add one port circuit to your TPS23861 design if our customer need 2 ports?

    About PD, output power 12W is enough.  Simple circuit configuration is desirable. There are no other requirements in particular.

    Best Regards,
    Kohei Sasaki

  • 0 in reply to K. Sasaki14
    TI__Genius 9230 points
    Hi Kohei,

    Yes, you are welcome to modify the reference design in anyway you see fit. We have provided it free to be used.

    The below PD reference designs use our TPS23753A type 1 PD + PWM controller:
    PMP9175: 5V/2.3A Synchronous Flyback
    PMP20931: 3.7V/2.9A Synchronous Flyback

    Regards,
    Tom Amlee
    PoE PD Apps Engineer
  • 0 in reply to Thomas Amlee
    Guru 10200 points

    Tom-san,

    Thank you for your reply.
    And I have additional question about PSE device.

    Is the host control needed or not for PSE device control generally?

    I think TPS23861 does't necessarily require Host control because it has Auto mode. How about other PSE devices?

    Best Regards,
    Kohei Sasaki

  • 0 in reply to K. Sasaki14
    TI__Genius 9230 points
    Hi Kohei,

    Let me notify our PSE expert for them to get back to you.

    Regards,
    Tom Amlee
    PoE PD Apps Engineer
  • 0 in reply to K. Sasaki14
    TI__Genius 15685 points
    Hi Kohei,

    Before I comment on the part selection, I want to understand your system better. Do you have control on both sides of the cable(PSE and PD)? Is is possible to connect a Type 2 class 4 PD to the PSE port? If yes, do you want the TPS23861 to limit the power to Type 1(15.4W) if a class 4 PD is connected? Thanks.

    Best regards,
    Penny
  • 0 in reply to Penny Xu
    Guru 10200 points

    Penny-san,

    Thank you for your reply.

    Now our customer is R&D phase about this PoE system. So system requirement has not been clear yet.

    We think they can have controller on both side(PSE and PD) if it is needed.

    What point should we care if Type2 class 4 PD is connected to the PSE port and we want to limit the power to 15.4W?

    In that case, should we change use device? or is the host control must requirement?

    Best Regards,
    Kohei Sasaki

  • 0 in reply to K. Sasaki14
    TI__Genius 15685 points
    Hi Kohei,

    If customer wants to limit the port power to type 1(15.4W) whenconnected with a class 4 PD and has host controller which has I2C bus, I would recommend TPS23861 as this is our most popular AT PSE device and we have a lot of support. If customer doesn't have any host controller to do I2C communication and still wants to limit the power to 15.4W for class 4 PDs, TPS2384 is the only device can do that. Thanks.

    Best regards,
    Penny