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TPS23880: TPS23880 Schematic review

Darren Yang
Expert 2000 points
Part Number: TPS23880

Hi，sir

we want to use TPS23880(PSE)+TPS2372-4 design as output power 90W，PD input, PSE output. PD input 90W, PSE output 90W; the attachment is  TPS23880 and TPS2372-4 schematic , 

Could you help to check the TPS23880 and TPS2372-4 schematic whether is ok? by the way , we also have other question need you help to check it ,the question is follow as

1. TPS2372-4 can use one chip to make 2 power input 90W power PD receiving end. Will the handshake signal have any effect?

TPS2372sch.pdfTPS23880sch.pdf

  • 0
    TI__Expert 5615 points
    Darren, You have entered a question over the weekend so E2E coverage is light.

    Our Strategic Apps expert will review this on Monday, US time.

    Thank you for your local promotion and support of PoE products from Texas Instruments,
  • 0 in reply to Thomas Lewis
    TI__Mastermind 41760 points

    Hi Darren,

    There are several design considerations for this type of application. From a power prospective, there will be some power loss from PD to PSE on the design so a 90W input to 90W output is not possible. And from a IEEE802.3bt standard prospective, in order to be compliant, a PD's max input power is ~70W so 90W at the PD input will be non-compliant.

    If compliance is required, then a single PD cannot work. Typically what we see in a single PD solution for PoE pass through applications (as an example) is 70W input (Class 8) and the output is dual AT PSE outputs (30W each).

    If your solution is non compliant, and you have control of the PSE and the PoE cable length then you can control the PSE to output higher power than 90W such that there is enough power at pass through output for 90W. In this case, then yes, a single PD can work since the TPS2372-4 has a 1.9A max current limit so if the voltage on the PSE is high enough, then even 100W is possible at the PD input (with a 53V input).

    Please let me know if this helps. Thanks!