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TPS23731: TPS23731

Michael Neputy
Prodigy 30 points
Part Number: TPS23731
Other Parts Discussed in Thread: PMP22806

Tool/software:

Hello, 
I am trying to design the TPS23731 in a system that will generate 24V on the output. I do not see many reference designs online and for whatever reason I am unable to download the P-Spice simulation tool on the website. Is there anyway you could send this to me via email or allow me to download it? Or is there another reference I can look at?

Thank you

  • 0
    TI__Mastermind 37081 points

    Hi Michael,

    Thanks for reaching out!

    Sorry that PoE parts currently do not have Spice model.

    Please find attached schematic & BOM that changes PMP22806 from 12V output to 24V output.  LDT1069-50R may be considered to change wire to become 24V out from 12V out. Let me know if you need additional information.

    PMP22806B(001)24V Version_ TI-BOM.xlsPMP22806B(001) 24V Version_Sch.pdf

    Best regards,

    Diang

  • 0 in reply to Diang Xing
    Prodigy 30 points

    Hello, I have made these modifications, but I am seeing the voltage drift up to ~36V with no load. In our design we are using this transformer: 750314782.

  • +1 in reply to Michael Neputy
    TI__Mastermind 37081 points

    Hi Michael,

    TPS23731 uses primary side regulation. This method will have a less accuracy load regulation compared to secondary side regulation. At open load, the Vout will normally higher than desired Vout. Meanwhile the inductance is 37 µH which causes DCM, which is worse for primary side regulation. 

    1. It is recommended to use transformer with higher mutual inductance. 

    2. Primary side regulation needs AUX and SEC windings having a better coupling coefficient than secondary side regulation

    3. If at a light load Vout can drop to ~24V, you may consider adding a dummy load with a Zener diode

    Best regards,

    Diang