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TPS2372-4EVM-006: IEEE 802.3bt compliant PD with Low Power Consumption

Harish Singh
Intellectual 995 points
Part Number: TPS2372-4EVM-006
Other Parts Discussed in Thread: TPS2372, TPS23734, TPS23731, TPS23734EVM-094

Hi,

I am designing a flow transmitter with Power over Ethernet(PoE) output. I am assuming the power consumption of the device is going to be low (< 11 Watts) for which power demand fall under 802.3at standard.

Now, the customer is demanding flow transmitter's supply designed to be compliant with 802.3bt (class 4, single signature) standard. I am well aware that PSEs are backward compatible.

My doubt is, If I design transmitter's power supply 802.3bt compliant (which is for high power PDs) and if the total power consumption in run mode to be (let's say) 5 watts, will there be any problem in operation?

The reference design I am using https://www.ti.com/lit/ug/slvub75a/slvub75a.pdf. 

If any further detail required to answer, please let me know.

Regards,

Harish KS

  • 0
    TI__Mastermind 21320 points

    Hello Harish, 

    The TPS2372 is a .bt compliant device. But that does not mean it has to draw up to 71W of power in every design. The TPS2372-4 is actually a standalone PoE PD, versus the TPS23734 has a PWM integrated into it as well. 

    If you want a Class 4 IEEE802.3.bt compliant IC, i would suggest the TPS23734 or TPS23731. 

    If a PoE design uses less than the maximum power that is fine - it is just a DCDC controller in the end. 

    The only minimum power consumption is the MPS signal (10mA)

    If this post answers your question, please indicate so by marking this thread as resolved. Thank you.

     

    Regards, 

     

    Michael P.

    Applications Engineer

    Texas Instruments 

  • 0 in reply to Michael Pahl
    Intellectual 995 points

    Hi Micheal,

    Thank you very much for your prompt and precise response.

    Since I have already designed the circuit as per TPS2372-4 reference design, Shall I move forward with it or shall I change the circuit as per TPS23734 or TPS23731.

    As you already suggested that but I am asking this again to save the the time of circuit design, component selection and procurement.

    Please suggest if you see any problem that I can face in future with TPS23722-4 in my said application.

    Regards,

    Harish KS 

  • 0 in reply to Harish Singh
    TI__Mastermind 21320 points

    Hello Harish,

    If the TPS2372-4 reference design meets your design requirements it will not have issues running at 5W. 

    You can look through our EVM's and reference designs to see if others suit your needs: 

    All i know is you want to use the TPS2372-4 running at 5W, with potential max load at 11W. I cannot foresee problems with this information. I encourage you to review the EVM user's guide for test report information.

    If this post answers your question, please indicate so by marking this thread as resolved. Thank you.

     

    Regards, 

     

    Michael P.

    Applications Engineer

    Texas Instruments 

  • 0 in reply to Michael Pahl
    Intellectual 995 points

    Dear Michael,

    Thank you for the reply.

    I would like to change my design  as per TPS23734EVM-094 due to its active forward DC/DC converter.

    Can you please share its transformer (LDT6037) datasheet?

    Regards,

    Harish KS

  • 0 in reply to Harish Singh
    TI__Mastermind 21320 points

    Resolved in private messenger.

    If this post answers your question, please indicate so by marking this thread as resolved. Thank you.

     

    Regards, 

     

    Michael P.

    Applications Engineer

    Texas Instruments