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TPS65987D: Source current capability

Koji Ikeda
Expert 6435 points
Part Number: TPS65987D


Hello Support team,

My customer is looking for solution, customer application is in sink side and they would like to know maximum supply current on source, does TPS65987D have such a function? If TI other device can support, please let me know. 

Thanks,

Koji Ikeda

  • 0
    TI__Mastermind 35426 points

    Hi Ikeda-san,

    The TPS65987D is capable of supporting up to 100W (20V/5A) for both sourcing and sinking power roles along with additional features such as support for alternate modes (i.e. DisplayPort, Thunderbolt for only DJ and DK variants, etc.). 

    Koji Ikeda said:
    they would like to know maximum supply current on source

    I'm not too sure exactly what you mean here, are you referring to how does our PD detect the maximum power the source can provide if it's in sink? During PD negotiations, if the source is also a PD it (source side) will send it's source capabilities and the sink PD will select a PDO that fits its needs. Current capability is also dependent on the Rp detection through the CC lines (different Rp value will select USB default current, 1.5A, or 3A). 

    Thanks and Regards,

    Raymond Lin

  • 0 in reply to Raymond Lin
    TI__Expert 6435 points

    Raymond-san,

    Thank you for your support. Customer would like to adjust maximum system load on sink side, by source supply current. They have some concerns.

    *E.g. if user uses TYPE-A to TYPE-C cable, source current might not have enough supply current which sink side requires. How does sink side detect this?

    *In case of power delivery, if sink requires higher power but source can't support, how does sink detect the maximum supply power in source side?

    Thanks,

    Koji Ikeda

  • +1 in reply to Koji Ikeda
    TI__Mastermind 35426 points

    Hi Ikeda-san,

    In the example of a Type-A to Type-C cable, the current capability is dependent on the Rp present on the CC line (internally in the cable). Attached below is from the Type-C specs that shows how much power (voltage and current) will be advertise from source side based on Rp:

    Do keep in mind for legacy cables (i.e. Type-A), the maximum power that can be delivered is 5V/3A (15W). 

    During PD negotiations, the source will advertise it's source PDO capabilities (i.e. 5V/3A. 9V/3A, 15V/3A, 20V/3A, etc.) and the sink PD will request the PDO that it requires. There's several settings that can be configured from the TPS65987D, such as what the offer priority should be:

    Thanks and Regards,

    Raymond Lin