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TPS65987D: changing sorce power dynamically

K.Yaita
Guru 29720 points
Part Number: TPS65987D


Hi Team,

My customer considers to use TPS65987D in his system.
The system is USB2.0 and provider (source only) application.

He wants to change source power dynamically depending on system state.
For example,
1) Consumer device is connected to the system (TPS65987D) through Type-C cable.
2) TPS65987D provides power to consumer device depending on PD communication (ex. 15V/3A).
3) CPU advertises TPS65987D to reduce power.
4) TPS65987D reduces power provoided to consumer device (ex. 15V/3A -> 5V/0.1A).

Is it possible scenario for TPS65987D?
If the answer is yes, how to achieve 3) process?
Is it required I2C communication between CPU and TPS65987D?

Best Regards,
Yaita

  • 0
    TI__Mastermind 30000 points
    Hello Yaita,

    I would recommend using the App config utility for this use case. If you open the "TPS65987DDH User Alternate Mode" app note (www.ti.com/.../slvae16.pdf), this feature is explained within section 4 advanced configuration. Basic functionality is that you set a GPIO to one of the App Configurations, and if a high or low value is sent to that GPIO, it will respond by changing its base configuration.

    How this would be done for your customers system is that before the EC goes into its low power state, it will send a signal to the TPS65987D GPIO set to app config, and the TPS65987D will change its source capabilities and resend them to the connected device.

    For reference, the Power DUO Source and Power Duo Sink boards used this feature. When the pushbutton is pressed, it will change either its source or sink capabilities accordingly.
    www.ti.com/.../tiduef3.pdf
    www.ti.com/.../tiduef4.pdf

    Let me know if this answers your question or not!
  • 0 in reply to Adam Mc Gaffin
    Guru 29720 points

    Hi Adam-san,

    I appreciate for your kind support.
    I will check your explanation but would like to ask one more.

    >TPS65987D will change its source capabilities and resend them to the connected device.
    Does TPS65987D operate above without breaking USB2.0 communication?
     
    Best Regards,
    Yaita

  • 0 in reply to K.Yaita
    TI__Mastermind 30000 points
    Hello Yaita-sa,

    No it does not. The app config does not cause a disconnect of the Type-C port, but changes the source/sink capabilities of the PD controller. So this will not cause any issues with USB2.0 communication.

    Let me know if you have any other questions!
  • 0 in reply to Adam Mc Gaffin
    Guru 29720 points

    Hi Adam-san,

    I also found the following application note in page 7 "3.2 Application Configuration GPIO Event Settings".
    http://www.ti.com/lit/an/slvae11/slvae11.pdf

    Is the content same with your following comments?
    >Basic functionality is that you set a GPIO to one of the App Configurations, and if a high or low value is sent to that GPIO, it will respond by changing its base configuration.

    Best Regards,
    Yaita

  • 0 in reply to K.Yaita
    TI__Mastermind 30000 points
    Yaita-san,

    Yes, this content is the same and this is actually a better example/walkthrough than the one I had originally shared. If you follow both of these documents, you should be able to implement app config successfully. Feel free to open a new E2E if you have any other questions about implementing app config
  • 0 in reply to Adam Mc Gaffin
    Guru 29720 points

    Hi Adam-san,

    Thank you for your kind support.
    I understand.

    Best Regards,
    Yaita