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TPS65988: Selection of PD controller

Nilay Patel1
Prodigy 60 points
Part Number: TPS65988
Other Parts Discussed in Thread: TUSB1002A, TPS25751

Tool/software:

Dear TI Support Team,

We are currently designing a 10 Gbps USB switch in which we are using the TUSB1002A redriver to support high-speed signal integrity. We are seeking guidance in selecting a suitable USB Power Delivery (PD) controller that aligns with the following system requirements:

  1. USB Data Role: The device functions as a USB Device (peripheral) from a logical data operations standpoint.
  2. USB Power Role: The system operates as a power source (power bank functionality) from a USB Power Delivery aspect. Can a PD controller support this combination of roles simultaneously—i.e., functioning as a USB Device (UFP) for data while also acting as a PD Power Source (SRC) for power delivery? If so, could you please explain how this is typically handled in TI’s PD controller architecture and whether any additional components are needed?

We would also appreciate any recommended PD controller(s) that fit this use case.

Looking forward to your guidance.

  • 0
    TI__Mastermind 18045 points

    Hi,

    Thanks for reaching out on E2E!

    Are you looking for alternate mode support? Let me confirm if the TPS25751 fits your needs here as it is our latest PD controller that can act as a DRP in the this case and support enter mode for up to USB3.2 speeds. Per USB PD spec on an initial connection, a UFP is a sink and a DFP is a source and the PD can either send a power role swap or a data role swap depending on what is best for your case!

    Thank you,

    Kevin

  • 0 in reply to Kevin Kosta
    Prodigy 60 points

    Thank you kevin for your support. We would like to clarify our primary requirement:

    • USB Data Role: The device should function as a USB Device (peripheral) from a logical data perspective.

    • USB Power Role: The system should operate as a power source from a USB Power Delivery (PD) standpoint.

    • Alternate Mode: Alternate Mode is not required for our application.

    As per the USB PD specification, during an initial connection, a UFP is treated as a sink and a DFP as a source. However, PD supports power role swap and data role swap, depending on system needs.

    In our case, we want to configure the system to behave as a power source (DFP) while also acting as a USB Device (UFP) for data. 

    Our questions are if PD controller can manage the above requirement:

    1. How does the PD controller manage this type of role configuration?

      • Is it handled through default behavior, or does it require explicit programming?

    2. If programming is required, could you please guide us on:

      • Whether this can be achieved through NVM configuration alone

      • Or if it must be controlled dynamically via I²C from the host MCU

    We appreciate your guidance on how to configure the PD controller for this use case.

  • 0 in reply to Nilay Patel1
    TI__Mastermind 18045 points

    Hi Nilay,

    Awesome thank you for confirming!

    Since no alternate mode is needed and you are looking for just USB data, my recommendation is to use the TPS25751!

    Nilay Patel1 said:

    • USB Data Role: The device should function as a USB Device (peripheral) from a logical data perspective.

    • USB Power Role: The system should operate as a power source from a USB Power Delivery (PD) standpoint.

    • Alternate Mode: Alternate Mode is not required for our application.

    For the TPS25751 we have an easy to use online GUI where you can configure those exact settings on the PD. You can store this firmware on an NVM with no EC intervention.

    ...

    For the settings you mentioned above, the PD will automatically try and get to the preferred power and data role using Data role or power role swap messages if the initial connection does not have these preferences automatically negotiated. For example, as a source during an inital connection the data role will always be DFP, and for a sink it will always be a UFP. Depending on the connection, the PD will automatically trigger a data role or power role swap so that your preferred device role (Source, UFP) is made. The only reason we would see a failure is if the far end device rejects any of these swaps.

    Nilay Patel1 said:

    How does the PD controller manage this type of role configuration?

    • Is it handled through default behavior, or does it require explicit programmin

    As explained above, the PD will automatically do this based on the settings in the online GUI.

    Nilay Patel1 said:

    If programming is required, could you please guide us on:

    • Whether this can be achieved through NVM configuration alone

    • Or if it must be controlled dynamically via I²C from the host MCU

    You can use an NVM to store the config and after loading the config you can always use the I2C of an MCU to change settings on the fly as you would like.

    You can find documentation on our site at: https://www.ti.com/product/TPS25751 

    Thank you,

    Kevin

  • 0 in reply to Kevin Kosta
    Prodigy 60 points

    Hi Kevin,

    Thanks for continuous support.

    Our board always operates in USB Device Mode (UFP), but we need to supply power from our board to a connected peripheral or host through our USB Type-C port available on board.

    How does the USB Power Delivery (PD) controller manage this during the initial connection stage where Host/Peripheral Board is not Powered Up and waiting for Power from Device Board (Our Board)?

  • 0 in reply to Nilay Patel1
    TI__Mastermind 18045 points

    Hi Nilay,

    Of course!

    In this case, your device would be a DRP or source only and as mentioned above the PD will automatically do a power role or data role swap based on the settings in the GUI. So in the case that you a DFP Source, the pd would issues a data role swap to be a UFP. In USB-C initial connection roles are set as Source DFP, and Sink UFP. 

    Nilay Patel1 said:
    How does the USB Power Delivery (PD) controller manage this during the initial connection stage where Host/Peripheral Board is not Powered Up and waiting for Power from Device Board (Our Board)?

    When connecting to a dead battery far end, our PD will become a source and provide power to the far end and negotiate a contract.

    Thank you,

    Kevin