• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 63 subscribers
  • Views 181 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS25751: Meeting USB compliance IEC62680 with TPS25751 PD controller

Naveen Kumar S1
Prodigy 230 points
Part Number: TPS25751

Tool/software:

Hi, 

We are planning to use USB PD controller TPS25751 in one of our designs. Please find attached the USB architecture block diagram for your reference.

A brief description about the architecture:

  1. The design demands 4 USB ports, out of which 3 are USB SS ports. The qualcomm processor supports only one USB port. In order to support multiple USB ports, a PCIe to USB bridge is used.
  2. There are two Type C ports(Primary and secondary) in the design with full SS support
  3. One of the Type C ports(Primary port) is directly interfaced to the processor as Primary USB for download and device mode operation
  4. There are 4 power input sources:
    1. 2 Type C ports, out of which one supports PD and Display over Type C
    2. One Dock interface with 27W input power with USB SS/2.0 interface.
    3. One expansion port with 12V input for charging and USB 2.0 interface

The OTG power supplies to the Type C connectors are provided through external OTG power supplies.

Will there be any USB compliance issues with this architecture? We are looking for IEC62680 compliance tests as per the latest USB standards. 

Have you come across any USB compliance issues by using external OTG power supplies or PD controllers?

Thanks,

Naveen


7658.Block_Diagram.pdf

  • 0
    TI__Guru 62811 points

    Hello,

    Naveen Kumar S1 said:
    Have you come across any USB compliance issues by using external OTG power supplies or PD controllers?

    Yes.  There are challenges with maintaining the timing relationships between when the PD notifies of a successful contract negotiation and when the regulator is adjusted to the contract voltage.  In your specific block diagram it appears that you only intend on sourcing 5V from the PP5V and then sinking to the 2:1 mux.  I believe this would conform to what we are describing as the EVM use case in the gui.

    https://dev.ti.com/gallery/view/USBPD/USBCPD_Application_Customization_Tool/ver/1.0.2/

    We are in the process of updating our documentation to reflect compliance with the latest PD specification; 3.2.

    Regards,
    Chris

  • 0 in reply to Chris Sterzik
    Prodigy 230 points

    Hi Chris, 

    Thanks for your inputs and updates.

    On the primary USB connector, we are using the PD controller inside the processor and feeding the external supply for OTG. This will enable us to use the primary USB to connect to PC to access the device as slave and also software download becomes seemless. Hence we had to use the PD controller of the processor.

    This supply will be enabled by the GPIO of the processor when a slave device is connected.

    Do you see a concern here for the compliance? If yes, what mitigation can be used here to address this?

    Thanks,

    Naveen

  • 0 in reply to Naveen Kumar S1
    TI__Guru 62811 points

    Hello,

    I do not see an issue.  As you mentioned the PD in the micro will need to control the regulator based upon the negotiate role.

    Regards,
    Chris