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TPS2546: USB3.0 can able to be detect after wake up from S3.

Part Number: TPS2546
Other Parts Discussed in Thread: TUSB522P, TPS2001D

Hi Team,

Customer are using TPS2546.

They found that when system wake up from S3, USB3.0 device are not able to be detect.

Then they short the IN and OUT on TPS2546 then this issue gone.

Do we have such experience? What’s the possible root cause?

Thanks

Shaq.

  • Hello Shaq,

    What are the levels of the CTL pins when the system is in sleep to when the system is in wake? Also, do you have any waveforms for the failure?
  • Hello Shaq,

    I am going to close this item. Feel free to respond to this ticket or create a new one if you have any questions.
  • Hi Adam,

    Here is update. There are two port on costume system. 

    port A: TUSB2546 + TUSB522P

    portB: TUSB522P + TPS2001D

    We did some experiment found that USB3.0 cannot work is something to do with Vbus.

    If customer short Vbus to connector ( bypass TUSB2546), this issue was gone.

    This issue was gone when CTL does not change setting in different mode.

    Customer issue condition on port A:

    1. reboot system

    2. USB 3.0 flash plug in. It was been detected and shown on device manager.

    3. system enter S3 ( sleep mode)

    4. system wake up from S3, USB 3.0 flash not able to detect by system.

    5. Unplug then plug in again are not able to been detect.

    Customer issue condition on port B:

    1. refresh or reboot system

    2. USB 3.0 flash plug in. It was been detected and shown on device manager.

    3. system enter S3 ( sleep mode)

    4. system wake up from S3, USB 3.0 flash not able to detect by system.

    5. Unplug then plug in again, USB 3.0 flash are able to been detect.

    This figure is shown when device enter S3.

    This picture shown device wake up from S3 but not able to get USB3.0 signal.

    Thanks

    Shaq.

  • Hello Shaq,

    When transitioning from one charging mode to another, per the USB spec VBUS is required to discharge for a specific amount of time. However, if the host tries to negotiate on the USB DP/DM lines before 5V has been presented back on VBUS, than there will be an issue. I do not believe the problem is due to the TPS2546 handling of VBUS, but how the host system is potentially handling the USB lines.
  • Hi Adam,

    We figure out that host should send warm reset after Vbus temporary disappear.

    Thanks
    Shaq.