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TUSB4041I-Q1: DESIGN REVIEW

Melbin Manuel
Intellectual 300 points
Part Number: TUSB4041I-Q1


Hello,

Kindly review the attached design using TUSB4041IPAPRQ1
Thanks,

Melbin

7115.TUSB4041IPAPRQ1_SCH_28DEC2020.pdf

  • 0
    Prodigy 180 points

    Hello,

    We are working on a project with TUSB4041IPAPRQ1 in it.
    Kindly review the attached schematics and let me know the review comments.

    TUSB4041IPAPRQ1_SCH_28DEC2020.pdf

  • 0
    TI__Guru*** 147460 points

    we will review and give comment soon

  • 0
    TI__Guru 60870 points

    Hi Melbin,

    This tiered hub design looks to be part of an embedded application with no exposed standard USB ports, so the port power switching does not need to be used.  Is that correct?

    Please note that the USB_VBUS input is a detection input and should only be high when an active upstream connection is connected to hub, there can be interoperability issues with connecting it directly to a power rail.  Two concerns are having USB_VBUS high while the host is inactive or not powered, and having USB_VBUS held high during reset (GRSTz).

    Regards,

    JMMN

  • 0
    TI__Guru 60870 points

    Hi Melbin,

    For USB compliance a hub should always implement overcurrent reporting, FULLPWRMGMTz should be set high to indicate that port power switching is not enabled, and any permanently connected port should be marked as non-removable using EEPROM or SMBUS.  If this is an embedded application that will not be required to obtain a USB logo, these are not functionally required.

    Please note that USB_VBUS is a detection input and should only be high when an active upstream connection is available.  Tying it directly to a power rail may cause interoperability issues.

    Regards,

    JMMN

  • 0
    TI__Mastermind 26826 points

    Melbin,

    I noticed that you have already posted this. In an effort to consolidate posts on E2E, I have merged the threads.

    Best,

    Danny

  • 0 in reply to JMMN
    Intellectual 300 points

    Dear JMMN,

    The power V_HUB0_3P3 is high only when the Host is active or powered. The MOSFET logic implemented at the top is for that purpose.

    What is the issue of a high signal present at  USB_VBUS during the reset?

    We have not provided external control for the reset pin GRSTZ.

    How can I implement the overcurrent reporting?

    The devices connected to the down-streams are fixed, but is it necessary to mark them as non-removable using EEPROM or SMBUS?

  • 0 in reply to Melbin Manuel
    TI__Guru 60870 points

    Hi Melbin,

    It appears that the MOSFET logic ensures the proper power up sequencing, does it also ensure that the power is only high when the host is active or powered?

    If this is an embedded system that does not require a USB logo, overcurrent reporting is not required.  Overcurrent events would typically be reported to the hub OVRCURz inputs from the downstream port power switches for the exposed ports.

    For the hub functionality, there is no difference in behavior if a port is marked removable or non-removable, this is only a USB-IF compliance requirement.

    Regards,

    JMMN

  • 0 in reply to JMMN
    Intellectual 300 points

    Dear Jimm,

    I n this case, can I just pull the pin FULLPWRMGMTZ to high and maintain the remaining section as it is?

  • 0 in reply to Melbin Manuel
    TI__Guru 60870 points

    Yes, functionally that will be fine.

    Regards,

    JMMN

  • 0 in reply to JMMN
    Prodigy 180 points

    Thanks JMMN