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TUSB8042A: Overcurrent detection period and power supply permission status

user3668508
Prodigy 160 points
Part Number: TUSB8042A

Dear Team,

The board of the overcurrent detection circuit is tested by referring to the data sheet chapter 9.2.1.2.6 of TUSB8042A.
When an electronic load is connected to the downstream USB3.0 port and 2.4A to 2.5A is passed, overcurrent detection works and PWRCTL1 (pin36) of TUSB8042A repeats High and Low.
If the total repetition time is less than 3 seconds, it will be stable at High after that, and if it is 3 seconds or more, it will be stable at Low after that.

What is the reason why pin36 of TUSB8042A may be stable at High or low after overcurrent detection?
Is there a possibility of thermal shutdown?

Thanks

  • 0
    TI__Guru 60865 points

    The behavior of the PWRCTL outputs of the hub are determined by both the OVERCURz inputs to the hub (when the overcurrent is asserted, PWRCTL will de-assert), and the USB host controller.  If the USB host controller disables the power on a port via USB command, PWRCTL will not re-assert even when overcurrent is de-asserted.

    Regards,

    JMMN

  • 0 in reply to JMMN
    Prodigy 160 points

    Dear JMMN,

    About the USB host controller disabling port power via command.

    Is the threshold for the USB host controller to disable port power via a command generally 3 seconds? Or does it depend on the USB host controller?

    Thanks

  • +1 in reply to user3668508
    TI__Guru 60865 points

    The time period for a USB host controller to disable port power via a command will vary depending on software.

    Regards,

    JMMN