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TUSB2077A: Hub triggers overcurrent event with no devices connected.

Henrik Jensen1
Prodigy 20 points
Part Number: TUSB2077A

I working on a design that includes a TUSB2077 hub for both some onboard USB devices and a few external USB A ports.
My issue is that when the hub gets connected to a host PC it will show multiple overcurrent error in windows.
The hub does get recognized and the two onboard FTDI chips does show up and works as expected.

when probing the OVRCUR pins going to the power distribution switches the signal is always low, even though they do have individual pull-up resistors and this have also been tested with the distribution switches removed.

tusb2077 circuit.pdf

  • 0
    TI__Guru 60870 points

    Hi Henrik,

    Can you share a portion of your layout?  The OVERCUR/ pins are inputs to the hub so they cannot be driving low.  Can you share the overcurrent error message received?  Is it consistently reported?

    Thanks,

    JMMN

  • 0 in reply to JMMN
    Prodigy 20 points

    I have included the schematic for the USB part of my circuit in the original post.
    The error message I was getting in windows is the one shown in the photo, and I received 5 of them every time the board got plugged into the PC, one for each of the ports that goes to a USB A connector.

    I am aware that the OVRCUR pins are input, hence my confusion of the behavior that led me to ask the original question.

    I have now replaced the chip for the second time for a brand new unused chip and the problem have gone away, indication to me at least that I was dealing with a partially damaged chip. The first replacement was with a chip that have been donated from an earlier version of the board on which it was working fine, and after the replacement it was showing the same error behavior as the chip that was originally mounted to the board, leading me to believe the issues I was having originated elsewhere.