Searching for a USB 3.x or 2.x hub.. with no backfeed

[Samudra Haque]

Add: the powered hub has a USB B superspeed 10 wire connector ... And a
USB-A connector at the very end.  Two parts with five pins each at the
powered hub and one four pin at the other end.

https://somanytech.com/usb-wiring-diagram-micro-usb-pinout-guide/

On Mon, Sep 6, 2021, 04:59 Samudra Haque <samudra.haque at gmail.com> wrote:

> Hi, a recent amazon USB powered hub I installed provides **backfeed** to
> the DC/DC converter that I installed in a chassis to power the same USB
> hub. I wanted a USB hub for servicing the various FPGA and MCU development
> boards ... But didn't expect the hub itself to power the DC/DC board in
> reverse direction when the DC power input cable is disconnected! And guess
> where it is drawing the the (albeit low power) ?
>
> The hub is drawing from my laptop (both 2.x and 3.x ports)
>
> For those of you that might have seen  backfeed is this part of the USB
> power protocol?
>
> Mitigation tips?
>
> 73 de N3RDX
>
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