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USB protection required when slave is powered, but master (i.MX8M) isn't

Question asked by arnemaathuis on Apr 7, 2020
Latest reply on Apr 9, 2020 by arnemaathuis



Our application is placed on a card which is mounted on a carrier PCB, out application is USB Master.


during certain situations the Carrier which contains the USB slave can be powered but the i.MX8M is still unpowered.

The slave can then provide power to the i.MX8M via the USB lines, which is undesired behaviour.


should we employ any safety precautions(eg with FSUSB104 buffers/switches) or can the USB peripheral handle this.

note: the USB1_VBUS is connected to the board 3V3 rail since the USB 5V power pin is not connected from slave to master.


regards Arne Maathuis