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USB Superspeed Peripherals

New Contributor

Hello Sir,

I'm developing a self powered device, I have connected the FX3 VBUS pin at the USB 5V pin and the other voltages (VDD, VIO, ecc...) are supplied by an external power supply unit.

What happens if the external power supply stays off and the device remains connected to the PC? I assume that only the PHY module remains powered while the rest of the chip will be turned off.

Is this situation dangerous for the FX3? Is there a risk of damaging something?

Thanks in advance.

Regards

Nick

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Moderator
Moderator

Hi Nick,

I think FX3 Power supply domains are supplied by an external power supply, is it right?If yes, in that case you are right.

What happens if the external power supply stays off and the device remains connected to the PC?

only the PHY block is active and rest of the chip should be turned off.

Is this situation dangerous for the FX3?

Nothing has happend for the FX3.

Regards,

Anil Srinivas.

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3 Replies
Moderator
Moderator

Hi Nick,

I think FX3 Power supply domains are supplied by an external power supply, is it right?If yes, in that case you are right.

What happens if the external power supply stays off and the device remains connected to the PC?

only the PHY block is active and rest of the chip should be turned off.

Is this situation dangerous for the FX3?

Nothing has happend for the FX3.

Regards,

Anil Srinivas.

View solution in original post

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New Contributor

Yes the FX3 Power supply domains are supplied by an external power supply but this remains off for a period of time during which only the VBUS is supplied to the FX3 PHY by the USB3 cable.

Are you sure that there is no conflict over the other power supplies domains of the FX3?

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Moderator
Moderator

Hi,

Are you sure that there is no conflict over the other power supplies domains of the FX3?

Threre is no issues in power supply domains of the FX3.

Regards,

Anil Srinivas.

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