i.MX6DualLite : USB_H1_VBUS behavior on unpowered processor

[koichisakagami]

Dear community,

We are investigating the USB_H1_VBUS  behavior on custom board.

We know that
In i.MX6 USB VBUS can be powered any time,even to unpowered processor
from IMX6DLIEC sect.4.2.1 Power-Up Sequence.
USB_OTG_VBUS and USB_H1_VBUS are not part of the power supply
sequence and can be powered at any time.

[Background]
In the case of the i.MX6 powers off ,while the USB_OTG_VBUS is added with 5V,
the USB_H1_VBUS remains about 5 V.

When the i.MX6 powers off, on impressing a 5V to  the USB_OTG_VBUS,
the USB_H1_VBUS remains about 5 V.

Meantime,
in the case of  i.MX6 never power on ,
even if the USB_OTG_VBUS is added with 5V,
the USB_H1_VBUS does not appear 5 V.

[Question]
We think that this behavior is caused for the description in the datasheet IMX6SDLIEC 4.3.2.3 LDO_USB.
Is my understanding right ?

Best Regards,
Koichi Sakagami

[art · Accepted solution]

Yes, your understanding is correct.

Have a great day,
Artur

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[宗標廖]

Hello,

Artur

I am now working on i.MX6DL.

I think the USB_OTG_VBUS(pin E9)  of i.MX6 can always be provided 5V voltage

regardless of i.MX6 OTG working as host mode or device mode.

Could you tell me whether is it right or not?

Thank you!

Best Regards,

ZongbiaoLiao