i.MX ProcessorsのトピックPower USB subsystem without +5V

Power USB subsystem without +5V

boudewijn-ame — Tue, 21 Mar 2017 13:00:48 GMT

Hello,

I have a small question. Is it possible to power VDDUSB_CAP ourselves? We changed our board design and do not have a +5V supply any more. Page 25 of the datasheet mentions it needs a minimum of 4.4V on either USB_OTG_VBUS or USB_H1_VBUS to power the internal 3V0 LDO.

Since we do not have 4.4V, i want to power it myself. Is this possible? And if yes, what precautions should i take? Such as USB_H1_VBUS GND/floating and/or registersettings.

Thanks in advance!

Kind regards,

Boudewijn

Re: Power USB subsystem without +5V

boudewijn-ame — Fri, 24 Mar 2017 10:33:53 GMT

Hello,

Just a small update: supplying 3V0 to VDDUSB_CAP with an independent power supply does NOT work. The usb peripheral gives a lot of errors. Although it does detect usb devices for some reason.

Grounding USB_H1_VBUS does not improve anything

Re: Power USB subsystem without +5V

CarlosCasillas — Tue, 28 Mar 2017 18:44:07 GMT

Hi,

For USB hardware design references, you could check all the USB-related sections of the “Hardware Development Guide for i.MX 6QuadPlus, 6Quad, 6DualPlus, 6Dual, 6DualLite, 6Solo Families of

Applications Processors” document, available at the following link:

http://www.nxp.com/assets/documents/data/en/user-guides/IMX6DQ6SDLHDG.pdf

Hope this will be useful for you.
Best regards!
/Carlos
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