Can we add a resistor between i.MX6SDL USB_OTG_VBUS and USB connector?

[satoshishimoda]

Hi community,

I have a question about i.MX6SDL.

Can we add a series resistor (120 ohm) to USB VBUS line between i.MX6SDL USB_OTG_VBUS and USB connector?

As per hardware development guide (IMX6DQ6SDLHDG Rev.1), USB_H1_VBUS should be directly connected a 5V supply.

But no recommendation about connection between USB_OTG_VBUS and connector in the document.

In fact, current leakage is shown in their custom board.

And adding series resistor (120 ohm) may prevent the leakage, so they want to add it.

Best Regards,

Satoshi Shimoda

[Yuri · Accepted solution]

Hello,

     Generally, 120 OHm series resistor in VBUS line does not allow to feed
external USB device, if i.MX6 OTG is configured in USB host mode. USB specs
require to provide 0.5A for external devices via VBUS. If i.MX6 OTG is not intended

to provide supply for external devices and i.MX6 is not designed to be powered

via VBUS as USB device, it is possible to provide voltage offset via a series resistor

to i.MX6 VBUS pin.

Have a great day,
Yuri

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[satoshishimoda]

Dear Yuri,

Thank you for your quick response.

OK, I understood a series resistor is not allowed if power is provided from USB host via VBUS with both case i.MX6 is USB host or device.

Best Regards,

Satoshi Shimoda