How to power when using USB-OTG?

#1

Hello,

I am currently experimenting with the ROCK 5B board and am very happy so far. However, now I want to connect it via USB-OTG to my PC to emulate a mouse and keyboard and possibly a storage device. I want it to be powered independent on whether the PC is running, so I need a way to power the board without using the USB-OTG-Port (which from my understanding is that same USB Type-C-Port, correct?).

I read that driving it via GPIO pins with 3A is cutting it very close if you are using the NVMe slot, which I do, and indeed, I wasn’t able to get it to boot up in this scenario. It seems to be stuck in a reboot loop.

So, my question is, is there any way to power the ROCK 5B board with sufficient (15W+?) power without using USB-C, so presumably by using 9V or 12V? Or is there some kind of adapter that allows me to power it via USB-C using a PD-power brick while at the same time having a PC connected via OTG at USB 3.0 speeds?

Thank you for your inputs!

#2

you can use a usb-otg-Cable like this~
下载.webp (45.7 KB)

#3

any usb-type c “dock” sold on the market should allow this. they usually have either a PD or DC Barrel connector while exposing multiple ports. this does also work as OTG

#4

I find it very hard to believe that I can use any USB Type-C dock to achieve what I want. I don’t want to attach a usb mouse/drive to my ROCK5 while powering it. I want the ROCK5 to act like a USB mouse/drive while powering it, while connected to a PC.

#5

@abel, thank you for the USB-OTG-Cable suggestion. Looking at a few options out there I can’t find a definitive answer as to whether they support USB 3.0 transfer speeds (5 Gbits) or only USB 2.0. Do you happen to have an answer to that?

#6

all the dock does is multiplex out usb-3 - at least with my cheap one from Renkforce this does work in OTG mode.(I couldnt test it with more than a teensy microcontroler as usb host though - limited imagination back then

#7

@John_Deaux Thank you for clarifying. I thought you were talking about more sophisticated “docks” with HDMI/Ethernet and stuff like that. But I take it you were suggesting something like this? This looks quite promising. I’ll give it a try!

#8

Honestly I was talking about one of those more sophisticated ones as that’s all I have(and therefore could test) problem imho is that the definition of “dock” is nothing like what I grew up on(anyone still remember the docking connectors on mid 90s and early 2000s notebooks will know what I mean. These modern day things do work nevertheless as they are actually pretty agnostic in terms of what they transmit

#9

Hi bobby,
Did this reinkforce cable work for you?
Or did you find any good alternative?

#10

Hi @Rockpi_fan,

unfortunately, that cable did not work for me. In the end, I decided to reduce the PCIe load to <15W and use GPIO to power it instead.