How does USB type C work?

richaron

Golden Member
Mar 27, 2012
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I need something like a new notebook to work while out of the house so I've been considering my options recently. I don't really need anything powerful, but do like a nice screen and I also appreciate a proper keyboard and mouse. Plus I realised I'm always carrying my Galaxy S8 which already has plenty of power for light PC duties. So I was thinking...

One option would be hooking up a USB monitor like the nice looking ASUS "ZenScreen Go" I've seen in a couple of reports from CES. A phone was driving in the the display booth and both have in internal battery. But it will draw power via it's USB type C port when it needs, which will obviously drain the phone in no time. Plus since the phone is plugged into the monitor you can't cable charge it either, the best you could do is last as long as possible on the phone's Qi charging (which might actually be OK).

But how does USB type C work with hubs and power delivery? I know power levels are negotiated on connection, and I'm sure I read power direction can be negotiated also. So I guess charging the phone from the monitor's battery is likely. But could I put active adaptor in the middle which charges them both at the same time? And that sounds like it's the first step towards a powered hub, but powered hubs don't charge the host also do they? And how would a hub affect the type C display alt modes? I know alt modes, like the power, are negotiated on connection but I'm guessing the hub controller needs specific support for alt modes to avoid mangling the signal? I've seen a few hubs advertised as having a type C power delivery passthrough so I guess it's a special thing and display alt mode passthrough might be also...

Thanks for any input. Just to cut a few posters off at the pass: I'm using Linux, there a a few ways to run a full desktop. Yes I understand there's already a "Dex" dock, I know it and other hubs exist with hdmi ports. Yes, I would rather spend more on a "portable" display/kb/mouse/hub/etc than buying an entry level notebook. I know all these things won't be as portable as a notebook. Etc. Just looking for some input into USB atm so I can understand the scope of what is or is not possible.
 

richaron

Golden Member
Mar 27, 2012
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Sounds like you want the HyperDrive... too bad it isn't out yet, so, no reviews.
In short, this can charge the phone at the same time, it is a kickstarter, and they already met their goal, so...when it will actually ship, I have no idea.

https://www.kickstarter.com/projects/hypershop/hyperdrive-usb-c-hub-75w-qi-wireless-charger-iphon
Ohh, yeah that's kinda close. I think I could build a crappy approximation of that with a separate Qi charger and a type C hub with built in network/hdmi ports and power passthrough. But that looks like it depends on the host for power delivery, which makes sense for a PC host but not really in my example.

And I would ideally like to drive the monitor I mentioned above with native type C displayport alt mode (only single type C input), even if it does have some driver based USB 3.0 fallback functionality, right?

Edit: Looking further at above device it does have a separate power input, so depending on how they implemented everything it could use a separate usb host to power source. Especially since I think I mis-understood power delivery passthrough "feature" is on these hubs, it does mean to charge the host?

Anyway, I can still ghetto rig something like the above up myself with separate components. But what about USB type C DisplayPort alt modes being passed through a hub? A little more reading confirms the data is packetized so maybe passing through a hub is a non-issue..
 
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Elixer

Lifer
May 7, 2002
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Sorry, have no experience with USB-C with video output & hubs.

At worst, the hub will send the data to everything connected, though, I don't think that will be a big issue, though, it really depends on the hub.