I'm wondering if there exists any kind of splitter USB-C splitter that allows for charging and Thunderbolt display through a single port. I know they have this for splitters the take a USB-C Thunderbolt and split it into a USB-C port and an HDMI, I'm wondering if this sort of thing exists for USB-C Thunderbolt displays.

I know large docks are made, but those are fairly expensive and have many extra ports that I'm not interested in. If this sort of thing doesn't exist, is there a reason why?

  • I don't think it exists other than with a dock. Power delivery over TB3/USB-C is managed using the USB-C data link. If you had a Y cable it would mean the display gets the data link while the power supply gets the power pins; But that wouldn't allow for the USB-C power delivery to work correctly when the display announces that it needs to push or pull power. The display and the power supply would have to coordinate, therefore they must be the same device. Maybe there is such thing as a TB3 box that can intercept the power delivery signals and supply power from its own source to either end. – Romen Feb 28 at 19:16
  • @Romen Could you put this in an answer, and possibly comment on why it is possible for display signals used in HDMIs or VGAs but not for Thunderbolt? – David G. Feb 28 at 19:36
  • HDMI and VGA devices "dumb" in comparison to Thunderbolt devices. So those adapters are essentially reporting themselves as the end of the line (the display) on the USB-C side and reporting themselves as video source on the video port's side. Like a man-in-the-middle on the video connection. A device like that could interfere with a Thunderbolt 3 connection though, and certainly would be against the TB3 spec if it hijacked the power delivery. – Romen Feb 28 at 19:45

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