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There are a few display devices available now that use a single USB-C input for both video (Displayport alt mode) and power (USB Power Delivery). However, only devices equipped with the appropriate USB-C port that supports this can utilize them out of the box.

Unlike traditional displays with their own power supplies, you can't just convert one display technology to another (Displayport to HDMI, for example). The source also must provide power, which a typical Displayport or HDMI connection can not do (or at least not enough of it).

Is it possible for a device to exist that accepts an HDMI or Displayport video input, as well as a USB Power Delivery input, and produce the appropriate output to drive this sort of display? I haven't had any luck looking for such a product, so I'm guess either I didn't come up with the right thing to call it, it's too niche for anyone to make, or it violates some specification rendering it impossible to produce legitimately.

Is this something that can/does exist? Or is there a reason why it can't/shouldn't be done?

For reference: This question relates to a wearable device which connects via USB-C, and must be fed a video signal and powered by the device it is connected to. For this device and others like it, the only options to use it (without some intermediate device as described in my question) would be certain phones and laptops which can output video and power via their USB-C port. The question is: is there a existant/possible/permitted configuration which would allow this device to accept a video source from say… A game console, and power from a standard AC adapter.

Giacomo1968
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zeel
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  • Notes: The configuration is the reverse of the typical USB-C video hub. Those charge a laptop, while the laptop outputs video to a display with its own source of power. Here, the configuration involves a display that is intended to be powered *by* the laptop. A similar device that charged *upstream* rather than *downstream* of the video signal would satisfy the question. – zeel Dec 06 '21 at 20:18
  • You’ll mostly find portable screens with these properties. That may not be what you’re looking for. Check [this](https://geizhals.eu/?cat=monlcd19wide&xf=12004_USB-C), but make sure to inspect every display in detail. The MateView series does use USB-C for power, but not from the display connection. – Daniel B Dec 06 '21 at 21:21
  • @Daniel B I'm not looking for a screen, I'm questioning whether or not a given configuration is even allowable. – zeel Dec 07 '21 at 00:38
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    For reference: This question relates to a wearable device which connects via USB-C, and must be fed a video signal and powered by the device it is connected to. For this device and others like it, the only options to use it (without some intermediate device as described in my question) would be certain phones and laptops which can output video and power via their USB-C port. The question is: is there a existant/possible/permitted configuration which would allow this device to accept a video source from say... A game console, and power from a standard AC adapter. – zeel Dec 07 '21 at 00:42
  • @zeel Good details! But it really should be in the question itself. I went ahead and did that for you, but just for reference. – Giacomo1968 Dec 07 '21 at 03:04

2 Answers2

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Okay, so you want a "reverse USB-C docking station" of sorts. Can something like this exist? Absolutely. After all, that's how the USB-C & DisplayPort signal in a PC (or other devices) is produced. There's plenty of USB-C controller chips available with support for Power Delivery and Alt Mode. These could be used to create a circuit that takes USB, power and DisplayPort (HDMI needs to be converted to DisplayPort) and combines it into a USB-C connection.

Does such a thing exist? No, apparently not. This is a quite the niche use case.

Update: I’ve discovered the Wacom Cintiq Pro Link Plus device. It’s for connecting a USB-C pen display to computers that do not have USB-C. It takes power, USB and HDMI/DisplayPort. It’s only $70, so maybe just try it.

Daniel B
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    I was skeptical, but this device does in fact produce the desired effect. This means it's not only possible, but at least one product exists. Odd that it's such a niche item. But I tried it, and it works. – zeel Jan 06 '22 at 22:29
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Googling 'portable lcd' yielded a pcmag.com article showing a external display that accepts input from HDMI & likely power from either a wall outlet or possible a standard USB-A. Asus ZenScreen Go MB16AHP can do this. Manual indicates it comes with:

  • USB Type-C to A Adapter
  • Power adapter
  • Monitor has internal battery even, apparently

I can't easily confirm if portable monitors with HDMI input can be powered via USB-C or USB-A, then usually mention using a wall adapter or internal battery in monitor. This Viewsonic VG1655 has HDMI input & says wall adapter is detachable type-C leading me to believe if your PC can deliver power (PD) it can power the monitor without wall adapter. What is the EXACT connector you want to power the monitor, USB-C? I don't know the USB specs enough as I am unsure if PD can be delivered via USB3-A connector or not.

Do know there are USB monitors on the market where the power from your PC & video are ALL output via regular USB3-A standard connector. However since you mentioned wanting output via HDMI or DP I didn't bother to look further at that.

gregg
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  • The original poster wants to know if there is a device that can take in HDMI or Displayport video input as input and convert it all to a USB C connection for modern displays that use USB C for data and power.How does this answer address the core question here: “Is it possible for a device to exist that accepts an HDMI or Displayport video input, as well as a USB Power Delivery input, and produce the appropriate output to drive this sort of display?” This “sort of display” is self-described by the original poster as a single USB-C input for both video and power. – Giacomo1968 Dec 06 '21 at 22:06
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    This answer doesn't really attempt to answer the question. I'm well aware of screens that accept HDMI and/or have their own power source. But to answer the question, one must assume that for whatever reason (not important) the particular monitor is not a variable that can be changed. – zeel Dec 07 '21 at 00:36