this post was submitted on 13 Nov 2023
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That’s not physically possible, negotiation is required for voltages over 5V. And the voltage may not be within the spec of the device. USB-PD provides higher voltages in order to push more power through a USB cable. Higher voltage means higher wattage for the same amps, meaning less power lost due to cable resistance. You can’t just push 5V 10A through a USB cable or it would melt, but you could push 20V 2.5A, for the same 50W total but with a non-melty cable. So the voltage may not be precise and is usually used to drive a buck converter at the other end to drop it down to a usable voltage again. All this requires expensive components and complex firmware.
What you’re probably looking for is a regular 12V DC power supply. There’s just no need for all the expensive USB-PD negotiation for your use case.
Plus, as others have said, USB-PD chargers will disconnect all devices whenever power requirements change. This can happen at any time even without the devices being unplugged-re-plugged, it happens whenever the power needs dictate a switch to a new USB-PD mode.