The way it works for power over Ethernet — and I assume USB power delivery must work the same way — is that it does not reduce bandwidth because they run the power and the signal over the same wires at the same time.
There is a a power injector at one end and a filter at the other end that separate out the high-frequency signal and the DC (no-frequency) power into different wires.
This is essentially the same thing as they’re already doing for multi-frequency stacking on those same wires (and on fiber) to get the crazy bandwidth in the first place. DC power is just one more low (very very low) frequency running on the same stack.
Based on this pin configuration, there’s only two dedicated power pins, which isn’t very good for large wattages. The rest are twinax signal pairs separated by ground to reduce crosstalk.
Usually when connectors are designed for power delivery, they’ll use bigger contacts to reduce the contact resistance (signal contacts tend to be small so you can fit more of them in the same space). I’m guessing the original DP connector form factor wasn’t made with such high power in mind, so it would make a lot of sense to use the spare signal pins for power delivery in this case. Running too much power through too few small pins can damage the contacts, by either by instant-welding the contact surfaces or by overheating the connector (see NVIDIA GPUs) ((also high voltages can cause arcing, which even in the best case will seriously degrade any connector)).
Take all of this with a huge grain of salt cause I just learned this stuff like a month ago, and my department has nothing to do with any of it. Just though someone might find it interesting.
That’s a lot of power! Are there even any devices that use this?
PCs can use >1KW.
I don’t know why you’d power a PC over DisplayPort though. New 8k monitors do go up to 190W, so we could exceed 240W if we try hard enough.
So if you have a beefy psu you should be able to power your monitor off tbe DP?
Or does carrying power limit data throughput?
The way it works for power over Ethernet — and I assume USB power delivery must work the same way — is that it does not reduce bandwidth because they run the power and the signal over the same wires at the same time.
There is a a power injector at one end and a filter at the other end that separate out the high-frequency signal and the DC (no-frequency) power into different wires.
This is essentially the same thing as they’re already doing for multi-frequency stacking on those same wires (and on fiber) to get the crazy bandwidth in the first place. DC power is just one more low (very very low) frequency running on the same stack.
It might? I think USB uses data lanes for power delivery above some point, and I wouldn’t be surprised if DP does the same.
Hi! I actually work at a major electrical connector company, so maybe I can shed some light on this.
I have no idea.
I used to work with electrical engineers, and whenever I asked about details, they’d shrug and say, “black magic?” Checks out.
Usually when connectors are designed for power delivery, they’ll use bigger contacts to reduce the contact resistance (signal contacts tend to be small so you can fit more of them in the same space). I’m guessing the original DP connector form factor wasn’t made with such high power in mind, so it would make a lot of sense to use the spare signal pins for power delivery in this case. Running too much power through too few small pins can damage the contacts, by either by instant-welding the contact surfaces or by overheating the connector (see NVIDIA GPUs) ((also high voltages can cause arcing, which even in the best case will seriously degrade any connector)).
Take all of this with a huge grain of salt cause I just learned this stuff like a month ago, and my department has nothing to do with any of it. Just though someone might find it interesting.