With the release of the Framework 16 and high power requirements when running the system under full load, I got to thinking, if the Framework 16’s internal USB ports are capable of handling 240w, would it be feasible to get a DC barrel jack adapted to USB-C so we could use aftermarket gaming laptop chargers? I think would be useful, especially given the cost of high power USB-C adapters and the Framework adapter can only go up to 180w at the moment.
Now, I know next to nothing about electronic circuitry, especially power conversion, but I’d be happy to learn since this seems like an “easy enough project” from my point of view. I’d like feedback on if this sounds feasible/doable and any good resources for me to get started with.
Thanks in advance!
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I don’t think the electronics needed to step up the voltage and negotiate PD would fit. You’d need electronics to increase voltage (~20V to 36/48V) and a controller to negotiate USB PD.
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Oh… so no luck then? 
Out of curiosity, do you happen to know what the USB PD spec is or where I can go to find it? My Google-fu is failing me
Wikipedia has a decent intro to USB-PD and a number of references for more info USB hardware - Wikipedia
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Wikipedia perhaps?
And yeah, you’d need something to handle the USB-PD Source negotiations. At that point you’re just re-implementing a USB-PD source, the only advantage is you’re literally plugged into the port that goes onto the mainboard, so you can rely (hopefully) on whatever barrel jack port to you are using to not have to have the USB-PD negotiations check if the cable is USB EPR spec or not.
So…no, there’s no point really trying this.
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Power = Voltage × Amperage
Most 240w barrel chargers achieve 240w by using 20 volts and 12 amps.
However USB is limited to only 5 amp charging. Instead 240w is achieved by cranking the voltage up to 48v.
So a barrel jack expansion card would need to step it up to 48v. That circuitry would require a lot more space than is available in an expansion card, not to mention being similar in difficulty/cost to develop a 240w USB-C charger directly (either way you’d be creating a 240w USB-C charger, it’s just a question of how it’s charged).
Practically the best way to achieve a barrel jack would be through the expansion bay, although that would require developing a new graphics card PCB to make room for it. The expansion bay spec is designed to run at 20v (so no conversion require) and supports charging. A charging bay module with a barrel jack would be able to deliver as much power as the module supports (no 240w limit) to the GPU and 90w to the rest of the system.
Although for the near future I think it is far more likely to see 240w USB-C chargers than a barrel jack module.
In future revisions USB-C could potentially be pushed to 324w or even maybe 360w, which should be plenty. USB-C is currently officially limited to 48 volts and 5 amps. I don’t expect voltage to ever increase due to safety and regulatory reasons, however other companies (Lenovo and Dell) already sell charges that push past the official 5 A limit and reach 6.75 A (which if combined with 48 V would mean 324 w) and some other brand (I think it might’ve been Asus) shared at one point that 7.5 A seems to be the limit for what the connector can safely and reliably handle, which would calculate to 360 w at 48 V.
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Hackaday has an excellent series on USB-PD for DIY folks, e.g. All About USB-C: Talking Low-Level PD | Hackaday. I think the author is on these forums, too?
Essentially, you would need to do a conversion like in this article, USB-C For Hackers: Build Your Own PSU | Hackaday. That said, it may not be as straightforward for a big beefy PSU depending on its design - many huge PSUs like that will include some communications with the laptop for monitoring or other purposes and may not work at full bore unless that communication channel is up (usually it’s 1-wire and it’s so the laptop doesn’t overdraw on a small adapter). E: And yes, if the big beefy PSU were 12V/20A, you would need a boost regulator to output 48V USB-PD. After losses you’d get around, eh, 200W would be safe, which is still good.
Interesting note, while I was reading these, I saw that Dell already makes such an adapter, albeit limited to 65W. Dell Adapter: 7.4mm Barrel to USB-C | Dell USA
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There aren’t any that I can find that support >100w, but this adapter from slimq is pretty much what you’re after. DC to USB PD3.0 Charging Hub – SlimQ Official Store
It takes the 12v 240w from a gaming brick and gives you 2 100w PD ports. So once higher wattage versions come around you’d be set. Having one in hand, it is way too big to ever fit in an expansion port.
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That looks like a very nice power unit. I’ll have to consider getting one of these.
Can’t see that link, just gives me an animated infinity sign, and nothing loads up. Must have an issue with my AdBlocker or the like. Guess I won’t ever be buying from them.
Couldn’t say, I use Ublock and a Pi-Hole and it still loads fine.
Maybe it’s Privacy Badger that I also use? I dunno.