Waste heat seems like it would be a thing? Even at 95% efficiency (which is unrealistic), we're looking at a 12W heater.
Has always been the case, i remember my legs getting cooked by apple's magsafe charger brick. GaN makes this better now though
240W USB-C PD chargers are nearly here, says Framework CEO
71–80 of 138 posts
Re: 240W USB-C PD chargers are nearly here, says Framework CEO
#72It's super frustrating that if I want a 2nd charger for my macbook pro, I have to either buy an overpriced apple adapter, or.... what? I haven't seen any USB-C compatible 140W chargers that are significantly cheaper than apple's.... but I can't charge my laptop with less. If I plug in my 80w charger, my laptop just goes "bong bong bong" as it turns charging on and off endlessly.
Re: 240W USB-C PD chargers are nearly here, says Framework CEO
#73I wonder if we'll start seeing devices other than laptops that currently use barrel jacks for power shift to USB-C. 240W covers the vast majority of things even an enthusiast might have on their desk. It'd be nice if they did, if only because there's a single agreed upon way to deliver power with USB-PD, and USB-PD bricks hash out the details with the connected device to deliver appropriate power. It's a considerably…
Already happening. My soldering iron, pimple-popper camera, and toy lightsaber all take USB-C. Though the lightsaber isn't compliant and just wired up the power and ground pins from the USB connector with no more complexity than barrel jack, rather than doing the proper USB-C/PD things to indicate how much power it can take, so some cables/chargers won't even give it anything.
Re: 240W USB-C PD chargers are nearly here, says Framework CEO
#74It's super frustrating that if I want a 2nd charger for my macbook pro, I have to either buy an overpriced apple adapter, or.... what? I haven't seen any USB-C compatible 140W chargers that are significantly cheaper than apple's.... but I can't charge my laptop with less. If I plug in my 80w charger, my laptop just goes "bong bong bong" as it turns charging on and off endlessly.
Anker 717 is much smaller and is cheaper, though not by much. Considering it just seems strictly better, it doesn't need to be.
Re: 240W USB-C PD chargers are nearly here, says Framework CEO
#75why was 240W picked as the upper limit for PD? Why does there even need to be an upper limit?
The usb-c connector is rated to 5 Amps (A). Usb-c went up to 20V already. 5A * 20V = 100W (where we are). We didn't want to change the connector. So we are stuck at 5A. But we can raise voltage & still have some margin. So voltage was raised to 48V. 5A * 48V = 240W. As for raising the voltage more, it's likely very technically feasible, but probably not, for safety reasons. There are various levels of what is conside…
Negotiating voltage after being connected avoids the problem of sparking while the connector is being plugged in, but I don't think it helps with avoiding sparking in the process of unplugging the connector? Unless one of the leads is shorter so that is disconnects first and the circuitry can detect that and turn off the power super fast?
Re: 240W USB-C PD chargers are nearly here, says Framework CEO
#76It's super frustrating that if I want a 2nd charger for my macbook pro, I have to either buy an overpriced apple adapter, or.... what? I haven't seen any USB-C compatible 140W chargers that are significantly cheaper than apple's.... but I can't charge my laptop with less. If I plug in my 80w charger, my laptop just goes "bong bong bong" as it turns charging on and off endlessly.
This is a very weird way of saying the that Apple charger is priced competitively and isn’t over priced at all.
Re: 240W USB-C PD chargers are nearly here, says Framework CEO
#77The Hdplex 250W [1] is pretty small, seems like it proves it's possible at least.
1: https://hdplex.com/hdplex-fanless-250w-gan-aio-atx-psu.html
Re: 240W USB-C PD chargers are nearly here, says Framework CEO
#78why was 240W picked as the upper limit for PD? Why does there even need to be an upper limit?
The usb-c connector is rated to 5 Amps (A). Usb-c went up to 20V already. 5A * 20V = 100W (where we are). We didn't want to change the connector. So we are stuck at 5A. But we can raise voltage & still have some margin. So voltage was raised to 48V. 5A * 48V = 240W. As for raising the voltage more, it's likely very technically feasible, but probably not, for safety reasons. There are various levels of what is conside…
> When plugged in, it's in a very limited 5V state.
Depending on what's on the other end, it's actually even better than that would imply most of the time.
If both sides of the cable are in spec-compliant USB-C ports, then the power pins will be left at 0v for the initial connection, and only the CC pins will have a minuscule amount of power coming from the source (charger) - just enough to detect specific levels of resistance on the sink (phone/laptop/etc.) for 5v power and/or negotiate a higher voltage for USB PD.
Once they've established that one side is a source and the other side is a sink, then the source will provide power on the power pins of the cable.
If a USB-C cable is used to connect one charger to another, for example, then the negotiation will fail and neither charger will provide power on the main power pins.
USB-A ports, on the other hand, always provide 5v, so USB-A to USB-C cables always provide 5v on the main power pins.
The reason some cheep chineese electronics with USB-C connectors can only charge with USB-A to USB-C cables, not with USB-C to USB-C cables, is that they skipped the CC pins entirely. I actually modded one device by adding in two half-cent resistors to make it able to charge from a USB-C port: https://www.nfriedly.com/techblog/2021-10-10-v90-usb-c/
Re: 240W USB-C PD chargers are nearly here, says Framework CEO
#79The Hdplex 250W [1] is pretty small, seems like it proves it's possible at least. 1: https://hdplex.com/hdplex-fanless-250w-gan-aio-atx-psu.html
ATX power supplies are a much easier task. Fixed voltages for everything. A USB-PD charger capable of 240W is essentially a variable power supply from 5 to 48V. Much more difficult in execution.
Re: 240W USB-C PD chargers are nearly here, says Framework CEO
#80Earlier quoted context omitted.
It’s designed around 48V and 5A. Higher voltages introduce additional risks around arcing and also get you into different safety regulations and requirements. Above 5A also starts to make cable and connector design difficult for a small connector like USB-C.
Last time I looked at the comms protocol, it seemed possible to request up to 10 amps. I'm not sure there's a physical spec for a matching cable, but there's also no way for a cable to communicate its current limitations.
> there's also no way for a cable to communicate its current limitations
I don't think that's quite right. USB-C cables that support >60W (>3A @ 20V) must have an e-mark, which is a small chip embedded in the cable that identifies it as being able to support specific levels of power, such as 5A @ 20V for 100W or 5A @ 48V for 240W.
Spec-compliant chargers won't supply more than 60W unless the cable has the appropriate e-mark.