3 ms·

The USB-C connectors on laptops and phones can deliver 240 watts [1] in a 8.4x2.7mm connector. 12VHPWR is 8.4x20.8mm so it's got 7.7x the cross-sectional area

The USB-C connectors on laptops and phones can deliver 240 watts [1] in a 8.4x2.7mm connector. 12VHPWR is 8.4x20.8mm so it's got 7.7x the cross-sectional area but transmits only 2.5x the power. And 12VHPWR also has the substantial advantage that GPUs have fans and airflow aplenty. So I can see why someone looking at the product might have thought the connector could reasonably be shrunk. Of course, the trick USB-C uses is to deliver 5A at 48v, instead of 50A at 12v [1] https://en.wikipedia.org/wiki/USB-C#Power_delivery https://en.wikipedia.org/wiki/USB-C#Power_delivery

6SixTy 2y ago
Nobody thought that they could push 50A at 12V through half the connector. It's management wanting to push industrial design as opposed to safety. They made a new connector borrowing from an already existing design, pushed up the on paper amperage by 3A, never changed the contact resistance, and made the parent connector push current near it's limit (10.5A max vs 8.3A). And oh, the insertion force is so, so much higher than ever before. Previous PCIe connectors push about 4A through a connector designed for about 13A. Worth also mentioning that the same time the 12VHPWR connector was being market tested was during Ampere, the same generation where Nvidia doubled down on the industrial design of their 1st party cards. Also there's zero devices out there that actually deliver or take 240W over USB-C. Texas Instruments literally only released the datasheets for a pivotal supporting IC within the last 6 months.
- michaelt 2y ago
  > Nobody thought that they could push 50A at 12V through half the connector. If you're saying that the connector doesn't have a 2x safety factor then I'd agree, sure. But I can see how the connector passed through the design reviews, for the 40x0 era cards. The cables are thick enough. The pins seem adequate, especially assuming any GPU that's drawing maximum power will have its fans producing lots of airflow; plenty of connectors get a little warm. There's no risk of partial insertion, because the connector is keyed, and there's a plastic latch that engages with a click, and there's four extra sense pins. I can see how that would have seemed like a belt-and-braces approach. Obviously after the first round of melted connectors they should have fixed things properly. I'm just saying to me this seems like regular negligence, rather than gross negligence.
- crote 2y ago
  > Also there's zero devices out there that actually deliver or take 240W over USB-C. Texas Instruments literally only released the datasheets for a pivotal supporting IC within the last 6 months. The 16-inch Framework laptop can take 240W power. For chargers, the Delta Electronics ADP-240KB is an option. Some Framework users have already tried the combination.
kersplody 2y ago
The connector could reasonably be shrunk. It just now has essentially no design margin so any minor issue immediately becomes major! 50A DC is serious current to be treated with respect. 5A DC is sanely manageable.
Miraste 2y ago
The spec may say it, but I've never encountered a USB-C cable that claims to support 240 watts. I suspect if machines that tried to draw 240W over USB-C were widespread, we would see a lot of melted cables and fires. There are enough of them already with lower power draw charging.
- DebtDeflation 2y ago
  Search Amazon for "240W USB" and you get multiple pages of results for cables. A few years ago there was a recall of OnePlus cables that were melting and catching fire, I had 2 of them and both melted. But yes 240W/48V/5A is insane for a spec that was originally designed for 0.5W/5V/100mA. I suspect this is the limit for USB charging as anything over 48V is considered a shock hazard by UL and 5A is already at the very top of the 3-5A limit of 20AWG for fire safety.
  - makeitdouble 2y ago
    We've had a variety of 140W laptops for a few years already, so the original spec has been far away for a while now. The advantage of USB-C is the power negotiation, so getting the higher rating only on circuits that actually support it should de doable and relatively safe. The OnePlus cable melting give me the same impression as when hair power cables melt: it's a solved problem, the onus is on the maker.
- makeitdouble 2y ago
  240W cables are here but at around a 10x price premium. Also cables are chipped so e.g. a 100W cable won't allow 240 in the first place. Users needing the 240W have a whole chain of specialized devices, so buying a premium cable is also not much of an issue.

6SixTy 2y ago

Nobody thought that they could push 50A at 12V through half the connector. It's management wanting to push industrial design as opposed to safety. They made a new connector borrowing from an already existing design, pushed up the on paper amperage by 3A, never changed the contact resistance, and made the parent connector push current near it's limit (10.5A max vs 8.3A). And oh, the insertion force is so, so much higher than ever before. Previous PCIe connectors push about 4A through a connector designed for about 13A. Worth also mentioning that the same time the 12VHPWR connector was being market tested was during Ampere, the same generation where Nvidia doubled down on the industrial design of their 1st party cards. Also there's zero devices out there that actually deliver or take 240W over USB-C. Texas Instruments literally only released the datasheets for a pivotal supporting IC within the last 6 months.

michaelt 2y ago
> Nobody thought that they could push 50A at 12V through half the connector. If you're saying that the connector doesn't have a 2x safety factor then I'd agree, sure. But I can see how the connector passed through the design reviews, for the 40x0 era cards. The cables are thick enough. The pins seem adequate, especially assuming any GPU that's drawing maximum power will have its fans producing lots of airflow; plenty of connectors get a little warm. There's no risk of partial insertion, because the connector is keyed, and there's a plastic latch that engages with a click, and there's four extra sense pins. I can see how that would have seemed like a belt-and-braces approach. Obviously after the first round of melted connectors they should have fixed things properly. I'm just saying to me this seems like regular negligence, rather than gross negligence.
crote 2y ago
> Also there's zero devices out there that actually deliver or take 240W over USB-C. Texas Instruments literally only released the datasheets for a pivotal supporting IC within the last 6 months. The 16-inch Framework laptop can take 240W power. For chargers, the Delta Electronics ADP-240KB is an option. Some Framework users have already tried the combination.

kersplody 2y ago

The connector could reasonably be shrunk. It just now has essentially no design margin so any minor issue immediately becomes major! 50A DC is serious current to be treated with respect. 5A DC is sanely manageable.

Miraste 2y ago

The spec may say it, but I've never encountered a USB-C cable that claims to support 240 watts. I suspect if machines that tried to draw 240W over USB-C were widespread, we would see a lot of melted cables and fires. There are enough of them already with lower power draw charging.

DebtDeflation 2y ago
Search Amazon for "240W USB" and you get multiple pages of results for cables. A few years ago there was a recall of OnePlus cables that were melting and catching fire, I had 2 of them and both melted. But yes 240W/48V/5A is insane for a spec that was originally designed for 0.5W/5V/100mA. I suspect this is the limit for USB charging as anything over 48V is considered a shock hazard by UL and 5A is already at the very top of the 3-5A limit of 20AWG for fire safety.
- makeitdouble 2y ago
  We've had a variety of 140W laptops for a few years already, so the original spec has been far away for a while now. The advantage of USB-C is the power negotiation, so getting the higher rating only on circuits that actually support it should de doable and relatively safe. The OnePlus cable melting give me the same impression as when hair power cables melt: it's a solved problem, the onus is on the maker.
makeitdouble 2y ago
240W cables are here but at around a 10x price premium. Also cables are chipped so e.g. a 100W cable won't allow 240 in the first place. Users needing the 240W have a whole chain of specialized devices, so buying a premium cable is also not much of an issue.