Wouldn't ordinarily mention a Youtube channel on HN but felt their detailed testing, comparisons and teardowns would probably be of interest for the topic.
I eagerly await more reviews of other USB-C PD chargers, e.g the 65W Lenovo ones you can get for pennies on ebay.
This kind of thing used to be more common in the US but in the 80s various trends, from ideological privatization to increased tolerance for "gaming the system" and an increase in regulatory capture, squeezed this kind of thing out. Not completely (car models get crash testing, for instance) but, for example, FDA no longer does its own prospective research, but responds to applications from the private sector (and when it has questions, has the requestor do the research).
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 nicer experience than with barrel jacks, with the various different sizes and pole configurations they can come in and their "dumb" nature all of which makes it easy to plug in a brick that physically fits but fries your device.
It'd also enable better modularity, making it easier to replace the bargain bin bricks that come with some devices with something higher quality.
I expect the trend to continue as it's likely cheaper to toss in a single USB-C port and controller chip than it is to supply a power brick. I can see most stuff shipping without an actual PSU very soon - I'd estimate 50% of devices already do so these days.
And USB-C is starting to become dirt-cheap to implement on the device side. 500mA @ 5V can be done without any controller chip whatsoever, and you can do up to 3A @ 5V without active communication. It's just easier to use USB-C than it is to mess around with a custom power brick!
Lenovo has also gradually been adding USB-PD to their gaming laptops, first at 100W and by now I believe at 140W. Though the one I use can use up to 300W and the only viable aftermarket charger is the SlimQ 240W, which can do either 2x100W PD or a range of barrel plugs (and lenovos high-wattage rectangle) on one relatively small brick.
My impression is that most devices with barrel ports don't use that much power and would be fine without USB-PD. They use barrel ports because they were designed before USB-C or because USB-C port is too expensive. I supsect many would be fine with USB-C to USB-A cable and charger.
https://www.adafruit.com/product/5450?gclid=CjwKCAjwm4ukBhAu...
Getting the full 5A @ 20V experience is possible with a chip costing less than $0.50, so even that isn't too expensive.
something like this is no more difficult to implement than a barrel plug https://www.aliexpress.com/item/1005005315614647.html
My Lenovo Legion 5 has a 300W charger. Caveats: (a) I'm not sure if that's input power or output power; and (b) it's not a USB-C PD connector , but my question isn't specific to this laptop.
Airplane A/C power outlets aren't willing to deliver that much power. And even if I was willing to slow-charge the laptop on an airplane or with my car, the laptop isn't willing to cap the charge rate, so it's simply not an option.
So I'm wishing for some scheme that lets me slow-charge a laptop in those situations, even if it meant having two different A/C adapters.
Right now most devices pick the highest power option (that they can handle). For a variety of reasons, it would be super sweet if we could pick lower power options! Maybe it's a multi-device charger & you want to leave more capacity for other devices. Maybe you want to slow charge your battery to extend it's life.
Almost every usb-pd device can accept lower power options, if plugged into a charger which doesn't offer the maximum rate. The only thing missing today is software, is user control over the power delivery negotiation process. Very very achievable, with minimal effort.
Not with how complicated the whole stack is...
We still can't say "don't charge if other device has no AC power" even tho that info can be propagated via USB-PD...
Unfortunately, due to cost or incompetent engineering, most devices only accept either a few charging configurations, often just one.
I didn't realize this as my first laptop with USB-C ports could be charged with any USB charger, even a dumb 5v 500mA phone charger would eventually get the job done over a couple days. I just assumed everything was like this, but unfortunately not. A lot of laptops and cameras will refuse to draw any power at all unless they can negotiate certain configurations.
so even without any software or clever switches to slow-charge your laptop, if you took a USB-PD laptop that prefers a 240W charger and plugged it into your 50W tablet charger or 20W phone charger, it would charge. it would just do it a lot more slowly than witht he high-power charger.
I suspect your lenovo works the same way - if you plugged it into a 65W thinkpad X1 charger, it'd probably slow-charge your laptop.
Charging a laptop from a 20W phone charger usually doesn't work because the laptop will have a minimum voltage/current requirement, but charging a phone from a 240W laptop charger will always work.
At first, with the adapter disconnected from the notebook, I charge the capacitors inside of the adapter by connecting and re-connecting repeatedly (1-2 seconds intervals). The first 5 times the breaker trips, but eventually the capacitors are charged, so no initial high current is drawn from the socket, and the breaker is happy.
Only then I connect the notebook to the adapter. I never tried to draw too much power from the airplane socket by playing GPU/CPU intensive games.
Wish you productive flights!
If someone is drawing 120w - 1 amp - your only control as a power source is to try to lower the voltage (voltage potential). Problem one: that will go out of spec with what devices expect, if you try to provide 80 vac instead. Problem two: switch mode power supplies that can handle sagged voltages will just try to draw more amps to get the same net power.
There's really not a good way to "cap out" power. The device just sees voltage potential (volts) and doesn't know to go lower. Blowing a fuse is the only real indicator we have.
>> The company says it uses Weltrend WT6676F, ON Semi NCP1622, and JoulWatt JW1556 controllers, as well as GaN switching parts from both GaN Systems and Navitas “peaking at an amazing 93% efficiency” for this 180W adapter. Both those parts and Chicony’s assistance as a power supply manufacturer are obviously there for other companies to use as well.
So likely even less efficiency for the higher rating. I'm very interested to see how they're venting this heat passively.
I think it's also super important that there is now a market of competing products too. Until recently, devices were sort of stuck using whatever the manufacturer provided. Almost no one shopped for power density. Now we have an interoperable standard & different companies can compete to be better.
USB-PD has been pretty epic so far, IMO.
My current charger of choice is the Anker 747 150 W, 3 usb c (equal capabilities per port of 100 W) and 1 USB A (24 watts) but there have been a lot of other models released since then. Somewhere around ~240 W might be when I look at options again, right now my MacBook won't charge at full speed due to the 100 W limit on the 747.
1: https://hdplex.com/hdplex-fanless-250w-gan-aio-atx-psu.html
And pretty much all power supplies are switched-mode power supplies anyways, whose controller usually requires you to explicitly define the output voltage using feedback components. Changing that to a variable power supply like USB PD doesn't really require much engineering.
Expensive in terms of cables or connectors?
In both cases, I've been paying considerably less for USB-C (cables and chargers combined) than for proprietary replacement chargers.
> it even works with a 45W adapter
My favorite thing about USB-C charging is that (at least Macbooks) it works even with lowly 5W chargers in a pinch! Sure, it takes more to fully charge a laptop that way – but I can sustain my Macbook Pro's charge with an 18W phone charger on an airplane no problem.
Is it? I’ve been using USB-C Macs since 2017 and I’ve never had any broken ports, despite some significant abuses (cable trips, grime in the port, etc). A few worn out cables, and failed chargers, maybe… but no problems on the laptop itself.
I don't really understand why anyone would lug around an enormous and expensive boat anchor, but I'm sure they aren't idiots: they must get value from doing so, even if I can't imageine what it would be.
One thing I love about capitalism is that it's a huge parallel processing system for satisfying these different needs. If I were the central planning czar, the folks who needed the big portables would be SOL.
Beyond gaming, the most interesting use cases I have seen and heard are CAD work/displays of highly complex models, creating heavy duty multimedia presentations, game development, and just about anyone in a country that either needs to do a lot of travel or does not have ready access to a high bandwidth connection. I don't know how prevalent those cases are, but they did surprise me a little.
But how many people need that? I was shocked to see another colleague doing CFD on his ipad.
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 considered safe voltages. Higher voltages have higher ability to injure humans, to cause shock or potentially spark. Voltage is a unit of electrical potential, essentially how bad some juice is desperate to get out. 50V is the "Safe Extra Low Voltage" (SELV) limit for AC. It's actually 120V for DC but 48V/50V has a certain dislodgable-for-now mindshare. https://en.wikipedia.org/wiki/Extra-low_voltage
Connectors also have limits to their voltage isolation. If you have 1000V that electric potential really wants to get out & will arc across gaps. If there's debris or a worn connector, the threat of say 200V causing some short is much higher.
We probably could go higher. Usb-pd is super safe. When plugged in, it's in a very limited 5V state. This is a high risk moment in the connection life cycle, as pins are sliding into place, but partially connected & likely not aligned fully yet; not having any real voltage applied at this phase is a colossal design win against so so so many power delivery mechanisms in the world. Device & source _after being connected_ then have to negotiate power, on the secured connection. They ongoingly perform bounds checking to make sure the power is flowing in an expected way & will disconnect if out of spec. The connector has good isolation. 120v * 5a would be 600W and is still SELV. Add some thermal protection to the ports to make sure everything's OK there and it's probably going to just work. But any mishaps (ex: puncturing the cable, debris inside the device causing a short) would be more severe/scary. I'd love for some hackers to find out how high our connectors can go. Maybe in lab conditions we can get a usb-c connector doing a couple hundred volts fine. I would be unsurprised. Being safe for the real world though, after wear, and what happens when there is a fault is why we have SELV. But again, SELV says we could go up to 600W on this connector maybe.
One non-concern should be any additional heat, such as on cables & connectors. Since amps are still only 5A, the power loss is actually the same. Pretty great.
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/
On a more fundamental level, there's the physics of how much power you can pass through a cable/connector safely.
Doing a quick bit of research there isn’t really any other option. Silver has 7% less resistivity than copper, but it tarnishes.
Aside from that, humanity hasnt discovered other options!
USB cables can only get so thick. And voltages only can get so high to not be dangerous to people.
Thus you get 5A @ 48V which is 240W.
Increasing current on the other hand heats stuff up which... is also dangerous
I'm not sure exactly how USB solves that for disconnecting (CCS locks the connector in) but I imagine the pilot would disconnect first and that would kill the PD pins during disconnect.
Obviously there's stepping up and down happening on both ends up this cable (since it's probably a 19V lithium ion battery in the computer), but at the end of the day you still need to decide on a safe and practical volts*amps number, and then spec the cables and connectors accordingly.
So unless you want to drag around an NEC type cable as thick as one of your fingers, you need to set a limit.
Edit: Fixed math. I haven't had caffeine yet.
Looks like the spec goes up to 48v now:
https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Deliver...
That’s only 5 amps, but such a high-ish voltage is enough to lead to arcing. Charging cables are likely to require additional safety measures.
