Sure it's more complicated per charger but it's simpler when you look at the range for proprietary chargers that it is replacing. Complexity consolidation.
the problem is that there is no "standard" usb-c cable. there's usb 3.0, usb 3.1, usb 3.2, usb 3.2 gen 2, usb-c thunderbolt, etc.
this is a major problem they need to figure out imo.
edit: or move to a new major version (usb 4.0) and make all new cables do all of that so if you get a 4.0 cable, you know you can use it for everything at once. i have no idea if this is currently the plan or not.
These aren’t rhetorical questions. I didn’t start looking into USB until two years ago when I got a work MacBook. Before then, it had been almost a decade and a half since I had a Mac.
- the USB C cable that came with the x86 Macs and most USB C charging cables are power only and don’t support data
- many USB C cables that do support data only support data at USB2 speeds and don’t support video over USB
- I think some cables can support video over USB C. But only support data at lower speeds than 10Gbps.
Yeah, no. There are no non-data Type-C cable assemblies. If you have a C-C cable without at least USB 2.0 data signals wired through, it's not standards compliant:
Actually, scratch that (can't edit anymore) - looking closer at what you linked to, this appears to be a perfectly fine, data-capable USB 2.0 cable. It's just not a fully featured cable capable of Thunderbolt, and connecting two Macbooks is a feature that relies on Thunderbolt and doesn't work over USB. So, it's just like I said in my initial reply.
Really, unless you need to get the highest bandwidth available from latest USB standards, it's not that complicated at all. In most non-Thunderbolt cases, all you need to know is whether your cable is USB 2.0 only or not - and Thunderbolt cables tend to be obviously marked as such.
There are four different versions and a wide variety of power choices that each “USB C” cable is permitted to make. So the answer to your question is “it depends”, since 100W support is optional in USB-C cables.
(Note: If you change “USB C” cable to “Thunderbolt 3” cable, those choices are all zeroed out. So the answer to that modified question is “yes”, since 100W support is mandatory in Thunderbolt 3 cables.)
This will get better over the next year for certified cables that print USB-compliant logos on them, with the end of SuperSpeed branding:
> Branding for certified USB Type-C cables is also being updated. Rather than simply listing their data transfer speeds, cables will also (for the most part) have to list the charging wattage they’re capable of carrying. So a cable can’t just be branded as being a 40Gbps cable as with last year’s guidelines, it’ll now also have to list a charging speed like 60W or 240W.
But I’ve never seen the USB logos printed on a cable before, so it remains to be seen whether the reduction in complexity to Gbps/W only is sufficient to persuade cable makers to certify their cables or not.
No. Nothing of this is mandatory except 5V 100 mA (the old USB 1 baseline), which every device must support - every USB power source must be able to support a dumb load at 5V that consumes 100 mA of current, and every USB power sink can assume that it can safely draw 100 mA of current at 5V.
That is why USB PD exists - it allows negotiation between a power source and a power sink to determine the voltage level that the source supplies and the maximum current that the sink can draw before the source shuts down for overcurrent protection. Additionally to that, there also exist a number of legacy current negotiation systems using pull-up and pull-down resistors between GND, Vcc and D+/D- (Qualcomm Quickcharge, Apple's stuff and I believe there is another proprietary Samsung scheme), and there is a legacy negotiation scheme from the USB 2 era that allows 5V at 500 mA. And on top of that, for the higher voltage and amperage ranges, cables carry their own "marker chips" that end up in the USB PD negotiation as well, to prevent dumb cables from overcurrent situation as well - IIRC it's >3A that need marked cables.
For device implementers, both on the source and sink (or dual-role) device, there exist a number of specialized ASICs and implementation example circuits that can do all the negotiations required on their own (preconfigured with a separate EEPROM chip or via bootstrap resistors) or in cooperation with a device's microprocessor. There have been a number of high profile fuck-ups along the way (e.g. Nintendo Switch third party docks that passed high voltage to the Switch without negotiating first or the first RPi 4 generation that messed up resistors preventing marked cables from working), but by now the lessons learned from these should have propagated through the industry and the how-to guides.
It's because standard have nightmarish level of complexity for something as simple as "pick a value from list one device provides and maybe change powering if that device signals you need to take less power"
That's what the PD standard basically is at core. It tucks on other things, too, like negotiating alternate modes, USB data roles, power roles, role swaps, etc. But the core of the standard is just "here's a list of values, and here's a way to tell the source which value I want to use" + method of communicating + some legacy USB stuff and some simplified alternative methods for power sources without PD chips (resistor pull-ups on CC lines to negotiate between legacy/1.5A/3.0A).
The device only has to support those voltage when it can source the matching power profile (i.e. 140W). But usually if you have to be able to generate two different voltages, it's not much more effort to make three or ten, as long as all the components can deal with the higher voltage.
I can't help but be reminded of the old-time Radio Shack "universal power adapters". They were a dc power adapter with a switch for voltage 3,6,9,12,... and an assortment of barrel jack power tips of different sizes.
Reflecting, this is quite off topic, but due to more voltages supported by USB PD, I thought I'd bring this up.
A few years back, I really wished all the AC/DC converters for smaller home appliances would ditch the fragmented round pins, and go for a universal USB-A (at the time) standard. E.g. some fans, routers, my smart desk, my key light, etc. Perhaps we would be able to optimize better unified AC/DC converters.
Perhaps it would be nice to think about something like this.
Instead of having bulky AC/DC converters, go for single multi-port USB-C PD converters?
It’s slowly happening - a great many small electronics have been transitioning to various USB connectors
for charging (everything from bicycle lights to small drones). Those are all 5V though, which is great for typical one cell lithium, which is 3.7-4.2V, and where 500ma-2A is the most you’d need or want anyway.
The issue so far is that for higher power levels or voltages the electronics are still complex
and expensive, even with the PD standards, so it adds a lot of cost doing it that way compared to a typical barrel connector.
Maybe in another 4-5 years and with some standardized and hopefully dirt cheap PD chips?
I have a Home Pod mini in my kitchen which is powered via USB-C. Right now Its just using Apple's 18 w power brick. One of these days I mean to to install on of those mains outlets with built in USB-C ports:
It will eliminate a bulky adapter and let me use the plug for things that actually need AC, like my toaster or kettle.
One wonders if it will start becoming common to have all plugs in newer/refab houses have these and they will be okay enough for most people.
This is a little different then what your talking about, but both could be the norm. I imagine the form of what your talking about would be that power strips with a bunch of type - c ports on them (and maybe some AC) replace the power strips we use now.
USB C has been around for some time, same with USB A. If you had both ports in your power outlet you'd have been set for nearly 20 years worth of peripheral charging.
I don't agree. The past few years have seen steady growth in terms of power delivery. Devices have gone from 5V 0.2A which equates 1W, to 240W. That's a huge leap. Most older chargers are simply insufficient for more modern devices, but can still be used to power more conservative things like small desk fans, led lights, night lights, and the likes. You can repurpose an old wall wart by putting it somewhere else physically where you need it, but with an in-wall power outlet you'd need to replace the whole module every 1-3 years. The jumps in power delivery were drastic at times.
However, now it's a good idea to go with these because it's unlikely power delivery for a lot of things will increase for a long while - see my other comment.
It was ~4.5 W before, wasn’t it? With some off-spec supplies up to 4 to 5 amps or 25 W. This is still a big deal, but only one order of magnitude, not two.
These ports are not really "hard wired". They're modules that fit into the mains plug well/niche, just like any other thing that fits in there. They can be changed for anything else once they become outdated, you just shut off your mains, unscrew three wires and put the new thing in. But they probably won't become outdated, because:
1. the USB C plug is here to stay for a longer while
2. with 240W we've already reached power delivery levels that exceed most small appliances you'd want to hook up like that; most larger appliances will take mains. 240W is a practical limit because if you go much above that, the consideration isn't really how much power can your device suck out of the wall, the consideration becomes: if you hold this thing in your hand, will it burn you? You can't escape the physics: 240W power dissipated means 240W power coming out of your device as heat.
3. we've just reached a new, more reliable and more power efficient semiconductor process (GaN) which only happens once every decade or two, so anything made in the next 20 years or so at the least will have roughly the same kind of performance, and anything in the next 50 years or so will probably not exceed it by unacceptable levels
Such a thing would have to be really smart about advertising power-delivery ability for each port without exceeding a total commitment of 1,800 watts (US 120 volts x 15 amps), but not actually needing an inefficient 1,800-watt AC/DC transformer, and then somehow still managing to be able to charge at least a couple high-power laptops simultaneously. All this to satisfy the reasonable desire to replace six bulky 15-watt transformers with one simple device.
Contrast your typical $10 AC power strip, which lets you plug in 10,000 watts of hair dryers at once, because it's understood that a circuit breaker will (hopefully) blow if you do. It doesn't need to be smart.
I think the basic problem is whether USB-PD allows a source to commit to delivering 100 watts to a port that asked for 20V/5A, but then notice that the port only needs 2 watts right now (because the device finished charging), so that it can reclaim 98 watts in its total power budget. So far I haven't seen a power supply that does this well.
Wouldn't that kind of overcommit be disastrous though?
If a device was granted a 100W budget, but only needs 2W now, maybe it suddenly needs to burst up to the full 100W? If the hub reclaimed those other 98W, now it can't deliver what it promised, so something fails to work, or gets powered off.
In the hair-dryer case, all six actually do turn on -- but only for a few seconds. The circuit breaker heats up and trips before the wires in the wall get hot enough to ignite the wood. Which sounds scary, but that's part of the design that enables normal spiky power usage of refrigerator compressors starting up, running a garbage disposal for a few seconds, etc., without constantly tripping a home's breakers.
If USB-PD has some way for a single supply to "overbook" its commitments, then it could model this system. Otherwise, its competition will be people plugging lots of individual USB power supplies to AC power strips, which is bulky and wasteful, but extremely functional.
If a USB-PD over commits, then the devices it tries to power will obviously get less power than advertised, or the internal over-delivering protections trigger and the source shuts down. The user will (maybe) notice and can do something about it.
I'm pretty sure everybody understands that you can't just plug 6 high power consumers in one USB device just because it has 6 ports and it supports USB-PD, just like people don't plug 6 kettles in one extension cord.
People absolutely do plug tens of thousands of watts' worth of appliances into a single 15-amp home circuit that can supply only 1,800 watts at once. And as long as they don't exceed 1,800 watts of momentary usage by too much or for too long, it works. AC power doesn't have a "commitment" in any sense but a physical plug shape. It just has circuit breakers to prevent fires.
A good example of the problem is a hypothetical USB-PD power strip that has 5 ports. The Amazon listing says it can deliver 120 watts. A person buys it, thinking they can use it for their 100-watt laptop and four other small things that each need barely 5 watts, 1 x 100 + 4 x 5 = 120, so the math adds up. They're still working from home post-pandemic, so they leave their laptop plugged in all the time on their desk. The laptop charges for maybe 45 minutes each day, but it still tells the power supply that it needs 20V x 5A = 100W constantly, and each of the small devices asks for the minimum of 5V x 3A = 15W.
For actual USB-PD supplies I've bought in this approximate situation, the laptop won't charge because the supply can't promise 100W. You hook up your Kill-A-Watt and find that the supply is actually drawing only 20 watts. The power supply is keeping all its promises -- 15W to each of four small devices, meaning it can't agree to supply 100W to the fifth device. So it instead says it can do maybe 12V x 3A for the laptop, which says forget about it and refuses to charge. Yeah, the laptop sucks for lying that it needs 100W 24/7, but what am I going to do? Get a new laptop? Or just put the USB-PD supply on a shelf and return to a regular old AC power strip with five individual USB transformers plugged into it? That's what I'll do, because that's what works.
In today's world, the "If" in your comment happens at the AC circuit-breaker level. In the USB-PD world, it would happen at the level of this little multi-port power supply. Your average consumer in a hurry doesn't want to be bothered by this kind of detail.
It seems there are more alternatives. Use the USB-PD supply for the laptop and another one for you 5 devices.
It's a bad laptop design. An iPad or Android phone/tablet can fast charge with a good supply or slow charge with a cheap one. The laptop should do the same, accept whatever the supply can deliver.
Also, what's the problem with the user using 5 individual small USB chargers versus a big one? The efficiency of all USB chargers is about the same, so it doesn't matter how you split them up. In fact, a small USB charger working at maximum output is more efficient than a large one working at 20% load.
You are correct that ideally the USB-PD supply should monitor the actual usage and route power accordingly, but I'm not sure it's such a problem in practice.
what's the problem with the user using 5 individual small USB chargers versus a big one?
:) This thread started with iamchp asking about "single multi-port USB-C PD converters."
The laptop should [...] accept whatever the supply can deliver.
And both sides should renegotiate when available/needed power changes. If a laptop could say "I could use 240W but I can deal with 18W," a supply said "I can give you only 18W, but I'll let you know when I can give you 240W," and the laptop later said "you know what? Now I really need only 36W," then I think USB-PD would be good. My experience is the negotiation happens once, possibly days earlier, when the device is first plugged in.
(By the way, it's not always the right product decision to include boosting circuitry from lower-voltage supplies. While a MacBook will charge from a 5-volt supply, you'll be sad when it dies during a critical work presentation even though it's charging, because the presentation needed more than 15 watts. It's a defensible product decision to require a minimum wattage, and thus effectively a minimum voltage, or refuse to charge.)
It would be pretty neat to have some kind of refresh interval, where both devices list their current capabilities and have it renegotiate to some optimal level.
As for the refusing to charge, my ThinkPad on Windows will alert me when the dock or power source isn't putting out enough power for it to maintain the current power usage trend.
Often you can convert things yourself. Back in the day USB only provided 5V, so anything that needed 12V still used a barrel plug wall wart. But nowadays you should be able to have simple breakout boards that negotiate PD to deliver the correct voltage (or correct "enough" that the thing can still operate, eg 14V instead of 12V).
I've been converting some of my more problematic devices, for example here's a pretty clean conversion I did of my Wii U Gamepad back in the day. That was before USB C ports and cables were easily available, so I went with micro. USB C wasn't even a consideration back then.
I have a number of Dell Wyse 3040 thin clients (5v version, there's also a 12v version) scattered around my property. I've converted two of them to PoE by the simple expedient of buying a USB PoE splitter, cutting off the USB connector, and soldering on the appropriate barrel connector (for future searchers: 4mm x 1.7mm, pin == positive). I also just purchased some pre-made USB-A to 4mm x 1.7mm cables to try out on the rest.
For anyone who wants to do this: it’s not that easy with PD.
I have a dozen USB-C PD bricks of various brands. Only 3 of them properly provide 12v, and one of those only does it properly when there are no other devices plugged in to it’s 3 ports.
Personally I would love to use USB-C PD for longer strings of 12V APA RGB LEDs as interior lights. In that case: not only is voltage a concern but also total wattage, heat, and long-term reliability. Is 60 or even 100W through a boost converter actually safe and easy?
Boost converter's the technology and can be done as safely or as dangerously as you'd like. Waiting for a totally safe commercial product will take longer than DIY, naturally.
There's nothing inherently unsafe about buck-boost converters, they are used on millions of every day products, including the highest end of high tech stuff like motherboards and gpus.
If a circuit is in itself safe (it might not be if it's executed poorly), then safety of the whole device depends on how you're using that circuit.
100W is just as fine as 1W. It just depends on whether you're being scammed. If you don't have the knowledge to find out whether what you're doing is safe... don't do it.
> An adjustable voltage supply mode allows the device being powered an ability to request intermediate voltages between 15V and up to the maximum available fixed voltage of the charger.
So devices with this should be able to power anything in the range of 15-48V?
I have a USB c docking device connected to a USB c charging block. The block has three ports. And can deliver 45w,30w,20w,15w,and 10w.
When plugging in a second device to the block, the docking device goes off and then turns on. Meaning the block has to turn off and boot on every time a device is removed or inserted.
Not an electrical engineer, but 240w through typical USB wire gauges doesn't seem safe at all.
Does somebody have a good resource for the state of the USB-C ecosystem? How to determine which cables support what features, which icons mean what, etc.
That's not true, a lot of the connectors just-so-happen to be rated for mains levels. This is because often USB chargers aren't ground referenced, so they hover at a little above 1/2 mains voltage. This is why if you touch some chargers or devices that are charging you get this weird electrical "sensation" sometimes.
No, they're not. Two-prong power supplies need to have EMI suppression capacitors which connect the secondary side of the power supply's transformer to mains [1]. The mains voltage is present on the output, but the maximum current is low enough that it is safe. It is considered not an issue by manufacturers [2] and it is a fact of many practical power supply designs. Please have any idea what you're talking about before you throw around technical terms like "galvanically isolated". You're clearly not an EE.
Galvanic isolation means "no current is allowed from primary to secondary side". This is true of capacitors... but only in theory. Real life capacitors have leakage resistance and therefore do not, in practice, form full galvanic isolation.
Capacitive coupling still counts as galvanically isolated. Dielectric resistance of typical Y caps is in GOhm range, so that's basically galvanically isolated, unless you're some kind of purist. You certainly will not be able to feel that.
Reactance of a typical Y capcaitor at 50Hz is in the range of single unit MOhm so even that does not cross perception thresholds of most individuals even at 230 V. But it may for some, I guess.
Also what the heck with the first link. Apliances with metal enclosure must be grounded. That guy has no business having 50V against ground on the metal enclosure.
Not really no - the term for if a wire will melt/catch fire is ampacity, which depends on amps.
It’s very possible to vaporize a wire with just a few volts with enough amps!
The safety issue with voltage is due to the need for thicker insulation to avoid shorts, but the difference for 5V vs 48v isn’t that much.
It’s possible to carry a lot more power for the same amps (aka same wire ampacity) by upping the voltage, as Watts=amps*volts
That is why interstate power transmission goes up to millions of volts.
Most electrical codes also have carve outs for ‘low voltage’ as it’s tedious to try to regulate all the various ‘not dangerous’ stuff, which is considered 48 volts and below, which is why it’s limited to 48v. It’s considered ‘not dangerous’ due to the resistance/insulation of human skin making it a bit harder to kill your self with it, but with some work, still possible. It doesn’t take much amperage, if you’re trying - USB 2.0 has more than enough.
AC needs thicker insulation vs DC, but that is due to the peak of the AC waveform being much higher than the nominal voltage. 170V for ‘120V’ AC, for instance.
It really depends on the voltage. Ohm's law says that current is proportional to voltage divided by resistance.
I = V/R
This means that as voltage increases with a given fixed amount of power, current decreases. Indeed, a watt is a measurement of power calculated by multiplying current in amps by potential in volts.
Joule's equation of heating says that the power (P) lost to heat in a circuit is equal to current (I) squared, multiplied by resistance (R).
P = I^2R
Thus, increasing voltage reduces heat generated over a given conductor.
Now, who would start to standardize lithium ion battery packs for different voltages? It would be quite nice to have a pile of packs of 12V that you can slap together to get the voltages 24, 36 and 48 as you need and all your tools from power drill to chainsaw, lawnmower and ebike could use the same packs - regardless of the brand.
(I assume there are some technical challenges regarding balancing a 1Ah pack with 80Ah pack when someone is going to slap them together to get 24V, but those can't be unsolvable.)
We already have standardized voltages, they're a defining feature of each chemistry. What Makita markets as 18V batteries and DeWalt calls 20V are actually the same battery with the same voltage range.
And regarding combining a 12V 1Ah pack and 80Ah pack together to create a 24V pack, you would end up with a 24V 1Ah pack, as by that time the first pack will have been emptied and you need to recharge it, while the other pack still has 79Ah remaining.
This has me wondering how to engineer a circuit to have the 80Ah constantly charging/balancing with the 1Ah to maintain both the full voltage and capacity capabilities of both cells without shorting out the leads to the load. Of course, the peak power/current is still limited by the 1Ah cell. I guess the simple way is just put the cells in parallel and use a boost converter.
This whole strand of consideration serves no purpose since nowadays if a hardware designer wanted specific voltages they'd use a buck/boost converter with the effect that any battery can output any voltage at any current up to its total safe power output limit, with losses so minimal that they are negligible.
Getting into FPV drones was super interesting because battery tech plays a huge part in the hobby. Rather than voltages, everything is normalized to number of LiPo cells in series, e.g. 1S, 2S, 4S.
Drone accessories also accept a super wide voltage range so they can be mostly powered by whatever battery packs you have laying around (excepting support for 6S, which is kinda rare).
However moving past drones, you'll start seeing other battery chemistries with different voltage ranges. Li-Ion can be discharged further than LiPo. LiFePO4 tops out at 3.6V, rather 4.2V. And so on.
I use a number of Makita "36V" tools, like their XCU04Z chainsaw [1]. Like their other yard tools and circular saws and other more power-hungry tools, you clip on two of their 18V LXT battery packs. If you don't need the chainsaw, you can clip one of them on a drill or angle grinder or whatever that only needs 18V.
Unfortunately, this endorsement is complicated because they just introduced their "40V" XGT line that's not backwards compatible with the LXT. [2] It's really 36V, just 10 series 21700 cells instead of one, two, or three parallel banks of 5 series 18650 cells.
You can get adapters to use your Makita (or red or yellow or orange or green whatever brand you favor) batteries on any other tool brand, but I haven't seen 2xLXT to XGT adapters yet; the form factor is difficult. Perhaps a lanyard with the batteries in a backpack or holster, and a smaller adapter at the tool...
Edit: On searching, apparently back in 2020 they filed a patent for a 2x18 to 40V adapter: [3] [4] but I haven't found a released product. The image looks like it could fit nicely in that leaf blower, but it would be absurd on an impact wrench or similar.
What's incredibly exciting about USB power delivery is that it offers a glimpse at a future world with a common, unified electrical socket. If you go into a house, and there's a USB-C port on the wall, it can be used by anyone, anywhere in the world, for anything that charges through USB-C.
Sure, at the moment, the supported voltages are relatively small. But over time, they will increase, and more and more gadgets and appliances can be powered through USB-C, the utility (network effects!) will only increase.
That has to be one long cable to charge anyone, anywhere in the world from a port in the wall.
Yokes aside, USB has been a nice unifying set of plugs but the shenanigans with versioning and reliability would make me hesitant to say revolutionary. The standard always delivers a little less than envisioned.
Wish the standard wasn't such a massive clusterfuck. IIRC someone tried to implement it on plain microcontroller (back then there were no chips dedicated to do the whole PD stuff) and it used 30k+ of memory which made using it for smaller devices... dubious.
Of course now we have chips that blackbox that complexity but the standard seemed to be way over-engineered from the start... for just essentially negotiating few values and a direction
True, if it is too general/flexible for future extension, devices might start only implementing part of it and we are getting limited by this blurry line of which device supports what
I've been thinking about getting a new laptop.
Anybody have suggestions for:
good linux support,
powered via USB-C,
able to use PCIe passthrough so I can play some windows games occasionally.
17" screen, cause I've got bad eyes.
Another Surface Laptop 4 owner, very happy with USB-C charging/docking, and I use Arch as my daily OS. Just be aware, there's currently no touchscreen support for this model: https://github.com/linux-surface/linux-surface/issues/532
As someone that owns more than a few synths and pedals, I hope one day that someone releases a decent multi-port USB charger that can power a bunch (10+) of 12V and 9V devices easily. All the ones I've found don't extend PD (QC3 would suffice) to all the ports.
118 comments
[ 2.9 ms ] story [ 191 ms ] thread- will it charge my MacBook Pro 16” and deliver the full 100W?
- will it supply data and if so, at what speed?
- can it deliver power and video over USB C and work with my portable secondary display?
this is a major problem they need to figure out imo.
edit: or move to a new major version (usb 4.0) and make all new cables do all of that so if you get a 4.0 cable, you know you can use it for everything at once. i have no idea if this is currently the plan or not.
https://xkcd.com/927/
They're already at USB4 version 2.0
If it's e-marked, then yes.
> - will it supply data and if so, at what speed? > - can it deliver power and video over USB C and work with my portable secondary display?
If it's not just a USB 2.0 cable, then yes.
- the USB C cable that came with the x86 Macs and most USB C charging cables are power only and don’t support data
- many USB C cables that do support data only support data at USB2 speeds and don’t support video over USB
- I think some cables can support video over USB C. But only support data at lower speeds than 10Gbps.
https://megous.com/dl/tmp/6e4e502cb9f6e709.png
https://www.macintoshhowto.com/hardware/why-your-usb-c-cable...
Really, unless you need to get the highest bandwidth available from latest USB standards, it's not that complicated at all. In most non-Thunderbolt cases, all you need to know is whether your cable is USB 2.0 only or not - and Thunderbolt cables tend to be obviously marked as such.
(Note: If you change “USB C” cable to “Thunderbolt 3” cable, those choices are all zeroed out. So the answer to that modified question is “yes”, since 100W support is mandatory in Thunderbolt 3 cables.)
This will get better over the next year for certified cables that print USB-compliant logos on them, with the end of SuperSpeed branding:
https://news.ycombinator.com/item?id=33034530
> Branding for certified USB Type-C cables is also being updated. Rather than simply listing their data transfer speeds, cables will also (for the most part) have to list the charging wattage they’re capable of carrying. So a cable can’t just be branded as being a 40Gbps cable as with last year’s guidelines, it’ll now also have to list a charging speed like 60W or 240W.
But I’ve never seen the USB logos printed on a cable before, so it remains to be seen whether the reduction in complexity to Gbps/W only is sufficient to persuade cable makers to certify their cables or not.
That is why USB PD exists - it allows negotiation between a power source and a power sink to determine the voltage level that the source supplies and the maximum current that the sink can draw before the source shuts down for overcurrent protection. Additionally to that, there also exist a number of legacy current negotiation systems using pull-up and pull-down resistors between GND, Vcc and D+/D- (Qualcomm Quickcharge, Apple's stuff and I believe there is another proprietary Samsung scheme), and there is a legacy negotiation scheme from the USB 2 era that allows 5V at 500 mA. And on top of that, for the higher voltage and amperage ranges, cables carry their own "marker chips" that end up in the USB PD negotiation as well, to prevent dumb cables from overcurrent situation as well - IIRC it's >3A that need marked cables.
For device implementers, both on the source and sink (or dual-role) device, there exist a number of specialized ASICs and implementation example circuits that can do all the negotiations required on their own (preconfigured with a separate EEPROM chip or via bootstrap resistors) or in cooperation with a device's microprocessor. There have been a number of high profile fuck-ups along the way (e.g. Nintendo Switch third party docks that passed high voltage to the Switch without negotiating first or the first RPi 4 generation that messed up resistors preventing marked cables from working), but by now the lessons learned from these should have propagated through the industry and the how-to guides.
http://www.technoblogy.com/show?3Y8J
A few years back, I really wished all the AC/DC converters for smaller home appliances would ditch the fragmented round pins, and go for a universal USB-A (at the time) standard. E.g. some fans, routers, my smart desk, my key light, etc. Perhaps we would be able to optimize better unified AC/DC converters.
Perhaps it would be nice to think about something like this. Instead of having bulky AC/DC converters, go for single multi-port USB-C PD converters?
The issue so far is that for higher power levels or voltages the electronics are still complex and expensive, even with the PD standards, so it adds a lot of cost doing it that way compared to a typical barrel connector.
Maybe in another 4-5 years and with some standardized and hopefully dirt cheap PD chips?
https://www.leviton.com/en/products/residential/usb-wall-out...
It will eliminate a bulky adapter and let me use the plug for things that actually need AC, like my toaster or kettle.
One wonders if it will start becoming common to have all plugs in newer/refab houses have these and they will be okay enough for most people.
This is a little different then what your talking about, but both could be the norm. I imagine the form of what your talking about would be that power strips with a bunch of type - c ports on them (and maybe some AC) replace the power strips we use now.
I really wonder about those.
I remember reading an article where someone tested a bunch of different power bricks and found that they really vary in quality.
The cheap ones had really bad voltage sag and other problems. And they were an unsafe design (not enough separation between the AC and DC sides).
Personally, I'd trust an anker or apple brick more than whatever lowest bidder device is in those outlets.
However, now it's a good idea to go with these because it's unlikely power delivery for a lot of things will increase for a long while - see my other comment.
1. the USB C plug is here to stay for a longer while
2. with 240W we've already reached power delivery levels that exceed most small appliances you'd want to hook up like that; most larger appliances will take mains. 240W is a practical limit because if you go much above that, the consideration isn't really how much power can your device suck out of the wall, the consideration becomes: if you hold this thing in your hand, will it burn you? You can't escape the physics: 240W power dissipated means 240W power coming out of your device as heat.
3. we've just reached a new, more reliable and more power efficient semiconductor process (GaN) which only happens once every decade or two, so anything made in the next 20 years or so at the least will have roughly the same kind of performance, and anything in the next 50 years or so will probably not exceed it by unacceptable levels
Edit: LOL these are going to be $90 a pop. Just get one of these instead: https://www.amazon.com/gp/product/B0874GDG93/
https://old.reddit.com/r/UsbCHardware/comments/t4l1dr/levito...
Contrast your typical $10 AC power strip, which lets you plug in 10,000 watts of hair dryers at once, because it's understood that a circuit breaker will (hopefully) blow if you do. It doesn't need to be smart.
I think the basic problem is whether USB-PD allows a source to commit to delivering 100 watts to a port that asked for 20V/5A, but then notice that the port only needs 2 watts right now (because the device finished charging), so that it can reclaim 98 watts in its total power budget. So far I haven't seen a power supply that does this well.
If a device was granted a 100W budget, but only needs 2W now, maybe it suddenly needs to burst up to the full 100W? If the hub reclaimed those other 98W, now it can't deliver what it promised, so something fails to work, or gets powered off.
In the hair-dryer case, all six actually do turn on -- but only for a few seconds. The circuit breaker heats up and trips before the wires in the wall get hot enough to ignite the wood. Which sounds scary, but that's part of the design that enables normal spiky power usage of refrigerator compressors starting up, running a garbage disposal for a few seconds, etc., without constantly tripping a home's breakers.
If USB-PD has some way for a single supply to "overbook" its commitments, then it could model this system. Otherwise, its competition will be people plugging lots of individual USB power supplies to AC power strips, which is bulky and wasteful, but extremely functional.
If a USB-PD over commits, then the devices it tries to power will obviously get less power than advertised, or the internal over-delivering protections trigger and the source shuts down. The user will (maybe) notice and can do something about it.
I'm pretty sure everybody understands that you can't just plug 6 high power consumers in one USB device just because it has 6 ports and it supports USB-PD, just like people don't plug 6 kettles in one extension cord.
A good example of the problem is a hypothetical USB-PD power strip that has 5 ports. The Amazon listing says it can deliver 120 watts. A person buys it, thinking they can use it for their 100-watt laptop and four other small things that each need barely 5 watts, 1 x 100 + 4 x 5 = 120, so the math adds up. They're still working from home post-pandemic, so they leave their laptop plugged in all the time on their desk. The laptop charges for maybe 45 minutes each day, but it still tells the power supply that it needs 20V x 5A = 100W constantly, and each of the small devices asks for the minimum of 5V x 3A = 15W.
For actual USB-PD supplies I've bought in this approximate situation, the laptop won't charge because the supply can't promise 100W. You hook up your Kill-A-Watt and find that the supply is actually drawing only 20 watts. The power supply is keeping all its promises -- 15W to each of four small devices, meaning it can't agree to supply 100W to the fifth device. So it instead says it can do maybe 12V x 3A for the laptop, which says forget about it and refuses to charge. Yeah, the laptop sucks for lying that it needs 100W 24/7, but what am I going to do? Get a new laptop? Or just put the USB-PD supply on a shelf and return to a regular old AC power strip with five individual USB transformers plugged into it? That's what I'll do, because that's what works.
In today's world, the "If" in your comment happens at the AC circuit-breaker level. In the USB-PD world, it would happen at the level of this little multi-port power supply. Your average consumer in a hurry doesn't want to be bothered by this kind of detail.
It's a bad laptop design. An iPad or Android phone/tablet can fast charge with a good supply or slow charge with a cheap one. The laptop should do the same, accept whatever the supply can deliver.
Also, what's the problem with the user using 5 individual small USB chargers versus a big one? The efficiency of all USB chargers is about the same, so it doesn't matter how you split them up. In fact, a small USB charger working at maximum output is more efficient than a large one working at 20% load.
You are correct that ideally the USB-PD supply should monitor the actual usage and route power accordingly, but I'm not sure it's such a problem in practice.
:) This thread started with iamchp asking about "single multi-port USB-C PD converters."
The laptop should [...] accept whatever the supply can deliver.
And both sides should renegotiate when available/needed power changes. If a laptop could say "I could use 240W but I can deal with 18W," a supply said "I can give you only 18W, but I'll let you know when I can give you 240W," and the laptop later said "you know what? Now I really need only 36W," then I think USB-PD would be good. My experience is the negotiation happens once, possibly days earlier, when the device is first plugged in.
(By the way, it's not always the right product decision to include boosting circuitry from lower-voltage supplies. While a MacBook will charge from a 5-volt supply, you'll be sad when it dies during a critical work presentation even though it's charging, because the presentation needed more than 15 watts. It's a defensible product decision to require a minimum wattage, and thus effectively a minimum voltage, or refuse to charge.)
As for the refusing to charge, my ThinkPad on Windows will alert me when the dock or power source isn't putting out enough power for it to maintain the current power usage trend.
I've been converting some of my more problematic devices, for example here's a pretty clean conversion I did of my Wii U Gamepad back in the day. That was before USB C ports and cables were easily available, so I went with micro. USB C wasn't even a consideration back then.
https://imgur.com/gallery/cx2gzxQ
I have a dozen USB-C PD bricks of various brands. Only 3 of them properly provide 12v, and one of those only does it properly when there are no other devices plugged in to it’s 3 ports.
Personally I would love to use USB-C PD for longer strings of 12V APA RGB LEDs as interior lights. In that case: not only is voltage a concern but also total wattage, heat, and long-term reliability. Is 60 or even 100W through a boost converter actually safe and easy?
If a circuit is in itself safe (it might not be if it's executed poorly), then safety of the whole device depends on how you're using that circuit.
100W is just as fine as 1W. It just depends on whether you're being scammed. If you don't have the knowledge to find out whether what you're doing is safe... don't do it.
So devices with this should be able to power anything in the range of 15-48V?
When plugging in a second device to the block, the docking device goes off and then turns on. Meaning the block has to turn off and boot on every time a device is removed or inserted.
It would only power devices which do not draw more current than (240 W/Voltage) Amps
Maybe next time I'll use JST?
Realistically you need 1.5-2.5kW+ to heat anything in a decent time frame
Does somebody have a good resource for the state of the USB-C ecosystem? How to determine which cables support what features, which icons mean what, etc.
We have 100W (so 20V at 5A), we will have 240W (48V at 5A).
Gauge doesn't change, since current stays the same
[1] https://electronics.stackexchange.com/questions/478607/feeli...
[2] https://www.dell.com/en-us/blog/notebook-tingle-sensation-wh...
If you're feeling "tingling sensation" your protection caps are fucked Mr. EE
Reactance of a typical Y capcaitor at 50Hz is in the range of single unit MOhm so even that does not cross perception thresholds of most individuals even at 230 V. But it may for some, I guess.
That's why you need an e-marked cable to be able to do that.
It’s very possible to vaporize a wire with just a few volts with enough amps!
The safety issue with voltage is due to the need for thicker insulation to avoid shorts, but the difference for 5V vs 48v isn’t that much.
It’s possible to carry a lot more power for the same amps (aka same wire ampacity) by upping the voltage, as Watts=amps*volts
That is why interstate power transmission goes up to millions of volts.
Most electrical codes also have carve outs for ‘low voltage’ as it’s tedious to try to regulate all the various ‘not dangerous’ stuff, which is considered 48 volts and below, which is why it’s limited to 48v. It’s considered ‘not dangerous’ due to the resistance/insulation of human skin making it a bit harder to kill your self with it, but with some work, still possible. It doesn’t take much amperage, if you’re trying - USB 2.0 has more than enough.
AC needs thicker insulation vs DC, but that is due to the peak of the AC waveform being much higher than the nominal voltage. 170V for ‘120V’ AC, for instance.
Voltage is largely irrelevant
Have a look at the gauge of mains wires (~14-22 AWG) compared to what you'd put on a serious 12V-48V battery (2-8 AWG)
I = V/R
This means that as voltage increases with a given fixed amount of power, current decreases. Indeed, a watt is a measurement of power calculated by multiplying current in amps by potential in volts.
Joule's equation of heating says that the power (P) lost to heat in a circuit is equal to current (I) squared, multiplied by resistance (R).
P = I^2R
Thus, increasing voltage reduces heat generated over a given conductor.
(I assume there are some technical challenges regarding balancing a 1Ah pack with 80Ah pack when someone is going to slap them together to get 24V, but those can't be unsolvable.)
And regarding combining a 12V 1Ah pack and 80Ah pack together to create a 24V pack, you would end up with a 24V 1Ah pack, as by that time the first pack will have been emptied and you need to recharge it, while the other pack still has 79Ah remaining.
Drone accessories also accept a super wide voltage range so they can be mostly powered by whatever battery packs you have laying around (excepting support for 6S, which is kinda rare).
However moving past drones, you'll start seeing other battery chemistries with different voltage ranges. Li-Ion can be discharged further than LiPo. LiFePO4 tops out at 3.6V, rather 4.2V. And so on.
Unfortunately, this endorsement is complicated because they just introduced their "40V" XGT line that's not backwards compatible with the LXT. [2] It's really 36V, just 10 series 21700 cells instead of one, two, or three parallel banks of 5 series 18650 cells.
You can get adapters to use your Makita (or red or yellow or orange or green whatever brand you favor) batteries on any other tool brand, but I haven't seen 2xLXT to XGT adapters yet; the form factor is difficult. Perhaps a lanyard with the batteries in a backpack or holster, and a smaller adapter at the tool...
Edit: On searching, apparently back in 2020 they filed a patent for a 2x18 to 40V adapter: [3] [4] but I haven't found a released product. The image looks like it could fit nicely in that leaf blower, but it would be absurd on an impact wrench or similar.
[1] https://www.makitatools.com/products/details/XCU04Z
[2] https://makitauk.com/xgt-qa
[3] https://i.redd.it/zd8ubj3ualq41.png
[4] https://www.reddit.com/r/Tools/comments/fu6vwk/someone_dug_a...
That said, I suspect power tools are a different animal because of current.
I see some indication that some dewalt 60v tools can pull 2400 watts.
Sure, at the moment, the supported voltages are relatively small. But over time, they will increase, and more and more gadgets and appliances can be powered through USB-C, the utility (network effects!) will only increase.
Yokes aside, USB has been a nice unifying set of plugs but the shenanigans with versioning and reliability would make me hesitant to say revolutionary. The standard always delivers a little less than envisioned.
I wouldn’t take that chance at most of my friends’ houses, much less any public place.
USB-C condoms that provide Power Delivery are quite hard to build and I haven’t seen any in the wild.
Of course now we have chips that blackbox that complexity but the standard seemed to be way over-engineered from the start... for just essentially negotiating few values and a direction
There is also a ton of optional stuff, which pretty much means every device needing above 5V needs to have buck/boost converter