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- Hacker News
- lots of hallucination or should i say misinformation in this articleby bar000n
- Madness. USB C doesn't even let you control which way the power goes. Try to charge your phone by plugging in a USBC power bank? Oops, the phone is charging the power bank instead of the other way around. Sometimes you can't even make that stop without a USB-A cable. I can't imagine what kind of fools invented that.
- I have found this ST Discovery kit extremely useful in figuring out what my USB-C power sources could actually supply.
"The STM32G071B-DISCO Discovery board is a demonstration and development platform for the STMicroelectronics Arm® Cortex®-M0+ core-based STM32G071RB microcontroller and particularly the USB Type-C™ and Power Delivery controllers.
...
The STM32G071B-DISCO Discovery board discovers and displays USB Type-C™ port capabilities such as data role, power role, VBUS and IBUS monitoring. ..."
https://www.st.com/resource/en/user_manual/dm00496511-stm32g...
Around ~$70 US now. Was around $50 when I bought mine a couple of years ago.
STM32G071B-DISCO at Mouser or Digikey.
by rpaddock - security-wise, usb-c is the worst scenario device I've ever seen -- unless you're Apple, you can't make a security-boundary without infringing patent US11205021B2
for laptops, a bad-actor usb-c cable/charger can do so much more, unless your laptop has AI that can distinguish "is this signal really coming from monitor/keyboard/etc ?" I'd rather have plain-old DC adapters (or usbc to dc)
by sysguest - "USB data blocker" on AliExpress yields you very small adapters that enable you to run USB-PD, but block the data lines.by v1ne
- What are the actual security issues, HID injection?by pjc50
- IMHO this is a classic example of extreme overcomplexity leading to fragility and regulatory capture along with increased opportunities for antiuser hostility. Practically all devices needed nothing more than +/- on a robust barrel jack, but now we have negotiable voltage (with disasterous consequences if there is a bug in the inherently software-driven process --- which will certainly happen) pushing insane amounts of current through a tiny effete connector with barely-visible pins, "authentication" schemes to enforce vendor lock-in under the guise of protection, and entire regions legally mandating this flustercuck.by userbinator
- The consequences of plugging the wrong voltage or polarity into a barrel jack, most of which are compatible enough, is pretty bad. Ask me how I know.by mmastrac
- Can I offer a counterpoint? Much like OG USB put a 5V supply within everyone's reach, USB-PD has made programmable, higher power supplies available to everyone. That's a big deal, because PSUs are an expensive portion of a product, especially for small manufacturers and hobbyists. Having a dedicated standard that supports multiple voltages and currents allows small players to take advantage of the same economies of scale as the largest electronics manufacturers.
Case in point, IKEA will happily sell you a very well built 20W power supply that provides 5, 9, 12, or 15V for less than $5 here in Canada, and you can get a similar price from legitimate Asian distributors, even when buying in limited quantities. If you're working on a small-batch electronic product, that's a boon to your BOM; if you had to go out and source a dedicated barrel-jack PSU with the same capabilities, it'd cost much more, and you don't know what kind of quality you'd be getting.
Where the standard really falls on its face, IMO, is in its opacity. You can get a chip that does the PD negotiation for pennies, but there is no way to inspect the protocol without shelling out thousands for a dedicated analyzer, so when things don't work, it's really hard to troubleshoot the reason.
(Disclaimer: I'm working on an open-source protocol analyzer, so this probably colours my view on the matter a little.)
by mtabini - 240 watts over a USB-C connector? What next, USB toasters and coffee pots?by Animats
- I mean my electric Fan and standing lamp are both powered by USB-C.
There are things that shouldn't be powered by USB-C. But there are plenty of sub 100W consumer electronics devices that really should be USB-C. I waited years before Panasonic released their lamdash shavers using USB-C.
by ksec - I remember scoffing years ago at USB powered coffee warmers. Maybe the situation has changed.by m463
- That's only a single ampre at standard European mains voltage. It's still a lot of power for those tiny connectors and insulation, but an order of magnitude insufficient for those appliances.
I bet that cable gets plenty hot at 200+ watts.
by dotancohen - You joke, but this is enough to make recharging an e-bike practical. E.g. https://amplerbikes.com/pages/novaby jeffbee
- Speaking of which, does anyone know a line of PD Decoy modules to convert barrel jacks to USB-C without the atrocious behavior of "oh, the charger doesn't have 12V, here's 9V have fun!" that the early ones all did? Ideally I'd like a little red light to come on or something, but I'd settle for not silently browning out the device.
- Actually, that was 5v, not 9!by dotancohen
- Don’t think you’ll find it cause it’s not an issue with the decoy - that’s the expected behaviour. 12v isn’t mandatory. Which is insane but here we are.
On the plus side some of the bottom tier anker chargers will do 12v.
Plus I think the very new PPS ones should too
by Havoc - Those are called trigger boards. I haven't found one with buck converter to make 12V. 12V is in earlier PD standard so lots of chargers support it but you have to check each charger and lots don't say. The guaranteed solution is PPS chargers that have variable voltage.by ianburrell
- There are things like this: https://www.adafruit.com/product/5501 haven't used it, trying to find one for my mini pc, mostly so I can use a usb c power bank as a tiny DC ups.by s0rce
- iirc theres ones that do. However I dont recall there being any clean fix to the amperage constraint issues. Especially when a lot of usb-c chargers will vary output as they heat up with usage.
Which is kinda part the issue, usb-c charging bricks, they aren't usb-c power supplies, there is no expectation of sustained output capacity. Thankfully at least some the multiport ones have renegotiation more or less solved cleanly rather than what is essentially rebooting the PD controller.
- The vflex has a status LED that shows negotiation status. When it fails it will still output 5V, though, they don't seem to have any mosfet to switch the output off entirely.
I don't think I've ever seen one of those type of converters output anything but 5V upon negotiation failure. Which one did you use that did that? Their logic being "pick the closest available voltage" I presume?
by tredre3 - I'm appreciating this recent spate of "Why Underappreciated Technology X is Good" articles. (For example, the recent EXIF one.) It's way too easy focus on the bad and foment outrage. But the world we inhabit is pretty good, and it's good to understand why it's pretty good.by quotemstr
- I'm looking forward to USB-C PD small format factor PC's. A decent amount of room in the PC cases is taken up by the power supply. And if USB-C could somehow provide a range of voltages to the motherboard, SFFPC's could be downsized even moreby hazkoulia
- There are some SFF PCs that can take USB-C power.
Lenovo have some,but sometimes require adapter cards. And a few of the Chinese N150 units will take PD power
It's great for hot swapping and more portable than a laptop.
by omh - Existing solution @ https://github.com/vk2diy/hackbook-m4-mini
- > And if USB-C could somehow provide a range of voltages to the motherboard, SFFPC's could be downsized even more
You reeeeeeally don't want to do that. Cable inductance is a big deal, among other issues. You want the main DC-DC regulators on the board, usually right at the load, for the main loads. Most of the PSU bulk is for dealing with mains itself: handling 50/60Hz or mains isolation is just physically large. Getting in secondary 20V DC (or so) from a single connector and then regulating it down on board is pretty much the ideal solution.
(I can't even begin to comprehend the horrors of a USB-PD negotiation involving multiple voltages. It's already the worst standard I've ever had to deal with.* Don't make it worse!)
(* Not hyperbole, it is truly, truly awful. At least things like 60601 are bad because, you know, they're covering lots of stuff like lifesaving medical devices. USB-PD is... holy hell, it is just bad.)
- The issue is that a USB charger is not a USB power supply. A charger does its best, but makes no guarantee of constant power delivery or duty cycle. The power supply absolutely must provide its rated output at 100% duty cycle.by dotancohen
- A lot of SFF PCs already come with a power brick. Just with a 12V barrel jack instead of a USB-C port. Compared to that design you really wouldn't safe much space. Though I admit that USB-C would be convenient. Maybe with a tiny batteryby wongarsu
- I have a couple like that in my mini rack. The problem is the power supply: these take 65W, so I figured I could get a quality 140W charger and power them both, but it turns out that things like "unplugging something else" would kill their power. I had to spend a lot more on a StarTech charger to get the performance I neededby ranger207
- Does PD include a specification that allows a client device to share its current battery level? How does Apriv know which device “needs” a high output level?
> Using dual-port modules, the system recognizes that, say, one smartphone battery in the vehicle is at 5 percent of capacity and a second phone is at 75 percent. The programming module gives the former device 100W and the latter 25W.
by itnerd