240 watts over a USB-C connector? What next, USB toasters and coffee pots?
USB Power Delivery: Plugging into the Benefits
11–20 of 127 posts
Re: USB Power Delivery: Plugging into the Benefits
#12Speaking 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.
Re: USB Power Delivery: Plugging into the Benefits
#13I'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 more
> 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.)
Re: USB Power Delivery: Plugging into the Benefits
#14Speaking 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.
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.
Re: USB Power Delivery: Plugging into the Benefits
#15240 watts over a USB-C connector? What next, USB toasters and coffee pots?
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.
Re: USB Power Delivery: Plugging into the Benefits
#16Earlier quoted context omitted.
Same! I've also returned a few USB devices that ship with a USB-A to USB-C cable and ONLY charge in that mode, they also MUST charge with USB-C PD. The two so far were a therapy light and some Zippo hand warmers. Like, who in the hell would design a device that has a USB-C port on it where only a fraction of chargers will work on it. It feels even worse than proprietary charges, because you see a USB-C port on it and…
The thing is, making a 5v-only device PD-compliant is literally one resistor. It costs well under a penny. It's pure ignorance, not a decision, but the lack of one. Lack of caring, lack of having an actual engineer involved, just slapping an oval-shaped port into a product where a trapezoidal port had been, and blindly thinking that magically makes it spec-compliant. Or not thinking about the spec at all. I return th…
It's two resistors, actually. But they cost $0.0003 each (that's 0.03¢, or just around 3,333 of them for US$1) from distributors. Though there appears to be a bit of a stock crunch right now.
So... yeah.
The bigger issue is not really the parts cost, it's the fact that it adds an extra part to the design that has to be purchased and tracked and assembled and blah blah blah. This is the real reason it often gets left off on the bottom-of-the-barrel products. Many times there is no other use for a 5.1kΩ resistor. And it might not even fit well at the cheap sizes (0603 or 0402), and going down to 0201-capable assembly factory flow just for these two resistors is not going to happen.
Re: USB Power Delivery: Plugging into the Benefits
#17Earlier quoted context omitted.
Same! I've also returned a few USB devices that ship with a USB-A to USB-C cable and ONLY charge in that mode, they also MUST charge with USB-C PD. The two so far were a therapy light and some Zippo hand warmers. Like, who in the hell would design a device that has a USB-C port on it where only a fraction of chargers will work on it. It feels even worse than proprietary charges, because you see a USB-C port on it and…
> I've also returned a few USB devices that ship with a USB-A to USB-C cable and ONLY charge in that mode... By "that mode", do you mean "1.5A @ 5V" permitted by BC, or do you mean "3A @ 20V" permitted by non-type-C PD? > Like, who in the hell would design a device that has a USB-C port on it where only a fraction of chargers will work on it. Who in the hell would design a charger that can do Type-C PD but can't do e…
> By "that mode", do you mean "1.5A @ 5V" permitted by BC
Neither - OP means devices with missing CC resistors which will fail to charge with a compliant PD source. (The A-to-C cable works because it provides 5V Vbus unconditionally.)
Re: USB Power Delivery: Plugging into the Benefits
#18Earlier quoted context omitted.
> I've also returned a few USB devices that ship with a USB-A to USB-C cable and ONLY charge in that mode... By "that mode", do you mean "1.5A @ 5V" permitted by BC, or do you mean "3A @ 20V" permitted by non-type-C PD? > Like, who in the hell would design a device that has a USB-C port on it where only a fraction of chargers will work on it. Who in the hell would design a charger that can do Type-C PD but can't do e…
> By "that mode", do you mean "1.5A @ 5V" permitted by BC Neither - OP means devices with missing CC resistors which will fail to charge with a compliant PD source. (The A-to-C cable works because it provides 5V Vbus unconditionally.)
The A-to-C cable often does not work because the resistors are supposed to be in there.
So if you are having complete charge failures, try a different cable.
Re: USB Power Delivery: Plugging into the Benefits
#19Earlier quoted context omitted.
Same! I've also returned a few USB devices that ship with a USB-A to USB-C cable and ONLY charge in that mode, they also MUST charge with USB-C PD. The two so far were a therapy light and some Zippo hand warmers. Like, who in the hell would design a device that has a USB-C port on it where only a fraction of chargers will work on it. It feels even worse than proprietary charges, because you see a USB-C port on it and…
The thing is, making a 5v-only device PD-compliant is literally one resistor. It costs well under a penny. It's pure ignorance, not a decision, but the lack of one. Lack of caring, lack of having an actual engineer involved, just slapping an oval-shaped port into a product where a trapezoidal port had been, and blindly thinking that magically makes it spec-compliant. Or not thinking about the spec at all. I return th…
Only if the device's consumption is < 2.5W, which is what a USB 2.0 computer USB-A's data port limit is. Anything above that, compliance gets a bit more involved and complicated.
Re: USB Power Delivery: Plugging into the Benefits
#20I've basically stopped buying any portable electronics unless they take USB-C. Currently travelling with a laptop, watch, toothbrush, eReader, camera, bug-bite treater, and phone - all charging from the same power brick. I'm guaranteed of getting a replacement cable / charger wherever I am in the world if I need it. The only slight snag is some cheaper itema refuse to use PD and insist on plain 5V/2A - buy most decen…
For travel I have a bunch of cables with adapters on the end (choose usb-c, lightning, micro-usb). Can use usb-c, but have the ability to use the others.
It has helped out in a bunch of unexpected situations (usually someone else's device)