Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

USB Power Delivery: Plugging into the Benefits

aptiv.com

Post reply on HN
Print view View original

41–50 of 127 posts

Re: USB Power Delivery: Plugging into the Benefits

#41

Post by codethief »

edent wrote: post #2

I'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…

What toothbrush do you have? I've been looking for a USB-C charger for mine (standard Oral-B toothbrush) but the only ones I've found were from no-name Chinese brands and didn't work at all.

Re: USB Power Delivery: Plugging into the Benefits

#42

Post by mschuster91 »

exmadscientist wrote: post #26
megous wrote: post #24

Earlier quoted context omitted.

A-C cable assembly always works, CC signal is connected within the cable to Vbus via 56kOhm resistor, but that's only relevant to the downstream port, not to the upstream USB-A power sourcing port which does not have access to the CC signal. Upstream port provides power unconditionally within some limits depending on port type (CDP/DCP/USB3.0/2.0 data port/...).

That's how it's supposed to work, yeah. But there is some trash out there in the world. A lot of it, actually. Some naughty cables work with some naughty chargers work with some naughty devices. Postel's Law in action, I guess? Usually the best place to fix it is by getting rid of the bad cables. Usually.

> Usually the best place to fix it is by getting rid of the bad cables. Usually.

No. There is no USB-C to C cable that will charge a badly implemented device with a standards compliant charger. That is the entire point.

An USB A to C cable is completely standards-compliant and safe, even if it always supplies 5V on the C end - any standards compliant USB-C device should not activate the MOSFET on its Vbus line unless it successfully negotiates via CC.

Re: USB Power Delivery: Plugging into the Benefits

#43

Post by wongarsu »

hazkoulia wrote: post #4

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 more

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 battery

Re: USB Power Delivery: Plugging into the Benefits

#44

Post by wongarsu »

dotancohen wrote: post #15
Animats wrote: post #11

240 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.

A full sized European electric kettle is about 2000 watts, but if you limit capacity to a single cup you can get acceptable performance on 200 watt. A USB-C coffee pot or kettle scaled to 0.2 liters (7oz) could work. Would be a great option for travel

Re: USB Power Delivery: Plugging into the Benefits

#45

Post by [deleted] »

wongarsu wrote: post #44
dotancohen wrote: post #15

Earlier quoted context omitted.

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.

A full sized European electric kettle is about 2000 watts, but if you limit capacity to a single cup you can get acceptable performance on 200 watt. A USB-C coffee pot or kettle scaled to 0.2 liters (7oz) could work. Would be a great option for travel

[deleted]

Re: USB Power Delivery: Plugging into the Benefits

#46

Post by helterskelter »

dabluecaboose wrote: post #35
helterskelter wrote: post #25

Earlier quoted context omitted.

There's an otherwise decent shortwave radio out there that was originally charged with a micro-usb, then they released a "new" USB-C model...except it will only charge with a 5V brick because they literally just swapped out the ports. Really annoying.

Oh man, please tell me it wasn't the CC GP-7. I have the micro version and have been hemhawwing about updating it.

You mean the CountyComm? If so, I'm 99% certain that radio is a rebranded Tecsun PL-360, which is in fact a 5V. I love Tecsun, but why they would cheap out on the USB-C refresh is beyond me.

https://www.tecsun-radios.com/product/pl360-radio-receiver/

Re: USB Power Delivery: Plugging into the Benefits

#47

Post by ianburrell »

smallmancontrov wrote: post #12

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.

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.

Re: USB Power Delivery: Plugging into the Benefits

#48

Post by gsich »

Animats wrote: post #36
dotancohen wrote: post #15

Earlier quoted context omitted.

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.

USB-C is limited to 48 VDC. Above about 50V, electrical safety codes apply.

You sure?

Those regulations go even higher.

https://en.wikipedia.org/wiki/Extra-low_voltage

Re: USB Power Delivery: Plugging into the Benefits

#49

Post by dgunay »

margalabargala wrote: post #37
mcsniff wrote: post #9

Earlier quoted context omitted.

I'll bite. What type of watch do you have that has a direct USB-C port on it?

They may be talking about something like the OnePlus watch, which does not have a usb-C port on it, but the charger device for the watch takes usb-C.

I have one and it's such a fantastic design. When I need to travel I just throw a tiny puck in my bag and it charges off the same brick that charges everything else I bring.

Re: USB Power Delivery: Plugging into the Benefits

#50

Post by itnerd »

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.

Post reply on HN