Variable Voltage USB

[jotasbrane]

I assume there is a very good reason that it would be impractical to design an extension to the USB standard that allows devices to use the data lines to request power that matches traditional in-home electrical outlets (e.g. 110V or 240V AC). Unfortunately, I do not know enough about USB to know why that is

Comments

[radiotelescope]

I don't know a *lot* about hardware, but I think the answer is that you don't want high-voltage AC running around inside your computer, and you *can't* have it running around in a chip built for regular digital processing. At the scale of today's microcircuits, house current would arc and burn everything out.

(And computers use commodity USB chips, so we *are* talking about putting it all in one chip.)

Also, what the hell uses house current these days? Practically every household device transforms it down to either low-voltage AC or low-voltage DC. The only exceptions are light bulbs (for historical reasons) and big electric motors. So what you're talking about is really only useful for that USB dishwasher you've been dreaming of...

[jotasbrane]

I was thinking that it might be useful to have right in your wall, without a separate computer, right alongside your regular power outlets. So you could plug in your USB cell phone charger, and then your laptop could get a USB power cable that already knew what voltage to request, replacing the ugly converter brick. And your TV, lamps, dishwasher, etc. could plug into it, requesting whatever voltage and current was most convenient for them.

If it worked, then the current system of random power supply and plug-shape standards from country to country could be phased out, along with the costly and inconvenient converter hardware inside each device, if it could all be done with a standard Variable Voltage USB jack connected to converter hardware built into the house's electrical system.

[duchez]

I got a bunch of these plug thingies that plug into my electric outlet, that has a usb port on the other end. So I plug my usb cable into that, the thing in the outlet, and i can charge up my devices.

I would totally love my house to have USB ports built in, but this is a nice compromise.

[radiotelescope]

I see where you're coming from. But I don't think you could fit it into the existing standard in any meaningful way. By the time you get through cable requirements, and plug compatibility, and the ability of old devices to plug in without catching fire, you've got a new standard that either extends or makes use of the existing USB.

This is a reasonable goal. But it is still a task of convincing a zillion hardware makers to buy into a new standard, when they can't even agree on a DC voltage.

[jotasbrane]

Yeah, I was thinking of it as a new standard that extended USB, keeping backwards-compatibility for current USB-powered devices.