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0 pointsilyt2y ago0 comments

There is, just not for "AC wall voltage". It could simply drop the voltage and expect the other device to say start limiting current when it goes 5% or more below nominal voltage. Akin to how MPPT works on solar chargers

It "just" requires both sides to support that. Which won't happen as we already have USB-C if you want to negotiate the power usage.

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rektide2y ago

We could invent other signaling strategies too. Maybe we lower the voltage by 5% as a "low" signal. Now we can yell at the device in binary, and more explicitly spell out the conditions.

Maybe the source sends S-O-S in Morse code. Maybe it sends a requested max power.

We can invent signalling strategies to communicate yes. EV chargers use HomePlug Green for example to commitcate. This could be consumerized & put into all devices, used to perform negotiations. https://en.m.wikipedia.org/wiki/HomePlug

ilytOP2y ago

If we wanted to go entirely analog just simple CV/CC on the power source side (meaning "keep constant voltage up till max amps, then start dropping voltage) + MPPT-like controller on the sink is enough. That's easy enough to be done on off-the shelf chips.

>We can invent signalling strategies to communicate yes. EV chargers use HomePlug Green for example to commitcate. This could be consumerized & put into all devices, used to perform negotiations. https://en.m.wikipedia.org/wiki/HomePlug

I'm kinda surprised that's relatively rare approach, in-band communication like that saves 2 wires so would technically allow USB-C to get extra 20% power boost over same connector. I think I saw it used in some solar stuff to coordinated various devices of same manufacturer.