3 ms·
Wouldn't that kind of overcommit be disastrous though? If a device was granted a 100W budget, but only needs 2W now, maybe it suddenly needs to burst up to the
by jasonjayr 4y ago
Wouldn't that kind of overcommit be disastrous though?
If a device was granted a 100W budget, but only needs 2W now, maybe it suddenly needs to burst up to the full 100W? If the hub reclaimed those other 98W, now it can't deliver what it promised, so something fails to work, or gets powered off.
- sowbug 4y agoDepends on your definition of disaster. In the hair-dryer case, all six actually do turn on -- but only for a few seconds. The circuit breaker heats up and trips before the wires in the wall get hot enough to ignite the wood. Which sounds scary, but that's part of the design that enables normal spiky power usage of refrigerator compressors starting up, running a garbage disposal for a few seconds, etc., without constantly tripping a home's breakers. If USB-PD has some way for a single supply to "overbook" its commitments, then it could model this system. Otherwise, its competition will be people plugging lots of individual USB power supplies to AC power strips, which is bulky and wasteful, but extremely functional.