2 ms·

Now that source/supply and sink/drain/device are usb-c, it seems like this kind of flexibility would be possible for a huge number of systems. It'd be interest

Now that source/supply and sink/drain/device are usb-c, it seems like this kind of flexibility would be possible for a huge number of systems. It'd be interesting for systems to expose their efficiency curves, to make these kind of decisions optimally. Maybe your charger is much more efficient at 20v that the power efficient optimal solution is to pipe 20V in, even at low power modes. There's all kinds of optimization problems we could tweak, if this sort of efficiency data were visible.

tpolzer 3y ago
Ideally with PPS, your device can actually just ask exactly for the regulated voltage it needs on USB-C. Most modern smartphones can use that to charge their batteries more efficiently/with less heating of the phone.
- jauntywundrkind 3y ago
  Sure but that doesn't take into account charger efficiency. Something designed to output 5V-48V might be quite inefficient at generating an asked for 6.65V, perhaps. Optimizing just for the device might be missing gobs of energy efficiency that could easily be found with a little testing & discovery. There's decent odds that a good PPS implementation on the device - one that can directly connect the supply and battery without having to do intermediary conversions - is the most efficient option. PPS probably is the best choice. But it's not guaranteed. And particularly as we create higher power higher voltage capable chargers, their optimization point might be tuned to much bigger outputs (where they will absolutely require that efficiency to keep cool enough under load). Losses from running your charger sub-optimally could dwarf losses from the device receiving power sub-optimally for it. The point seems to hold: we need data to know what the best option to do is. This submission showed one way of DIY'ing that data, but devices could also do better jobs self-reporting, which would let everyone tune better.
- Scoundreller 3y ago
  I think the bigger win will be cheap charging cables won't corrode as quickly at their contact points with higher voltages.

tpolzer 3y ago

Ideally with PPS, your device can actually just ask exactly for the regulated voltage it needs on USB-C. Most modern smartphones can use that to charge their batteries more efficiently/with less heating of the phone.

jauntywundrkind 3y ago
Sure but that doesn't take into account charger efficiency. Something designed to output 5V-48V might be quite inefficient at generating an asked for 6.65V, perhaps. Optimizing just for the device might be missing gobs of energy efficiency that could easily be found with a little testing & discovery. There's decent odds that a good PPS implementation on the device - one that can directly connect the supply and battery without having to do intermediary conversions - is the most efficient option. PPS probably is the best choice. But it's not guaranteed. And particularly as we create higher power higher voltage capable chargers, their optimization point might be tuned to much bigger outputs (where they will absolutely require that efficiency to keep cool enough under load). Losses from running your charger sub-optimally could dwarf losses from the device receiving power sub-optimally for it. The point seems to hold: we need data to know what the best option to do is. This submission showed one way of DIY'ing that data, but devices could also do better jobs self-reporting, which would let everyone tune better.
Scoundreller 3y ago
I think the bigger win will be cheap charging cables won't corrode as quickly at their contact points with higher voltages.