Pogo pins power clarification - reading schematics
02-28-2021, 07:17 PM
(02-14-2021, 11:00 PM)dsimic Wrote: Thus, the keyboard case, as already expected, will include built-in separate charger circuitry, but with a twist: it will charge both batteries.
Ha!
Quote:You can plug a convergence dock into it or use it for any other common USB-C devices, e.g. thumbdrives.
Wait...
Is the keyboard/battery case using DCIN?
What if the keyboard/battery case provides power to DCIN, and the Pinephone simultaneously enables USB host mode by turning on the LP6226 and the LPW5206?! Isn't that what would happen?
So two power sources could get shorted together: the Pinephone's LP6226/LPW5206 output, and the keyboard/battery case. All it takes is for the Pinephone to decide to be a USB host, which is what it would do to talk to the convergence dock or a flash drive.
I don't understand how this is OK; maybe I'm missing something. If I'm right about this, and if the keyboard/battery case uses DCIN without some other safety check, then the February update is wrong, and you shouldn't use the Pinephone's USB C port at all.
(02-14-2021, 11:00 PM)dsimic Wrote: Another twist is that the case will have a separate USB Type-C port, which looks like a workaround, IMHO.
Exactly. To me, the extra USB C port feels like a "hacky" solution to work around:
(1) switching between (or simultaneously) drawing power and providing power via pogo pins; as implemented, the keyboard doesn't need to draw power to charge its own battery
(2) lack of isolation between pogo pin #1 and the USB C port
The problem of isolation between pogo pin #1 and the Pinephone's USB host mode is still unsolved even by this workaround?
(02-14-2021, 11:00 PM)dsimic Wrote: Now, I'm wondering what will happen to the charging through the phone's USB Type-C port?
(02-14-2021, 11:00 PM)dsimic Wrote: It will probably be incompatible with the keyboard case, so the phone's USB port will be used for data only...
Yeah, with the keyboard/battery case attached, I'd say we aren't allowed to charge through the phone's USB Type-C port anymore.
Quote:This effectively completely frees up the USB-C port on the PinePhone.
To add USB ports, I would have thought, why not just plug a charger into the convergence dock, or a similar USB C "power delivery capable" hub? Seems like we're not allowed to, though.
