On Mon, Nov 21, 2022 at 10:33:50PM -0500, D. Hugh Redelmeier via talk wrote:
I've seen a video that disassembled a Lenovo charger that supplies more current than USB C allows.
Apparently Lenovo has its own private protocol for these beyond-standard power levels.
<https://www.youtube.com/watch?v=BF83eREIYwU> <https://www.youtube.com/watch?v=Pj3NtY6YRWY>
Hmm, so they made a custom cable and increased the current from 5A to 6.75A. Obviously they must have some custom signalling to indicate to the charger that it is the right cable and device for the extra current. Of course if they used USB PD 3.1 they could have just used the standard and gotten up to 48V 5A, and hence 240W. I guess they either did this before PD 3.1 was done, or they want 20V rather than something higher. I think one of the videos said the chip inside the cable was certified for PD 3.1 but seems the charger is only 3.0, so perhaps they just had a reason to use 20V and wanted a higher current. Needing a custom cable and charger is certainly annoying but I would hope it also works fairly well with 100W on a standard cable and charger. -- Len Sorensen