Hot when charging
01-10-2021, 10:41 AM
(This post was last modified: 03-09-2021, 05:07 AM by dsimic.
Edit Reason: Fixed a small typo
)
Alright, in that case there's probably nothing serious to be afraid of. You heard something resembling a sort of rapid clicks coming out of the phone, right? I've also experienced the same behavior, and truth be told, it sounded quite weird, maybe even a bit scary. 
After some investigation, the cause of those weird sounds turned out to be rapid resets of the IC (ANX7688) that controls some of the functions of the phone's USB Type-C port. The ANX7688 actually initiated the resets itself, as a result of (yet to be investigated) overcurrent protection. Each of those resets caused the plugged-in USB device (in this case, a charger or a powered dock) to be removed and attached again, at the logic level of course, which in turn caused the operating system to successively play back the sound that indicates an USB device plug-in event.
The above-described overcurrent protection is somewhat weird and remains to be investigated further.
After some investigation, the cause of those weird sounds turned out to be rapid resets of the IC (ANX7688) that controls some of the functions of the phone's USB Type-C port. The ANX7688 actually initiated the resets itself, as a result of (yet to be investigated) overcurrent protection. Each of those resets caused the plugged-in USB device (in this case, a charger or a powered dock) to be removed and attached again, at the logic level of course, which in turn caused the operating system to successively play back the sound that indicates an USB device plug-in event.
The above-described overcurrent protection is somewhat weird and remains to be investigated further.