Chosen Solution
Hello! I have strange problem with iPhone 5. When I connect it to external power source, it immediately 0.5A current for ~1sec, then nothing for 1sec, then 0.5A for 1sec and its looping. iPhone is booting normally, works for some time, then shuts off and coming back to “current loop”. Is it PMIC fault?
On the iPhone 5, the charging is managed by the PMIC once the proper communication has been set via Tristar (U2). Have you tried to connect your iPhone to iTunes and do a Sync/Backup? That would help determine if Tristar is functioning properly. If it does, then your problem may indeed be caused by the PMIC. If there is no iTunes communications or if the Sync failed partway, then it would probably be Tristar related, unless iTunes gave you an error that would point to something else.
