Closed Loop Control. Modern Control Engineering. Katsuhiko Ogata.
Since you can't replace your batteries... you want them to last longer. I'm looking at an Iphony right now.
But I see so many ways it can go wrong(tm). Assume a circuit is increasing V to a transistor, because it aged... then you replace this transistor. New transistor, with higher V fries instantly.
Actually it goes well with their walled-garden policy, because when THEY repair the aging transistor, they recalibrate the compensation circuit to fresh-new, lower V, or it would otherwise blow up in your unauthorized face... Unless you try the lower value of V every time you want to fire that transistor... (or after every boot).
On the other hand, every car that runs on any mix of gasoline and etanol already does that... it samples the fumes of the first few strokes and corrects the timing of the spark plugs on the fly, every motherboard has some sort of fine voltage regulation for the overclockers out there, and every PSU has to sample the mains current from 110V to 220V to deliver clean 12 Vcc to the rails.
It is called closed loop control, and there is an entire Engineering career based on it. Google Katsuhiko Ogata "Modern Control Engineering".
There is NOTHING NEW done by Apple. I cry previous artwork.
They COULD release a paper called "Closed Loop Control Applied To Microcircuits To Improve Reliabilty Against Aging" though. It would be a nice Graduation Thesis theme.