I'm impressed. We got a new wind-up flashlight and while the light was great, the fluctuating USB power output was intolerable to the cellular phone. I'm sticking with my little inverter off the car battery for chanrging devices when power failures or travels keep us off the house power. Meanwhile, just be glad that you didn't have to fix a broken iPhone "flashlight". It could be a lot of work fixing a cell phone to get a few lumens in the dark.
I also have a bunch of the 34063 switchers taken out of old automotive Cigarette lighter plug to cell phone power adapters. Whenever someone throws a cell phone automotive power plug away I rescue it from the garbage and reuse the entire PCB assembly.
I have found that most cell phone automotive adapters use this IC in them.
Nice story Brice and good work - those wind up flashlights almost never work properly (which I suppose is whey they are so cheap...)
The 34063 is a great little chip. The nearest thing there is to a universal switched-mode power supply IC. I have a bunch of them scavenged from an old comms system that had one on each board, As I recalll the datasheet has some PCB designs for step-up and step-down designs - I want to make a run of both to have them handy whenever I need one.