Thiiis one's special. Not my design, but I need to do analysis on it.
So we have a sensor that needs +/- 5 V power. Threw on a
switching regulator to take care of that . Problem is, the output is bipolar, need to make it unipolar. Op Amp you say? Fshaw, silly! Lets do something else.
Split the rails, drop the potential for the AVR microcontroller.
There has GOT to be a plethora of things that are wrong with this. For one, there's no charging protection on the battery, but disregard that. It's the least of my concerns. When the sun is not there, the switching regulator no longer runs, so the microcontroller is back at normal potential.
Can anyone tell me WHY this design is bad? Innately I know this, but I can't explain WHY.
Edit: Fixed the schematic, was wrong on something.