For an upcoming road trip, [Patrick] needed a small variable power supply. Instead of lugging around a bench supply, [Patrick] did the sensible thing and reverse engineered a cell phone charger to fit his requirements.
After cracking open an old Kyocera car charger, [Patrick] found a small PCB with completely labeled, all through-hole components – excellent reverse engineering potential. After finding an On Semi MC33063 IC, [Patrick] tore through the datasheets, generated a netlist, and developed a schematic that closely resembled the reference schematic given by the datasheets.
With all the grunt work done, [Patrick] set out to finish what he started – modifying the charger to output 3-10 Volts. After replacing a resistor with a 5k multiturn pot, [Patrick] was left with a power supply with a variable output from 2.8 to 8.8 Volts. Not exactly what was desired, but more than enough for the application at hand. While this hack isn’t a disco floor, it’s a great walkthough of the hacking process – building or modifying something to suit a need.