Most car chargers available sport a MC34063 based DC-DC converter to step down 12 volts to 5 volts. MC34063 based circuit within USB Car chargers Such chargers can be used to derive 5 volts from 12 volt power supplies/lead acid batteries while constructing projects. Using the charger to get 5V from 12V power supplies in projects. This charger is a bit different from the regular ones. It can supply upto 2 amperes. Instead of MC34063, it uses the IC CX8509