High Efficiency Power Converting Apparatus

A system includes a first coil configured to be magnetically coupled to a second coil, a rectifier coupled to the first coil through a capacitor, a first power stage connected between an output of the rectifier and an output voltage node, and a second power stage coupled between the output voltage node and a battery, wherein the first power stage is configured to charge the battery, and the second power stage is configured to provide isolation between the first power stage and the battery.