The Portable Media Player (PMP) Docking Station reference design showcases Texas Instruments' PowerWise® power converters, battery charging circuitry, audio drivers, and display interface. The reference design saves more power by initiating a power-saving mode when the PMP is unplugged from the wall power, automatically reducing the maximum brightness of the display as well as the output power of the audio drivers. The LM3658SD, a dual source, USB/AC Lithium chemistry charger IC, receives a wall wart or USB input and converts either input into a source voltage that, via the LM20124 synchronous buck regulator, powers the docking station as well as providing the charging current to an external Lithium-Ion back-up battery pack.