High-efficiency Portable Music Player Dock

Showcasing PowerWise® power converters, battery-charging circuitry, audio drivers and display interface circuits, this design initiates 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.

Source: National Semiconductor
11/10/2008

The Portable Media Player (PMP) Docking Station reference design showcases National Semiconductor’s 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 docking station 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 Li chemistry charger IC receives a wallwart 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.

The LM20124 provides the source voltage which biases both the audio and DS90UR241/124 serializer/deserializer (SERDES) segments of the video transport sections of the system. The LM4674 stereo Class D audio amplifier drives two 2W speakers. Boost regulators will be used to generate 12V and 5V, which will supply the bias voltage to the AVP-1280 video interface controller and the USB charger IC for the docking station, respectively. This controller converts the analog video output signal from the docking station into digital inputs for processing by the SERDES segment. Finally, the output of the DS90UR124 deserializer is taken and displayed by the Sharp LQ104S1DG21 TFT-LCD display, which is illuminated by an LED backlight with dimming capability.

Click here for more information