You can charge your MP3 player even when you don't want to use your computer for any other reason. Most computers allow for power to be sent via USB while they are asleep, and some even allow it when they are turned off. If your computer doesn't supply USB power while in sleep mode, you will have to change your computer's power settings.
USB Power and Ports
MP3 players are powered via USB. USB power is sent over the outer two pins of a USB jack. This power supply can carry 5 volts. There are three types of USB ports: standard downstream ports, charging downstream ports and dedicated charging ports. Computers typically have ports categorized as standard downstream or charging downstream ports. The USB 2.0 specifications dictate that both of these port types can send up to 500 mA of current to a device. USB 3.0 ports can send up to 900 mA.
The motherboard is a circuit board that holds the internal components of a computer. USB ports are attached to the motherboard, as is the computer's power supply. Therefore, the motherboard routes power to the computer's USB ports from the power supply. It is this fact that allows power to travel to the ports when the computer is asleep.
Changing the Settings
On a PC, the power settings of a motherboard are changed through a Basic Input Output System. The BIOS of a motherboard can be accessed either directly during system startup or through the operating system. On an Apple computer, the power settings can be accessed through the Mac OS X Energy Saver preferences in System Preferences. USB power will be delivered through an Apple computer when the computer undergoes display sleep, but not always during full computer sleep.
External USB Hubs
If your computer is incapable of supplying the adequate current to charge your MP3 player while in sleep, you can charge the MP3 player through an external USB hub instead. External USB hubs connect to your computer and supply extra USB ports. Some USB hubs are externally powered. These hubs will be able to charge your MP3 player even when the computer is off, regardless of the motherboard configuration.
Laptops and Sleep
Depending on the manufacturer, laptops may handle USB power differently while asleep. Some may have different USB power settings for when the lid is closed versus open. Others may have different USB power settings when the computer is plugged into an outlet versus running on battery power. Experiment with all possible configurations if you have trouble charging your MP3 player while your laptop is in sleep mode.
- Photo Credit NA/AbleStock.com/Getty Images