Charging Portable MP3 Player (Not IPod)

The USB specification is for a maximum of 500ma from a port to a device that can send a highpower request. Otherwise, the limit is less (180ma?). However, the player will charge on less current; it just takes longer.

If you plan to charge the player overnight, then a 100ma source is probably adequate.

Otherwise, set your bench supply for 5 volts and set the current limit to 500ma and let it charge.

John

My MP3 player uses a rechargable AAA battery. I bought a

Hi!

"High power" is an Apple-esque description of a USB port that is part of a *powered* USB hub or built in to a computer (a "root port").

Basically, as long as you plug the MP3 player into a USB hub with its own power supply or directly into the computer, it will be fine.

If you were to plug it into a "passive" hub such as that found in a monitor or keyboard with USB ports, there might be a problem with insufficient power being available.

Be very aware of polarity, and make sure the power supply's regulation is as good as you think it is, especially with light loads. The designers of your MP3 player may have assumed that its power input would never be mistakenly reversed or set to a voltage that was just too high.

You are looking for 5 volts DC at a maximum of 500mA.

William