On Tue, 23 Feb 2010 07:42:34 -0500, wrote:

Hi,
I want to buy a portable MP3 player (not IPod), but it requires a
"high power" USB port on a computer to charge it. The alternative is to spend
around $30.00 for a "wall wart" type of charger.

I am a service technician, and I thought about using one of my regulated
power supplies. You can set voltage and current. Also I have the USB
connector (same type computer has), but I don't know what current
I should set to charge the MP3 player. I realize that may depend on the MP3
player, but I am looking for a nominal value as a reference.

Do you have information on the typical charging current?

Thank You in Advance, John

PS, Remove "ine" from my email address


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