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From: jaugustine on 23 Feb 2010 07:42 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
From: news on 23 Feb 2010 11:38 On Tue, 23 Feb 2010 07:42:34 -0500, jaugustine(a)verizon.net 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
From: William R. Walsh on 23 Feb 2010 12:58 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. "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. > I am a service technician, and I thought about using one of my > regulated power supplies. You can set voltage and current. 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
From: jaugustine on 12 Mar 2010 08:10
Hi, This "problem" with the MP3 player may have been a "fluke". I went into "system tools" and activated a "reset". When I tried to play music, it presented a "refresh" option, which I did. I found technical information on the web about charging an IPOD/MP3 player. This time I set the current limit to 600MA. I charged the MP3 player, and now everything seems fine. John PS, Remove "ine" from my email address |