USB-IF Steps in USB Battery Charging Standard

The official USB promoter group today releases a battery charging specification that defines on a standard way on how gadgets like MP3 players and cellphones should draw current through USB from wall chargers or PCs. One of the primary issues addressed in the new specs is defining a mechanism for devices to detect whether they are attached to a AC charger, host or hub. Should the gadget detect it's plugged into a high-powered port, it can negotiate for power in excess of 500mA. Otherwise, the current limit is 2.5mA, 100mA or 500mA. The group also comes up with a provision in the new specs to allow portable devices with dead batteries to recharge at 100mAh even if they are not able to power up.

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