An interesting change from Apple today

As long as I’ve know, other than a couple of very odd “non standards”, Apple’s USB ports have provided 5V 500mA of power, regardless of it being USB 1.0 or USB 2.0. Now today, a tech document was updated by Apple;

http://support.apple.com/kb/HT4049

“On some newer Intel-based Macs, such as the MacBook (13-inch, Late 2007), when a device requiring more than 5V and 500mA is connected, the port with that device connected to it becomes a high-powered port capable of offering up to 1200 mA at 12 V. That port will continue to operate as a high-powered port until the device is removed.”

Very very interesting. This obviously must be for the iPad, which is going to take a 10W power source;

So… Perhaps we’ll be seeing some kind of enabler being included with Mac OS X 10.6.3 or in the iPad software CD that’s bound to be included with them. Wonder if that means people with older systems will just recharge slower?

The old article is cached here (Probably not for long, though)

It clearly says :

“The USB ports on Macintosh computers provide 5 V and 500 mA for each port, regardless of whether the port is USB 1.1 or USB 2.0. This is in compliance with USB specifications.”

The only other Apple system to include a higher power USB port that I can think of is the MacBook Air, for it’s external superdrive, but there are no specs at all on what power it’s drawing, or that the USB port is putting out anything more than 5V. This comment about 12V is very, very interesting.


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  • Apple’s HT4049 document has been updated again. The extra power from the MacBook (13-inch, Late 2007) is now described as “up to 1100 mA at 5 V”. That seems more reasonable than increasing the voltage as well as the current.

    It also falls within the limits specified by the USB 2.0 battery charging specification, which allows a USB port to supply up to 1500 mA while running in low/full speed mode, or 900 mA while running in high speed mode.

    The battery charging specification is available here:

    http://www.usb.org/developers/devclass_docs/batt_charging_1_1.zip




  • There were other Macs that shipped with higher-power USB ports. The Cube was one; the higher-power ports were to power the orange-sized round Apple Pro Speakers. The backside USB ports of the G4 series ADC-connector monitors also are listed as capable of powering the Apple Pro Speakers; by implication, they are higher-than-usual power. There is a strong warning to not plug the Apple Pro Speakers into any port other than these ports. While I’m not familiar with some G4 flat-panel iMacs, some of them if I recall are pictured with those speakers, and they might also have higher-than-0.5W ports.




  • Good point – had forgotten the external SuperDrive is an option with the mini Server. Thanks!




  • The MacBook Air was the first Apple machine to supply more than 5V to the USB port, as you say, for the external Superdrive. However, the new Superdrive-less Mac mini running OS X Server can also supply enough power over USB to run the external Superdrive. Maybe other Macs and MacBooks can, as well.