USB 2.0 output power?

[Raymond Lin]

I just got this text from a friend

"What is the official output voltage of usb 2.0 and do you know any problems charging the new ipod nano/touch/iphone from a 5v charger?"

Normally I would just tell him to get a apple charger but i think it's to do with a design project he is doing so he need the spec rather than a physical product solution.

 

[james.miller]

1.21 gigawatts!!!


ahem. no, its actually a maximum of 500ma allowed from a usb connector. the volatge is allow to be no more than 5.25v and no less than 4.75. if the device is plugged in to a bus-powered hub (ie a hub that doesnt have its own power supply) the limit is reduced to 400ma

 

[Raymond Lin]

so I presume if you can make your own charger output that then you can charge the ipod with it?