Power Adapter and iPad Connectivity issues

Hi, I just got the UR22 home, and attempting to get it working with iPad. Have successfully made it work with the laptop already. Confused by external power, since when plugged in to a standard issue 5v plug, no light comes on the unit so I’m not sure if it is even on, when I have it switched from USB bus power to external power nothing happens. Of course when I have it set to USB bus power, the iPad tells me the connected device needs too much power to work. Can anyone tell me how to get this to work?