My device uses >400 ma (but <500mA) .  Is it possible to configure it as a bus powered device?

Question: My device uses >400 mA (but <500mA). Is it possible to configure it as a bus powered device?  What are the options and restrictions for configuring a device of this power consumption?

 

Answer:

If all these USB devices are used at the one time they would need 1102mA of power but the total provided by the motherboard USB is only 500mA. The only way to use many USB devices at once is to get a Powered USB hub.

A powered USB hub uses 0mA (from Bus) and has up to 500mA available. If you want to or need to use many USB devices at a time, you have to get a powered hub. Some devices like scanners, even on their own need a powered hub. They can run off the motherboard, but it is not recommended if they use over 400mA. Some devices can also be plugged directly into power and use self-power mode rather than using the bus-power provided by the motherboard. You could check to see if this is an option for any devices you use.