how can I keep USB's ports active while in sleep mode?

I find that if the MacBook is connected to power, the USB ports continue to charge iDevices, even if it is sleeping.

Curt

you can go into system preferences, click energy saver, computer sleep to never and display sleep to however long you want. This allows your screen to go black and usb ports still active 🙂

Thanks so much for this explanation, ShwebM! I was wondering why my devices were not charging unless the display was active. Glad to hear it was something easily fixable and not a hardware issue.