How, and can, I change the settings of my usb port?

I plug my phone into the usb and it charges fine, as long as I'm using the computer. As soon as the screen saver kicks on the phone no longer charges. I assume this is a for saving power. Being that my laptop stays plugged into the wall 99.9% of the time I don't really care about power saving. Is there a way to keep power to the usb ports at all times without changing the parameters of my screen saver or time out? Sorry if I'm not quite hip to computer lingo. I just want to be able to plug my phone into the usb and have it charge regardless of whether or not the screen's active or black. Thank you.