Dell WD19DCS not powering peripherals when laptop off.

I have a WD19DCS dock with a Precision 5570 laptop. I use a battery powered Poly speakerphone for conference calls. I keep it plugged into the dock all the time. It works perfectly. However, when I turn my laptop off the power to the speaker drops, and it reverts to battery power. Which means when I start work the next day the battery is dead. I know I could simply unplug and turn off the speaker manually, but I forget too often. I know this is a minor issue but its frustrating for me so wanted to see if there is a simple solution. 

Is there any way to keep power on the usb ports of the dock permanently? I've tried all the dock usb ports. 

Thanks