Why does my new dualshock 3 controller keep turning on my ps3 automatically?

I just bought a new dualshock 3 controller and it works fine except for the part when I try to turn off my Playstation 3 system. It makes the beeping sound when it turns off, my TV screen goes blank and in a few seconds (without me touching anything) the Playstation turns back on! This is my third controller and none of the previous two had this problem. Please help.