Laptop USB ports/AC adaptor problem

I recently received a new AC adapter for my Toshiba Satellite A205 S4577 Laptop. After switching over AC adapters, I discovered that my USB ports were not working as well as they should. I tried plugging in my iPod and it would constantly connect and disconnect. I also tried using a game controller and this too constantly would not stay powered on. After trying everything i could think of, I discovered that when unplugged from the AC adapter, and using battery power my USB ports all worked perfectly! When I plugged my computer back into the AC adapter I had the same problem though. I have changed all the performance and screen brightness settings to match when using battery or AC, but I still have the same problem. Any suggestions? Any advice would be greatly appreciated.