No its not recommended to do it that way....You will overload the USB port. USB port is limited to 100MA if I'm not mistaken.
USB/2 Ports are not meant to be power supplies for big loads.
It may potentially damage the circuitry of the TV related to the USB.
On notebooks or PC with overloaded USB/2 ports...It normally crash the computer or go to force reset until the overload condition is removed.