The Roku® Streaming Stick® and certain Roku streaming players, such as Roku Express, can be powered by connecting to the USB port on your TV.
So, why does my Roku streaming player restart every time I turn on my TV?
Roku Streaming Sticks and Roku streaming players connected to the USB port on the TV will lose power when the TV is turned off. Also, depending on your television, many will lose power when the TV goes into standby. This means that your Roku device must “boot-up” every time the TV is turned on. Although this is generally fast, it can be avoided by connecting the Roku device to a wall power outlet. Also, much like “apps” on your smartphone, Roku channels are cached the first time they are launched so they load faster; however, this cache is emptied whenever the Roku device powers down.