I have my PSP set up at work and listen music to it often. Many times I jump on your site to download new updates of games to download on to my PSP so I leave my USB cord plugged in most of the time. I was doing a check on my battery when lo and behold it is telling me on and off that the PSP is using external support then battery then external and so on. Is my PSP actually using the USB cord to help power the thing therefore saving valuable battery life???