When I tried to put my PSP 2000 to sleep, the screen turned black (but not off) and the power light started to blink. I just left it blinking like that and while I googled (turned up nothing relevant) it shut itself off. I'm guessing it blinked for about a minute or so. When I turned it on, it said the battery was at about 50%, so it was adequately charged.

It hasn't happened again, but I'm worried that this might mean my battery's gone bad or something