Google maps problem

I tried searching here and via google and couldn't find any answers.

Anyone else finding the googlemaps essentially useless due to the screen timing out? Everytime googlemaps is open eventually the screen goes dim and then eventually black, where I have to push the home button again just to turn it on, then click on the lower left so the map reorients my location (the blue dot).

I asked some of my iphone 4 buddies, but none of them say they have this problem. Even my crappy windows based Samung intrepid did not time out with google maps. Pretty surprising since it renders the maps almost useless. Any way to turn off the screen sleep mode while in maps only?