God Of War Infinite Health Cheat Code for PSP?

I found one at http://www.cheatcodes.com/ but I can't get it to work:

Unlimited Power and Health:

Pause game play and press

L, L, R, R, Circle, Circle, Triangle, X, X, X

But every time I enter the code, the game unpauses all by itself before I can even finish entering the whole thing. Am I not entering it fast enough? Or am I supposed to enter it on the main menu screen or somewhere else? Any help would be greatly appreciated. Or if anyone has a code they'd like to share with me, that'd be cool. Just let me know if I have to pause the game first and where I should enter it :)