Hi all,
I am using smartgpu2 LCD from Vizic Technologies for displaying the data using arduino. When I am giving the power using the cable from computer it is working fine.When I replaced the power supply using 9v Duracell battery ,there is a fading in the LCD display.Please advise.
"9v Duracell battery"
You mean this? 
No wonder! 
yes Paul.I mean the same one.
Well, you can read your data sheet. The display backlight will take a large current. The intelligent controller will take a significant current. The Arduino takes tens of mA even without anything connected.
Now look at the capacity of your 9V battery. e.g. 350mA-hour. So you can expect 3.5 hours at 100mA or 1 hour at 350mA.
I would guess that your battery can not supply the large currents used by the backlight PWM. You would be better off with 3 AA cells or a LiPo.
No, I have not read your data sheets. That is your job. I have just invented some numbers. You need to see exactly what currents your display draws. And look at the characteristics of your particular 9V battery at these high currents.
David.
Thank you David for your advise.