Problem with PWM on BLANK input of CAT4016 LED DRIVER

Hi i am working on a big static display with 120 shift registers CAT4016 and 1920 leds.

All works great,

today i decided to make the display to have the abillity to increase/dicrease the brightness . So the only solution i found is to use PWM on blank pins of CAT4016. (when this pin is LOW the leds are ON when it is on HIGH the leds are OFF)

it worked, but sometimes now i have some small flickering problems, just before displaying some text.

is there any help? is it posible PWM of arduino to be the reason of this? (maybe it uses large amount of it's speed?)

is there any other solution so i can controll the brighness of the leds?

I've not had a problem with this on my 4016 setups. Can you post your sketch?

Sounds (like always) a supply decoupling problem. Try adding a few extra large capacitors every eight or so chips in addition to the 0.1 uF capacitors you have on every chip.