Screen starts to flicker when brightness is raised above a certain value
Hi everyone,
I can print nice pictures & transitions on the display of my custom board.
But when I'm rasing the brightness of the display (by setting the PWM backlight value), at a certain value the screen starts to flicker. Controls are shaking and if I continue to raise the brightness it flickers more.
Below that critical value it's working well, as you can see on the pictures joined.

I'm using a LCD TFT (parallel interface) with external SDRAM & TouchGFX.
What could cause this ?
Thanks