Just a simple question that can ADD5211 or ADP8140 control dimming individually on each of multi strings of LEDs ?
If not, please let me know any products can have individual string control ?
No, the ADD5211 or ADP8140 cannot control each string individually. However, the ADP8140 can be easily connected in parallel, so that you can control up to 2A of LED current individually on each ADP8140. But it requires a separate IC for each LED string.
To control multiple individual strings with one IC, you can use the ADP8860/1/3, ADP8870, or ADP8866.