How to drive Dot-matrix colorful LED display ...

[hm_fa_da]

MODERATOR ACTION: topic moved here Fragrance

if we use 3 color LED , we can make all colors if we could light them in different powers ... ,
for example if we choose 256 levels of light for each color , then we can make 256*256*256 colors ( RGB ) with one 3 color LED ,
now if we use a dot matrix display , for example 20*20 LEDs , we should make this different levels of light in a way , if we use different refreshing rate , then our circuit should be able to run in very high speed .... , i mean we can make different levels of each light with changing duty cycle of LED being on ... but this way we need very high speed ....

other way is to use 8bit digital to analog ICs for each line of matrix for each color , this way we can use lower speed , no need to change duty cycle ... , but this way also we need too many pins and large circuit ...

which way you think is better to use , or which is standard and used in this projects ? has anyone done it ?
notice it is different with multi color or one color LED displays ....

Thanks & Regards .

 

[cristianp]

You can use this circuit or similar products.

 

[hm_fa_da]

Thanks for the Datasheet, it helped me,
and some questions :

1 - how much is minimum time for LED to turn on ? can it be 1uS for example ?

2 - and is luminance linear with period of LED being on ? for example 30% of period being on causes 30% of luminance ?

Thanks & Regards ...

 

[cristianp]

Thanks for the Datasheet, it helped me,
and some questions :

1 - how much is minimum time for LED to turn on ? can it be 1uS for example ?

Data sheet, page 10:
Iout propagation delay is about 40ns

2 - and is luminance linear with period of LED being on ? for example 30% of period being on causes 30% of luminance ?

Thanks & Regards ...

In data sheet (page 15) the luminance mechanism is explained.

Regards