led driver

this one:

How many 4794 chips could the Arduino board handle?

Does the 4794 support 8 LEDs?



the 4794 can handle 8 simultaneous outputs, but you can daisy chain it and add more chips in series. We have a project here now with 64 double-coloured LEDs at once.

On the other hand, there is another LED driver, from Maxim, the 7219 that handles 64 LEDs at once, but that is more complicated to wire.


Thats very interesting indeed. Do you know anywhere online to buy this chip?

Do you have any documentation online about how to daisy chain it?

I have a 7219 that I am using for an LED matrix, although just starting.



If you are in Englad, you could get it from http://www.elfa.se , they sell over the net and accept credit card. Also Farnell and Digikey may have it, but I haven’t searched there.

The datasheet is available in our web repository:



Hi David,

is there a more generic name for the 4794??

i’m trying to find an equivalent chip from RS (as I have an account with them) (http://rswww.com) but when i search for led drivers, i don’t find the right sort of chip

Is it a multiplexer?? or …???

Thanks a lot



the proper name for this component is actually: 8-stage shift-and-store register LED driver, HEF4794B. But in a superficial search through your provider’s website I couldn’t find it.

However there are some alternatives you should be able of using any other LED drivers, or shift registers.


Hej again,

actually the:

8-digit LED display driver,MAX7219CNG
RS Stock no: 311-473

will be able of driving up to 64 LEDs with one single resistor :wink:

This one will make the magic for you,


Thats great!

i’ll report on my experience of using the chip!

Thank You!


or you can get one of these for testing:


they are slightly expensive but good.