Is it feasible to use a CD4040 ripple counter to control LED matracies?

Hi to all,

I have hand built a 12 x 12 LED matrix and wondered if it was possible to use an IC that could cover all 12 connections on the common side instead of chaining maybe two 595s?

I have in my box some CD4040be ICs and since it is a 12 stage ripple counter I was thinking maybe I could use that to control either the rows or columns. I don't mind using something else to beef up the capabilities of the IC as it will be eventually driving two identical displays that will both show the same characters simultaneously. I was thinking possibly a couple of ULN2803s for each side or at worst case 12 single power transistors to drive both.

But will the 4040 do the job that is usually done by 595's. From the datasheet I can't figure out if the outputs are on one at a time or one more each cycle and whether I should source or sink for the required effect?

Any help or ideas will be much appreciated, even if the info shoots down my idea at least I will know then that I have to order some 595's. Doh!

Al

hi Al,
Only problem with a binary counter is the output pattern on the output pins, it would not select individual rows/cols in isolation , but in groups in binary format

ie: 0001, 0010, 0011 ....


Eric

Hi Eric,

DOH! Back to the drawing board! I completely missed that in the sheet.

BTW how is your bro?

Al

You could use a ring counter - CD4017 for example

Hi mate,

But is there a single IC that can do the 12 lines or columns on my display?

Al

I'm unaware of a 12-line ring counter, but you can certainly cascade two 4017's for the job. These are handy as they only require two lines to control - clk and reset.