Wednesday, July 8, 2015

LED driver chips

After looking at the many options for driving LED displays (5x7/8x8 matrix, 7/14/16/25 segment, common anode/cathode, single/bi-color/RGB), I put together this list of commonly used LED driver chips, to have a better picture of possible combinations, and use it as reference for future projects.


The bottom 5 rows are not actually LED drivers, just substitutes (require current limiting resistors).

Some of the driver chips (e.g. "8x8" in the "channels" column) provide internal multiplexing, being designed specifically for driving array of LEDs. The others, where "channels" is just one number, would require extra circuitry (e.g. transistors) and logic (micro controller code) for multiplexing.

The "CA" column indicates "common anode", "CC" stands for common cathode.

There seem to be more options for driving common anode LED displays, probably because sinking current (by the chips' LED outputs) allows for higher currents and also for using a separate power source (usually higher voltage) for the LEDs.


Posted by FlorinC at 12:27 PM
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4 comments:

  1. BratanJuly 9, 2015 at 9:47 AM

    It's funny, but I also was researching driver chips yesterday :) And came to conclusion that there's really nothing better than HT1632c as far as stand alone driver goes. I'm wondering how are they driving gigantic LED arrays used for billboards. Probably using array of ARM processors instead of driver ICs...

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    Replies
    1. FlorinCJuly 9, 2015 at 5:40 PM

      That's a good question. I would be interested in an answer myself too.

      Delete
    2. BratanJuly 15, 2015 at 1:50 PM

      Found some good information. It's much more complex than I thought... http://www.edn.com/design/led/4432914/How-to-design-LED-signage-and-LED-matrix-displays--Part-1

      Delete
    3. FlorinCJuly 15, 2015 at 5:38 PM

      Nobody said it's easy :)
      On the other hand, check out this video (there is raspi code in github too) on this 64x64 RGB screen:
      https://www.youtube.com/watch?v=i52IwH9loLU
      It probably can be expanded as well.

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