How does this circuit look for PWM'ing 40 RGB LED's?

Discussion in 'The Projects Forum' started by MatCat, Oct 8, 2012.

  1. MatCat

    Thread Starter New Member

    Aug 18, 2012
    2
    0
    I am putting together a house lighting project using RGB's, my plan is to use a TLC5940 driving 5 RGB LEDS (15 PWM's), and multiplexing 8 LED's onto each channel, giving 40 total RGB LED's with this setup. I would like anyone with much better expertise then my own as to if the circuit I designed is adequate enough. I did breadboard the design with 4 multiplexed LED's per channel and it seemed to run fine (though I will probably have to use dot correction for best results...). Note that the schematic is not complete, I did not bother at this point to fully schematic out the 595 and 5940's power, ground, and arduino connections, but the schematic for the LED's is there. I am biasing the 5940 for 40ma per channel considering how fast the multiplexing is happening to get a good brightness (I could go to 60ma but I will be taxing my available power supplies doing so).

    I am not sure either about the best placement of capacitors for power smoothing, as I noticed with the scope that the multiplexing power or PWM is not as clean as it should be, so any ideas on that would be great too, thanks!

    Schematic:
    [​IMG]
    http://www.digikey.com/schemeit/project/a4g/LED-Project
     
  2. MatCat

    Thread Starter New Member

    Aug 18, 2012
    2
    0
    Well I built the strip, and it has been running for an hour now and not a single part is any warmer then when I took them from the parts bin, so I think it's working, but any suggestions are still welcomed!

    http://www.youtube.com/watch?v=kq6DjnXVV-0
     
Loading...