Go Down

Topic: How does this circuit look for PWM'ing 40 RGB LED's? (Read 1 time) previous topic - next topic

MatCat

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 switching or PWM is not as clean as it should be, so any ideas on that would be great too, thanks!

Schematic:
http://www.digikey.com/schemeit/project/a4g/LED-Project

MatCat

#1
Oct 09, 2012, 11:14 am Last Edit: Oct 10, 2012, 08:12 pm by MatCat Reason: 1
Here is a video demonstrating my circuit, been running for about an hour now and all components involved are as cool as when I pulled them from the parts drawer, so I think it works however any ideas are still welcomed!

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

MatCat


Quote
Wow 51 views and not a single reply!

Got to tell you something about your previous behavoure then.

Excuse me?

Go Up