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Topic: TLC5940 Flickering (Read 2 times) previous topic - next topic

konjurer

First, I'm an electronics noobie.  I've daisy chained 4 TLC5940s on a breadboard exactly as shown on the Arduino TLC5940 Library page and a total of 21 RGB LEDs.  One diversion from that setup is that I used a 2.2K resistors instead of 2K resistors (my local Radio Shack didn't have 2K resistors).

It works pretty well expect that sometimes one or two of the TLC5490s flickers it's LEDs. Any ideas?

Thanks! 

kbates666

How long are the connections between the tlc's?

Also, which tlc's are the ones flickering? The last two on the chain or is it random?

Grumpy_Mike

I suspect you have no decoupling capacitors on the TLC5940s.
http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html

konjurer


How long are the connections between the tlc's?

Also, which tlc's are the ones flickering? The last two on the chain or is it random?


Four TLCs altogether.  Usually happens on the 2nd and or 3rd TLC.  Connections are about 3 inch jumpers. 

konjurer


I suspect you have no decoupling capacitors on the TLC5940s.
http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html


Thanks Mike.  I'm an electronics beginner so some of your tutorial was over my head but I think I got a rough understanding.  So the VCC and GRD on are pins 21 and 22 on the TLC5940NT.  Would I run a 0.1 µF capacitor between those two pins on each IC, correct?


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