I'm working on this project where I want to control 108 LEDs using 7 TLC5940.
My current set up:
I have the 7 TLC5940 daisychained, powering them with the 5v from the arduino UNO. The distance between TLCs and arduino is ~40cm. The LEDs I'm of course powering with a separate power source. This external power source I'm regulating from 9v to 5v (although I just got the input i could just use the 9v - i wonder why i didn't think about that earlier). Then I have a connection in between the GND of the external power and the Arduino GND.
Using this setup I have the following problem: Even when I'm only using 4 of those TLC the voltage regulator of the ardunio (the chip in between the jack and the USB) is getting hot, like 100°C. But not instantly, it takes about 30-60 secs.
I really have no clue where the problem could be.
Next step I will do is measuring the current in the different parts of the circuit, but I would be much happier if you could give me a better advise!