Hi. Does the resistor I put at IREF depend on the voltage supplied to the LEDs, or should it always be 2K ohms?
I intend to daisy chain 24 TLC5940NT chips to control 128 RGB leds. Right now I’m testing only 3 chips, connected to the arduino’s 5V, and 16 RGB leds connected to an adapter with 12V/5A.
With the the 2K resistors the ICs get extremelly hot! Measured with a multimeter I get total current of around 1A when I set the LEDs to white, which makes sense (16320mA). But if I change the color of some to red, and others to blue, the current shoots to several amperes (instead of dropping). If I use 5.6K resistors the ICs don’t get as hot, but the LEDs lose a lot of brightness…
So… Should IREF be 2K? If so, any idea why the ICs are getting so hot, and why the maximum current at anytime isn’t under 1A? Should I remove the 10K pull-up resistor?
Thanks in advance!