Hello, i was wondering if anyone would be able to help me. I'm trying to make a name plate. I have 53 RGB LED's (3.7V 20mA Cathode common) they don't need to be individually controlled Im using the arduino uno r3 for the PWM signal.
I have tried using ULN2003A and even with all the input and outputs tied together the LED's weren't fully illuminated.
I am currently testing two L298N's everything is lighting up now but now im almost getting an unintentional chasing effect(I think this may be because im running the leds in parallel)
In short I was wondering anyone had anyother thoughts on how I should be trying drive the LED's any help is highly appreciated
Since you choose RGB LEDs, I assume you want to control the colour as well as the brightness using 3 PWM pins? Otherwise you could simply have used single colour LEDs.
It was a mistake to choose common cathode, I suspect. If you had asked sooner, the forum would probably have recommended using common anode.
ULN2003 would not be able to control the colour of common cathode RGB LEDs. It can only switch on the cathode side of the LEDs.
L298 would be able to control the anodes and control the colour of the LEDs, but it also has a very high voltage drop. What voltage power supply are you using?
P-channel MOSFETs would be best, I think. I can't suggest a part number, I only know N-channel models, which would not be suitable.