Fine tuning dimming LEDs with PWM

Using Arduino LEDs and Multiplexing
6

Magician:
I think, that you make a design w/o math. Data sheet for driver says: 43.2 ~ 52.8V
Even it's adjustable, I don't believe you can drop it to 8 x 3.5 = 28 V w/o consequences.
My guess is, when you request (by pwm) to drop current below 25% driver become unstable, as it moved out of "normal" operation zone.
This confirmed, why it's working with 10 leds, because 10 x 3.5 = 35 V
Solution:

edited:

  1. change driver for .... ooopss, eln-60-27 (good for 8 leds maximum)
    you can split diodes in a group of 4 leds, and use 2 drivers eln-60-12

  2. add more leds in series, up to 52.8 / 3.5 = 15, minimum 43.2 / 2.8 = 15,
    again 15, now we know how they calculate their data sheet :slight_smile:

May be 10 would be o'k, but as you can see, there is no warranty.

2+ more LEDs I can do. Can't say I follow the math exactly but I need between 10 and 15 LEDs for it to run optimally? Or are there specific numbers of LEDs that would work optimally? I was already planning to add a few more LEDs so this is the perfect time to figure out how many of each would work best.