PWM driving of High Power RGBA LEDs with PCA9685

Other Hardware LEDs and Multiplexing
1

Hello everyone :),
I am writing to ask you for a suggestion.

In my project, I will need to drive through PWM signals 5/6 RGBA LEDs with a maximal forward current of 500 mA.
I would need to calibrate the DC of the PWM train to precisely set the luminance of each color channel of the LEDs to obtain a background light stimulus and then one RGBA at a time would provide a different light spectrum changing the DC of the 4 color channels.
I will start calibrating the current only in one RGBA LED and after that, I will repeat the circuit for the other LEDs.

I would therefore need several individual PWM signals. I have at home some PCA9685 boards, each one characterized by 16 PWM outputs ( 4 RGBA LEDs ). However, the current output provided is 25mA.
May I connect a transistor together with resistors to the PCA9685 board to drive the LEDs with a higher current exploiting the full 500mA of the LED?

Are there typical LED drivers to use together with the PCA9685 to drive high-power LEDs?

If you have other smarter suggestions to drive these LEDs obtaining a precise regulation of the current through PWM, please, let me know.

And.. thank you for your time! :slight_smile:

2

Hello.
To handle anything that consumes more than 10mA, I use the buz11 transistor, which is cheap and supports up to 30A with the following circuit, (for example), and I don't even calculate anything. I connect it to the exit and get out of trouble.
Greetings.

buz11.png

buz11.png

3

If you want exactly 500mA LED current, then you also need four 500mA constant current LED drivers per RGBA LED.
Like the Meanwell LDD-500.
Could get messy, so I build my own PCA9685 + 16 CC driver boards.
Example here (picture post#2).
Leo..

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