Hello everyone!
I'm building flight simulator hardware and I'm running into a question. There are multiple ways to skin this cat, and I am curious to see what other people would prefer as a solution.
Situation: 10 indicator/warning 'lights', each is illuminated by 2 LED's (Würth 151034YS03000) in parallel. This all runs at 5 volt with each LED drawing 25mA (2x 10 LED's = 500mA in total).
It should be possible to individually turn on and off each indicator, but brightness control (PWM) should be the same for all. I do not have enough PWM pins on my uC to have individual PWM control for each indicator. So I prefer to have one PWM pin that does the brightness control for all 10 indicators simultaneously.
Possible solutions:
- Have one PNP PWM'ing the 5V to all indicators for brightness control, and a NPN for each indicator to turn them on and off individually.
- Have a NPN for each indicator to turn them on and off, and one NPN below this to do the PWM'ing for the brightness.
I hope this is clear, if not then I apologize, and shall draw the proposed schematics.
There may be more solutions to this which could work better. Thank you all in advance!