Morning! I am looking to use an Arduino to control a buck converter, five independent converters to be exact, but we will just stick with one for now. I need some help with where to start, etc.
The goal is to have a controller with PWM for the new Cree MK-R so that I have extensive control over the brightness... 125mA for 20% flux to 1166mA for 150% flux. However, I can live with any current limitation beyond 700mA since I will have heat dissipation issues.
The voltage source would be LiPo 4S, 5S, and 6S hobby batteries which are 14.8v, 18.5v, and 22.2v respectively. I will have to monitor voltage since these are not protected batteries, but that is not a big deal.
Now my understanding of buck converter (my EE experience is not strong) is that I can use duty cycle to regulate the voltage on the output. So if the Arduino is programmed for the different LiPo batteries called out above, I can just use PWM to regulate the output voltage to 12v no matter the input... unless the components are not sized properly or cannot be versatile enough for this. This is where I need help in selection of of them.
Then to add on to that, how do I regulate the current or the effective on current on the LED to regulate the brightness? How does that play into the buck converter such that the circuit does not become out of balance?