I want to drive two sets of 3 LEDs. They are all 35V but the two sets differ in color spectra and current: the first set needs 900mA the other 500mA.
I want to freely mix the two sets using PWM, so that the total power consumption always stays between 72W and 100W.
One easy way to do this would be to connect each set in series and use two dimmable drivers (e.g. ELG-100-C). But this seems to be quite a waste in terms of cost and size; and probably also efficiency considering one of the drivers might be much less utilized at any given time.
It seems to me a cleaner way is to use a 100W power supply and 2 buck converters.
But I have trouble finding an off the shelf constant current buck converter that supports PWM dimming and the 105V needed. Nor any reference design for such a thing.
Using boost converters seems to be more common - but this is likely to be less efficient. Another possibility around this would be to drive the sets in parallel and use a current mirror (or a more fancy LED balancer) - not sure how this fares efficiency wise.
My main questions are:
- Is using 2 buck converters a good idea worth investigating further? (Any pointers would be nice!)
- Is there another easy solution I'm missing?
- Am I in way over my head? I had some EE classes during my Computer Engineering Bachelor, and now again skimmed Chapter 9 of the Art of Electronics.
I am willing to dive into the material but want to avoid to find out I spent months working on an idea that was doomed from the start - because I won't be able to match (or exceed) the efficiency of two professional 100W LED drivers.