Texas Instrument Product Engineer David Zhang shares insights on LED color tuning technology in a recent blog post. As Tim Sullivan indicated in an earlier blog as well, LED lighting is a relatively new technology. Engineers that used to change bulb color through the glass fixture are now finding themselves figuring out how to change or tune lighting color in high-end LED fixtures. One of the easiest ways to do this is through multiple strings of different color LEDs with dimming. I wrote a paper, "Dimming multiple LED strings enables color-tunable luminaires", on this topic that was published recently in LEDs Magazine. As well, I included a link below to a video demonstration on this topic.
Pulse-width modulation (PWM) dimming is a very simple idea (as far as engineering goes), but to achieve high frequency PWM dimming at low duty cycles is not easy. It's important for the lighting designer to pay close attention to the details of how PWM dimming is implemented. And I personally learned a lot as I wrote this article about LED color mixing.
A two-string dimmable LED driver uses a buck converter for one string and a linear regulator for the second string. (LEDinside/Texas Instruments)
Earlier this year while I was writing this article, Avnet, one of our distributors, created a gesture-controlled color-tunable LED lighting demonstration for this year's Lightfair conference. It was a great example of multiple string LED color tuning or "color-tunability", and I invite you to watch the video we took here:
