The current that an LED luminaire is driven at is one of the most important decisions of the entire product design. Sometimes, lighting designers find that the cost of the system can be reduced by driving LEDs at higher currents (though never exceeding the LED datasheet, of course). And new LEDs are pushing this as high as 4A. Many of the LED drivers are buck regulators (the inductor of the buck's output stage looks like a current source to the LED, so it is a natural choice). And while there are lots (and lots) of high current buck regulators, very few of them are for controlling LED current at >1A. The few that do are often expensive and really not that feature rich. So why not take a high efficiency buck regulator and convert it into a super smart LED driver?
In this month's Analog Dialogue I offer some tips, tricks and examples for doing exactly that. The article looks at accurately controlling the LED current with maximum efficiency, various fault modes and protections for the LEDs, and implementing some popular dimming methods (PWM, analog, and thermal). You can read the article here:
I would love to hear any feedback, comments, or questions. Have you done or seen something like this before? How did it turn out? What features matter most to you (and which do you think are just marketing fluff)? What are some issues remaining to be solved in this system?