Contributed by Jefferson Chua and Rob Williamson
It is no surprise that High Voltage LED Drivers is one of the hottest topics at the APEC. In fact, a lot of people (in the average range of 300) flock to HV LED sessions in order to understand more about this technology while exhibitors, such as Fairchild, TI, Monolithic Power, NXP and many others try to showcase their HVLED portfolio. This industry is no cosy duopoly but a fiercely competitive one with dozens of billion dollar suppliers touting their latest products.
So with all these driver companies vying for sockets, why don’t I have a single LED light bulb in my home? Several speakers at the 2012 APEC conference either had a slide on the subject, or spoke to issues during their talk, so we will summarize here.
The power industry has a perception problem in the mainstream. Nobody understands it and LED is a clear example as to why:
1) “They” use terms like 50,000 hour bulb life – which is confusing a consumer isn’t going to do that math at point of sale. Moreover, it is misleading since the buyer will think that their average bedroom light, that is used about 2 hours per day, will now last their entire lifetime (when the capacitors won’t)
2) They tout fundamental changes in the national power consumption (lighting was shown during a plenary session at APEC to use 3% of the total grid so there are better places to put our environmental mindshare)
3) They cite the low efficiency of traditional lighting but if a consumer is smart enough to know where the efficiency loss goes (heat), and if they live in a cool climate, then they are probably smart enough to know that waste heat is (a relatively expensive) benefit 75% of the year.
4) They use terms like “color” to explain the light quality when compared to incandescent, they are all white. And a white that most of us aren’t really happy with anyway.
5) And finally, since we can’t do the math, the bulbs have high cost compared to a $.25 incandescent one.
Despite these challenges, it still seems more than obvious that LED lighting is the future. Proof of the strange dichotomy in the power industry that innovates like crazy and making a real difference in small increments.
The history of LED lighting drivers started innocently and simply enough – according to Matt Reynolds of TI, people used to take a buck-boost converter and convert it to an LED driver. While that may work on Gen 1 LEDs, it is not going to work on Gen 2 and 3 LEDs.
He then talked about the retro-fit dilemma of having 250 billion sockets needed to fill, and if only (I/they) could get 1% of market share. In the rest of the technology industry there is no such thing as 1% market share (to quote the movie Antitrust, technology success is binary, you are either a one or a zero), but in power technology the market is crowded yet everyone seems to be successful, and gains are measured in small increments after all.
So what innovations are going on to make a good SSL LED IC Driver? Lower cost, high (improved)-efficiency, reliability, good LED current regulation, good dimmer decode, and good system protection are among those mentioned.
One vendor solution for LED (Fairchild) - click to enlarge
LED drivers have been the weakest link in LED systems because of component failure, PCB board defect, lightning/surge failure, solder junction failure and so much more. Reynolds then talked about the possible solutions to these LED driver challenges such as the use of GaN, high-voltage LED stacks, and AC LEDs.
Having said all of this, it is no wonder why companies are showing off their chipsets and reference boards for LED lighting with new controller products from such as ON Semiconductor, NXP, Fairchild, TI, and Monolithic Power.
To finish up, here is a demo video on the dimming quality of today’s chips in the Monolithic Power booth.
After all, the mythical 1% market share in the case of LEDs, is a whole lot of sockets.
