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ed ro

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President

Ed Rodriguez was founder/CEO of Theta-J Corp(now the Clare division of IXYS Corp). In that role he developed the optical MOSFET solid state relay, now a global defacto standard in the telecommunications industry. He is a veteran of the power semiconductor, power supply and LED lighting technology industries.Early on, before becoming an entrepreneur, he was a product manager with Unitrode (now part of Texas Instruments.) Keynote speaker at 1986 MIT national conference on advanced power electronic technology, he has published dozens of feature articles in the leading technical trade magazines. He also has been noted in Forbes and Wall St Journal. He holds 22 patents with 8 pending, virtually all involving successfully commercialized products. In 2005 , he formed OptoThermal Technologies to focus on thermal management technologies related to high-power LED lighting.


ed ro

's contributions
  • 10.30.2013
  • That 60W-equivalent LED: What you don’t know, and what no one will tell you…
  • sktrMccluskey--- You have touched a hot button of much interest to me. I am quite involved in these kinds of issues. If this was a problem for you, it probably is a problem for guys doing similar jobs all over the country. This site is not the forum to have a lengthy technical discussion which bores others, but if you get a chance, please email me your contact info at etrod@comcast.net. From a selfish viewpoint I'd like to learn from your experience but at same time might be able to provide you with some interesting info. I am presently involved in a program to develop advanced "high bay" luminaires for warehouses. It is our premise that 99% of existing LED fixtures have a very high max-to-min ratio (NOT GOOD--wasteful) for footcandles in the floor. That means folks must use high powered,fairly close-spaced fixtures in order to meet, not the "average" light levels,, but rather the "MINIMUM" levels needed. So you end up with glare right under it and darker out a ways--but in tghe end, lousy, cost ineffective light distribution. The premise----. If one can take the same amount of light, steal from the high peak and send it to the sides,. you can establish the same min light levels, eliminate the glare and do it with HALF AS MANY FIXTURES---(translate "lower cost"). But I also wonder why your LED fixture cost was so high. Regards
  • 11.19.2013
  • High bay LED lighting: Specmanship is alive and well
  • Not sure if you are pulling my chain but here goes. RPI is Rensselaer Polytechnic Institute in Troy NY. It is one of top engineering schools in US but also unique in easily being the leading university in LED lighting technology, especially in its graduate school programs. They have published papers on every imaginable aspect of LED technology--from chip and phosphor physics to luminare design aesthetics and commercial product analysis-- and have a formidable R and D capability in Troy NY Now for the air cooling--don't get me started.You might want to read my other entry on this site some weeks ago on www.edn.com/electronics-blogs/led-insights/4422914/cooling-high -power-leds There is no question that air cooling ( ie active cooling) can dramatically reduce the size and weight of high power LED fixtures. But there is a real hangup among many or most mfrs about fans or other air moving devices. That wall is slowly coming down, brick by brick ,as an increasing number of "enlightened" companies embrace the advantages, I find it amusing that the Internet is gaga over the prospect of a Google-controlled, driverless car but engineers still apprehensive (due to lack of knowledge) about a rock-solid cooling technique which can reduce weight by a factor of 4-5 , size by a factor a 2, knock 25 % off cost, lower shipping cost by a factor of 4 and significantly simplify installation.
  • 11.19.2013
  • Overcome the challenges of driving parallel LED strings
  • You know the old expression: "Don't build me a clock ,just tell me what time it is". This piece on current sharing is WAY more complicated than it needs to be--and does not reflect what folks really typically are doing out there- I realize this is well intentioned effort to sell TI product, and I'm OK with that. The issue involved is mainly associated with higher power LED luminaires--over 25 watts., with strings up t about 50V (nobody wants to go higher than that because of UL SELV complications-----Cree please take note) For COB arrays, which go up to 100 Watts, the issue is "not an issue" unless your luminaire is rated over 100 watts.--Although many high power fixture people, for visual purposes, still want (or need) to use large numbers of paralleled 1-2 watt devices instead of a couple 50 or 100 watt COBs But in any event every engineer with basic analog power management savvy knows he can simply put in a really cheap TO-220 low dropout voltage regulator, operate it in a constant current mode in any string and set its max current with a resistor . By the way any imbalance up to 10-12 % is not evident to the human eye !! and even 15% is not very obvious. No matter what the approach, there will be the tiny bit of power lost in the sense R--no big deal. The lengthy description here is laudable as an intellectual exercise but sort of like chartering a bus to go from one side of Times Square to the other. Hundreds of folks are already addressing this issue in markedly simpler ways. In an increasingly price-competitive (ie nasty) LED luminaire and lamp world, there is little room for design solutions which are "neat" but won't pass the "Do-I think-my-competitor-can-figure-out-how-to-do-it-simpler/ cheaper" test