the legacy system of AC and sockets has a huge inertia, so , for a long time the power conditioning will be coupled intimately to the illuminator. so far the led bulbs i've deconstructed can be repaired to the component level. as a lover of electricity this makes sense. too costly to run a business repairing them. lots of fun sub-assy's in some of them that you can redeploy.
Since "noisy" electronics is within these lamp packages, there would be certain EMC norms/standards to be met. What are EMC certification standards applied to LED lamps? I believe, this is applicable to the CFL lamps as well. I see the major LED lamps available in the market have CE marks. Though this is one time cost for each version, this is a very costly affair. The cost burden would go away with high volume. But it is a concern for the cheaper LED lamps available in the market...are those really compliant to EMC norms?
The manufacturers are probably not counting on the bulbs meeting the specified life but rather replacing them in the future with cheaper to manufacture products. Or just counting on consumers to not follow up with early failure replacements, as we were trained to accept with CFL bulbs which failed to live up to the marketing claims.
I have two remarks:
1. 105*C capacitors are commonly used in PC power supplies and PC mainboards. They still die in much lower temperature than 105*C.
2. 105*C capacitors are more expensive than typical one (like 85*C). I don't think if typical LED bulb goes higher than 80*C, so why someone should use 105*C capacitors?
I guess problem is not in high temperature but capacitor quality.
If you develop a PFC LED driver, you can use the deramic cap instead of the E-Cap. The E-cap life time shrinks one half for every ten degree ambient temperature. We have been designed the ACDC offline LED drivers for the LED lighting and to reduce the BOM cost. If you are interested in the products, please check out the web site.
We design our products in the 700V process, so the 500V HV NMOS and the 700V Power MOSFET can be integrated.
Please send email to Phil.Lei@sqme.com.tw to find out more.
I just picked up your query about my design. Yes it is still an application but has no objection raised as yet. It applies to UK, Europe and USA. If you can tell me a little more about what you'd like to know I'd be happy to help. email@example.com
A concern that I don't see addressed is vibration. I have had a CFL blowout in a ceiling fan installation. I haven't seen vibration ratings for CFLs. I These board designs with the air-chassis electrolytics don't look to have reliability in a vibration environment such as a ceiling fan fixture.
A Book For All Reasons Bernard Cole1 Comment Robert Oshana's recent book "Software Engineering for Embedded Systems (Newnes/Elsevier)," written and edited with Mark Kraeling, is a 'book for all reasons.' At almost 1,200 pages, it ...