CREE 60W LED lightbulb teardown: lot's of interesting engineering - Page 1
Forum section: electronics / general

author: electronupdate
author_rank: Regular Contributor
timestamp: April 27, 2013, 03:51:58 pm
content: A light bulb teardown. How excitingActually there's lots of clever engineering going on.With a sell price of $12 the engineers probably only had a BOM budget of $4-5.... with that money they needed to solve some fairly difficult thermal and reliability criteria.1st thermally conductive PCB that I have ever seen... rather than an epoxy this product has ons made out of aluminium.Video at the link:

author: ResR
author_rank: Regular Contributor
timestamp: April 27, 2013, 05:59:15 pm
content: Hmm... The heatsink looks kinda small for the rated power. Good teardown, mate.

author: IanB
author_rank: Super Contributor
timestamp: April 27, 2013, 08:06:34 pm
content: I'm partly through watching the video, but I'm slightly bemused by your surprise at the aluminum PCB? Mounting high power LEDs on thermally conductive aluminum PCBs is entirely typical and normal in the industry and has been for as long as I can remember. Nothing unusual here at all. The surprise would be if itwasn'tdone this way...

author: bilko
author_rank: Frequent Contributor
timestamp: April 27, 2013, 08:29:54 pm
content: According to the packaging, it appears to be a 9.5W LED not 60W

author: Fsck
author_rank: Super Contributor
timestamp: April 27, 2013, 08:32:50 pm
content: Quote from: bilko on April 27, 2013, 08:29:54 pmI'm guessing it's a 60W incandescent equivalent

author: bilko
author_rank: Frequent Contributor
timestamp: April 27, 2013, 08:38:58 pm
content: I'm guessing it's a 60W incandescent equivalentYes, That sounds about right.

author: Rufus
author_rank: Super Contributor
timestamp: April 27, 2013, 09:25:52 pm
content: Quote from: IanB on April 27, 2013, 08:06:34 pmI haven't seen one grooved and bent before. Pity the video didn't show it before it was flattened again.Also interesting to seen 60 LED die in series. I wonder if they have some built in fail short or anti-fuse type mechanism.Also 9.5W into 60 LEDs makes it about 50mA so they are quite low power LEDs.

author: armandas
author_rank: Frequent Contributor
timestamp: April 28, 2013, 09:57:18 am
content: Quote from: Rufus on April 27, 2013, 09:25:52 pmThis video shows the teardown. He took apart a few other bulbs in other videos too.

author: free_electron
author_rank: Super Contributor
timestamp: April 28, 2013, 02:48:32 pm
content: Cool. But.. A few corrections1) LED's dont run on voltage.. They run on current . That current produces a burden voltage.2) it ain't a common mode choke if it doesnt share a common core !

author: Corporate666
author_rank: Unknown
timestamp: April 29, 2013, 04:56:40 am
content: Cool video.I can't believe they can *retail* that light for $12-15. Retailers usually want keystone pricing, so it must be highly automated for assembly, and very low margins. $4 or $5 in parts. Amazing.I am also amazed that the inside of that bulb is running >90C! Especially when they have a significant portion of the bulb housing made of plastic!

author: electronupdate
author_rank: Regular Contributor
timestamp: April 29, 2013, 02:01:12 pm
content: Heat must be the #1 killer of these types of products. Those electronics are running so hot it's difficult to imagine that it would run for the entire warranty period of 10 years @ 6 hours per day (21,900 hours). On one of the capacitors, alone, gets dereated to a much lower number of hours. The cree bulb is probably not unique in this regard.I suspect that there is a very careful calculation made when creating a warrenty which balances the number of customers who run at the full service life of 21900 hours, who can remember when they bought the bulb (10 years is a long time....) and who can be bothered to met the warranty requirements (it has to be returned back to the manufacturer at the owners cost) .Quote from: Corporate666 on April 29, 2013, 04:56:40 am

author: staxquad
author_rank: Frequent Contributor
timestamp: April 29, 2013, 06:24:45 pm
content: Quote from: free_electron on April 28, 2013, 02:48:32 pmnitpickingYou can't have current without voltage, at a specific constant current through the led is a specific Vf, more Vf, more current

author: marshallh
author_rank: Unknown
timestamp: April 29, 2013, 10:33:10 pm
content: A couple more teardowns from EDNhttp://www.eetimes.com/design/smart-energy-design/4407465/Teardown--LED-light-shrinks-size--cost-with-non-isolated-driverhttp://www.edn.com/electronics-blogs/readerschoice/4311242/Remote-Phosphors-Philips-LED-bulb-Tear-down-Part-II

author: Corporate666
author_rank: Unknown
timestamp: April 30, 2013, 12:24:48 am
content: Quote from: electronupdate on April 29, 2013, 02:01:12 pmWhat is most surprising to me is that if they are already going to the trouble to make a metal core PCB and (from what I would guess) get custom zinc or aluminum heat sinks cast, it would seem the extra cost of having the plastic base and/or other stem cap made in the same material would be trivial, especially considering the aforementioned warranty/life issues.Is it really possible to calculate failure rates that accurately when you are at the higher end of component ratings? I guess it must be... I've tried to get information from component manufacturers about failure rates at elevated temperatures and it's difficult information to get, especially for stuff like caps. Nobody wants to make a commitment about how many of their caps will actually last at a specific temperature, or how many more will last at a few degrees less.I guess Cree is maybe big enough to lay down the law to the component manufacturers, though