Embedded Systems Conference
Breaking News
Comments
Newest First | Oldest First | Threaded View
<<   <   Page 2 / 3   >   >>
J---
User Rank
Author
re: Teardown: LED light shrinks size, cost with non-isolated driver
J---   3/4/2013 2:25:50 AM
NO RATINGS
The two picture of an old design and a new design DO NOT represent generational changes, simply different design choices. I have a driver extracted from a LED lamp (non-isolated) that is 18-24 month old that is simpler in design than either of the examples shown. It is not the greatest design in terms of efficiency, but it works ..... other than the Rudycon ... yes Rudycon capacitor. It even passed UL, though I have a hard time believing it passed any conducted emissions tests.

J---
User Rank
Author
re: Teardown: LED light shrinks size, cost with non-isolated driver
J---   3/4/2013 2:09:26 AM
NO RATINGS
Keep in mind that radiated power is a function of the temperature of what is radiated. Heat sinks are relatively cool so they do not radiate much heat and much rely on convection (and some radiation). A bulb radiates most of its energy into the environment. To dleske below, actually we are up to 30-40% in some cases for modern LEDs in terms of percentage of power that is light, though high CRI, low color temp bulbs are generally lower today. As the LED efficiency goes up, power supply requirements go down linearly, but heat sink requirements drop quicker as less and less power is generated as heat.

J---
User Rank
Author
re: Teardown: LED light shrinks size, cost with non-isolated driver
J---   3/4/2013 2:05:41 AM
NO RATINGS
The LEDs are good for 50,000 hours or more. However, bulbs have force a smaller than ideal heat sink and limited ability to isolate the power supply from the heat sink. I don't think you mean plasma emitting diodes, but plasma light sources. They are still going strong somewhat, but there are few companies working on it. As LED costs come down and efficiencies go up, their market space keeps getting smaller.

J---
User Rank
Author
re: Teardown: LED light shrinks size, cost with non-isolated driver
J---   3/4/2013 2:03:38 AM
NO RATINGS
I have evaluated several LED bulbs and have found the temperature in the power supply to vary between about 65C and 90C across a range of designs in a typical installation environment. If you are using 2000 hour 85C caps then you are going to have issues in all of those bulbs depending on how tight the required tolerance is of the power supply. On the other hand, if you have 5000 hours 105C capacitors, most of the designs will see lifetimes that match the product claims.

l8mackey11
User Rank
Author
re: Teardown: LED light shrinks size, cost with non-isolated driver
l8mackey11   3/1/2013 3:25:14 AM
NO RATINGS
I thought one of the nice attributes of the LEDs was long life (like on the order of 50,000 hours) if the heat management is designed right? Anyone hear about the Plasma Emitting Diodes. Saw an article about them awhile back but not much since then.

Dave1010101
User Rank
Author
re: Teardown: LED light shrinks size, cost with non-isolated driver
Dave1010101   3/1/2013 2:34:53 AM
NO RATINGS
I think the caps will not be that hot but eliminating them--or making them smaller--is probably a design project somewhere. I know that there was much work done in multi-phase power converters to power very high current (but low voltage) with fast voltage adjustment. Perhaps more IC integration will simplify the overall architecture and make the system more reliable and easier to manufacture.

PCB_Tom
User Rank
Author
re: Teardown: LED light shrinks size, cost with non-isolated driver
PCB_Tom   2/28/2013 9:41:05 PM
NO RATINGS
Yep, those electrolytics will almost certainly be the weak link that fails in these.

Etmax
User Rank
Author
re: Teardown: LED light shrinks size, cost with non-isolated driver
Etmax   2/27/2013 4:10:41 AM
NO RATINGS
Interesting, 2 electrolytic capacitors. From memory the life span at 100degC is 2000 to 5000 hours for the good ones. I think this needs to be re-thought.

DrQuine
User Rank
Author
re: Teardown: LED light shrinks size, cost with non-isolated driver
DrQuine   2/27/2013 3:11:26 AM
NO RATINGS
This bulb having the same form factor as a traditional light bulb is a great benefit. I do hope that they prove as reliable as promised. While the LEDs may have a long life, most of the package is other components. I know that I've returned at least 10% of my 7 year guaranteed compact fluorescent lamps (CFLs) because of failures within 2 years. The CFLs also suffered from slow start-up (anything over "60 watt" replacement could take a minute or more to become bright despite their packaging claims to the contrary). Dimmers and remote controlled outlets, of course, were non-starters.

anne-francoise.pele
User Rank
Author
re: Teardown: LED light shrinks size, cost with non-isolated driver
anne-francoise.pele   2/26/2013 2:39:45 PM
NO RATINGS
FYI, this has been fixed... Thanks for your interest. Anne-Francoise Pelé

<<   <   Page 2 / 3   >   >>


Radio
NEXT UPCOMING BROADCAST
In conjunction with unveiling of EE Times’ Silicon 60 list, journalist & Silicon 60 researcher Peter Clarke hosts a conversation on startups in the electronics industry. One of Silicon Valley's great contributions to the world has been the demonstration of how the application of entrepreneurship and venture capital to electronics and semiconductor hardware can create wealth with developments in semiconductors, displays, design automation, MEMS and across the breadth of hardware developments. But in recent years concerns have been raised that traditional venture capital has turned its back on hardware-related startups in favor of software and Internet applications and services. Panelists from incubators join Peter Clarke in debate.
Flash Poll
Top Comments of the Week
Like Us on Facebook

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
Special Video Section
The LTC®4015 is a complete synchronous buck controller/ ...
10:35
The LT®3042 is a high performance low dropout linear ...
Chwan-Jye Foo (C.J Foo), product marketing manager for ...
The LT®3752/LT3752-1 are current mode PWM controllers ...
LED lighting is an important feature in today’s and future ...
Active balancing of series connected battery stacks exists ...
After a four-year absence, Infineon returns to Mobile World ...
A laptop’s 65-watt adapter can be made 6 times smaller and ...
An industry network should have device and data security at ...
The LTC2975 is a four-channel PMBus Power System Manager ...
In this video, a new high speed CMOS output comparator ...
The LT8640 is a 42V, 5A synchronous step-down regulator ...
The LTC2000 high-speed DAC has low noise and excellent ...
How do you protect the load and ensure output continues to ...
General-purpose DACs have applications in instrumentation, ...
Linear Technology demonstrates its latest measurement ...
10:29
Demos from Maxim Integrated at Electronica 2014 show ...
Bosch CEO Stefan Finkbeiner shows off latest combo and ...
STMicroelectronics demoed this simple gesture control ...
Keysight shows you what signals lurk in real-time at 510MHz ...