U.S. CitiesCity-Data Forum Index
Go Back   City-Data Forum > General Forums > House
 [Register]
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
View detailed profile (Advanced) or search
site with Google Custom Search

Search Forums  (Advanced)
Reply Start New Thread
 
Old 09-06-2019, 05:06 PM
 
Location: Lone Mountain Las Vegas NV
13,365 posts, read 5,115,885 times
Reputation: 5946

Advertisements

Just as the administration lifts the regulations on light bulb efficiency a new device has been developed that likely will wipe out the incandescent. Or at least those not used primarily for heating.

The device is basically a large number of LEDs on a common substrate with four diodes. The LEDs are in a serial string and basically run directly off the 120 volts with the diodes providing rectification. So basically you have the whole device built into a simple die of a nitride semiconductor. That reads dirt cheap.

Only draw back may be 120 cycle pulsing. But that will certainly be fine for industrial apps and things like street lights. And high output devices may well be very simple.
Reply With Quote Quick reply to this message

 
Old 09-06-2019, 05:40 PM
 
Location: D.C.
2,295 posts, read 1,920,569 times
Reputation: 3584
90% of that went right over my head. But the 10% I did pick up on generates the following response from me....

Sweet!
Reply With Quote Quick reply to this message
 
Old 09-06-2019, 06:10 PM
 
125 posts, read 33,196 times
Reputation: 421
Quote:
Originally Posted by lvmensch View Post
The device is basically a large number of LEDs on a common substrate with four diodes. The LEDs are in a serial string and basically run directly off the 120 volts with the diodes providing rectification. So basically you have the whole device built into a simple die of a nitride semiconductor. That reads dirt cheap.

Only draw back may be 120 cycle pulsing. But that will certainly be fine for industrial apps and things like street lights. And high output devices may well be very simple.

They've had similar setups for years; in fact, you might own one if you have LED Christmas lights.


Do you have a link to where this is something different?
Reply With Quote Quick reply to this message
 
Old 09-06-2019, 06:16 PM
 
Location: Lone Mountain Las Vegas NV
13,365 posts, read 5,115,885 times
Reputation: 5946
Quote:
Originally Posted by b-nasty View Post
They've had similar setups for years; in fact, you might own one if you have LED Christmas lights.


Do you have a link to where this is something different?
No. This is a single piece of semiconductor with two wires attached. Tie it to 115 volts and it lights up...brightly. And it should be fully dim-able by simple lowering the voltage. So basically you shove it into a bulb and you have a workable equivalent to the incandescent at lower costs and much higher efficiency.

There is an article on it in IEEE Spectrum. When I have a chance I will post it.
Reply With Quote Quick reply to this message
 
Old 09-07-2019, 05:08 AM
 
Location: Colorado Springs
4,954 posts, read 5,094,742 times
Reputation: 17714
Link: https://spectrum.ieee.org/energywise...st-of-lighting

"According to Penn State engineering professor Jian Xu, who led the research, integrating the LED’s driver system onto the gallium nitride chip could cut the cost of manufacturing LED lighting as well as the cost of maintaining that lighting. As much as 60 percent of the cost of an LED bulb comes from the driver electronics, he says. And because those silicon driver electronics are typically less robust than gallium nitride, they tend to fail before the LED itself does.

The existing driver circuits in an LED lamp perform three main functions: They convert the AC to DC (rectification), smooth out ripples in the resulting DC, and lower the voltage to a more LED-friendly level.

The on-chip driver system that Xu’s group constructed only performs the first function (rectification) while eliminating the need for the third (lowering the voltage).

The driver consists of four Schottky barrier diodes (SBDs) arranged into a bridge rectifier circuit. SBDs are diodes formed by the junction between a metal and a semiconductor. They are common in power electronics, because they have a low forward voltage drop. Gallium nitride is an especially good material with which to make them, because it has a high breakdown voltage; that prevents the flow of current in the reverse direction.

In order to get the right voltage to the LEDs, the devices are built as an array and cascaded in a chain of 22 to 40 pixels per rectifier. In that way, the total voltage drop is the 110-120 V from the wall socket, but each LED pixel sees only a few volts.

A white LED lamp using the prototype integrated chip produced a respectable 89 lumens per watt. However, because the SBD bridge outputs a rectified version of the AC input rather than a roughly constant voltage, the LED has a 120-hertz flicker, which would make it more suitable for outdoor lighting applications such as lamps for parking lots and roadways, where low maintenance cost is critical but light quality is less important.

Integrating an LED light’s driver circuits might seem like an obvious idea, but it’s been out of reach until recently. “Gallium nitride is a fairly new material system,” Xu says. “The technology has become mature only recently, that’s why integration on a single chip is a very new idea.” Previous attempts have required the use of either specialized LED structures or manufacturing processes that were too complex to scale up or were too damaging to LED efficiency."
Reply With Quote Quick reply to this message
 
Old 09-07-2019, 06:27 AM
 
Location: Somewhere in northern Alabama
18,123 posts, read 54,838,404 times
Reputation: 31115
"In order to get the right voltage to the LEDs, the devices are built as an array and cascaded in a chain of 22 to 40..."

translated: series connection of devices needing low voltage, like the old series connected Xmas thee light strings. When one unit in the series fails, the rest go dark. Inferring: the new configuration is likely to have a lifespan far shorter than current configurations in addition to the 60 hz X 2 flicker that worsens as a leg fails.

The configuration doesn't appear to me to be a game changer except as another way to make cheap annoying electronics. Make a better RC circuit on the same substrate and you might get my attention.

Eventually, some energy guru will figure out that homes need 12VDC power sockets (with fault protection) just as much as 120VAC ones. Many now have 5 volts supplied by various USB adapters, which can be used for some circuitry, but 12VDC is more flexible and powerful per amp.
Reply With Quote Quick reply to this message
 
Old 09-07-2019, 09:37 AM
 
Location: Lone Mountain Las Vegas NV
13,365 posts, read 5,115,885 times
Reputation: 5946
Quote:
Originally Posted by harry chickpea View Post
"In order to get the right voltage to the LEDs, the devices are built as an array and cascaded in a chain of 22 to 40..."

translated: series connection of devices needing low voltage, like the old series connected Xmas thee light strings. When one unit in the series fails, the rest go dark. Inferring: the new configuration is likely to have a lifespan far shorter than current configurations in addition to the 60 hz X 2 flicker that worsens as a leg fails.

The configuration doesn't appear to me to be a game changer except as another way to make cheap annoying electronics. Make a better RC circuit on the same substrate and you might get my attention.

Eventually, some energy guru will figure out that homes need 12VDC power sockets (with fault protection) just as much as 120VAC ones. Many now have 5 volts supplied by various USB adapters, which can be used for some circuitry, but 12VDC is more flexible and powerful per amp.
There is no reason to believe such devices will not go 100 of thousands of hours. The material system is more robust than silicon. I think you will find these devices close to eternal.

I would think a cap across the device would certainly lower the flicker. Have not seen enough on the device characteristics to know if it feasible.
Reply With Quote Quick reply to this message
 
Old 09-07-2019, 10:00 AM
 
12,329 posts, read 6,855,224 times
Reputation: 13295
Bottom line - it either gives me a headache or it doesn't.
Reply With Quote Quick reply to this message
 
Old 09-07-2019, 10:47 AM
 
879 posts, read 418,130 times
Reputation: 2769
The issue with all LEDs is the driver. A bad driver wastes energy, causes flicker, and is the reason many LED bulbs fail long before their expected lifetimes. This “new” direct connect concept is just a miniaturized rope light. A FWB rectifier typically uses filter capacitors to smooth the ripple current inherent in the design when AC is converted to DC. This solid state rectifier omits those capacitors and it will have varying light output (essentially a strobe) at 120 Hz.

A way to fix this is to use blue or UV LEDs that shine on a phosphor coating to re-emit the light at a color in the normal range (just like fluorescent bulbs). The phosphor has a long time lag (tenths of a second) and would smooth the pulsing light output. However this further reduces efficiency.
Reply With Quote Quick reply to this message
 
Old 09-07-2019, 12:52 PM
 
Location: VT; previously MD & NJ
2,273 posts, read 1,418,880 times
Reputation: 6657
Quote:
Only draw back may be 120 cycle pulsing.
So we finally got rid of the florescent flicker only to replace it with LED flicker?

I just want an LED bulb that doesn't go bad. I have spent way too much money replacing bad ones.
Reply With Quote Quick reply to this message
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.

Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.


Reply

Quick Reply
Message:


Over $104,000 in prizes was already given out to active posters on our forum and additional giveaways are planned!

Go Back   City-Data Forum > General Forums > House
Follow City-Data.com founder on our Forum or

All times are GMT -6.

© 2005-2019, Advameg, Inc. · Please obey Forum Rules · Terms of Use and Privacy Policy · Bug Bounty

City-Data.com - Archive 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 - Top