S. Korean firm unveils new LED AC lighting

[PhotonBoy]

Yahoo News article

"SEOUL (AFP) - A South Korean semiconductor maker said it had pioneered an innovation that will allow energy efficient light-emitting diodes (LED) to light homes, officies and other buildings...."

'"Differently from existing LED devices, we have found how to feed AC directly into a LED without changing AC to DC through a converter," technology advisor Lee Keon-Young told AFP.'

[jtr1962]

No clue as to exactly how it works but interesting. My main concern here though is flicker. Don't any LED manufacturers remember that 60 Hz flicker is one thing that hindered (and still does despite flicker-free electronic ballasts) acceptance of fluorescent lighting? This is why I consider unfiltered rectified DC or PWM both bad ways to drive an LED. I also wonder if this new method gives an efficiency hit as opposed to using straight DC. If there are no drawbacks then fine but it never ceases to amaze me how a manufacturer will produce an inferior product that flickers for want of a $0.10 filter capacitor, or some other inexpensive part.

[Frangible]

Interesting but currently flourescent is more effecient than LED.

[udaman]

[ QUOTE ]
jtr1962 said:
No clue as to exactly how it works but interesting. My main concern here though is flicker. Don't any LED manufacturers remember that 60 Hz flicker is one thing that hindered (and still does despite flicker-free electronic ballasts) acceptance of fluorescent lighting? This is why I consider unfiltered rectified DC or PWM both bad ways to drive an LED. I also wonder if this new method gives an efficiency hit as opposed to using straight DC. If there are no drawbacks then fine but it never ceases to amaze me how a manufacturer will produce an inferior product that flickers for want of a $0.10 filter capacitor, or some other inexpensive part.

[/ QUOTE ]

Hehe, jtr; I think we'll both grow old and die while being amused/and or constantly irritated by poor choices of miniscule costs in all manufactured products.
At least we know that G-d did not skimp on the production of G_ddess S*preme JA, don't we [img]/ubbthreads/images/graemlins/crackup.gif[/img] (inside joke between jtr&me)--- all quality materials in that make up [img]/ubbthreads/images/graemlins/grin.gif[/img].

Heck I'm even annoyed by the flicker on a outdoor Sylvania/Osram Calypsite(sp?) IR coated 90w PAR38 bulb, halogen/incandescent can flicker to AC frequency too! Newer (more costly [img]/ubbthreads/images/graemlins/wink.gif[/img] ) fluorescent ballasts are being made that operate at higher frequencies, so as to not interfere with other electronics devices.

Yeah, I'm all for using $1,000 regulated DC power conditioned & regulated voltage supplies for all devices (just need a tens of thousands to set up bank of batteries run off solar panels). Also got to have a $800 high-end python diameter audio power line connector to filter out all kinds of gremlin noise in the AC line, before hooking it up to the power supply for my iPod [img]/ubbthreads/images/graemlins/grin.gif[/img]

http://www.avsforum.com/avs-vb/showt...p;pagenumber=3

"Come on, even a novice audiophile knows the sound stage and imaging is much smoother with power from an old coal fired plant versus a nuclear power plant. Nuclear generated AC power is harsh sounding!

And what about those hydro plants like Hoover Dam and Niagra Falls, I find the power from those a bit heavy on the bass.

LOL!"

[Ironman]

This article offers some clues as to how they may be doing this.

link

[gadget_lover]

OK, so they took 70 leds that are forward biased and 70 that are reverse biased and built it into one die. Is that worthy of a patent? Haven't many folks here suggested a similar design for AC driven LED strings?


Daniel

[evan9162]

Sounds like something Lamina should do...

[Adrian]

LOL, two sets of LEDs with only one set conducting on alternate cycles? Four 1N4004 diodes would double the light output at a stroke.

[VidPro]

i have done that reverse 1/2 of them trick
for a 13V AC light
i set them in banks that gave the same brightness as they would when driven DC, and it burned for Months, but fried out the things in eventuality. after a the TIME, some of the leds had yellowed and browned, around the gates.

they WERE to high powered, aparentally for an led, you should think of 110-120AC as 175 at its max.

anyways i would never do that again.

so i was thinking about THIS, do you think it would work?
have a whole string that makes up 150-170V or so of leds
run a bridge rectifyer on the ac, with a 250V Large capacitor.
kinda a 120DC light.

other than it being slightly impractical, would that function?

[PhotonWrangler]

I connected a string of 120v Foreverbright Christmas lights to a bridge rectifier and thus ran them off of 120v DC. It cured the flicker issue and they appeared subjectively to be a little bit brighter.

[VidPro]

cool, so i am not going to blow anything up if i hook a bridge of sufficient voltage and amperage properly up to 120v housey stuff.

cause i wondered WHY they didnt do that (or similar with a bit of protection) for them AC connecting, led bulb arrays, they charge out the wazoo for.
seems like 50 white leds, and a bridge rectifyer, and a cap, would be very efficient. mabey toss in a micro fuse in case of mondo spikes.