# NEW Quad Die SSC P7! Any Info?



## lukestephens777 (Feb 3, 2008)

Any one have any news or information about the new SSC 4 Die P7 LED? Seems surefire are using this new LED in their upcoming U2B Invictus. https://www.candlepowerforums.com/threads/188408

Where can we find some more information?? 400 Lumens from a Led Flashlight will just be awesome!!


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## Kiessling (Feb 3, 2008)

We can hope that this time, the LED will be made to last, contrary to the LuxV of old ... 

Exciting news indeed. The question is ... how difficult will it be to focus, will it work with the photon management systems we have at our disposal ... and how hard can it be driven? 

bernie


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## Nitroz (Feb 3, 2008)

The race is on! I can't wait to get ahold of one of these. 

I had built a 4D mag quite some time ago for my father-in-law with a Lux V. He works for the water department and uses a flashlight alot. Well, on this one night he left it at a house, when he went back for the light the person said that they had not seen it.  Yeah, right.

This would be the perfect replacement for the old Lux V. He really loved the huge intense flood that the lux V produced. I have since built a Seoul p4 for him, but he still misses the old light.


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## lukestephens777 (Feb 3, 2008)

I'm curious as to the efficiency of the P7.... Will it just be 4 x SSC P4 dies thrown together in a single package? If so, this will probably lower efficiency etc...

Still if it has a long lumen maintenance, it should be interesting to see what manufacturers can do with this led, in terms of reflectors, battery choice etc...

Interesting times for sure!! Does anyone know where any spec can be found? Had a quick look at the Seoul website, but couldn't uncover much...


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## 3rd_shift (Feb 3, 2008)

+1


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## Nitroz (Feb 3, 2008)

lukestephens777 said:


> I'm curious as to the efficiency of the P7.... Will it just be 4 x SSC P4 dies thrown together in a single package? If so, this will probably lower efficiency etc...
> 
> Still if it has a long lumen maintenance, it should be interesting to see what manufacturers can do with this led, in terms of reflectors, battery choice etc...
> 
> Interesting times for sure!! Does anyone know where any spec can be found? Had a quick look at the Seoul website, but couldn't uncover much...



I've looked around quite a bit since reading the shot show news and found nothing. This is what I came up with so far, and I am sure this is not it.http://techon.nikkeibp.co.jp/english/NEWS_EN/20070921/139483/


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## Jay T (Feb 3, 2008)

here are the only specs I could find.



> *21.01.2008 - P7 - New LED of Seoul Semiconductor W724C0 (Z-POWER LED Series)*
> _November 2007 - Seoul Semiconductor CO., LTD put on the market new LED with super high Flux up to 670 Lumens! New LED of Seoul Semiconductor W724C0 (Z-POWER LED Series) emits 385 lm at current 1.4A and forward voltage 3.45 V._Correlated Color Temperature of this LED is 6300 K (pure white), view angle is 110 deg. The luminous flux can be increased up to 670 lm at current 2.8A and forward voltage 4 V.
> Z-Power series is designed for high current operation and high flux output applications. Z-Power LED's thermal management perform exceeds other power LED solutions. It incorporates state of the art SMD design and thermal emission material.
> Z Power LED is ideal light sources for general illumination applications, Automotive interior / exterior lighting, Automotive signal lighting, Automotive forward lighting, General Torch, Architectural lighting, LCD TV / Monitor Backlight, Projector light source, Traffic signals, Task lighting, Decorative / Pathway lighting, Remote / Solar powered lighting, Household appliances.
> The detail information about Z-POWER LED and Technical Datasheet for W724C0 can be obtained at website of company www.zled.com


from http://www.elecom.kiev.ua/full_news_ind.php#77


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## Nitroz (Feb 3, 2008)

Nice find! Now we just need some pictures, and a place to buy them.


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## lukestephens777 (Feb 3, 2008)

I Found this!! Here : http://seoulsemicon.co.kr/_homepage/home_eng/asp/news_content.asp?news_idx=43

_*SEOUL, KOREA (September 19, 2007) - Seoul Semiconductor (KOSDAQ; 046890), the eighth-largest LED manufacturer in the world, announced today that its R&D team has achieved the industry’s highest brightness single LED at 400 lumens. Seoul Semiconductor’s high performance LED is significantly brighter than conventional single LED which can only emit up to 100 lumens. Seoul Semiconductor’s high performance LED is the next-generation lighting source and is expected to accelerate the conversion of conventional lighting to LEDs. Seoul Semiconductor’s new high-performance single LEDs [pictured on the left] delivers higher brightness of 420 lm compared to conventional LEDs of comparable sizes like the Z-power P4 LED series [pictured on the right] which delivers only 100 lm. 

The higher brightness and successful miniaturization of Seoul Semiconductor’s latest LED technology translates to substantial cost savings for customers. Seoul Semiconductor’s single package product emitting up to 420 lumens at 600 mA at maximum and 350 lumens at average, is the world highest brightness among conventional LEDs at the level of 8 watt. The size is ultra slim, similar to that of a single LED package emitting 100 lumens. In addition, the brightness of Seoul Semiconductor’s new product at 420 lumens is comparable to that of more than four conventional LEDs. The new LED technology’s ultra-compact size coupled with the higher performance at 420 lumens gives engineers greater design flexibility and substantially lowers the cost of the application. By contrast conventional LED severely limits the design options available to engineers as more units are required to attain the same level performance.

“The competition in the LED industry is heating up as customers increasingly demand brighter and smaller products,” said Yanghee Han, vice president of sales and marketing at Seoul Semiconductor. “Seoul Semiconductor’s high performance LED technology at 420 lumens enables the company to not only satisfy the high expectations of the marketplace but it also opens up a new market where conventional LEDs are excluded due to its inherent performance limitations.” 

Seoul Semiconductor has been able to concurrently achieve technology capable of delivering higher performance at a more compact architecture. This milestone is a result of Seoul Semiconductor’s consistent investment in research and development, and focus and commitment to position itself as a world leading LED manufacturer. Seoul Semiconductor is already the leading LED manufacturer in South Korea.

Seoul Semiconductor’s high performance LED can be used for universal applications such as general residential lighting, automotive headlights, architectural lighting, headlight for task, streetlight, torch lighting, camping lighting, and signage lighting. 

The higher performance, compact architecture and cost advantages afforded by Seoul Semiconductor’s new LED technology will enable the company to penetrate markets that are inaccessible and beyond the reach of conventional LEDs. This suggests that the application area for the technology is unlimited. Seoul Semiconductor is planning to commercialize this new product by the fourth quarter, 2007.*_

Sounds pretty Cool to me....


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## W-c.Scenario (Feb 3, 2008)

heres the datasheet


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## greenLED (Feb 3, 2008)

What was that about SF not being at the forefront of flashlight technologies?


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## monkeyboy (Feb 3, 2008)

lukestephens777 said:


> I Found this!! Here : http://seoulsemicon.co.kr/_homepage/home_eng/asp/news_content.asp?news_idx=43


 
That's a different product which was announced a while ago, max output 420lm 4x1 die configuration.

The link that W-c.Scenario has posted appears to be the new ssc p7. Max output 670lm, 2x2 die configuration with 4 dice in parallel. max current 2800mA (700mA per die)


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## 270winchester (Feb 3, 2008)

greenLED said:


> What was that about SF not being at the forefront of flashlight technologies?



the budget light junkies are too busy asking the lowest price on Q5 light with 16 modes to notice this thread.


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## Manzerick (Feb 3, 2008)

wow!! How nice will it be to start mods with this?

I have a 7 X SSC torch that would BLAZE with these!!!


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## PhantomPhoton (Feb 4, 2008)

Well my initial thought is that if the emitter package being 4x parallel it is a good thing. It makes it easier to run one off of a single LiIon cell; buck circuits are more efficient; newer LiIon chemistries like LiFe PO4 can easily handle a 3A current draw.
I like this better than the 2S/2P of the Luxeon V.
Anyone else have thoughts or insight on such things?

Hmm after looking at the VF graph running off of a single LiIon with a buck doesn't seem like it's gonna happen. 4.0V @ 2800mA


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## jtr1962 (Feb 4, 2008)

PhantomPhoton said:


> Well my initial thought is that if the emitter package being 4x parallel it is a good thing. It makes it easier to run one off of a single LiIon cell; buck circuits are more efficient; newer LiIon chemistries like LiFe PO4 can easily handle a 3A current draw.
> I like this better than the 2S/2P of the Luxeon V.
> 
> Anyone else have thoughts or insight on such things?


IMHO this is the worst design decision they could make, unless they found some way of matching dies, or unless they're just using one larger die instead of four smaller ones. The datasheet doesn't give a clue either way. Two or more dies should always be in series. The 2S/2P arrangement is why the Luxeon V had a short lifetime. One die was bound to get more current than the other, and degrade faster. It should have been 4S from day one. In many cases the Luxeon V required a boost driver anyway, so it wouldn't have made any difference whether it was 2S/2P or 4S.


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## Canuke (Feb 4, 2008)

jtr1962 said:


> The 2S/2P arrangement is why the Luxeon V had a short lifetime. One die was bound to get more current than the other, and degrade faster.



I thought the Lux V lifetime issue was a function of phosphor degradation, not die degradation, in white ones?

The data sheet for color Lux V's gives the usual "up to 100K hours" claim.


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## jtr1962 (Feb 4, 2008)

Canuke said:


> I thought the Lux V lifetime issue was a function of phosphor degradation, not die degradation, in white ones?


It may have been, but I suspect the reason for the degradation was excessive heat buildup precisely because the dies were in parallel. One might have a slightly lower Vf, carry most of the current, and start degrading the phosphor layer. It's generally considered very bad electrical engineering practice to parallel diodes or MOSFETs or any other similar component without circuitry to ensure that one device doesn't hog the current.


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## monkeyboy (Feb 4, 2008)

The manufacturing process produces large differences in Vf between LED dies. Some of the modders on CPF have found that direct driving parallel emitters, even ones from the same reel, can result in as much as twice the difference in drive current between emitters.

Of course the dies in the SSC p7 will have to be Vf matched. If not, the LEDs would burn out very quickly. These companies employ some of the world's top scientists in the field, they know what they're doing.


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## Amonra (Feb 4, 2008)

so where do i buy some ?


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## precisionworks (Feb 4, 2008)

> the budget light junkies are too busy asking the lowest price on Q5 light with 16 modes to notice this thread.


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## betalight (Feb 4, 2008)

Here is a German Flashaholic site talking about the SSC P7:
http://www.messerforum.net/showthread.php?t=52660

And the google translation:
http://tinyurl.com/yr3vmn


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## LukeA (Feb 4, 2008)

So when/where can we get these? I've got a 3D mag that's now waiting for one of these.


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## AndyTiedye (Feb 4, 2008)




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## WadeF (Feb 4, 2008)

270winchester said:


> the budget light junkies are too busy asking the lowest price on Q5 light with 16 modes to notice this thread.


 
SF doesn't plan to have the SSC P7 U2 available until the end of '08 right? I wonder how many budget lights will come out with the SSC P7 long before SF releases their new U2 with it. 

I can't wait to see how the SSC P7 performs, should be nice for high lumen floody lights.


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## shroomy (Feb 4, 2008)

greenLED said:


> What was that about SF not being at the forefront of flashlight technologies?



Well, I must admit that I have argued that point before.... But I find that a 400 lumen flashlight using a brand spanking new LED is sufficient evidence to prove me wrong. 

Let's play nice Winchester.

Oh and AmonRa, This is a bit off topic but maybe you should be getting one of these. 

http://www.RaLights.com/Twisty.html



So this LED is putting out 385 lumens at 1.4A and a vf of 3.45? That's an optical efficiency of almost 80lumen/watt right? I'm not to up to date on rechargeable batts but I think they have .7 mah about (???), but I think two of those should be able to push 1.4A for about an hour (did I get my physics right?, I'm pretty new to this stuff). I think that's pretty awesome. I am still an Osram fan though.


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## L.E.D. (Feb 5, 2008)

*Sits around waiting for a multiple-P7 light from ElektroLumens...*


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## TorchBoy (Feb 5, 2008)

shroomy said:


> But I find that a 400 lumen flashlight using a brand spanking new LED is sufficient evidence to prove me wrong.


Huh. I haven't seen the LED yet, let alone the torch from SF. If it comes out at the end of the year, it won't *be* new tech by then! :wave:


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## IMSabbel (Feb 5, 2008)

270winchester said:


> the budget light junkies are too busy asking the lowest price on Q5 light with 16 modes to notice this thread.



Well, rest assured as they will most likely still use that LED in 3 years, the stereotypes will be true again soon enough 
On the other hand, how about the "Surefire only uses proven technology because their products have lives at stake" group?


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## Kiessling (Feb 5, 2008)

Gentlemen ... I think it is about time we end the SF vs XX battles and live our lives as flashaholics happily together as it once was. That said, the discussion should now shift back on topic, which is the new LED.
Thanx 
bernie


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## 3rd_shift (Feb 5, 2008)

Kiessling said:


> Gentlemen ... I think it is about time we end the SF vs XX battles and live our lives as flashaholics happily together as it once was. That said, the discussion should now shift back on topic, which is the new LED.
> Thanx
> bernie


I have to agree with this one.

More new info on the SSC P7 is what I and many others here are really after at this stage. :wow:  :rock:


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## greenstuffs (Feb 6, 2008)




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## CandlePowerForumsUser (Feb 6, 2008)

is that a photoshop greenstuffs?

Man I can't wait for this new emitter.

upgrades on the horizon for some insane outputs.


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## znomit (Feb 6, 2008)

Thats an Acriche, pic is here


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## nein166 (Feb 6, 2008)

Heres some comparisons between the P4 and P7 according to the PDFs 
It may not be and easy upgrade, should be able to take advantage of a larger reflector like Maglite.
It looks to me like Homer will love this LED... Mmmmm Donut!
Good thing SF is using a TIR optic.






Do Not Be Decieved By My Poor Photoshoping They Aren't Scaled The Same.


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## Amonra (Feb 6, 2008)

so will these work with Lux V TIR optics or reflectors ?


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## tebore (Feb 6, 2008)

Aw. The foot print seems much bigger than the old P4 or the old LuxV. There goes my dream of dropping this in an HDS.


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## orbital (Feb 6, 2008)

+

Its great to see SSC come out with a new product, 
with a focusable system and the right reflector, could be very interesting.

Must say though, just because one company says that are going to use this Seoul engine doesn't mean they are leading tech. developments. 
Its really just a plug-in. 

Any number of companies will undoubtedly be running this quad-die in a few months.


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## mds82 (Feb 6, 2008)

Cree is soon going to release their own quad die LED as well.


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## lukestephens777 (Feb 6, 2008)

I'm a little confused about the efficiency of this new 4 Die SSC...

Will it essentually be 4 x SSCP4 Dies all drawing 4 x as much power? As far as i can understand it's no more efficient just has a lot more potential for greater output in a relatively small package size... Is that right?

Interesting to hear rumours of a 4 Die Cree also will make for interesting times for all of us!!


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## Amonra (Feb 6, 2008)

that is right. basically it's 4 P4's in one package. the main problems with these is running them with a driver as most drivers cannot reach the 2.8A required for full output and focussing the light properly, it will have similar problems as the LuxV.
the Cree version of this would great if they wired the dies in series and had the same package size.


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## IMSabbel (Feb 7, 2008)

lukestephens777 said:


> I'm a little confused about the efficiency of this new 4 Die SSC...
> 
> Will it essentually be 4 x SSCP4 Dies all drawing 4 x as much power? As far as i can understand it's no more efficient just has a lot more potential for greater output in a relatively small package size... Is that right?
> 
> Interesting to hear rumours of a 4 Die Cree also will make for interesting times for all of us!!



Well, how much does one SSC P4 draw?
The answer: just as much as you give to it.

Those quad-dies will allow, for the same output, a lot higher efficiency.
Or, otoh, for the same efficiency, a lot more power.

I see them most useful for fixed lighting/automotive sector. Not so much for most small flashlights (where the emitter size might be a restricting factor).


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## easilyled (Feb 7, 2008)

Maybe the SSC P7 would be the ideal led to make a new generation
MRX. 

Someone tell "hotbeam", please.:naughty:


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## skalomax (Feb 7, 2008)

easilyled said:


> Maybe the SSC P7 would be the ideal led to make a new generation
> MRX.
> 
> Someone tell "hotbeam", please.:naughty:


 
I like the way you think.


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## milkyspit (Feb 7, 2008)

jtr1962 said:


> IMHO this is the worst design decision they could make, unless they found some way of matching dies, or unless they're just using one larger die instead of four smaller ones. The datasheet doesn't give a clue either way. Two or more dies should always be in series. The 2S/2P arrangement is why the Luxeon V had a short lifetime. One die was bound to get more current than the other, and degrade faster. It should have been 4S from day one. In many cases the Luxeon V required a boost driver anyway, so it wouldn't have made any difference whether it was 2S/2P or 4S.




Jtr, I think the Vf of the chips could be matched well enough... operative word being COULD. That doesn't necessarily mean it WILL! But IMHO there's another downside to the parallel arrangement: high current throughout the system means all those teensy resistive losses where head/body/tail thread together, and where the cells contact the springs, and through the switch contacts themselves, and going through the possibly small circuit traces leading to the LED package itself, etc., will all become magnified in significance. Not to digress, but isn't that the whole concept behind why long-distance delivery of electrical power from the power plants takes place at an extremely high VOLTAGE rather than lower voltage and higher current? :thinking:

As for LuxV, I was under the impression the main source of degradation was an excessive amount of HEAT generated in a small area... basically the thermal transfer mechanism couldn't keep up, and the LED slowly stewed itself.

In fairness, it seems relatively few LuxV have croaked since their introduction, at least based on personal experience plus what I've read on CPF... so perhaps there's hope for the P7! 

Disclaimer: I'm WAY out of my league debating this with you.


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## tebore (Feb 8, 2008)

milkyspit said:


> Jtr, I think the Vf of the chips could be matched well enough... operative word being COULD. That doesn't necessarily mean it WILL! But IMHO there's another downside to the parallel arrangement: high current throughout the system means all those teensy resistive losses where head/body/tail thread together, and where the cells contact the springs, and through the switch contacts themselves, and going through the possibly small circuit traces leading to the LED package itself, etc., will all become magnified in significance. Not to digress, but isn't that the whole concept behind why long-distance delivery of electrical power from the power plants takes place at an extremely high VOLTAGE rather than lower voltage and higher current? :thinking:
> 
> As for LuxV, I was under the impression the main source of degradation was an excessive amount of HEAT generated in a small area... basically the thermal transfer mechanism couldn't keep up, and the LED slowly stewed itself.
> 
> ...



That was the main problem with the LuxV. The secondary problem was some premature deaths caused by extreme VF difference resulting in 1 die getting extreme amounts of current and cooking that die. Tests showed that 1 die was brighter than the rest then it dimmed and just glowed. 

The LuxV used a 2P2S connection while the the P7 uses a pure P connection. Maybe the Seoul engineers know something we all don't. 

The only thing I can think of is that the Lux I dies didn't take overdriving too well pumping an amp in would degrade them quickly. The Cree dies have proven to be "tougher" P4's are rated up to 1A. Seoul has almost decreased the C/W but I don't know if those 2 points are enough.


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## jtr1962 (Feb 8, 2008)

milkyspit said:


> But IMHO there's another downside to the parallel arrangement: high current throughout the system means all those teensy resistive losses where head/body/tail thread together, and where the cells contact the springs, and through the switch contacts themselves, and going through the possibly small circuit traces leading to the LED package itself, etc., will all become magnified in significance. Not to digress, but isn't that the whole concept behind why long-distance delivery of electrical power from the power plants takes place at an extremely high VOLTAGE rather than lower voltage and higher current?


That would be probably be true regardless. Based on the 2.8A spec, each die is run at 700 mA. Consider if all the dies are in parallel and your power source is a single 18650. You would probably use a low-dropout linear regulator here. Since each die gets 700 mA you would have 2.8 amps from the cell, switch contacts, etc. Now suppose you put them in parallel. You now need to step up the voltage to perhaps 14V but with a current of only 700 mA. Factoring in a regulator efficiency of 90%, that means the cell must supply 10.9 watts. At an average cell voltage of 3.7 this is roughly 2.95 amps from the cell, practically the same as the parallel arrangement. However, this is an unusual case since the cell voltage is closely matched to the LED voltage for the parallel arrangement. Normally you'll have regulator losses of ~10% whether you have to use step-up or step-down, so the current though the battery and switches will be the same since the power supplied to the LEDs is the same.

When you win with the series arrangement is that you can potentially have a more efficient regulator. MOSFET losses are probably similar for a given MOSFET, and depend only upon the current drawn from the battery. This would be the same for any given power level of the dies, regardless of how they are hooked together. However, in a parallel arrangement you have four times the current going through the inductor. This means 16 times the I²R losses for a given inductor. Practically speaking it means that a parallel arrangement requires a beefier inductor for a given regulator efficiency. Since a series arrangement already has the inherent advantage of matching current among dies, this other reason further favors such an arrangement. Sure, parallel arrangeements can be made to work with mechanisms to spread the current evenly among dies, but life gets so much easier when you just put the dies in series.



> As for LuxV, I was under the impression the main source of degradation was an excessive amount of HEAT generated in a small area... basically the thermal transfer mechanism couldn't keep up, and the LED slowly stewed itself.


That was quite true, although I strongly believe that the reason why this occurred was as tebore described. The LuxV package was probably up to the thermal loads imposed upon it if all four dies dissipated similar amounts of power. It's just that when the thermal load became unbalanced, one die would fail. This stressed the remaining three, with the one hogging current failing next, and so forth until all four were gone. It all probably happened so fast that nobody caught this mechanism in action. Maybe this time SSC has decreased the thermal impendance enough so that even if one die hogs current it will still not get too hot. Or so we hope.


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## milkyspit (Feb 8, 2008)

jtr1962 said:


> That would be probably be true regardless. Based on the 2.8A spec, each die is run at 700 mA. Consider if all the dies are in parallel and your power source is a single 18650. You would probably use a low-dropout linear regulator here. Since each die gets 700 mA you would have 2.8 amps from the cell, switch contacts, etc. Now suppose you put them in parallel. You now need to step up the voltage to perhaps 14V but with a current of only 700 mA. Factoring in a regulator efficiency of 90%, that means the cell must supply 10.9 watts. At an average cell voltage of 3.7 this is roughly 2.95 amps from the cell, practically the same as the parallel arrangement. However, this is an unusual case since the cell voltage is closely matched to the LED voltage for the parallel arrangement. Normally you'll have regulator losses of ~10% whether you have to use step-up or step-down, so the current though the battery and switches will be the same since the power supplied to the LEDs is the same.
> 
> When you win with the series arrangement is that you can potentially have a more efficient regulator. MOSFET losses are probably similar for a given MOSFET, and depend only upon the current drawn from the battery. This would be the same for any given power level of the dies, regardless of how they are hooked together. However, in a parallel arrangement you have four times the current going through the inductor. This means 16 times the I²R losses for a given inductor. Practically speaking it means that a parallel arrangement requires a beefier inductor for a given regulator efficiency. Since a series arrangement already has the inherent advantage of matching current among dies, this other reason further favors such an arrangement. Sure, parallel arrangeements can be made to work with mechanisms to spread the current evenly among dies, but life gets so much easier when you just put the dies in series.


 

Thanks for the explanation, though it'll take another read after a good night's sleep to let it really sink in. What you say makes a lot of sense... I would add that in a series arrangement one always has the option of providing higher voltage via multiple cells, alleviating the need for high current draw at all... then with the linear regulator arrangement one gets the benefit of linear regulation with a well-matched input voltage AND the lower current draw that will occur throughout the entire light. In parallel there's no choice but to pump out lots of current at some point in the circuit, just can't be avoided at all... by definition the parallel arrangement requires it.

Also, with the smaller cells (123 primaries or RCR123, or even RCR2, for example) there's pretty horrendous voltage sag and derating of battery capacity as current draw rises... but even a stack of primaries delivering lower current could stand up to the same output power without becoming overly stressed.

Now to change gears entirely, and argue in favor of the parallel arrangement(!)... in terms of potential failure mode as you and Tebore speculate, seems to me with all chips in parallel the loss of one puts the remaining chips in less jeopardy than they would be in a 2x2 array: in pure parallel, if a single chip fails the remainder need to handle 33% more input power, which they probably can handle without too much trouble... but in a 2x2 array, a single die failing means TWO are out of action, and suddenly current through the other string doubles... that's a more substantial bump upward and a steeper efficiency loss since the remaining chips are markedly farther down the lumens per watt curve... just doesn't seem as robust.

Actually, the intriguing thing to me is the potential to UNDERDRIVE the P7 and still generate a meaningful amount of light, which could open some formats that just aren't practical right now... heck, I could see direct driving the P7 off a primary 123 cell with nice results, something that's not particularly feasible with the other high-powered emitters out there due to pretty dim output and relatively rapid dimming from there.

Wonder when/how we can get our hands on some samples to begin to play with some ideas?


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## EntropyQ3 (Feb 8, 2008)

OK, so we've seen pretty good arguments as to why parallel is a bad connection scheme.

But I can't believe that the engineers at Seoul are complete dimwits and are unaware of these issues.
So there has to be more to it.

What are the potential _advantages_ of a parallel arrangement?


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## milkyspit (Feb 8, 2008)

EntropyQ3 said:


> OK, so we've seen pretty good arguments as to why parallel is a bad connection scheme.
> 
> But I can't believe that the engineers at Seoul are complete dimwits and are unaware of these issues.
> So there has to be more to it.
> ...




Uh... here's one, from the post (#48) immediately above yours (#49)? 



milkyspit said:


> Now to change gears entirely, and argue in favor of the parallel arrangement(!)... in terms of potential failure mode as you and Tebore speculate, seems to me with all chips in parallel the loss of one puts the remaining chips in less jeopardy than they would be in a 2x2 array: in pure parallel, if a single chip fails the remainder need to handle 33% more input power, which they probably can handle without too much trouble... but in a 2x2 array, a single die failing means TWO are out of action, and suddenly current through the other string doubles... that's a more substantial bump upward and a steeper efficiency loss since the remaining chips are markedly farther down the lumens per watt curve... just doesn't seem as robust.


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## EntropyQ3 (Feb 9, 2008)

milkyspit said:


> Uh... here's one, from the post (#48) immediately above yours (#49)?


I saw it, but don't think it's much of a factor since it doesn't come into play until the die actually starts to fail.
"Fails marginally more gracefully" doesn't make a strong engineering argument. 

The question of why Seoul decided to choose a parallel arrangement has two possible answers.
1. Their engineers fail to see issues that even the rankest amateur on CPF can understand (that would be me ).
2. There is more to it, and we haven't seen the bigger picture yet.

I'm somewhat more inclined to believe number 2.


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## MarkIAlbert (Feb 11, 2008)

L.E.D. said:


> *Sits around waiting for a multiple-P7 light from ElektroLumens...*


 
My MT IV is arriving today/tomorrow. Would have been great with P7.


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## FirstDsent (Feb 12, 2008)

Manzerick said:


> wow!! How nice will it be to start mods with this?
> 
> I have a 7 X SSC torch that would BLAZE with these!!!


Dude, How would you power that? Huge Vf, and 2.8 amps?

If you build it, I will come!
Bernie


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## W-c.Scenario (Feb 12, 2008)

FirstDsent said:


> Dude, How would you power that? Huge Vf, and 2.8 amps?
> Bernie



Huge Vf?, doesn't the datasheet say 3.4V @ 1400mA = 375 lm and 4V @ 2800mA = 670 lm or have I misunderstood it?


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## Curious_character (Feb 16, 2008)

milkyspit said:


> Thanks for the explanation, though it'll take another read after a good night's sleep to let it really sink in. What you say makes a lot of sense... I would add that in a series arrangement one always has the option of providing higher voltage via multiple cells, alleviating the need for high current draw at all... then with the linear regulator arrangement one gets the benefit of linear regulation with a well-matched input voltage AND the lower current draw that will occur throughout the entire light. In parallel there's no choice but to pump out lots of current at some point in the circuit, just can't be avoided at all... by definition the parallel arrangement requires it.
> 
> Also, with the smaller cells (123 primaries or RCR123, or even RCR2, for example) there's pretty horrendous voltage sag and derating of battery capacity as current draw rises... but even a stack of primaries delivering lower current could stand up to the same output power without becoming overly stressed.
> 
> ...


All excellent points. But in my long experience with semiconductors I've almost never seen one fail as an open circuit. Typically the junction melts and you end up with essentially a blob of semiconducting metal, with a very low resistance. About the only time one opens is if the source can provide enough current through the very low resistance to cause it to completely melt, explode the package, or blow a bond wire. If LEDs tend to fail the same way, then a series string would actually be more reliable than a parallel connection.

Power transistors have been fabricated as parallel connected cells for a long, long time. They're usually really an integrated circuit, with all cells being on the same piece of silicon, rather than separate dice from different places on a wafer mounted on a substrate. This results in inherently good matching. Then some ballasting is added, which amounts to adding a tiny bit of resistance in series with each one. They remain at very close to the same temperature because of their proximity on the same chip, which helps minimize hogging. SSC is possibly using some or all these techniques.

Some time ago I speculated that what we need to look at is total light output, even invisible infrared, when thinking about efficiency. The power that's left is what needs to be dissipated. I noticed that the Seoul announcement said something about the radiating ability of the phosphor. Perhaps it's getting rid of some of the wasted power by radiating it at IR wavelengths. If that's so, there's less heat needing to be conducted away. And that's the big accomplishment SSC has pulled off, assuming the LEDs show up and work as claimed -- getting rid of the heat, one way or another. That's really been the major factor in limiting the amount of light we can get out of an LED.

With all my Luxeon lights modded to an SSC P4, and all my Cree lights upgraded to Q5, I was beginning to get a little bored with the flashlight world. This oughta get the juices flowing again!

c_c


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## jtr1962 (Feb 16, 2008)

Curious_character said:


> Some time ago I speculated that what we need to look at is total light output, even invisible infrared, when thinking about efficiency. The power that's left is what needs to be dissipated. I noticed that the Seoul announcement said something about the radiating ability of the phosphor. Perhaps it's getting rid of some of the wasted power by radiating it at IR wavelengths. If that's so, there's less heat needing to be conducted away. And that's the big accomplishment SSC has pulled off, assuming the LEDs show up and work as claimed -- getting rid of the heat, one way or another. That's really been the major factor in limiting the amount of light we can get out of an LED.


At this point in time the overall conversion efficiency of the best LEDs at nominal current (i.e. 350 mA) is around 30%. The phosphor conversion process is something like 75% efficient, implying that the blue die is around 40%. If you assume the power input at 350 mA is around 1.15 watts, then that means around 0.7*1.15, or 0.805 watts of heat needs to be gotten rid of. Of that 0.805 watts, 0.69 watts is attributable to losses in the blue die. A mere 0.115 watts comes from the phosphor. My guess is if SSC got some of the phosphor losses to emit as IR then it had little to do with reducing the overall heat to be removed from the package. It likely had more to do with reliability. 0.115 watts of heat in the phosphor probably causes a greater temperature rise there than the 0.69 watts from the die due to the poor thermal coupling of the phosphor. Cut that heat even in half, and you improve reliability significantly. Perhaps it even helps with droop at higher currents. It's also interesting to note that this problem becomes more acute as blue emitter efficiencies increase. When blue emitters were only 10% efficient, the phosphor only had to convert about 0.115 watts of light energy, and the heat losses were on the order of 30 milliwatts. When blue emitters hit 80%, which I feel may happen in a year or two, the phosphor will be converting around 0.9 watts, with heat losses in the 230 milliwatt area (and much more at higher currents). Sooner or later this problem will have to be dealt with. More efficient phosphors help, but the Stokes shift limits conversion efficiency for the wavelengths involved to at best the low 80s.


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## 2000xlt (Feb 16, 2008)

WadeF said:


> SF doesn't plan to have the SSC P7 U2 available until the end of '08 right? I wonder how many budget lights will come out with the SSC P7 long before SF releases their new U2 with it.
> 
> I can't wait to see how the SSC P7 performs, should be nice for high lumen floody lights.



wadef I bet we will see a trip p7 from Dx


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## dse93 (Feb 26, 2008)

http://www.ledsmagazine.com/news/5/2/27

SSC P7 / 10W / 900 lumens / 90 lm/w


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## TorchBoy (Feb 26, 2008)

The comparison photo in that article strikes me as a tad misleading, taking the CFL "on" photo end-on like that.


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## milkyspit (Feb 26, 2008)

Don't get me wrong, this is good news for pretty much everyone, most of all the crazed flashaholics of the world like us!  At the same time, the article has the feel of a press release, fluffing-up the P7. The point on photo vs. CFL is a good one, plus I'm finding the 900 lumens figure a bit ambitious: if the P7 uses the same chips inside as the P4 does and each chip sees 700mA, the most ridiculously optimistic estimate of output would barely reach 800 lumens... my guess is 680 lumens would be a more realistic estimate. As for CFL, I think there are some that do better than 60 lumens/watt, but by all means correct me if not!

:thinking:

Anyone know when these will be available?


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## tebore (Feb 26, 2008)

milkyspit said:


> Don't get me wrong, this is good news for pretty much everyone, most of all the crazed flashaholics of the world like us!  At the same time, the article has the feel of a press release, fluffing-up the P7. The point on photo vs. CFL is a good one, plus I'm finding the 900 lumens figure a bit ambitious: if the P7 uses the same chips inside as the P4 does and each chip sees 700mA, the most ridiculously optimistic estimate of output would barely reach 800 lumens... my guess is 680 lumens would be a more realistic estimate. As for CFL, I think there are some that do better than 60 lumens/watt, but by all means correct me if not!
> 
> :thinking:
> 
> Anyone know when these will be available?



Perhaps they are using the later revision Cree dies and since the package is different perhaps their phospher application process is different and is even more effective when the die surface is bigger.


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## TorchBoy (Feb 26, 2008)

milkyspit said:


> As for CFL, I think there are some that do better than 60 lumens/watt, but by all means correct me if not!


I've seen Philips claiming 70 lm/W for their Tornado (or whatever they're called) but that's when new. I'm pretty sure CFLs dim a bit after a few hours of use. (But then, don't LEDs as well?  )


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## ernsanada (Feb 27, 2008)

Look at CPFMP BST, Sell SSC P7


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## Led_Blind (Mar 26, 2008)

TorchBoy said:


> I've seen Philips claiming 70 lm/W for their Tornado (or whatever they're called) but that's when new. I'm pretty sure CFLs dim a bit after a few hours of use. (But then, don't LEDs as well?  )



The proble tho is that 1/2 of the emitting surfaces point inward for CFL's so that their actual output in a fitting efficency is 50lm\w. Could be wrong


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## skcheng (Apr 3, 2008)

They're available. Kaidoman just posted them for sale on the CPF forum. I'm new to all of this, but I'm very interested in trying one of these out.


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## woodrow (Apr 22, 2008)

I try to look at cpf almost every day.... even if only on my phone. Somehow I have missed all the new SSC P7 info. I started to see light threads with P7 leds yesterday, and this thread was the result of a search of "Seoul P7" 

I just bought a $230 led light that does not have one of these new leds in it, but that might be my last led purchase for a while until I can grab a light with a P7 in it.

Its nice to see the technology continues to improve and that Q5 lights are not where (led) brightness ends in lights. I look forward to more manufactures putting lights out with this new led. Keep the reviews and information coming.... I can't wait to get one of these.


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## Edwood (Apr 22, 2008)

Would it be at all practical to run a single P7 off of two 123's in series? What kind of runtime and brightness would be the sweetspot?

We need to bug Don more to get some McRs reflectors made for the P7.


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## Supernam (Apr 22, 2008)

Hold your horses there fellas... 1) There are limited options on running the P7 at it's 2.8A specification (nothing to drive it) 2) More light, more heat. Not many hosts can handle it unless it's in a custom Mag or the like. 3) there are limited options on reflectors/optics SPECIFICALLY designed with the P7's quad die design.

The point being is that the couple of lights that the Chinese spat out are NOT designed with the aforementioned in mind. You are not missing out.

It is my opinion that the only light suitable to handle the P7 at 2.8A is a Maglite or something with similar heatsinking characteristics. Small handheld lights cannot hold and dissipate heat fast enough at that level of power. Runtimes mean nothing if it cannot run for the entire time!

In a handheld light configuration, the best option would be to run it at it's 1.4A spec good for around 400lm, which is awesome too! SF KL9 and UB2?


My overall point is that the P7 truly is an amazing LED however it's not quite as versatile and easy to work with in many ways. Manufacturers of production lights must take into account it's design characteristics. Accommodations need to be made for a P7's size, die configuration, heat output, and power consumption in order for me consider it a worthwhile purchase.


In the mean time... These P7's are great in M*g hosts!


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## easilyled (Apr 22, 2008)

Supernam said:


> Hold your horses there fellas... 1) There are limited options on running the P7 at it's 2.8A specification (nothing to drive it) 2) More light, more heat. Not many hosts can handle it unless it's in a custom Mag or the like. 3) there are limited options on reflectors/optics SPECIFICALLY designed with the P7's quad die design.
> 
> The point being is that the couple of lights that the Chinese spat out are NOT designed with the aforementioned in mind. You are not missing out.
> 
> ...



Actually the cheap Dx MTE P7 is a nice size and puts out a nice
beam (that I estimate at about 350 lumens) on high.

I realise that many superior lights will probably take its place, but
I was very pleasantly surprised. Its about the same size as
a McGizmo 27LT

Bear in mind that I have many high-end lights in my collection.


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## TigerhawkT3 (Apr 25, 2008)

So, does anyone have any news on why the P7 was designed with parallel dice? How about news on the Cree multi-die mentioned earlier in this thread?


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