Ultrasound V2 specs? (Re next gen LED's)

[TroyO]

I'm mostly curious about the actual output for the LED, and how it's regulated. I tried a search, and I may just not be using the correct terms but I haven't been able to find the info.

Is it limited by the setting entirely or could it work with other LED's? I guess the question is whether total wattage is limited, or just the amperage.

If the below guesstimates are around correct, but the Voltage is allowed to go up to 12V -some overhead... (I would guess under .5V since that's the overhead on a K... requires 6.84V and needs 7.2V source.... ) then it would seem that using the 1.5A "Luxeon K" setting you *could* drive a LedEngin 10W LED with it.

Luxeon 3 (Around 1A?)
Luxeon 3 red (Around 1.4A?)
Luxeon 5 (Around .7A?)
Luxeon K (Around 1.5A?)
Luxeon 3 overdrive (Around 1.2A?)

Since you can get to all dice seperatley on the LedEngin LEDS, you can wire them as two series pairs... then paralell the series pairs to power all 4 LED's at once. Your voltage requirement gets divided in half that way, but your current requirement doubles. So a LED that would require 10V @750 MA would now need 5V @ 1500 MA to get the same output.

Soooo..... wired that way, using the K setting on an UltraSound V2:

Using LedEngin Max Forward Voltage Bins...
LedEngin 10W Red 6.4V @ 1500 MA (750 MA Per LED) +.5V=6.9V (6 Cells. Nimh 7.2V)
LedEngin 10W Green 8.8V @ 1500 MA (750 MA Per LED) +.5V=9.3V (8 Cells. Nimh 9.6V)
LedEngin 10W Blue 8.3V @ 1500 MA (750 MA Per LED) +.5V=8.8V (8 Cells. Nimh 9.6V)

That would be the "Worst case" scenario based off of the highest Forward Voltage bins that LedEngin has.

That gives you the following wattage and lumen ratings (Based on the assumption that the higher voltage Bins are also the highest lumen Bins, but not counting that extra 50 MA from 1.5 \ 2 =750 MA instead of the 700 MA that they are rated at):

LedEngin 10W Red 6.4V @1500 MA (750 MA Per LED)=9.6W ~445 Lumens
LedEngin 10W Green 8.8V @ 1500 MA (750 MA Per LED)=13.2W ~695 Lumens
LedEngin 10W Blue 8.3V @1500 MA (750 MA Per LED)=12.45W ~182 Lumens

Not bad! Of course, standard voltage bins would knock ~15% off of the Fwd Voltage requirements, but would also drop wattage and lumens by a similar amount.

Overall.... this may be the card to get for running the next gen of LED's! (A 2A "Maximum drive" setting would have been a little better, though. ;-P)

Bleh.... I may have to do a new saber, in blue this time. Hehehe.... so addictive.

[xwingband]

You are correct. The wattage is not limited there is no voltage lock on the settings. If you think about it that would be stupid... LEDs vary. I've gotten V's as low as 6V for 1A of current. Now if the board tried to send 6.8V and 700mA it'd be all screwed up.

People have a serious lack of understanding on that amps matter more than the voltage for LEDs because the volts follow the current. Then don't even get me into the watts stuff that flys around (If I had a forum I'd ban anyone that refers to an LED by watts as a form of natural selection).

[Novastar]

lol X! :) I agree there on natural selection...

And Troyo, you know I think the reason 2A+ is tough for little boards like these is simply: heat.

It doesn't seem like boards "could not" spit out a ton of amps... it's just that the heat would kill 'em! So... I imagine SOMEday... we'll start seeing (of all thing) heatsinked boards! :)

But until then... I don't really know about 2A.

It's sad too--considering the P7 which wants... what is it... 2.7A? or something...

[TroyO]

I'm not sure why heat would be such an issue.... it shouldn't (I would think) be the board sinking heat anyway.

The batteries that generate (Or release) the power, sure. The LED that uses the power, sure. Why does the unit which only passes the power through it have to generate big heat?(Especially using PWM and not resistive modulation.. )

As I understand PWM, it's basically flicking a switch on and off really fast. There's sure to be SOME heat involved in that but not much. I don't think it would have to actually sink that current in any way because it shuts the current off and on, it doesn't sink it to ground or add resistance to it's flow. Or rather, the resistance is either infinite or negligable... neither of which would generate heat.

(In a perfect world, anyway.......) Negligible resistance would mean negligible power dissapation and negligible heat, and infinite resistance would mean no power flow and no heat. Either state.... off or on wouldn't be sinking any power into heat.

It does have to be able to PASS that much current.... much like you wouldn't want to use a thin wire.. Ahhh well, now I'm rambling, LOL.

I refer to the LedEngin LED's as 10W... mostly because that's the way the manufacturer refers to them. I know it's not accurate... but it's easy, LOL.

As noted, even using the min spec 700 MA they are either at or above (In one case 32% above!) 10 Watts. At full juice it would be 17.6 Watts for a greenie.... now THAT's getting a little hot, LOL!

Anyway... right now these seems like a good buy to me! Not as configurable as CF, but readily available (we hope) and sound good even with just a default setting.

[xwingband]

Well, heat doesn't even equate to wattage either OR the light output! A Rebel is as good if not better, but when you go by watt per lumen (an efficiency rating) there's a huge difference.

For heat of the board, PWM does help but the whole converting extra voltage to current thing isn't perfect. Say it's 90% efficient (don't quote me but I believe that is the actual number) that means 10% is lost as heat. So for a LED running 10W, that 10W is the 90% and the board is absorbing the rest (about 1W).

The same goes for LEDs! The reason they make heat is because the conversion of the energy to light (visible that is) isn't perfect. So you could make a very bright light by putting a lot of inefficient diodes together (READ: Lux V, which is four Lux I's in one) but it generates a lot of heat. Example: I's, III's, K2's and Rebels are aren't that different. You can run 1A through a I and treat it like a III, but the reason they rate it at 350 mA is because the inefficiencies get magnified at that level and the heat is unreasonable. Using the same thinking I did for boards an I would be like 70% effiecient and a III 80%. (Just numbers, not actual reflection)

[DACOTA]

So it really doesnt make sense to even choose a l.e.d completely based off of lumens, because lumen means luminous flux not luminous intensity or brightness.Correct?

[TroyO]

(From Wikipedia)
In photometry, luminous flux or luminous power is the measure of the perceived power of light. It differs from radiant flux, the measure of the total power of light emitted, in that luminous flux is adjusted to reflect the varying sensitivity of the human eye to different wavelengths of light.
__________________________________________________ __________________________

It would still seem to be a valuable tool..... a unified measurement that can be used to figure out the "Bang for the watt" from that various LED's we use. You might not use total lumens as the only gauge, but combine it with the rest of the info to find the best fit for your application.

I wonder about how well Lumens is at compensating for the percieved light, tho.... it seems to me that blue looks a lot hotter than it's lumen output would suggest.

*Le-Sigh* with electronics I understand just enough theory to not understand why what I think should work doesn't, LOL.

[Ari-Jaq Xulden]

okay so in laymen terms does this mean this board will or will not run three lux 3s as in acerockets tri-lux setup?

[xwingband]

okay so in laymen terms does this mean this board will or will not run three lux 3s as in acerockets tri-lux setup?

Not to the full extent. Corbin's newer board can though as can buckpucks.

For what Troy quoted, a lumen is based on 525nm light (yellow green) so it does compensate for perceived light... to an extent. Again, as I've stated before in a linear way our eyes may see 525nm 3x better than a blue color, BUT brightness is perceived in logs. So that gain is a bit diminished even when you have two identical lumen LEDs next to each other.

[Goodman]

**UPDATE**

I just ordered two LedEngin 10W (red and green) from Mouser. As soon as they arrive, I'll hook them up to my two remaining USv2 boards and see what happens so we can answer this question for good. Two dies in series, paralleled together, K setting.

Troy, you used TCSS's 10 degree lens, right? Which lens holder did you use?


If anyone else has any suggestions/requests/tips before I begin, now's the time to chime...

[TroyO]

I used the K2 optic holder...

http://www.thecustomsabershop.com/Luxeon-K2-Lens-Holder-P8.aspx

It still took some fine tuning with a needle file, but mostly just to clear the solder lumps. ;-P

[Agash]

I have already hooked up a ledengin 10W red ina 2x2 Setting to a US2.0 in December.
It is functioning without any problem. I am running the K Setting. I just got 5,7 Volts running into it at 750mA per set of dies.
I use it with a ultrasabers stuntblade. I was using a 6 degree lense.
But then I finished my CF saber ... I have done a Ledengin red 10 Watt 2 dies in series setup. One set at 1000mA on the CF and one set on a 1000mA LED driver for clashes. For this one I used a carclo fiberopticslense and a medium ultrablade. I just use 2 dies for normal operation, but that cf saber is beating the crab out of my US2.0 saber ... its awesome bright.

I have now ordered a second fibreoptics lense to check if that is the best lense solution. I will report if my US2.0 saber gain brightness.

Edit: I forgot I am using lux3 lenseholders with the insert cut out. So just the 4 pins are left on the downside.

One note. I would never try to run 4 dies of a 10 watt in a saber at max capacity. Even with 4 dies at 750 mA you will after 15 min constant on notice that the area around the bladeholder is going to be a bit more than hand hot.

With my CF I could just with desolder and resolder one cable make all 4 dies run at 1000mA but then I think fighting will not be possible anymore.

In any case you will need enough air around the heatsink and also dont forget the LED drivers heat also the LED heats. That means with such LEDs you always have to think about air management.

[Eandori]

Just to make sure we are all "on the level" when referring to voltage/current/watts etc.

The reason small electronic boards cannot do 2 amps very well is not based on HEAT, it's because the more current that flows the thicker wire you need to use. A 5-millimeter wide trace will not handle 2000mA of current. If you want to see this effect, just take a close look at fuses. Notice the very thin wire in a fuse? That's because as the current gets higher the wire gets hotter until it literally vaporizes. As you get higher amp fuses, the wire gets thicker.

Typical electronic components may handle a certain WATTAGE but the wires, solder joints, and internal silicon traces are not fat enough to handle high current. Thus... hitting 2A with small electronic boards made with typical components does not work.

Now... let's talk about watts.

Watts is the PRODUCT of voltage and current. As in, you need BOTH voltage and current to get a high watt value. Quite literally, you multiply voltage and current to get watts. Anything multiplied by 0 is zero. So a million amps at 0 volts is 0 watts. (ex.. that's a wire...) A million volts at 0 amps is 0 watts (a disconnected battery...)

ONLY when you get both voltage and current, you get wattage. (a battery that is now sourcing current)

If you are following and you now understand that, here's the final key. HEAT is generated by WATT dissipation on components. If there is 5 watts of power across a device... it will get hot. If there's 0 watts of power across a device, it will stay perfectly cool.

Some of you might now say "why does a thin wire heat up and vaporize then? It's just current right?"

Wrong.

A thin wire heats up because as current increases, resistance in electrical conductors also increases. As the resistance increases you suddenly get a voltage drop across that WIRE. Now that you have a voltage drop, and you have current... you now are dissipating watts of power in the form of heat. And heat... vaporizes the wire.

The thinner the wire, the faster it's resistance raises as current is applied.

Hopefully that made sense and now we are all experts on voltage/current/watts :)

Cheers,

[Novastar]

Thanks for that info, Edwin! That explains it REALLY well (at least--I think I understand). I'd love to see that cut & pasted into some informational section here on TCSS--maybe also under "new technology" in some way.

One question with that (although not trying to de-rail the USv2.1 specs too far)... with the Seoul P7 handling/"wanting" ~3A... how in the world does it handle this when we all know that there are SUPER tiny traces/wires/whatever you want to call them... that lead into the LED dies under the dome? I mean, I'd understand if it was "spreading" that current over each die... but... no, it looks like the specs say that you can feed it ~3A to get the maximum results. How the HECK can it handle that?!??!?!? :confused:

[Eandori]

My understanding of the Luxeon V series of LED's (if somebody knows otherwise please correct me here...) is that they are built with 4 dyes on one LED. 2 of those Dyes are in series, and those (sets of 2) are in parallel.

So 1A of current comes in, splits into two lines of 0.5A of current, and each of those 0.5A lines runs through 2x LED dye's in series before going into ground etc. That's why the Luxeon V series is twice the voltage and about the same current. This also means you literally can run a Luxeon V series at higher currents without damaging the dye.

==== Novastar, now about your specific question... the Seoul P7's =====
Go to this website (http://www.seoulsemicon.com/en/product/prd/zpowerLEDp7.asp), click to open the spec datasheet and look at page 3. You'll see that inside the actual P7 package all 4 Dyes are wired in parallel. Which is why as your current goes up to 3A, you maintain the normal voltage around 3.5v.

3A comes in, splits into 4 lines of 750mA and goes through each actual LED at 750mA and 3.5v

So in short, there is no small thin wire inside the P7 running at 3A. They are all running at 750mA max which is "normal" for Luxeon style LED's.