# AMC7135 Circuit board @ Kaidomain



## Der Wichtel (Apr 25, 2007)

Just found this:
http://kaidomain.com/WEBUI/ProductDetail.aspx?TranID=1746

The funny thing is that Kaidomain rates this with 700mA output and the manufacturer only 350mA xD

http://www.micro-bridge.com/AMC7135.asp

edit: Just noticed the board uses 2 regulators in parallel


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## sparkysko (Apr 25, 2007)

*DROOLS*
A question I have, is this just a boost/buck circuit, or a boost/buck WITH regulated output? I know they have the runtime diagram on kai, but I'm not sure if that brightness plateau is from the battery or from the regulator.


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## datiLED (Apr 25, 2007)

I just took a chance and ordered a set. The price is for five (5) boards, and ten wires!!!


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## roverjohn (Apr 25, 2007)

Did anyone see dimentions for the board?


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## Bertrik (Apr 25, 2007)

sparkysko said:


> *DROOLS*
> A question I have, is this just a boost/buck circuit, or a boost/buck WITH regulated output? I know they have the runtime diagram on kai, but I'm not sure if that brightness plateau is from the battery or from the regulator.


It's not a boost or buck circuit, but a linear regulator. As far as I can tell from the datasheet (bottom-left graph on page 3), it provides very good regulation as long as Vbattery > Vled + 0.12V.


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## Varroa (Apr 25, 2007)

I just ordered a set plus a couple of CREEs, go to try them out on the CREEs and some K2s I have kicking around.


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## moon lander (Apr 25, 2007)

can you use 2 or more of these on 1 battery? can i use 2 boards to power 2 crees all from 1 18650? i think 3 would just barely exceed the maximum current for an 18650 (2amps) but 2 is ok right?


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## jsr (Apr 25, 2007)

Whoever gets these, can you please take diameter and overall height measurements of the driver?

Could you also measure the output current to confirm if it's 700mA or 350mA?

moon_lander - the max discharge of most Li-Ion cells is 1.5C, so for a 18650, that's over 3A.


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## sPEARs (Apr 25, 2007)

Its parallel 2x 7135 to get 350ma x 2
max Vin :6V
min Vin : 2.7V
so it fits for 2 x CR123A / 1 X Li-ion

If Vin > Vf , its Regulated , however Vin < Vf , its Direct drive
u may consider as a buck circuit


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## davenlei (Apr 25, 2007)

Anyone know how efficient it is?


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## evan9162 (Apr 25, 2007)

These are linear regulators, which means that any voltage difference between the LED Vf and the input is dropped and dissipated as heat. The efficiency depends on the ratio of input voltage to output voltage.

If you ran an LED with a Vf of 3.4V from 3 Alkaline cells (4.5V), then the efficiency is 3.4/4.5 = 76%. As the battery voltage drops, the efficiency increases. The closer the input voltage to the LED voltage, the more efficient it will be.


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## mmmflashlights (Apr 25, 2007)

As Carl would say, 'this is freakin awesome'.  This will make life much easier for modding noobs that want something more sophisticated than a simple direct drive or resistor. Already looking forward to using this with a Cree and 18650.


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## Mel_PL (Apr 25, 2007)

mmmflashlights said:


> As Carl would say, 'this is freakin awesome'.  This will make life much easier for modding noobs that want something more sophisticated than a simple direct drive or resistor. Already looking forward to using this with a Cree and 18650.



IMVHO it's easy to use an external 350/700 mA switch with this driver. If the 7135s are in parallel, cut the supply path to one circiut, solder two wires to the separated sides of the path and a switch. Press (close) to get 700 mA, release (open) to drive with 350 mA.
Just an idea.

-- M.


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## Der Wichtel (Apr 25, 2007)

but since it is linear this circuit is not very effective like a real buck/boost converter


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## evan9162 (Apr 25, 2007)

It can be very efficient given the right battery/LED combination.

Drive a Cree or Seoul (Typical Vf = 3.2V @ 350mA, 3.5V @ 700mA) from 3 NiMH cells or a single Li-Ion, and you're talking about efficiencies of 85-95%. Just as good (or better in many cases) as a switcher.


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## wakibaki (Apr 25, 2007)

evan9162 said:


> It can be very efficient given the right battery/LED combination.
> 
> Drive a Cree or Seoul (Typical Vf = 3.2V @ 350mA, 3.5V @ 700mA) from 3 NiMH cells or a single Li-Ion, and you're talking about efficiencies of 85-95%. Just as good (or better in many cases) as a switcher.


 
Er, I think this is a bit optimistic. A dropout voltage of 3.2 + 0.6V is 3.8V which is higher than the nominal lithium voltage of 3.7 and 3 NiCds is 3.6V. There's quite a lot of energy left in the battery @ lower voltages than these.

Linear regs are good when driving strings of LEDs, or when working with a power supply with good long term stability. The problems involved in making efficient use of a battery to drive a single LED are non-trivial.

w


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## frenzee (Apr 25, 2007)

judging by the relative size of the SOT-89 package, the PCB's diameter should be around 19mm. Also the circuit seems to be using two 7135s in parallel, so the output, at least in theory, should put out around 700mA.


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## wakibaki (Apr 25, 2007)

7135? - I googled this and got nothing. Datasheet?

w


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## moon lander (Apr 25, 2007)

search for amc7135, its the 4th hit


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## HGUE (Apr 25, 2007)

I guess this is the page moon_lander refeers to http://www.micro-bridge.com/AMC7135.asp. It's no longer the 4th hit on google, it's up to second place. Google works in mysterious ways (especially when half the LED forum googles the same thing)


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## evan9162 (Apr 25, 2007)

wakibaki said:


> Er, I think this is a bit optimistic. A dropout voltage of 3.2 + 0.6V is 3.8V which is higher than the nominal lithium voltage of 3.7 and 3 NiCds is 3.6V. There's quite a lot of energy left in the battery @ lower voltages than these.
> 
> Linear regs are good when driving strings of LEDs, or when working with a power supply with good long term stability. The problems involved in making efficient use of a battery to drive a single LED are non-trivial.
> 
> w



You should check your facts before replying. The AMC part has a dropout of 0.12V. And yes, it is trivial to make a linear regulator with 0.1V of dropout or less.


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## wakibaki (Apr 26, 2007)

Evans9126

While I freely admit that the 0.6V figure is one that I just pulled from the air, an improvement of 0.48V in the dropout voltage doesn't nullify the general point that I am making. You should be aware that the 3.2V forward that you are quoting is only typical. Even taking your figures, from 3.32V downward all this thing does is waste power (and voltage) while failing to regulate. Linear regulators waste power by design. And the figure is 3.5V @ 700mA.

Switching regulators , on the other hand, convert power or control it's rate of delivery. They waste it inadvertently, not by design. The problems involved in designing and producing a miniature switching regulator to make efficient use of a battery to drive a single LED are non-trivial in my opinion. Otherwise you'd be able to buy one cheap. Whereas you can't get one for any price. QED.

Why not just use a lithium rechargeable, hot off the charger at 4.2V? Put a power diode in series with the LED to drop about 0.6V (it's that number again) if you're worried about blowing up the LED. 3.6V should be OK but of course you can always buy a few LEDs and diodes and measure and match them. You can put a switch across the PD for 2 power levels or when the battery goes flat. I bet this genuinely intelligent switcher outperforms your regulator in efficiency for 9 individuals out of 10. 

It's not a torch if it doesn't go flat.

w


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## lexina (Apr 30, 2007)

I admit I don't know enough to analyse the pros and cons of a linear regulator. Wakibaki prob has a point that a switching regulator would do a better job. But what I want to know is, for someone like me who is currently just using a plain resistor in a 1 C-LiIon light driving an SSC 3.5Vf led, would this board be better than my resistor? If so, I guess it's worth the $2 (average price per board). My only reservation is that, I may only be able to drive the led at 700mA instead of 1A.


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## NetKidz (Apr 30, 2007)

lexina said:


> My only reservation is that, I may only be able to drive the led at 700mA instead of 1A.


 
I think it's the same pcb:






It could be installed with 4 AMC7135. From Kai's photo, I think the bottom two are 0 ohm SMT resisters. I think you could take off one and solder one more AMC7135 and one diode to achieve 1A.


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## lexina (Apr 30, 2007)

Thanks for the suggestion, NetKidz. Unfortunately, soldering (or desoldering) any SMT components is beyond my skill level! :shakehead


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## vetkaw63 (Apr 30, 2007)

NetKidz said:


> I think it's the same pcb:
> 
> 
> 
> ...




I would be willing to buy 5 of these to cannibalize 1 if, you could tell me the exact diode that I would need and where to get it.
Thanks,
Mike


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## davenlei (Apr 30, 2007)

If we can bump it up to 1000ma I will definetly buy them and mod them.

Did anyone ever mention the dia. size of the board?


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## BobG1 (Apr 30, 2007)

Here is a link (in chinese) to setup those for 2.7 to 8 volts input.
http://my3c.com/D5/viewthread.php?tid=6594&sid=kLZvnD
And here are pics showing how the AMC 7135 is setup for 1.4 and 1.05 A
outputs:


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## Illum (Apr 30, 2007)

Der Wichtel said:


> http://kaidomain.com/WEBUI/ProductDetail.aspx?TranID=1746
> The funny thing is that Kaidomain rates this with 700mA output and the manufacturer only 350mA xD



estimate using the lower of the two might be much safer
350ma's pushing it for luxeons....as for SSCs....


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## mikeh (May 1, 2007)

Whats the point of these?
With decent heatsinking, you can put a Cree on a full 4.2V cell. It'll draw over an amp at first, but soon get down to around the same 0.7A. Then as the battery voltage drops, that 1.2V dropoff will become a problem, and you get less than 0.7A.
So the regulator gains some run-time, and looses some brightness, but basically isn't needed for running a Cree from a Li-Ion battery. Or 3 x NiMH.
However, unlike a buck/boost regulator, there is no coil to break. And if using unprotected 18650s, the built-in thermal protection is nice.
The best use for these, IMHO, would be to remove one chip, and get a constant 350mA, thereby getting much longer run, and steadier brightness than from a resistor.


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## NetKidz (May 1, 2007)

davenlei said:


> Did anyone ever mention the dia. size of the board?


 
Haven't got Kai's but one local saler here said it's 17mm.


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## TorchBoy (May 3, 2007)

BobG1 said:


> Here is a link (in chinese) to setup those for 2.7 to 8 volts input.
> http://my3c.com/D5/viewthread.php?tid=6594&sid=kLZvnD


Google translation:

http://translate.google.com/transla...&hl=en&ie=UTF-8&oe=UTF-8&prev=/language_tools


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## uk_caver (May 3, 2007)

wakibaki said:


> Even taking your figures, from 3.32V downward all this thing does is waste power (and voltage) while failing to regulate.



Still, from 3.3V downwards, both Li-Ion and 3xNiMH packs _are_ practically empty. The power wasted by the dropout voltage can be made pretty minimal, if it's considered to be important.



wakibaki said:


> Linear regulators waste power by design. [...]
> Switching regulators , on the other hand, convert power or control it's rate of delivery. They waste it inadvertently, not by design.



In one sense, that's true, but in a practical sense, I'm more bothered about what the efficiency is, not the reasoning behind why it's what it is. If it was theoretically possible to have a 99% efficient switching regulator, that doesn't make a 90% efficient one any better. If anything, it might just make it more annoying.

If someone was looking for 350mA draw, and LED Vf was ~3.2V, on 3xNiMH a decent linear regulator would only drop out at something like 90% of battery capacity used, with an average efficiency of about 3.2/3.6 = 89%, (possibly a touch lower on a lithium cell?), which is pretty much what many switching regulators seem to achieve.
At lower powers and Vfs, then although dropout becomes even more delayed and unimportant, the efficiency of linear *will* decrease relative to switching, as long as the switching circuit doesn't use PWM with a low duty cycle and high 'on' current, in which case linear drive might prove rather more efficient than switching.

Clearly, there are many battery-voltage/LED-Vf combinations where linear regulation is bad or even nonfunctional, but it's not at all bad for nominal 3.6/3.7V cells and single LEDs, as long as the required power output and hence LED Vf isn't so high as to result in undesired early dropout.


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## 2xTrinity (May 3, 2007)

uk_caver said:


> Still, from 3.3V downwards, both Li-Ion and 3xNiMH packs _are_ practically empty. The power wasted by the dropout voltage can be made pretty minimal, if it's considered to be important.
> 
> 
> 
> ...


Absolutely agreed. In the case of LiIon, a lot of people simpyl sue direct drive as it really doesn't take much voltage drop (which directly translates to efficiency loss) to keep the current under control when dealing with LiIon. In the case of the Linear Regulator, you essentailly have a "smart" direct drive resistor that lowers the resistance as the cell drops down, keeping the output constant.

Now, if one wanted to power a light off of higher voltage, like 2xCR123, then a buck circuit wuodl be more reasonable, and if someone wanted to run an LED off of a 1.2 NiMH, or do something like run three LEDs in series off of 3xNiMH or 1xLiIon with variable brightness, then a switcher makes more sense. Of course, if only fixed brightness is needed, then IMHO wiring the LEDs in paralell and using a separate linear regulator on each would probably be cheaper and just as efficient.


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## TorchBoy (May 3, 2007)

Getting back to what KaiDomain sells, are the resistors mentioned 0 ohm surface mount resistors for shorting the other two locations on the PCB where AMC7135 chips could be mounted?


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## AndyTiedye (May 3, 2007)

moon lander said:


> can you use 2 or more of these on 1 battery? can i use 2 boards to power 2 crees all from 1 18650? i think 3 would just barely exceed the maximum current for an 18650 (2amps) but 2 is ok right?



3 on an AW "C" cell wound be a good match.


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## AndyTiedye (May 3, 2007)

2xTrinity said:


> Of course, if only fixed brightness is needed, then IMHO wiring the LEDs in paralell and using a separate linear regulator on each would probably be cheaper and just as efficient.



You could easily have several levels by turning some of the LEDs off.


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## NetKidz (May 4, 2007)

Kai now has them all. 

350mA 20pcs $15 http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=1804
700mA 20pcs $19.99 http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=1803
1050mA 20pcs $27.32 http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=1805
1400mA 20pcs $33.99 http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=1806


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## lexina (May 4, 2007)

has anyone tried these? they look like a bargain and getting harder to resist! i only wish they sold them in smaller quantities (like 5!) i am tempted to use 3 of them to run 3 leds in parallel off 1 C-LiIon - just trying to figure out where I would stick them in the light.


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## Led_Blind (May 4, 2007)

Mikeh, The idea is to get regulated output that remains constant throughout the life of the battery. 
I have moded many 3d maglights for the family and have used .7A buck boost regulators in all. What the family likes is how it completly drains the bateries. 
We proved this by getting 2 old 3D mags with cells that would make the fillament glow weakly. Take those cells and dump them into the modded led version and you get another 3ish hrs of full bright light then declining for 30 mins. You then change the cell.


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## 2xTrinity (May 4, 2007)

Led_Blind said:


> Mikeh, The idea is to get regulated output that remains constant throughout the life of the battery.
> I have moded many 3d maglights for the family and have used .7A buck boost regulators in all. What the family likes is how it completly drains the bateries.
> We proved this by getting 2 old 3D mags with cells that would make the fillament glow weakly. Take those cells and dump them into the modded led version and you get another 3ish hrs of full bright light then declining for 30 mins. You then change the cell.


For lights desigend to use primary cells and extract every last mAh of capacity out of them, then a buck/boost is the best idea for sure. For a light driven on LiIon though, it's generally best not to completely discharge them -- and the time at whcih output starts to dip noticeably will most liekly coincide with the time that the cell should be switched/recharged anyway. Either way, considering these aren't much more expensive than 1- and 2-watt resistors, it's clear to say that these are a good deal for what you get. I'm just debating on which current level to buy (700mA, 1050mA)


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## TorchBoy (May 4, 2007)

lexina said:


> i only wish they sold them in smaller quantities (like 5!)


They do, for the 700mA version, at least. http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=1746

Hey, why do all four models (different currents) give the same lumens? I take it they shouldn't all have the same graph?


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## joedm (May 4, 2007)

If I get the 20x 1A set from Kai then I'll have just too many...
I wish he had these in 10x sets.

or if someone else would like to go halves? We could just split the extra cost to ship from me to you.. just a thought.


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## kanarie (May 4, 2007)

> If I get the 20x 1A set from Kai then I'll have just too many...
> I wish he had these in 10x sets.
> 
> or if someone else would like to go halves? We could just split the extra cost to ship from me to you.. just a thought.


Already asked Kai for 5x sets(like with the 700 mAh) you should do the same..


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## Nake (May 4, 2007)

joedm said:


> If I get the 20x 1A set from Kai then I'll have just too many...
> I wish he had these in 10x sets.
> 
> or if someone else would like to go halves? We could just split the extra cost to ship from me to you.. just a thought.


 
I'll go halves with you.


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## wakibaki (May 5, 2007)

2xTrinity said:


> I'm just debating on which current level to buy (700mA, 1050mA)



Just bear in mind my comments regarding Vf.

I never said these devices are no good. I just took issue with what I thought was a slightly over-enthusiastic endorsement of them. You have to be quite picky if they're going to achieve good efficiency or even work at all, and they will get beginners into problems

If you go at 700mA then your Vf will rise to ~3.5V. Plus dropout voltage you are already at the nominal voltage of 3 series NiMHs, and your 2 parallel regulators aren't doing anything. Lithium rechargeables have useful power down to 3V, NiMH 3.3V. Course you can go to 4 NiMHs, but now your efficiency's going to take a hit. Forget lithium primaries or rechargeables, you'll need 2 and the efficiency is out the window.

Of course what they have done is protect your LED from overcurrent when the battery was hot and slightly improve runtime becuz the current drain is less. How much risk was the LED really at though? If you're running NiMHs they don't stay hot that long...

These are just typical figures. YMMV. A great deal of the effort in robust electronic design goes into accounting for the variation of device parameters. The validity of beamshot information on this site is gliobly accepted when comparisons between individual samples of different makes is actually meaningless. Anyway this is another subject...

Coming at this another way, @ 350mA your Vf may be as low as 3.0V.Hot off the charger 3 NiMHs will run 4.2V. Efficiency at this point is 71% Of course it rises as the battery voltage falls to maybe 97% (guess), with an aggregate of 84%plus (the battery voltage declines non-linearly). You will, however, be able to run the battery down close to the recommended minimum for Lithium rechargeables and past the useful point for NiMHs and obtain a regulated output all the way (while the current holds up).

Unfortunately to achieve this usage requires LEDs that fall within a comparatively narrow range of Vfs. As the Vf rises, the operational efficiency actually improves, but more and more power is left in the cell hitting runtime from a different direction and the device actually functions less and less of the time and when it's not in operational range the LED is less bright than it would be if the thing wasn't there.

Looking at the binning information for White Seoul Semi Z-LED P4, for Vf I see a range of bins D thru M in 0.25V steps from 2V - 4.5V (no obvious current stated). Lux IIIs are all quoted at 700mA but there's a spread of 2.79 - 4.23V. If we are now going to select and maybe sort LEDs to obtain ones that work well with our device, I think that this has gone well beyond beginners electronics. Anyway why not just sort for ones that can tolerate your chosen battery?

A buck/boost or other off-the-shelf switching regulator, while not perfect, will more probably fulfil the requirements of the would-be constructor wishing to attempt a regulated design, or unwilling to accept a direct drive or resistor- or diode-loaded design for whatever reason. 

w


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## TorchBoy (May 5, 2007)

wakibaki said:


> Of course what they have done is protect your LED from overcurrent when the battery was hot ...


That's actually really important. It's when the battery voltage will be changing at its fastest, after all (except perhaps when the cells die). Efficiency sometimes has to take a back seat to important things like this, since it can kill LEDs - instantly or prematurely, either is bad.



wakibaki said:


> A buck/boost or other off-the-shelf switching regulator, while not perfect, will more probably fulfil the requirements of the would-be constructor wishing to attempt a regulated design, or unwilling to accept a direct drive or resistor- or diode-loaded design for whatever reason.


So who sells those at $1-2? Or are you advocating us spending quite a bit more (and for the same efficiency, from the graphs I've seen)? I still don't get your problem with them.


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## wakibaki (May 5, 2007)

What I'm saying is this.

These devices are good (very good) for 1 Watt designs with 3 NiMHs or 1 Lithium rechargeable with LEDs with Vfs of 3.0V.

Cree XLamp 7090 XR-E has a typical Vf of 3.3V and a quoted maximum Vf of 3.9V @ 350mA. They put these numbers in the datasheets for a reason. 

Most builders are looking for higher currents. Since an average LED will self regulate with these cell combinations at nominal voltages at about 700-800mA, why not just leave the regulator out and save the $1-2? Make the heatsinking good and the LED will survive a hot battery, or just avoid using a hot battery (you know you won't). 

The fact that people are talking about 1050mA just demonstrates that what people who self-build are really interested in is is brightness.

You can't get 1050mA from these cells other than briefly with an average LED without a boost regulator. You've got more chance without one or three of these in circuit.

Course you can use 4 NiMHs or maybe alkalines, but what am I, designing this torch?

w


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## 2xTrinity (May 5, 2007)

edit: disregard this


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## moon lander (May 6, 2007)

I just had a thought. i ordered the 5 pack of 700ma chips and i was bummed i cant get a few of each (i dont need 20 of each). cant i just remove half of a 700ma to make it a 350ma? then add that in parallel to a 700ma to get the 1050ma version?

Another thought: these things would be so much more useful if they could accept a higher voltage. is there a mod for that? 

I think i finally understand the point of these. it is to increase runtime by reducing current while the Vin>Vf. lets use the 1050ma chip as an example.
using 1 18650 (fully charged to 4.2v) to power 1 Cree P4 direct drive (no chip). you will start with around 1.4 amps and will quickly drain the cell down to a lower voltage. if you were to add the 1050ma chip to the same setup, it would take longer to drain the cell down to that lower voltage because it will be drawing 1050ma from the cell, not 1.4 amps (1400ma). even while the cell is pushing 4.2v, the current will be limited 1050ma and the time it takes to get the cell's voltage down will increase. so these chips dont only act as over current protection, they also increase runtime while Vin > Vf. or else im completely wrong about this whole thing, in wich case i hope someone will point that out.


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## TorchBoy (May 6, 2007)

moon lander said:


> using 1 18650 (fully charged to 4.2v) to power 1 Cree P4 direct drive (no chip). you will start with around 1.4 amps and will quickly drain the cell down to a lower voltage.


And that's OK according to wakibaki??? :huh:


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## mikeh (May 7, 2007)

TorchBoy said:


> And that's OK according to wakibaki??? :huh:


Its OK according to me. The current soon drops down to roughly the 700mA in my tests. Assuming the heat-sinking is good, the LED is fine. And the total energy spent on that excess current is only small. ie not much impact on burn time.
What else bothers you?


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## Nake (May 7, 2007)

moon lander,

If joedm splits a 20 pack with me I can send five of mine to you.


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## moon lander (May 7, 2007)

Nake said:


> moon lander,
> 
> If joedm splits a 20 pack with me I can send five of mine to you.



sounds good are you getting the 1050ma version?


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## Nake (May 7, 2007)

moon lander said:


> sounds good are you getting the 1050ma version?


 
That's what I assume joedm means when he says 1A in post #43.


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## TorchBoy (May 7, 2007)

mikeh said:


> Its OK according to me. The current soon drops down to roughly the 700mA in my tests. Assuming the heat-sinking is good, the LED is fine. And the total energy spent on that excess current is only small. ie not much impact on burn time.
> What else bothers you?


How "soon" is soon, and how long do you want to spend getting the _LED junction_ that hot anyway? Even a diamond heatsink (with ten times the thermal conductivity of aluminium) isn't going to do much for _that_ in the short term because the heat still has to get out of the LED before your heatsinking does _anything_. So what effect is that going to have on the long-term service of it?


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## uk_caver (May 7, 2007)

wakibaki said:


> Unfortunately to achieve this usage requires LEDs that fall within a comparatively narrow range of Vfs. As the Vf rises, the operational efficiency actually improves, but more and more power is left in the cell hitting runtime from a different direction and the device actually functions less and less of the time and when it's not in operational range the LED is less bright than it would be if the thing wasn't there.



The _circuit_ efficiency of a linear setup might improve with a higher Vf LED, but the overall package efficiency won't change, if comparing LEDs with the same lumens-per-milliamp rating. All a higher Vf would do is make sure more heat was produced in the LED rather than the circuitry, and accelerate the onset of dropout. Unless dropout is actually desired at some point as a warning of low battery, or the regulator can't handle the heat, lower Vf is better for dropout reasons, but not actually for efficiency reasons.


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## joedm (May 8, 2007)

Nake, I sent you a PM but Kai's site isn't working at the moment. I've already sent an email to Kai asking whether he will sell smaller lots and also asking for access to Kaidomain.

Will see what he says.


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## Nake (May 8, 2007)

joedm said:


> Nake, I sent you a PM but Kai's site isn't working at the moment. I've already sent an email to Kai asking whether he will sell smaller lots and also asking for access to Kaidomain.
> 
> Will see what he says.


 
I'm in Cleve. Ohio. Keep us informed about your email to Kai. If you have to buy 20 I'll split with you, then split my half with moon lander. These are the 1050mA ones correct?


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## mikeh (May 8, 2007)

TorchBoy said:


> How "soon" is soon, and how long do you want to spend getting the _LED junction_ that hot anyway? ... So what effect is that going to have on the long-term service of it?


It doesn't get too hot, with a decent heatsink. (ie good connection to the torch body). Cree now rate the XR-E at 1A, with 50,000 hours (70%) if junction temp is 80 degrees. How many hours do you want from a torch? I think we can afford to push the specs a bit. There is no problem avoiding the 145 degree max. allowed junction temp.
Anyway, the Cree has only 8 deg/W resistance, so 40 deg for 5W isn't a huge problem. So long as the star isn't too hot to touch, you are fine.


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## RV7 (May 8, 2007)

wow, this thread is still going on!

moon lander - you hit the nail on its head.
torch boy - those resistors are not 0 ohm ones. The board can take four 7135's in parallel, but only two are mounted on the 700mA version. Those resistors take the vacancies to boost initial output a little when the battery is strong.

Caver and trinity have explained the whole thing quite well. imho, for single 3.7v li ion Cree or SSC lights, these boards provide high performance at an unbelieveably low price. Cree + 1x18650 + 2x7135 = Perfect balance between power and runtime and efficiency.


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## TorchBoy (May 8, 2007)

Mikeh, how do you know how hot the junction is getting? If you have a decent heatsink that will keep things cool on the outside, sure, but what about on the inside?

Do you think it's a similar situation to a 5mm LED being run at more than 20mA? I measured the total current in a 9 LED torch last night powered from three (I think) fully charged Eneloop AAA cells. Total ~450mA, which means an average 50mA per LED. I don't really have any trouble with that since 5mm LEDs are pretty inexpensive (perhaps 1/60 that of a Cree XR-E P4).


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## TorchBoy (May 8, 2007)

RV7 said:


> torch boy - those resistors are not 0 ohm ones. The board can take four 7135's in parallel, but only two are mounted on the 700mA version. Those resistors take the vacancies to boost initial output a little when the battery is strong.


:huh2:
If they effectively short out the regulation for new batts the output current wouldn't be very well regulated.


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## uk_caver (May 8, 2007)

TorchBoy said:


> If they effectively short out the regulation for new batts the output current wouldn't be very well regulated.



It _would_ seem a bit odd to have regulation and then add extra components to degrade the regulation.


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## RV7 (May 8, 2007)

uk_caver said:


> It _would_ seem a bit odd to have regulation and then add extra components to degrade the regulation.


 
Agree. But as we all know, some flashaholics like to tout the maximum lux readings of their lights, or give it special weight when shopping. The manufacturers surely know how to please them with minimal cost. 

Anyway if you don't like the resistors you can easily remove them with an iron or probably just a plier.


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## joedm (May 9, 2007)

Nake, Yes the 1050mA ones.
I received a reply from Kai but he didn't answer my question about the 5 item sets, just said that they were experiencing problems with the site and it would be back in so many hours...


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## TorchBoy (May 9, 2007)

Kai's site is back up (for me) and I see mentioned now that the board is 17mm diameter. Great.


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## TorchBoy (May 10, 2007)

Just when things were quieting down...

3.6V~9V 800mAh Regulated IC Circuit Board for Cree and SSC Leds (4-pack)
$6.44 http://www.dealextreme.com/details.dx/sku.3256


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## uk_caver (May 10, 2007)

It seems to be already mentioned in http://candlepowerforums.com/vb/showthread.php?t=164362
Presumably it's buck-only, and the efficiency can only be guessed at.


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## joedm (May 13, 2007)

oh well... I have been trying everyday to get onto Kai's site but have not been able to..
So sorry Nake... have not ordered yet. 
For now I'm going to try the set of 5 from DX - 3.6V-9V 800mA (http://www.dealextreme.com/products.dx/sku.3256)

When and if Kai's site becomes available, I'll think about ordering that set of 20 circuits (1A versions).


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## Nake (May 13, 2007)

joedm said:


> So sorry Nake... have not ordered yet.


 
No worries mate.  Maybe he'll sell them in smaller quantities later.


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## Monolith (May 13, 2007)

I've ordered some 700's and 1a, but so far nothing has shown up (including my Rex lights).


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## jsr (May 14, 2007)

A heads up for those looking the 700mA and higher versions of this with Cree XR-E and SSC P4 LEDs...the circuit will not likely be in regulation at levels at and above 700mA for most of the Li-Ion's life. Here's why:

From test data of XR-E and P4 LEDs (on CPF):

XR-E VF = 3.46V @ IF = 700mA
XR-E VF = 3.58V @ IF = 1A

SSC P4 VF = 3.58V @ IF = 700mA
SSC P4 VF = 3.72V @ IF = 1A

Typical Drop-out voltage of AMC7135 chip is 120mV (0.12V).

3.72V is already at/above the "typical" voltage of a Li-Ion cell. It will be in regulation until the battery hits about 3.84V, at which point it is DD.

3.58V + 0.12V = 3.7V. Again, right where the Li-Ion typical is. Will be in regulation until approx 3.82V. DD thereafter.

3.46V + 0.12V = 3.58V. This will actually stay in regulation for most of the life of the Li-Ion battery. But, this is only at 700mA and with a low VF XR-E.

Even USxxH bin SSC P4s will likely not stay in regulation for much of the life of the battery if driven at 700mA or greater. Cree XR-Es tend to have a lower VF, but again, you have to find the right one. For most XR-E and SSC P4 LEDs, this driver will not work it's best with a single Li-Ion. And as mentioned, off 2x Li-Ions, efficiency is poor since it's an LDO.


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## joedm (May 14, 2007)

so are you saying that going direct drive would be a better alternative?
I really do not want to pay > $15 for a circuit per light... so the other available options out there are just too expensive for use in cheap hosts and cheap custom lights.


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## TorchBoy (May 14, 2007)

joedm said:


> so are you saying that going direct drive would be a better alternative?


Not necessarily, since the initial current with fresh batteries might be higher than you really want.



joedm said:


> I really do not want to pay > $15 for a circuit per light... so the other available options out there are just too expensive for use in cheap hosts and cheap custom lights.


I quite agree. A dollar or two per regulator is much better even than making my own from components.


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## nanotech17 (May 18, 2007)

got the board today but the lead wires is not soldered.
anybody know which wire to go which hole?


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## Enrico Fermi (May 19, 2007)

It seems this board as VDD of Q1 and Q3 being open. :thinking: 
correct?


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## nanotech17 (May 19, 2007)

depend on which miliamph you choose.


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## lightbug (May 19, 2007)

Received mine today. soldered the black wire to the spot above Q2, and red wire in the middle (right next to hole of center). Tested out 2 of them, one works, the other one didn't. Hope this is the right setup. :thinking:


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## nanotech17 (May 20, 2007)

any photos?


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## lightbug (May 20, 2007)

Nanotech,

I messed up. The blob on black wire I soldered to the the spot above Q2 touches the negative contact spot by accident. Which make it a direct drive, perhaps that was the reason why it worked earlier.


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## nanotech17 (May 20, 2007)

Aww!That hurts!Have you tried to solder the lead wires to one of the 3 holes on the left & right of the board?
And test it with used cell not the fresh of the charger.


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## lightbug (May 21, 2007)

Yes I did, but not with a used battery. As I have said before, the only reason it worked is because one wire soldered in the middle which is the + contact spot, and the other wire solered to the - contact spot (one of the 3 small holes on the edge).

This circuit board should be 16mm and it is little bit bigger than circuit board came with ELLY flashlight. I sanded it down, and installed it to the ELLY with a cree emitter. 

With a freshly charged ultrafire 14500, it worked for about 20 seconds, then it just automatically shuts off. I tried on the 2nd time, but it turns off again in few seconds. After a few more clicks, it went completely dead. 

By then I realized the clicky switch on ELLY won't "click" anymore, and the bottom of flashlight tube is getting quite hot. So, I quickly disasssembled the clicky switch and battery, and discovered both of them were very hot.

Fraustrated, I knocked out the circuit board from my ELLY and threw it into the garbage can. :ironic: Next time, I'll buy the circuit board with the wires pre-installed. 

Luckily I don't have anymore AMC7135 Circuit board on me, no more headaches! (My friend and I split the 5 units of AMC7135 Circuit board ordered from Kaidomain)

Good luck with yours nanotech.


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## nanotech17 (May 21, 2007)

Thanks lightbug,
I'll try mine and will post the outcome.


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## NetKidz (May 21, 2007)

Hello lightbug,



lightbug said:


> Yes I did, but not with a used battery. As I have said before, the only reason it worked is because one wire soldered in the middle which is the + contact spot, and the other wire solered to the - contact spot (one of the 3 small holes on the edge).


 
I didn't get my 1050mA boards yet but I think the above soldering is wrong and make it as direct drive. I think the board is the one I posted before: http://candlepowerforums.com/vb/showpost.php?p=1994424&postcount=24

I think the +ve to LED is in the central hole (directly connect to battery +ve). There's a round spot near Q2 (AMC7135 OUT pin), that's for the -ve to LED. Connect battery's +ve to bottom central spot and -ve to the outer ring. I think this should be right. I'll test if it'll smoke out when I get my boards.


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## nanotech17 (May 21, 2007)

what about those 3 holes at the edge of the board ( left & right)
are those suppose to be for the +ve & -ve lead wires?

https://www.kaidomain.com/WEBUI/ProductImages.aspx?TranID=1746


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## NetKidz (May 21, 2007)

nanotech17 said:


> what about those 3 holes at the edge of the board ( left & right)
> are those suppose to be for the +ve & -ve lead wires?


 
No, they're not for lead wires. They're through-hole via to connect the top and bottom copper ring.


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## Mel_PL (May 21, 2007)

NetKidz said:


> No, they're not for lead wires. They're through-hole via to connect the top and bottom copper ring.




I'm still waiting for my boards 
Maybe you can backtrace the correct wiring using the schema:







Just an idea...

-- M.


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## mikeh (May 21, 2007)

TorchBoy said:


> Mikeh, how do you know how hot the junction is getting? If you have a decent heatsink that will keep things cool on the outside, sure, but what about on the inside?


Temp = ambient + power * thermal resistance. And I think my resistance is OK from heat measurement at the star while partly assembled. You can find the emitter->star resistance from the spec's. 
Perhaps I should worry more though about currents over 1A though.



> Do you think it's a similar situation to a 5mm LED being run at more than 20mA? I measured the total current in a 9 LED torch last night powered from three (I think) fully charged Eneloop AAA cells. Total ~450mA, which means an average 50mA per LED. I don't really have any trouble with that since 5mm LEDs are pretty inexpensive (perhaps 1/60 that of a Cree XR-E P4).


Those are scarey. Since they are sold in pairs, its a good chance to compare them after running one for a few hours. I bet it gets dimmer 
They are amazingly bright, especially with a full 18650 cell.


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## TorchBoy (May 21, 2007)

mikeh said:


> Those are scarey. Since they are sold in pairs, its a good chance to compare them after running one for a few hours. I bet it gets dimmer
> They are amazingly bright, especially with a full 18650 cell.


Perhaps it's too late at night here, but ... what's scarey, what are sold in pairs (Eneloops? but why would an Eneloop get dimmer?), and what are amazingly bright?


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## Essexman (May 21, 2007)

Okay, bear with me, electronics is not my best subject. Could I use one of these drivers with 3 off 1.5V (total 4.5V) alkaline batteries?
I was thinking of using 3 Cree emitters, 3 of these boards (800Ma) in a 3 D mag. I know it's not the ideal solution, but it would be cheap !
Constructive criticise welcome.


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## lightbug (May 21, 2007)

Hi Netkid,

I have done that before, which is soldered the wire on + contact in the middle and - wire on the round spot above Q2. It didn't work.
However, if you make the solder blob on - spot little bit bigger and touch one of the 3 small holes on the edge, it will work.


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## scottv (May 21, 2007)

Essexman said:


> Okay, bear with me, electronics is not my best subject. Could I use one of these drivers with 3 off 1.5V (total 4.5V) alkaline batteries?
> I was thinking of using 3 Cree emitters, 3 of these boards (800Ma) in a 3 D mag. I know it's not the ideal solution, but it would be cheap !
> Constructive criticise welcome.


 
you woul get one 1400mA model and run the three Crees in parallel at 466mA each
you would turn it off after a few minutes to keep from burning yourself from the heat output
guess you could fin the flashlight head to dissipate that much heat

keep in mind that the Cree XR-Es are most efficient when driven below 350mA
they get brighter at higher currents but way less efficient.

You can even use a 4D


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## lexina (May 21, 2007)

lightbug said:


> Hi Netkid,
> 
> I have done that before, which is soldered the wire on + contact in the middle and - wire on the round spot above Q2. It didn't work.
> However, if you make the solder blob on - spot little bit bigger and touch one of the 3 small holes on the edge, it will work.



From my limited experience with the flupic and the D2Dim, I think it's safe to assume that the +ve battery wire goes to the centre +ve contact on the base of the board and the -ve battery wire goes to the outer ring. The -ve led wire can usually share the same ground connection with the -ve battery wire but would usually have its own solder point on top of the board. The toughest part would be figuring out the +ve led solder point - good luck! Btw, have you tried to email Kai? In the end I didn't get these but got the DX 800mA boards instead - still waiting for them.


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## nanotech17 (May 21, 2007)

i already emailed to Kai,guess what was the answer?
This is the replied email from Dora -
Thanks for your email.

Please ask someone skilled for help 

Cheers,

Dora

And i would say


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## NetKidz (May 21, 2007)

They don't know what they sell?  

I'll try it when I got mine.


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## lightbug (May 21, 2007)

Email Kai? 

He still has not reply the email I sent a week ago. Also, he didn't refund the $60 he owes me since last month. I would never buy from kaidomain again. I hope any of you would think twice before buying anything from this guy.


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## nanotech17 (May 21, 2007)

lightbug,
Go to Paypal and issue a refund request.


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## lightbug (May 21, 2007)

For paypal, the claim must be filed within 45 days of payment. It has been over 2 months since I paid.


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## joedm (May 22, 2007)

I always pay via my credit card through paypal. That way if paypal doesn't want to do anything about my transaction I can always go back to the credit card company and get them to do something.


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## lightbug (May 22, 2007)

Luckily, I was paying with the credit card as well. Just called my credit card company, now all I can do is wait and see.


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## NetKidz (May 24, 2007)

Kai had updated the photos including the wire instructions. Please re-check the 700, 1050 and 1400mA boards.


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## kanarie (May 30, 2007)

DX is now also selling them (in 20 pieces and 10 pieces)
Too bad the don't sell them in 5 pieces


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## nanotech17 (May 31, 2007)

Finally i managed to hook this board to my modded Elly with Cree and power it with 14500 cell and it's great with the glass lens from Kai's.
The output is of course bright but direct drive is always brighter,but with this this board the emitter can last longer and the Elly runs brighter almost without the heat 
And waiting for this to come - https://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=1488


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## lexina (May 31, 2007)

nanotech17 said:


> And waiting for this to come - https://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=1488



I ordered 10 of those about a month back and I just got a message from Amy (of Kai) that it shipped 2 days ago :naughty:


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## nanotech17 (May 31, 2007)

Lexina,
You won't be dissappointed,trust me :thumbsup:
I just wonder how to solder the lead wires to the 1050ma in mag 2D with SSC P4 & 1400ma board in mag 2D with K2 Luxeon :thinking:


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## lexina (May 31, 2007)

nanotech17 said:


> Lexina,
> You won't be dissappointed,trust me :thumbsup:
> I just wonder how to solder the lead wires to the 1050ma in mag 2D with SSC P4 & 1400ma board in mag 2D with K2 Luxeon :thinking:



If you already know where to connect the wires to the led; then connecting to the mag switch should not be a problem - just solder the +ve wire from the magswitch to the centre of the bottom of the board (where the +ve of your Elly cell would touch) and solder the -ve from the switch to the outer ring also at the bottom of the board.


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## nanotech17 (May 31, 2007)

YES !
Thanks Lexina .This is cool woohooo....!!!


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## lexina (May 31, 2007)

I have posted my feedback on the other 800mA board by DX here:-

http://candlepowerforums.com/vb/showthread.php?p=2029452#post2029452


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## nanotech17 (May 31, 2007)

That is fine.
I want to run it with 1 x 18650 cell only as stated.

Thanks.


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## FlashCrazy (May 31, 2007)

I just tested one of the 700 mA boards I ordered from Kaidomain. Using a 14500 cell and an SSC P4 H binned emitter, I measured 3.37V and 710 mA at the emitter. I haven't measured the current draw from the battery yet.

These boards (the 700 mA ones anyway) are set at 350 mA from the factory, and have to be configured for 700 mA by soldering a jumper blob as shown in Kai's photos. I didn't realize that until I revisited the pics on his site.


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## TorchBoy (May 31, 2007)

kanarie said:


> DX is now also selling them (in 20 pieces and 10 pieces)


Now, that made me sit up and take notice. How'd I miss that? And what else have I missed recently?


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## Nake (May 31, 2007)

FlashCrazy said:


> These boards (the 700 mA ones anyway) are set at 350 mA from the factory, and have to be configured for 700 mA by soldering a jumper blob as shown in Kai's photos. I didn't realize that until I revisited the pics on his site.


 
Is the last picture in this link what you are refering too? I've been wondering about it.

https://www.kaidomain.com/WEBUI/ProductImages.aspx?TranID=1805

I installed a 700mA board in a cheap mod light with a Seoul and drew about 780mA with 3AAA alkalines. I didn't do the jumpering with solder. Before the board install it was drawing 1.1A in direct drive. :shrug:


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## lexina (May 31, 2007)

Nake said:


> Is the last picture in this link what you are refering too? I've been wondering about it.
> 
> https://www.kaidomain.com/WEBUI/ProductImages.aspx?TranID=1805
> 
> I installed a 700mA board in a cheap mod light with a Seoul and drew about 780mA with 3AAA alkalines. I didn't do the jumpering with solder. Before the board install it was drawing 1.1A in direct drive. :shrug:



I don't have these boards but from the fourth and the last photos, my guess is that for the 700mA board, you only need to enable Q1 and Q2 (the bottom two slots). Since Q2 is already enabled by default, you prob need to solder points 3 and 4 to enable Q1. You shouldn't need to connect points 1 and 2 unless you have the 1400mA board. Again, this is just my guess!


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## FlashCrazy (May 31, 2007)

Nake said:


> Is the last picture in this link what you are refering too? I've been wondering about it.
> 
> https://www.kaidomain.com/WEBUI/ProductImages.aspx?TranID=1805
> 
> I installed a 700mA board in a cheap mod light with a Seoul and drew about 780mA with 3AAA alkalines. I didn't do the jumpering with solder. Before the board install it was drawing 1.1A in direct drive. :shrug:


 

Yeah, the last picture in your link. Here's another link...read the specifications part, Kai mentions that it's 350 mA by default. This link is for the 20 pcs lot. He doesn't mention it in the description for the 5 pcs lot. :shrug: It sounds like yours are already configured that way...dunno. I'll have to try one of mine that I haven't jumpered, to see what it's delivering to the emitter.


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## Randy Shackleford (May 31, 2007)

There is new 1.5V 300mA Circuit Board at DX


300mA is pretty low for my uses


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## FlashCrazy (May 31, 2007)

lexina said:


> I don't have these boards but from the fourth and the last photos, my guess is that for the 700mA board, you only need to enable Q1 and Q2 (the bottom two slots). Since Q2 is already enabled by default, you prob need to solder points 3 and 4 to enable Q1. You shouldn't need to connect points 1 and 2 unless you have the 1400mA board. Again, this is just my guess!


 

The pics show that you need to solder points 1 and 2 to enable Q3. On the 700 mA board, Q1 and Q2 quadrants are empty, so nothing to enable there. On the 1050 and 1400 mA boards, I guess you'd have to connect points 3 and 4 in addition to points 1 and 2.

Has anyone that has the 1050 or 1400 boards checked actual current output? Did you have to connect the points talked about here?

I'll do some testing later today (on the 700 mA boards)


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## FlashCrazy (May 31, 2007)

Ok, I tried one of the 700 mA boards as it comes from Kaidomain. Using a 14500 Li-Ion and an SSC P4 H bin emitter, it delivered 350 mA to the emitter, and had a current draw of 340 mA from the battery. So the ones I have do need to have contacts 1 and 2 jumpered to set the boards up for 700 mA.


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## lexina (May 31, 2007)

FlashCrazy said:


> The pics show that you need to solder points 1 and 2 to enable Q3. On the 700 mA board, Q1 and Q2 quadrants are empty, so nothing to enable there. On the 1050 and 1400 mA boards, I guess you'd have to connect points 3 and 4 in addition to points 1 and 2.
> 
> Has anyone that has the 1050 or 1400 boards checked actual current output? Did you have to connect the points talked about here?
> 
> I'll do some testing later today (on the 700 mA boards)



yup, you are right! in the picture, the 700mA board was upside-down


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## TorchBoy (Jun 1, 2007)

FlashCrazy said:


> it delivered 350 mA to the emitter, and had a current draw of 340 mA from the battery.


That sounds a bit funny. I thought it was a simple buck supply.


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## FlashCrazy (Jun 1, 2007)

TorchBoy said:


> That sounds a bit funny. I thought it was a simple buck supply.


 
That was on a fully charged Li-Ion, so the input voltage under load was probably about 3.7 or so volts. The Vf of the LED is a bit less, about 3.5V...so I guess it makes sense that the circuit would draw a little less from the battery at that point in time. I'm definitely no expert on this, so I wouldn't be surprised if I'm way off base...lol.


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## joedm (Jun 1, 2007)

I ordered the 800mA circuits from DX (in a 4 pack) and stuck one in my Mag 4D with a SSC P4 and Heatsink from Litemania. Seems pretty good so far... but haven't taken any measurements.

I'm waiting on my set of 10 AMC7135 (1A) ordered from DX which I will then swap into my Mag4D.


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## griff (Jun 1, 2007)

nice boards


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## joedm (Jun 4, 2007)

so how many of you have got these circuits going in a multiple emitter configuration?

I'm keen on 2 SSC's driven at both 1A. Does this mean that I need to use 2 of these 1A circuits in parallel? What would the current across each led be if I ran them in series?

Anyone tried these on 2x18650's? I read somewhere that this configuration turned a SSC angry blue? Anyone had any luck so far?


----------



## lexina (Jun 5, 2007)

joedm said:


> so how many of you have got these circuits going in a multiple emitter configuration?
> 
> I'm keen on 2 SSC's driven at both 1A. Does this mean that I need to use 2 of these 1A circuits in parallel? What would the current across each led be if I ran them in series?
> 
> Anyone tried these on 2x18650's? I read somewhere that this configuration turned a SSC angry blue? Anyone had any luck so far?



Were you referring to the 800mA boards from DX in the last part of your post? I have not tried the AMC7135 boards but the DX board (which uses the C310 chip) did cause my SSC to turn blue on 2 X 18650s.


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## joedm (Jun 5, 2007)

no, I am referring to the AMC7135 which supplies ~1A.


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## TorchBoy (Jun 5, 2007)

joedm, run the SSCs separately, each one with a 3xAMC7135 board. That may be what you intend, but from your wording I'm not sure if you were thinking of linking the outputs of the boards so that they're in parallel with each other, supplying a total 2 amps to two LEDs (which would themselves be in parallel). That wouldn't be so good, since if their operating voltage isn't identical one would draw more current than the other, and hence draw more than 1A.


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## joedm (Jun 5, 2007)

That's what I meant. A separate 3xAMC7135 board for each SSC however configured in parallel from the battery source (2x18650 or more)

Maybe this will help... this is what I'm thinking of.. dunno whether it's feasible or done before..


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## StefanFS (Jun 5, 2007)

I got my AMC7135 drivers yesterday. 1050 mA and 1400 mA. Mine came from DX, but it's the same product from the same manufacturer.

I measured 4 of each in a test setup, mA to the led with a fully charged AW 18650 @ 4.20 Volt and with 3 new AA alkaline @ a total of 4.7 Volt, and 3 almost empty AA alkaline @ a total of 4.3 Volt. One lead detached from the led, measured with multimeter, led on copper slab with thermal compound under it. 

*The 1050 mA model:*
- 990 mA to the led on fresh alkalines and 18650. Slightly over 700 mA 
on drained alkalines. All four measured the same, exactly.

*The 1400 mA model:*
- 1180 mA to the led on fresh alkalines. 1320 mA on fully charged 18650. 
Slightly over 950 mA on drained alkalines. All four measured the same, 
exactly.

One 1400 mA driver had a defective etching on the PCB, unusable. The other 19 (I ordered 10 of each) were very nicely made, seems to be high quality. I wonder what the discharge curve looks like? Anyone done this?
It got the impression that the driver stabilizes on a slightly lower mA level after a short time on LiIon when the initial voltage goes down from 4.2 Volt, I didn't test that though.
Stefan


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## cy (Jun 5, 2007)

hmmm ... good feedback so far?


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## TorchBoy (Jun 5, 2007)

joedm said:


> Maybe this will help... this is what I'm thinking of.. dunno whether it's feasible or done before..


Yep, that's the accepted way of using them.
:tinfoil:


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## TorchBoy (Jun 5, 2007)

Stefan, that is great test data. Thank you very much for sharing. What were the voltage levels of your batteries under load? (I'm not sure I'd agree that alkalines are almost empty at 1.43V.) Do you have any NiMHs you could try?


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## StefanFS (Jun 5, 2007)

TorchBoy said:


> Stefan, that is great test data. Thank you very much for sharing. What were the voltage levels of your batteries under load? (I'm not sure I'd agree that alkalines are almost empty at 1.43V.) Do you have any NiMHs you could try?


 
The alkalines had been used in a digital camera so the cells were pretty far gone regarding the remaining capacity, although the voltage was still 1.43 V. I only tested configs I plan to use with these drivers, I don't have enough time to do additional testing. Output should be a bit higher with NiMH compared to alkaline. It would be really interesting to see what kind of regulation these drivers have.
Stefan


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## RV7 (Jun 11, 2007)

Stefan, these are linear regulators, working like a smart variable resistor. When battery voltage is higher than the LED Vf, it changes its resistance to maintain a constant current. When battery drops below Vf, it will no longer be able to maintain the consant current. Instead, it becomes direct drive, with a 0.12v drop across it. 

It's best for one LiIon and no more than 700mA. If the current goes higher, everything will be against its performance:
- Vf goes higher
- The battery voltage is lower due to internal resistance
- the battery voltage drops quicker
As a result, it will provide regulated output for only a short time.


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## Krit (Jun 11, 2007)

I doubt for 750 mA version. I feed with 4.5 V current draw 0.36A from my transformer. When I feed with 5 and 6 volt the current still draw 0.36 A equal.


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## mikeh (Jun 11, 2007)

joedm said:


> so how many of you have got these circuits going in a multiple emitter configuration?
> 
> I'm keen on 2 SSC's driven at both 1A. Does this mean that I need to use 2 of these 1A circuits in parallel? What would the current across each led be if I ran them in series?
> Anyone tried these on 2x18650's?



I suppose you could use one regulator with two emitters, and two Li_Ion cells, all in series. That would make sense if you were starting with a 2-cell Li-Ion battery. But that would still mean twice the heat output in the regulator, so better to use a switching regulator, or a separate reg for each LED.
You certainly dont want 2x18650's with a single LED on this. The reg would blow up, and probably take your emitter with it.


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## moon lander (Jun 11, 2007)

has anyone noticed that DX now has a 1AA light that uses the AMC7135? hmm something here doesnt add up... i thought this board needed at least 2.7v, i dont know how they could be using 1AA to power a cree with this board. :thinking:

http://www.dealextreme.com/details.dx/sku.1892


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## mikeh (Jun 11, 2007)

moon lander said:


> has anyone noticed that DX now has a 1AA light that uses the AMC7135? hmm something here doesnt add up... i thought this board needed at least 2.7v, i dont know how they could be using 1AA to power a cree with this board. :thinking:



No, they can't and they don't. You need a switching regulator. Which light?
And 2.7V isn't nearly enough for a Cree or any other white LED. .. . although I suppose a switching reg might possibly have a amc7135 chip too??


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## moon lander (Jun 11, 2007)

sorry, meant to include the link:

http://www.dealextreme.com/details.dx/sku.1892

this light claims to use the AMC7135, a cree led, and 1AA.


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## mikeh (Jun 11, 2007)

moon lander said:


> http://www.dealextreme.com/details.dx/sku.1892
> 
> this light claims to use the AMC7135, a cree led, and 1AA.


It aint the first time Kyle got the description wrong.


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## Randy Shackleford (Jun 11, 2007)

mikeh said:


> It aint the first time Kyle got the description wrong.



yeah, that's probably the case.


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## StefanFS (Jun 12, 2007)

RV7 said:


> Stefan, these are linear regulators, working like a smart variable resistor. When battery voltage is higher than the LED Vf, it changes its resistance to maintain a constant current. When battery drops below Vf, it will no longer be able to maintain the consant current. Instead, it becomes direct drive, with a 0.12v drop across it.
> 
> It's best for one LiIon and no more than 700mA. If the current goes higher, everything will be against its performance:
> - Vf goes higher
> ...


 
I also doubted these regulator boards before I tried them out. I have temporarily mounted one 1050 mA board in one of my D-minis and one 1400 mA board in my MRV. It's true they need one LiIon cell to work and the function is limited to regulation only. After running these for 5 days on the same cell and using them daily I feel that they function very well. Ideally the MRV and D-Minis would be much better lights with regulated multistage drivers, like the kind you are planning. If you do make these I plan on replacing the AMC7135 drivers in my lights.
Stefan


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## StefanFS (Jun 13, 2007)

Because of all the speculation about this driver I decided to make a runtime test in my D-Mini with the AMC7135 1050 mA driver. The circuit delivers 978 mA to the led installed in the light.







This runtime started with a cell that had been resting for one week. Starting voltage was 4.16 Volt, stop voltage was 3.13 Volt at 180 minutes.
At 55 minutes the circuit flashed the led as a low voltage warning, about 15 times. It then went on driving the led. Even two percent output from a D-Mini is useful. I terminated at 3 hours and I feel that it could have been going on for a while. 

Starting throw Lux read was 11500 Lux. The actual graph is a product of my lightbox readings, not throw readings. At 50% the throw Lux is still 6000 Lux! That’s at 52 minutes!
This driver keeps my D-mini at a much higher or as high Lux level for 40 minutes compared to the stock drivers 25 minutes of full output. The stock driver shuts the led down completely after ~25 minutes. With this driver I get useful light for 60 minutes and then at least 3-4 hours of low level light. 

I have Lumapowers two-level click switch in this D-mini, I started a runtime test on low at work yesterday. After eight hours at work I had to abort and go home, those eight hours was a flatline. I really like this driver that cost me $1.57, and 30 minutes of work to install it (in the D-Mini led pill). For my needs it’s a great improvement over the stock driver. It does need a LiIon cell to work though. An ordinary CR123 isn’t enough to drive it, it will produce light, but at a lower level compared to LiIon.
Stefan


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## RV7 (Jun 13, 2007)

Nice chart Stefan! The chart looks very much like that of a resistor direct drive, which indicates that the 7135 is in direct drive mode from the beginning. That surprises me because I figured it could have provided regulated output for at least a short time. Perhaps you got a high Vf LED and the internal resistance of that RCR123 is much higher than that of a typical 18650.

I'm pretty sure you can get the same result with simply a resistor of around 0.5 ohm, which costs much less than $1.57!


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## TorchBoy (Jun 13, 2007)

Nice work Stefan. The graph isn't as flat as I'd expect. How much of that is due to heat?



StefanFS said:


> The circuit delivers 978 mA to the led installed in the light.


How often did you measure the current?



StefanFS said:


> Starting voltage was 4.16 Volt, stop voltage was 3.13 Volt at 180 minutes.


Were these rest voltages or under load?



StefanFS said:


> At 55 minutes the circuit flashed the led as a low voltage warning, about 15 times.


Are you serious? The board does that as well? Does it indicate the end of regulation? It certainly looks like about the time the battery started dying.


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## StefanFS (Jun 14, 2007)

TorchBoy said:


> Nice work Stefan. The graph isn't as flat as I'd expect. How much of that is due to heat?
> 
> How often did you measure the current?
> 
> ...


 

I had the light in a plastic bag immersed in water between measurements.
I measured the current to the led when I installed it in the led pill. It would be messy to desolder it every couple minutes in the runtime test.
Rest voltages.
I did this three times and the light flashed all three times at about 55 minutes, it could have been 10 times as well I didn't count them. It was like a momentary strobing. The only explanation I can think of would be that it's a function in the circuit.
Possibly the curve would be flatter with 18650. RCR123 isn't the ideal cell with it's resistance and limited capacity.
Stefan


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## FlashCrazy (Jun 14, 2007)

I have the 700 mA version that I put into a couple of lights....an Elly using a 14500, and another light that uses an 18650...both have SSC P4 emitters. They're working great, and draw about 710 mA from the battery (while under regulation). I haven't done any runtime tests yet, so haven't noticed any strobing on these. However, I put in two 3.7V rechargeables in the 18650 light just to try it. It starts strobing immediately when turned on. It strobes continuously...a slow strobe, more like flashing. I guess it's true that these only work up to 6V input! Of course I read that in the specs _after _I tried it.


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## Randy Shackleford (Jun 14, 2007)

The 6V spec'd limitation is why I went with these 3.6V~9V 800mA Regulated IC Circuit Board instead of this board. I know it is different board, but two 3.7V rechargeables work fine with it.

.


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## moon lander (Jun 14, 2007)

will the board really flash the led to indicate end of regulation? thats amazing! if its true, that would be the most useful function of the board for me, so i can stop ruining my li-ion cells.


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## Nake (Jun 14, 2007)

moon lander,

Did you get my PM about splitting some 1050mA boards?


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## moon lander (Jun 14, 2007)

pm sent



Nake said:


> moon lander,
> 
> Did you get my PM about splitting some 1050mA boards?


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## StefanFS (Jun 14, 2007)

moon lander said:


> will the board really flash the led to indicate end of regulation? thats amazing! if its true, that would be the most useful function of the board for me, so i can stop ruining my li-ion cells.



I don't know for sure if this is a function of the circuit or some other phenomenon. But since it did so three times in a row in my runtime test at approximately the same time, 55 min, I draw the conclusion that it is.
Stefan


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## FlashCrazy (Jun 14, 2007)

I'll try it with my 700 mA boards today, using a 14500 and the 18650.


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## RV7 (Jun 14, 2007)

FlashCrazy said:


> That was on a fully charged Li-Ion, so the input voltage under load was probably about 3.7 or so volts. The Vf of the LED is a bit less, about 3.5V...so I guess it makes sense that the circuit would draw a little less from the battery at that point in time. I'm definitely no expert on this, so I wouldn't be surprised if I'm way off base...lol.


 
I guess that small discrepancy is a multimeter error. The current drawn from the battery should be a tiny bit higher than that supplied to the LED due to 7135 being a linear regulator. So its initial efficiency is only about 80%. But as the battery voltage goes down, the efficiency improves, with an average of nearly 90%, which is not bad considering its price.


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## TorchBoy (Jun 14, 2007)

Randy Shackleford said:


> The 6V spec'd limitation is why when with these...


Why when what?


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## TorchBoy (Jun 14, 2007)

StefanFS said:


> I don't know for sure if this is a function of the circuit or some other phenomenon. But since it did so three times in a row in my runtime test at approximately the same time, 55 min, I draw the conclusion that it is.
> Stefan


The 1050mA board has three AMC7135 controllers on it - what are the chances they'll be doing a flashing thing all at exactly the same time? Was the flashing a diminishing of light or a total cut of light?


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## Randy Shackleford (Jun 14, 2007)

Randy Shackleford said:


> The 6V spec'd limitation is why I went with these *3.6V~9V 800mA Regulated IC Circuit Board* instead of this board. I know it is different board, but two 3.7V rechargeables work fine with it.
> 
> .





TorchBoy said:


> [size=-2]Why when what?[/size]



When, now went:naughty:


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## mikeh (Jun 14, 2007)

RV7 said:


> The current drawn from the battery should be a tiny bit higher than that supplied to the LED due to 7135 being a linear regulator. So its initial efficiency is only about 80%.


Only a very tiny bit, and it has (almost) nothing do do with the efficiency.
Practically, battery current = LED current. Its the *voltage* drop with same current that makes these lossy. A switching reg. will increase current using the power from the voltage drop.


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## RV7 (Jun 14, 2007)

mikeh said:


> Only a very tiny bit, and it has (almost) nothing do do with the efficiency.
> Practically, battery current = LED current. Its the *voltage* drop with same current that makes these lossy. A switching reg. will increase current using the power from the voltage drop.


 
You're absolutely right but I don't think I implied that "tiny bit" has anything to do with efficiency? I got the 80% efficiency by calculating voltage drop, just as you explained.


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## FlashCrazy (Jun 15, 2007)

I tried my 700 mA board (installed in an Elly) with a 14500. Never got any flashing. I stopped the run at 1 hr 45 minutes. The current draw at that point was about 50 mA. Unloaded battery voltage was 3.0V. No flashing warning, but at least the light gets very dim...which is warning enough for me.


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## TorchBoy (Jun 15, 2007)

I think Stefan might be a little premature in concluding it's the board when he tried it three times with exactly the same setup (especially battery). I don't doubt it's repeatable with his particular setup tho.


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## StefanFS (Jun 15, 2007)

TorchBoy said:


> I think Stefan might be a little premature in concluding it's the board when he tried it three times with exactly the same setup (especially battery). I don't doubt it's repeatable with his particular setup tho.


 
Could be. I'll just have to see if it happens with other lights I have these drivers in. It strobed for a few seconds.


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## TorchBoy (Jun 15, 2007)

StefanFS said:


> Could be. I'll just have to see if it happens with other lights I have these drivers in. It strobed for a few seconds.


It'll be great if it does that as well, Stefan, and all in such a tiny package. Do you have any other batteries you could try with it? Some of those mostly dead alkalines perhaps? (4 instead of 3?)


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## shinbone (Jun 15, 2007)

Those that have installed and used these boards, are you having to solder bridges to get them to operate at the advertised amperage?


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## Nake (Jun 15, 2007)

I installed a 700 board and connected points 1&2. With fresh 3 AAA alkalines at 4.8V it shows 700mA at the battery. With older batteries (4.0V) it draws 350mA. :shrug:


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## joedm (Jun 15, 2007)

shinbone said:


> Those that have installed and used these boards, are you having to solder bridges to get them to operate at the advertised amperage?



I installed a 1050mA version in my Elly. had to file down the edges. and also soldered the bridges. it was quite difficult as they are tiny. I guess I was lucky. I tested each time I soldered a bridge and the ouput was substantially brighter. 

however after using it for 10 mins mine became very dim. I tapped the light and it went back to full brightness. could this be a grounding problem?
anyone who's done this to their elly, did you have to fold the black/ground wire into the screwhole as per how the original elly was wired?


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## FlashCrazy (Jun 15, 2007)

shinbone said:


> Those that have installed and used these boards, are you having to solder bridges to get them to operate at the advertised amperage?


 
I had to with the 700 mA boards. I tested them as they came, and they delivered 350 mA to the emitter. After bridging, they delivered 700 mA.


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## FlashCrazy (Jun 15, 2007)

joedm said:


> however after using it for 10 mins mine became very dim. I tapped the light and it went back to full brightness. could this be a grounding problem?
> anyone who's done this to their elly, did you have to fold the black/ground wire into the screwhole as per how the original elly was wired?


 

No, you only have to solder the ground wire to the star. In fact, if you extend the ground wire to the screw, the board won't regulate properly. What you DO have to do is make the ground ring/circle on the bottom side of the regulator board ground to the pill. Battery negative travels through the body of the light, and needs to have a path to that ring on the board. If the pill wasn't made of aluminum, this would be as simple as soldering a little blob from the ring to the edge of the pill. What I did on my Elly was to snip a small piece of copper desoldering braid and solder that to the outer ring on the regulator board (bottom side). The piece protrudes about 1/8" away from the pill. When the pill is threaded into the body of the light, this little piece of wick gets smashed against the light's housing, completing the path for battery negative. 

Hope this helps!


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## joedm (Jun 15, 2007)

Yup thanks, that's exactly what I thought I had to do. When I filed the board down to fit in the pill I made sure that it was exact hoping that the outer ring would have good contact with the pill. obviously it doesn't.

Anyway I should have realised that connecting the black wire (-ve) to the screw in the pill would in effect make it direct drive just like what I had before swapping the board for the original.

Thanks again.

Having said that, I'm quite impressed with this board.


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## shinbone (Jun 17, 2007)

Thanks for the replies. I'll jumper one of my 700s and try to fit it into my shorted DX 6P drop-in.


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## TorchBoy (Jun 28, 2007)

When these drop out of regulation and go to direct drive, should the voltage drop across the regulator be zero, or 0.12V, or the 0.61V that I just measured?


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## Kill-O-Zap (Jul 28, 2007)

TorchBoy said:


> When these drop out of regulation and go to direct drive, should the voltage drop across the regulator be zero, or 0.12V, or the 0.61V that I just measured?


Folks, I'm a bit out of my element here, I may be way off base. But here's a thought:

DX's description claims:
Reverse input polarity protection (won't burn out if battery is installed the wrong way)
Does this mean there's a diode external to the chip, that is costing that .6V discrepancy TorchBoy reported (.61 instead of .12V), and if so, could the diode be bypassed? I think that would explain why the chart in the earlier post looks like DD, with that much of a drop...


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## TorchBoy (Jul 30, 2007)

With that much drop the thing was acting as much worse than direct drive. I think it may have been some fancy balancing thing going on between the operating voltage of the LED, the loaded voltage of the battery, and the operating voltage (voltage drop) of the regulator chip allowing for the 0.6V of the diode.


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## Bertrik (Jul 30, 2007)

TorchBoy said:


> When these drop out of regulation and go to direct drive, should the voltage drop across the regulator be zero, or 0.12V, or the 0.61V that I just measured?


I think the 0.12V is only in the normal operating region, I believe the behaviour for Vin < Vout + 0.12V is unspecified.


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## HiltiHome (Jul 30, 2007)

I guess the flashing StefanFS noticed during his runtime test is caused by the protection circuit of the battery.

After 55min. a RCR123 is almost drained, but the current is to low to make the circuit shutdown.

I noticed a similar effect, when running a PWM light on low. The protection circuit in the AW battery didn't cut the circuit, the battery was drained to 2,2V when i stopped the test. The battery is still usable, but has very high self discharge since that.


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## Gadget_Guru (Jul 31, 2007)

The diodes on these boards should be removed for best performance. They are only there for input reverse polarity protection. The diodes drop about 590mV, so they're really not helping when trying to keep in regulation as the batt. voltage drops.

I just installed a 700mA board in a 30 LED 3D light, with the diodes removed. I will try to post a run-time light output graph later, if I can get around to modding my cheapo light meter to work with my PC-enabled DMM.

Darron


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## joedm (Aug 1, 2007)

how about posting some pics of how to remove the diode?


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## koala (Aug 1, 2007)

For all the boards no matter what mA output.
The diodes are the red glass vials with black strip, they look like ants..


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## joedm (Aug 1, 2007)

Thanks Pal.
So just got to remember not to insert batteries the wrong way...
otherwise? burning smell?:candle:


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## Nake (Aug 1, 2007)

What's the secret to bridging solder points? When I did the two initial bridges the solder kept sucking back and wouldn't cross. Would soldering a wire to connect two points be alright?


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## KrisP (Aug 1, 2007)

A tiny bit of solid "leg" cut from a resistor seems to work well to link pads.


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## RV7 (Aug 1, 2007)

Wait a minute guys... the diode leads to the Vdd of the IC which takes only 0.2mA and requires at least 2.7V. It's not in the LED circuit and will not affect the drop out between the IC's OUT and ground when the battery voltage is above 3.3V.

When the battery voltage drops below 3.3V, due to the drop over the diode, the Vdd will get less than 2.7V and thus the 7135 tends to stop, and thus the higher drop between the OUT and ground. Since a Li Ion is almost fully discharged near 3.3V, this "side effect" effectively serves to protect the battery from over discharge. Removing the diode just helps drain the battery when it's already dying.


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## koala (Aug 1, 2007)

I wasn't the one who proposed the idea, I only edited some pictures 



RV7 said:


> Wait a minute guys... the diode leads to the Vdd of the IC which takes only 0.2mA and requires at least 2.7V. It's not in the LED circuit and will not affect the drop out between the IC's OUT and ground when the battery voltage is above 3.3V.
> 
> When the battery voltage drops below 3.3V, due to the drop over the diode, the Vdd will get less than 2.7V and thus the 7135 tends to stop, and thus the higher drop between the OUT and ground. Since a Li Ion is almost fully discharged near 3.3V, this "side effect" effectively serves to protect the battery from over discharge. Removing the diode just helps drain the battery when it's already dying.


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## Kill-O-Zap (Aug 2, 2007)




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## TorchBoy (Aug 5, 2007)

RV7 said:


> Wait a minute guys... the diode leads to the Vdd of the IC which takes only 0.2mA and requires at least 2.7V. It's not in the LED circuit and will not affect the drop out between the IC's OUT and ground when the battery voltage is above 3.3V.
> 
> When the battery voltage drops below 3.3V, due to the drop over the diode, the Vdd will get less than 2.7V and thus the 7135 tends to stop, and thus the higher drop between the OUT and ground. Since a Li Ion is almost fully discharged near 3.3V, this "side effect" effectively serves to protect the battery from over discharge. Removing the diode just helps drain the battery when it's already dying.


Agreed. The diodes don't just provide polarity protection. It's all very clever, IMHO; quite tunable for current and operating voltage.

I'm using NiMH cells so if I stick to just one regulator chip (nominal 350mA, measured 310mA) and three cells I'm quite happy to leave the diodes in there, meaning at 1.1V per cell (loaded) it'll drop out of regulation. If I go for the full three regulator chips on my boards (nominal 1050mA) I'd probably want a lower drop out voltage due to voltage sag of the battery under load, so removing (or just bridging) the diodes would be the way to go. The loaded voltage of my cells could be as low as 0.9V before regulation dropout. Nice.

If I used alkalines I'd also want to remove the diodes.


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## Upplyst (Sep 17, 2007)

Anyone that has done any more tests with these amc 7135 circuits? How did it go?


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## ardo (Oct 5, 2007)

I just got my 1050mA boards from DX, and they look different from those pictures on Kaidomain. oo: Am I supposed to bridge anything? And, does anyone have a picture of where the output is taken from? Thanks.


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## TorchBoy (Oct 6, 2007)

ardo said:


> I just got my 1050mA boards from DX, and they look different from those pictures on Kaidomain. oo: Am I supposed to bridge anything?


:shrug: How 'bout a good quality photo?



ardo said:


> And, does anyone have a picture of where the output is taken from? Thanks.


The positive LED output is the positive terminal right in the middle while the negative LED output is the mostly round pad next to where "Q2" is written on the board... unless your boards look different to those everyone else has, in which case you would have to post a good quality photo so someone could advise you what to attach to where.


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## Nake (Oct 6, 2007)

ardo said:


> I just got my 1050mA boards from DX, and they look different from those pictures on Kaidomain. oo: Am I supposed to bridge anything? And, does anyone have a picture of where the output is taken from? Thanks.


 
KD is back up and has pictures of what to bridge and where to hook up the wires.


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## ardo (Oct 7, 2007)

Thanks guys, I've since found another thread that was specifically for the DX board, and got my answer. Oh, the power of Google! Sorry about that.


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## paulr (Oct 7, 2007)

It's pretty obvious from the temperature graph that it's not a linear regulator, otherwise with constant output current the board would get cooler as the input voltage dropped.


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## TorchBoy (Oct 7, 2007)

paulr said:


> It's pretty obvious from the temperature graph ...


Link please.


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## TorchBoy (Oct 7, 2007)

ardo said:


> Thanks guys, I've since found another thread that was specifically for the DX board, and got my answer. Oh, the power of Google! Sorry about that.


This thread. And yes, the new board does look very different.


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## rizky_p (Oct 16, 2007)

Can anyone please explain the 7135 driver(old one) in the picture the +ve is in the middle between the diodes and the -ve is on Q2 isnt that the same thing? shouldn't the -ve is on the board's ring and the positive is on the Q2?

thanks


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## TorchBoy (Oct 16, 2007)

rizky_p said:


> Can anyone please explain the 7135 driver(old one) in the picture the +ve is in the middle between the diodes and the -ve is on Q2 isnt that the same thing? shouldn't the -ve is on the board's ring and the positive is on the Q2?
> 
> thanks


The negative on the outer ring is the input. Only the AMC7135 chips are connected to that. They control the current the LED - on the positive side of those chips - is getting. Thus the negative of the LED is connected to the other side of the 7135 that the battery negative is. The positive is common to the chips and the LED. If you find the AMC7135 datasheet there's a diagram of how things are connected.


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## Nake (Oct 16, 2007)

I don't know if this might help.

http://www.micro-bridge.com/data/ADD/AMC7135.pdf


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