# Elly low voltage start up problems



## Corona (May 10, 2007)

I've noticed the Elly (MXDL 1W) that I've used for a violet laser project has trouble starting with a partially discharged alkaline. It won't start at all with a NiMH cell.

When it is in this mode, loosening the tailcap a bit and tightening it again seems to help get it to fire off. Working the clicky doesn't have the same effect.

Is this a common issue, or is the one I have dodgy?

I suspect this is either a connectivity problem via the anodizing on the 2 aluminum mating pieces (tailcap & body) or some inherent startup voltage issue with the wee little boost controller IC.

Perhaps the act of making an intermittent connection introduces small voltage spikes on the controller and allows it to start. I'm going to try adding a small tantalum cap right on the PCB and see if it makes this better or worse...

It's easy to see that the boost controller's 3 pins have these functions (left to right looking at it with the heatsink tab at the top)

Pin 1 - Negative supply rail
Pin 2 - Boost voltage input (positive supply for IC and sense input for boost voltage regulation)
Pin 3 - External FET gate drive output

EDIT - found the datasheet, it sure looks like it's a Rohm RH5RH!! Supposed to operate down to 0.9V _at light load_

Hmmm...


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## robk (May 10, 2007)

Yup, I've found the same thing with the driver in the Elly. If a NiMH is slightly used, the circuit refuses to start, didn't try any used Alkalines. I thought it was just me. If you find an answer, please post it as I'm using one to drive a DVD LD.
Here's where I'm at: first the setup





Then the filtering / protection network:





Rob


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## Kenom (May 10, 2007)

that looks vaguely like a HDD magnet monted on a fuse puller?


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## SenKat (May 10, 2007)

Knowing Robk wel, I can almost guarrantee it is ! Now- can you identify where the circle of metal is from ??


Muahahahaha ! Just kidding - I have no idea !


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## robk (May 10, 2007)

You guys are pretty good! Yes, a fuse puller with a 1/4-20 nut epoxied to it for tripod mounting, stuck to a hard drive magnet on a circular metal scrap. Now - where did the circle come from? I save everything, I make things from garbage. I have a Maha 801 charger and some cells heat up a bit when quick charged, so I needed a fan to keep things cool. I took an old ATX power supply, took the fan out, used half the enclosure as a stand to sit over the battery charger, mounted the fan in the center and you can guess where I got the circle of metal using a nibble tool!





Rob


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## SenKat (May 10, 2007)

Awesome ! One mans' junk is truly his own treasure ! Err...well, you get the idea !


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## Kenom (May 11, 2007)

LOL entirely too funny. Great idea for the cooler though. and for the mount. I work at an automotive parts retailer (they just notified us that we are not supposed to mention ^&^&^#% in forums or chat) and I recognized the fuze puller. that and I have about 7,000 magnets all pulled from HDD. What is it with geeks and thier pull or attraction to lights (ooooh shiney bright thing....Pretty!) and magnets that are strong (must seperate to remove broken finger!!! rrrrraaaahhh....)


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## Kenom (May 11, 2007)

oh and I hope you don't take offense to the "geek" statement. If you did I apologize in advance.


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## SenKat (May 11, 2007)

Kenom - I cannot believe you called him a geek ! LOL !!!


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## Kenom (May 11, 2007)

LOL uuhhh if it's any consolation I consider myself a geek so it's a compliment right???!!!


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## SenKat (May 11, 2007)

Yeah - I think me and a few of the folks on here are actually twins, seperated at birth ! :laughing: :laughing:


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## robk (May 11, 2007)

HaHa I am a geek! Only here and a few other places on earth I find people who understand my mental condition. My wife thinks I'm crazy - I save weird things like product packages (especially plastic cylindrical), the little triangle platforms that come on delivery pizzas ( I swear I will find a use for them), all kinds of stuff. I enjoy making useful things from what others consider junk! Last week I cut down a hairspray aerosol cap to about 1/2" deep to cover my can of Miller Lite when I leave it in the garage to go back inside to take care of business - keeps the bugs out (this is Florida!). It's amazing what you can build with stuff that other people consider junk. You should see my garage - it's like a museum - I can't throw anything away!

About the magnets - they are extremely useful in a thousand ways. Every dead hard drive that passes by me gets torn down for magnets and some surface mount parts like caps, power sockets, whatever.

Rob


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## Corona (May 15, 2007)

Thread-jackers!! 

lol - the startup problem I'm experiencing was due to my modding the circuit to add a silicon diode in series with the power/sensing pin on the boost controller - while it did bump the boost voltage up by 300mV, it also increased the startup voltage by 300mV. Anything but a freshly unwrapped alkaline would NOT start it, and worse, I could run the thing for 10 minutes, no problems with the +5V output at all once it was started - but click the switch and it would refuse to come back on.

Carry On


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## Daedal (Jun 2, 2007)

Hey Corona, Just wanted to get your views on this 'new' circuit in the Elly.






I have looked for some info on that new chip, and this is one link I have found. 
http://www.datasheets.org.uk/specsheet.php?part=2106F
And this is just the same info hosted elsewhere it seems...
http://www.americanmicrosemi.com/information/spec/?ss_pn=2106F

I measured the output at 1.5V. Any feedback would be greatly appreciated 

Thanx;
DDL


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## Daedal (Jun 3, 2007)

Ok, well... After some looking at this thing, I know how the circuitry operates and how the chip works now, but I can't distinguish the pinouts. I have a couple possibilities on paper, nothing solid though. I have no idea how to test this, and I blew my DMM a few days ago. 

If anyone can help, please... any input is very much appreciated;
DDL


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## Daedal (Jun 3, 2007)

Further testing has uncovered something very odd. The LED is not running when 1.5 volts are applied, but does turn on when 3.0V are applied. The circuitry does not get a 3V laser to lase, But powers the LED. Testing voltage while across the LED while it is running still shows 1.5V output. Obviously... there is something I am doing wrong. I really have run out of ideas on this one... 

--DDL


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## Corona (Jun 4, 2007)

Well, while the part number DOES say "2106", that can't be a dual diode or it would not work as a boost circuit. That p/n is either an abbreviation or a "house number" - large OEMs can order parts from the semiconductor maker by their own in-house part number; this also makes reverse engineering the circuit tougher as finding datasheets is near impossible.

Or it could be a Chinese semiconductor fab house disguising counterfeited parts with another part number, to avoid royalty payments (to Rohm, for example).

Looking at it I can see it's still a classic boost circuit, just simplified by using a boost controller with an internal FET. The older Elly circuit used that obsolete Rohm part (I posted a datasheet link somewheres on CPF), with an external MOSFET.

The boost diode, being a glass part, may not be a Schottky (more cost savings). If true, this will certainly increase the startup voltage. In this case changing it out for a Schottky part will at least improve that. But, it could be OK as-is, just free associating...

Here's what I think is wrong; you don't have a good connection to negative. Remember that the flashlight body is the negative connection for the circuit, and that the negative (blue wire on this one) must be touching the Elly case in order for the battery power to get to the circuit. 

So your voltmeter is measuring the battery voltage through the components of the circuit, but the circuit is not operating. It should make 5V, just like the original circuit.

Also I see you have chipped a bit off the inductor; not a big problem though it will lower the inductance a bit and result in higher peak currents in the internal FET. This new circuit is probably not as robust as the old one with external FET, but probably works just as well for violet and DVD red laser diodes.


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## Comidt (Jun 7, 2007)

So Did you get it to work?
I want to know if it works before I risk my cash on it
Thanks
Jonno


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## Daedal (Jun 15, 2007)

I'm really sorry. My internet took a dump and I finally got it up today.
I sent the picture over to Conrona and once I hear anything I'll let you all know.
I also bought another one and got it in yesterday, as well as the other 1W LED flashlight. I'll post both of them as soon as I get the time.

--DDL


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## Corona (Jun 18, 2007)

Had a look and I don't like what I see. This new circuit is a cost-reduced version of the original Elly boost design and has some significant shortcomings.

First is the fact that the load (LED or laser) is connected to the "flying" end of the inductor, not the rectified & filtered output of the boost circuit. This means that the load will see some very high voltage spikes. I've seen this done in other LED drive circuits and while it works, it's not a very good idea.

Also, because the load "rectifier" has a different voltage drop than the wee little rectifying diode on the PCB, the regulation is not going to be very predictable.

And, since there is no filtering of the pulses, an LED or laser diode connected will not be truly CW; it will be pulsed. At least, it will as long as it withstands those spikes. It will be 100kHz or higher, so you wouldn't notice it visually - but it will be pulsed - and in order to get the average current up to where a DVD burner diode will actually make enough RMS power to do cool stuff, the PEAK current will be nasty indeed; upwards of an amp or more. 

Did I mention the high voltage spikes? LEDs are fairly robust and a white LED might be OK with this, but I would NEVER connect a sensitive and costly laser diode to it as-is.

The "filter" capacitor in this design is nothing more than a tiny ceramic capacitor, meant to filter the supply to the IC, and nothing more.

I would not use this one for laser duty without modifying it to:

1) Replace the little MELF (round glass SMT) diode with a beefier Schottky SMT part. Remove the old diode, can't piggyback MELFs very well and you don't want them both in there at the same time anyway.

2) Add a significantly larger tantalum filter capacitor where that little ceramic part is (10uF 16V or so). Piggybacking it would be fine.

3) Most critical - move the (+) load connection (the red wire) from the flying end of the inductor, to the (+) side of the added filter capacitor.

And of course, provide some method of limiting the load current, after evaluating the regulation capability of this new circuit at higher load currents.

If I come across one of these, I'll do the mod and testing and report back, but I'm not going to consciously seek one out.


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## Daedal (Jun 19, 2007)

Well... I'm really sorry to have been late on my original response, and again, I am sorry to have vanished like this yet again... my damn COMCRAP internet is dead again... this is 2 weeks of no internet or cable TV. I AM paying the bills though, mind you. Now they estimate another 2 weeks before they can find someone to rewire the outside cable that goes from the community cable hookup to where it gets to me. This is rediculous and VERY GROSSLY expensive! 

::Just editing to add the fact that my internet has been dead since COMCRAP took over my old and significantly smaller cable company! Which was much better, faster, more reliable, and best of all.. WORKING!!::

Either way, while that is all taking place, I am still working on the same project. My Blu-Ray diode is wired and placed very comfortably in its new home in that brass AixiZ module, and has been for a while now. The elly is still in pieces, but I did get the other one that I had ordered, along with another one that I had ordered, but still have had no chance to open it up and try it out. It is the other 1W LED flashlight. It is smaller than the Elly and has the exact same battery problems as the Elly in that once the battery gets to about 20 minutes of use time the light won't even start. This is ofcourse using regular Duracell Alkalines. Haven't bothered to even try it with AA lithiums. I doubt they'd even start given the voltage on lithiums.

I'll probably be taking that other 1W apart and investigating the circuit. it's a very sleek and tiny light. I think it would look mych better as a laser host than the Elly, but it's definately not as resilient. The body is much more flimsily made.

I should have the time this weekend to go and get the required parts and rewire the newer circuit as required and report back on the findings. Thank you very much for the support Corona. I'm definately not gonna be trying it out on the Blu-Ray until I have some for-sure test results guaranteeing the life of this new module. I burnt one already, and hope to not burn this new one. I will make sure I provide the detailed pictures and prodecure so that Coronoa's wonderful guide can also be followed with a few adjustments to make it work for the new circuit. Also, hopefully the other 1W can be modded in the same way.

If I run into any problems, and if Corona wouldn't mind putting in the time and effort, I could mail the new Elly for him to work on and possibly come up with some more solid results given the circuit in-hand.

Till next time, I hope that'll be pretty soon;
DDL


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## Comidt (Jun 20, 2007)

Cool, thanks Daedal, mailing it to him would be a great idea... Help everyone out.

I'm not too sure what to do know, I think I will wait until it is all sorted out. I've already ordered elly, so I'll just use it as a light for now.

Jonno


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## Corona (Jun 21, 2007)

DDL said:


> if Corona wouldn't mind putting in the time and effort, I could mail the new Elly for him to work on and possibly come up with some more solid results


PM me, and we'll work something out. Hope you have something to horse-trade 

And yes I will append to the original mod document to also support the newer circuit.


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## teaken (Jul 10, 2007)

The problem with the elly I just received is a little different, the step-up circuit seems entirely nonfunctional considering there is 0 ohms between the cathode on the LED and the +ve battery terminal . Will dismantle when I get some spare time and see what the deal is, this is my first elly i'd be interested to know if anyone else has had this issue.
On the positive side no low voltage problems 
Anyone got a decent schematic for a nice boost controller laser diode driver?


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## Corona (Jul 24, 2007)

Ugh. I have just evaluated this new boost circuit and it's a dog, at least for Bluray diode use. With a single cell feeding it, the load regulation is horrible, although the output is "regulated" to 7.0V (the old Elly circuit was 5.0V), this is only achieved at no load. With only 10mA on it (white LED and 68 ohm resistor), the voltage sagged big time. 

With a Bluray diode attached, the highest current I could manage is not even at the laser threshold; <30mA. Since building a couple violet lasers is my current active project, this was my focus - and I am sorely disappointed by this circuit.

This is likely due to the weak FET switch in the chip (the ON resistance is too high to allow higher current as the FET drops too much voltage when ON). With higher input voltages, it will deliver more current though. 

It will probably work with a DVD red, I'll be doing some additional testing since this seems to be the hottest project going for others on the forum.

Definitely need to replace the cheap silicon diode with a Schottky (I have a REEL of MELF Schottky diodes if anyone needs any) and add a decent capacitor, and move the output - DON'T EVEN THINK of connecting an expensive laser diode to the original output location on this circuit, as it applies several volt spikes to the diode. Also, the output waveform is not CW, it is pulsed (hmmmmm). After the simple mods, it's at least a clean DC waveform (though gutless).

More to come...


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## Daedal (Jul 25, 2007)

Well that sux! 
Thank you for evaluating it though... 

Hope there is some kind of fix for this;
DDL


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## Comidt (Jul 25, 2007)

i'm just gonna get any old CR123 batt torch from DX, well, it's not a bad flashlight for me.
Jonno


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## Corona (Jul 30, 2007)

BTW on the original thread topic, my old Elly works fine with a NiMH and the new circuit appears to start up well below 1V (it's just gutless down there).

I haven't done anything with a DVD red and the new circuit yet, but in order to use this circuit for a violet laser it simply needs more input voltage. Not much, as just below 2V it fires the Bluray diode OK, and regulates just fine with a 50mA load.

So I modded a CR123 based flashlight (DX "6W Super Bright", Luxeon3-based) into a VioLaser, using this new Elly boost on 3V works great. And this particular flashlight has a rear-mounted clicky with bright/dim, it just so happens that with a 47 ohm resistor between the boost output and diode, I get about 55mA on "high" and "something less but over threshold" (I'm guessing 30-35mA) on "low". Kinda nice, I can be easy on the diode, if I want to be.

Zetex has some SOT-23-5 package single-cell boost ICs that use an external transistor; these might be a basis for a decent driver board or (somewhat intensive) mod; I need to build another violet and a DVD red for another member so I'll be coming back with additional findings & info "soon".


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## Comidt (Jul 31, 2007)

Cool, let us know on how it works with a DVD diode!


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## Corona (Aug 2, 2007)

I didn't have one on hand to test with but used a 1W Luxeon red emitter as a "dummy load"; it has about the same forward voltage as a DVD red laser. And after the simple mods, I can say that it will work. 

The gist of the mod is this:

1) Remove the red wire from where it is originally. This location results in the LED seeing some nasty negative voltage spikes, and the drive being pulsed.

The black wire location remains the same, but you'll need to remove it temporarily for a following step...

2) Replace the little round diode with a Schottky device with at least a 500mA rating. Using a Schottky will enhance the low voltage startup characteristic and efficiency of the boost circuit (the original diode is a common silicon signal diode with a higher voltage drop and unknown switching characteristics)

3) Replace the ceramic filter capacitor (after the diode) with at least a 10uF 10V part. I'd shoot for a 33uF or bigger, if you can fit it. There will be some square wave ripple on the output at higher currents and the bigger the cap, the lower this ripple will be (and the higher the DC component of the output current through the diode).

4) Take the laser feed from across this capacitor (red wire goes to the [+] side of the cap now).

I "torture tested" this with a 1 ohm resistor and the Luxeon, I saw peak currents near an *ampere* and a couple hundred milliamps of ripple current; with a more realistic resistor (for a laser) at say, 200mA, the ripple should be quite low (this with a 10uF aluminum electrolytic that was several years old, scavenged from an old sound card).

I really need to get some better SMT capacitors ;D

Anyway, there you have it.


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## RDZombie (Aug 26, 2007)

hey guys, ive been messing aound with the elly and the blu ray diodes as well. i was wondering if anyone has experience with the inverter circuit from the HX-G011 3W led light in conjuncion witht the bluray diode? it too uses a 1.5v input but is a different cicruit that than elly uses.


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## Corona (Aug 29, 2007)

Looks like a simple power oscillator, the feedback winding likely drives the base of a single transistor. The main winding is the boost "inductor". Technically it's a transformer but the winding with a small number of turns does not factor into the power transfer, only to provide a feedback signal of the proper phase and current to cause the transistor to switch on & off.

I see no rectifying diode so I suspect that the LED itself performs the rectification function - same as the late-model Elly. LEDs don't seem to mind, but this scheme is not advisable for laser duty. 

Any chance of getting some other views of the driver circuit (nice clear close up / macro shots) and/or the markings on the components?

If this circuit is what I suspect, it is not regulated - so the output will vary with load and battery voltage, and in order to use it with a Bluray diode (or any laser diode), some sort of current regulation scheme will need to be added. That means that the circuit needs to provide several volts when _loaded_ so there is adequate voltage "headroom" for the current control scheme (a series pass element acting as a variable resistor, essentially).

There is still No Free Lunch, it seems...


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## RDZombie (Sep 5, 2007)

yes you are correct no regulation what so ever, also the driver transistor has had all of the marking removed. all of my equipment is still in storage after moving (all of 1 1/2 years ago) so im not really able to test it in depth other than my trusty multimeter. just wondering if anyone has messed around with this booster yet.


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## Yobresal (Nov 13, 2007)

So I have a ps3 blue-ray diode hooked up to an Elly I just received in the mail today, and the diode appears to be lasing. here is a picture of the diodes output.


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## mzzj (Nov 15, 2007)

There is a trick to modify Elly driverboard to start reliably every time with less than 0.8v input, all you need is NPN-transistor and one 1k resistor... 

Connect NPN transistor parallei to Q1. It's very difficult if not impossible to manufacture mosfets with gate treshold voltages below 1v, but ordinary NPN transistor works already with 0.7v!

Emitter goes to Q1 upper pin. (Hold driverboard with inductor upwards.)
Collector goes to Q1 middle pin.
Base connected with 1k resistor in series to Q1 lowest pin

I used BC337-40 transistor but any fairly similar transistor should work. Something "around" 10-100v, 50ma-1A and HFE more than 100.


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