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NJG-18, multimode boost driver for 445nm.. and possibly 650nm

SHIN

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Hi.:yh:

No laser driver around has "modes" as far as I know.
I'd like to build my laser with modes.

I have tested several LED drivers for 445nm LD from cheap sites as DealExtreme, KaiDomain.
And I found a proper 445nm LD driver for one Li-ion.

http://www.kaidomain.com/ProductDetails.aspx?ProductID=1672#

I think the following driver is the same one, but it is "back-order" state.

DealExtreme: $4.26 3W 19-Mode Universal Regulated Circuit Board for Flashlights

The board is marked as "NJG-18".

With my custom test load( 4x 1N540x, 1ohm) and one 18650, I set the potentiometer of the board, the current is:
50mA-400mA-1200mA

After building with my custom laser P60 module and aixiz 445nm lens, the power of A140 is:
70mW-350mW-1160mW
Unlike the explanation, it has 3 mode. Low-Med-High. No strobe mode.

Awesome! It is really 3 mode laser!

I can't understand the mismatch of power-current of the low mode.
I guess there was an error in the calculation of test load at low mode or I didn't understand the charateristics of 445nm LD....
But I am happy to have 3-mode laser and low mode is visible unlike my expectation.

SHIN

ps)It is hard time for me to wait "v6".....
 

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goninanbl00d

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Re: 3 mode driver for 445nm

Hi.:yh:

No laser driver around has "modes" as far as I know.
I'd like to build my laser with modes.

I have tested several LED drivers for 445nm LD from cheap sites as DealExtreme, KaiDomain.
And I found a proper 445nm LD driver for one Li-ion.

http://www.kaidomain.com/ProductDetails.aspx?ProductID=1672#

I think the following driver is the same one, but it is "back-order" state.

DealExtreme: $4.26 3W 19-Mode Universal Regulated Circuit Board for Flashlights

The board is marked as "NJG-18".

With my custom test load( 4x 1N540x, 1ohm) and one 18650, I set the potentiometer of the board, the current is:
50mA-400mA-1200mA

After building with my custom laser P60 module and aixiz 445nm lens, the power of A140 is:
70mW-350mW-1160mW
Unlike the explanation, it has 3 mode. Low-Med-High. No strobe mode.

Awesome! It is really 3 mode laser!

I can't understand the mismatch of power-current of the low mode.
I guess there was an error in the calculation of test load at low mode or I didn't understand the charateristics of 445nm LD....
But I am happy to have 3-mode laser and low mode is visible unlike my expectation.

SHIN

ps)It is hard time for me to wait "v6".....

Yes, the power mismatch on low mode is normal.

At the bottom end of the spectrum, approaching the diode's threshold current, efficiency is very low.

The A130/140 diodes have a threshold current ranging from 200-250mA, for an output of 50mW or so. 70mA=/=70mW.

Consider that at 1000mA, it is putting out 1W. This is not the case near threshold, however.
 

3zuli

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Messages
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Re: 3 mode driver for 445nm

did you test what is the max driver current? can it go up to 1,5A?
nice laser! I'd suggest placing an 100uF/10V capacitor to the diode leads to prevent voltage spikes and protecting the diode...
 

JLSE

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Re: 3 mode driver for 445nm

Typical DX order for me, has me waiting for my 7135's... In the meantime I was also thinking of trying a 5 mode from the Tank007 flashlights.

It will be interesting if they work well having low, med, high, SOS and fast pulse strobe and memory of the last setting.

I still have to test on my o-scope as well to see how clean the driver is, but I like the idea of having a 5 mode driver powering a 445 :san:
 

SHIN

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Messages
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Points
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Re: 3 mode driver for 445nm

Thank you. goninanbl00d.

And thank you. 3zuli.
My laser is for one Li-ion. Because I heard two mixed batteries "may" cause explosion.
I'm a coward.:yh:
With one Li-ion battery, maximum current is 1200mA.

SHIN

edit) I heard some CPF members "MOD" this driver to above 1.5A. But I am way off the electronics......
 
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SHIN

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Messages
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Re: 3 mode driver for 445nm

Hi. wannaburn.
I also tested with several 7135 based drivers.
But those were not for one Li-ion, but two Li-ion batteries.
The current of 16340 is about 800mA, so I think two 18650s are needed for stable 445nm LD.

SHIN
 

3zuli

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Re: 3 mode driver for 445nm

edit) I heard some CPF members "MOD" this driver to above 1.5A. But I am way off the electronics......

can you post a link pls?
 

JLSE

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Re: 3 mode driver for 445nm

Hi. wannaburn.
I also tested with several 7135 based drivers.
But those were not for one Li-ion, but two Li-ion batteries.
The current of 16340 is about 800mA, so I think two 18650s are needed for stable 445nm LD.

SHIN


I found that a 1400mA 7135 board works very well with the 445's, but does
require 2 x 16340's...

The runtimes for this configuration is nice, and there is no drop in power
from an overheating boost driver trying to keep up.

The great thing with the 445's is that they can handle so much current,
there are many drivers that can be tried.

Nice build BTW, I will be ordering a few of these drivers to try out. I just realized
the 5 mode drivers I have are NOT boost :( I will have to see if they can handle
5v+...
 

SHIN

Member
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Jul 25, 2009
Messages
207
Points
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Re: 3 mode driver for 445nm

@3zuli
I searched CPF but it is hard to find. I'll keep trying continuously.
IIRC, there was something about change of sense resistor and formula something...

SHIN

edit)@wannaburn. AFAIK input voltage of amc7135 is max 6-7 V, not 8V.
 
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JLSE

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Re: 3 mode driver for 445nm

edit)@wannaburn. AFAIK input voltage of amc7135 is max 6-7 V, not 8V.


Ive tested and used them with 2x 3.6v and 445 LD's with no problems...
 

Pontiacg5

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Re: 3 mode driver for 445nm

So the low mode is 50mA and you can still get the diode to lase? That is odd.

How did you take that reading? I'm assuming you just used a multimeter, no o-scope?

I'd be interested to see the output of these drivers, that diode should not lase at 50mA.

I think I know why it is lasing down so low, the low output is pulsed. You are only reading the average across the resistor with a multimeter. I would imagine there are spikes above 200mA on the low setting but they are really short so you only get a reading of 70mW.

These diodes refuse to lase below 200mA, most start around 210mA. There is no way you could get a coherent beam with 50mA of clean power.
 
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3zuli

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Re: 3 mode driver for 445nm

@3zuli
I searched CPF but it is hard to find. I'll keep trying continuously.
IIRC, there was something about change of sense resistor and formula something...

SHIN

edit)@wannaburn. AFAIK input voltage of amc7135 is max 6-7 V, not 8V.

well DX says it's up to 3A:evil: I ordered one
 

RA_pierce

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Re: 3 mode driver for 445nm

I have tested a few DX 5-mode LED drivers.
Low and Med mode was "pulsed" at a high frequency.
I'm not sure if it was just those specific drivers, a power source issue or what.

Check that your diode is not being pulsed.
An analysis on an o-scope will be best for determining which drivers are suitable for laser diodes, if any.
Spikes are dangerous for sensitive components like laser diodes.
 

Pontiacg5

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Re: 3 mode driver for 445nm

I have tested a few DX 5-mode LED drivers.
Low and Med mode was "pulsed" at a high frequency.
I'm not sure if it was just those specific drivers, a power source issue or what.

Check that your diode is not being pulsed.
An analysis on an o-scope will be best for determining which drivers are suitable for laser diodes, if any.
Spikes are dangerous for sensitive components like laser diodes.

That's what I thought, I would not expect these to be any different.

Can you try sweeping the laser across a wall really fast? A pulsed laser will look like this



These drivers might be pulsed a lot faster though, so you might have to sweep the laser pretty fast to see the dashed line.
 

RA_pierce

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Re: 3 mode driver for 445nm

That's what I thought, I would not expect these to be any different.

Can you try sweeping the laser across a wall really fast? A pulsed laser will look like this



These drivers might be pulsed a lot faster though, so you might have to sweep the laser pretty fast to see the dashed line.

The drivers I have are definitely pulsed at a few kHz.
It may be hard to tell without moving the laser very fast.

@SHIN:
It would be easy to check using a spirograph- a mirror attached to a spinning motor or fan. If you don't have any other means to check, that would be a good option.
 

SHIN

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Jul 25, 2009
Messages
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Re: 3 mode driver for 445nm

Hi. Pontiacg5 and RA_pierce

There is no pulsation at fast moving of low-med-high all that mode.
I expected the low mode were not visible, but visible.(I'm happy!)
I used 4x1n5404 and 1ohm resistor.
I wondered my test load calculation was not correct at low current.
I understand now why the mismatch of current-power was.
Thank you. Pontiacg5 and RA_pierce

SHIN

edit) YES. I can see "high freguency pulsation" at very very rapid moving of "low mode".

I also worried about spike and ripple. But I built mine bravely..And it is working fine..
I don't know the longevity but I enjoy 3 mode now..
I wish it will last long time.
 

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