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

[lazeerer]

Re: NJG-18, multimode boost driver for 445nm

Kinda upset right now. I just got the driver in and when hooking it up it started making a ringing nose, witch i think i remember reading some where that ringing nose comes from the Inductor. Anyways my driver was on for 10 seconds then died.

This stinks. I really wanted to use it. I guess i have to wait till my other comes in From DX. This one that broke on me was from the US seller.

You win some you loose some.

 

[DTR]

Re: NJG-18, multimode boost driver for 445nm

Found some info on these that I have not seen posted before.:beer:


Some random thoughts on the NANJG-18 | BudgetLightForum.cz.cc

 

[SHIN]

Re: NJG-18, multimode boost driver for 445nm

That's great! Thank you. DTR.:wave:

It's hard for an amateur like me to understand this info...
I hope some expert member can mod a NJG18 LED driver to a true LD driver, which can supply upto 2A for 445nm by modding Ra/Rb in the link you posted...

I couldn't find the formula or the equation for these resistors.(sense resistor?)

SHIN

 

[DTR]

Re: NJG-18, multimode boost driver for 445nm

That's great! Thank you. DTR.:wave:

It's hard for an amateur like me to understand this info...
I hope some expert member can mod a NJG18 LED driver to a true LD driver, which can supply upto 2A for 445nm by modding Ra/Rb in the link you posted...

I couldn't find the formula or the equation for these resistors.(sense resistor?)

SHIN

It is all Greek to me as well. My hope is somebody who knows what it means can give us some useful tricks with it to reach 1.8W with a single Li-Ion. They give me 1.5A with 4.2V but I can also get it to give almost 1.9A with 5V from the battery. So I am thinking maybe a dual Li-Ions in series set up with a 5V regulator or two in parallel if they can not handle the current. The LM7805 5V regulator is rated for 1.5A and the current draw when set to 1.8A with 5V from the battery is 2.4A and I was wondering if I put two of the regulators in parallel if they would split the current running through them and handle 3A total?

 

[lazeerer]

Re: NJG-18, multimode boost driver for 445nm

When i get my replacement in i will give it a try and see if i can figure it out. I wish i order 2 from the US seller at the time.

Iam trying to look over the board but cannot find anything wrong with the one i got. Nothing fried or anything. Hopefully DX doesn't take forever or the US seller gets them in sooner.

 

[qumefox]

Re: NJG-18, multimode boost driver for 445nm

One thing I don't really like is that this is a constant voltage driver and not a constant current. While it will still technically work, CC drivers are safer for laser diodes. Though as the a fore mentioned article states, the Ra/Rb resistor divider network is what has to be changed to vary the driver's output voltage. I cant see the traces in the pic well enough to figure out how that section is wired, so you'll have to wait until I get the batch I ordered for more info.

Also, the components circled in red, green, and pink are the components that would benefit from heatsinking.

Laseerer, try removing the solder bridge below C1 to cut power to the mode controller, then connect the (-) of the test load or LD straight to ground instead of the driver. According to that article, the mode controller is driven parallel with the load. It's possible you cranked the voltage up too high and killed it. If the driver still works by bypassing it, then that's what happened.

 

[DTR]

Re: NJG-18, multimode boost driver for 445nm

Ok so I built another one and this time sinked the chips circled in red and green in the picture I linked to on the last page per qumefox's recommendation. Did not sink the chip circled in pink on the other side of the driver this time but it seems to be working great.

I started out by making a huge hole in the coin and then using my dremel with a cutting wheel to make slots on the side so the coin can sit on the chips I am trying to sink. I also put some electrical tape just so there is no shorts.

Then I put the driver in the coin with the three chips in contact with the metal of the coin.

Now I made a mess with the thermal adhesive but I got it bonded to the coin.

Then I wired it into the pill of the MXDL.

Bonded the coin to the pill.

Screwed the pill into the host.

Soldered my diode to the driver.

Then slapped it all together and tried it out.

And I did a 10 minute run with a peak of 1740mW. Sorry did not feel like taking it all night to upload so I compressed the video quite a bit.

 

[warriorx15]

Re: NJG-18, multimode boost driver for 445nm

Hey do you happen to know how to get rid of the modes? I want one of those without any modes.

 

[qumefox]

Re: NJG-18, multimode boost driver for 445nm

Simple. Connect the LD- directly to ground instead of to the driver. Though the driver can be modified to eliminate the modes too. It says how in one of Shin's posts in this thread.

 

[netwave]

Re: NJG-18, multimode boost driver for 445nm

Great thread Shin Subscribed

 

[3zuli]

Re: NJG-18, multimode boost driver for 445nm

well it seems that I have some bad luck with this driver... I ordered another one like month ago and when it came here, I connected it to my testload (4x 1N4007 and 1R resistor) and it went only up to 500mA on high mode

 

[ReNNo]

Re: NJG-18, multimode boost driver for 445nm

I also had bad experience with one of these drivers ordered from KD.



These two chips almost exploded when I connected driver to dummy load.
But second driver works just great, giving more than 1200mA.

 

[qumefox]

Re: NJG-18, multimode boost driver for 445nm

well it seems that I have some bad luck with this driver... I ordered another one like month ago and when it came here, I connected it to my testload (4x 1N4007 and 1R resistor) and it went only up to 500mA on high mode

Read all the posts in this thread.. Instructions for modifying it to work correctly are here somewhere.

 

[DTR]

Re: NJG-18, multimode boost driver for 445nm

I also have one that I put too much voltage in that fried and is now only giving 500mA and turning the pot does nothing. I am weary to hook it up to an actual diode for fear that it may damage it.:beer:

 

[LarryDFW]

Re: NJG-18, multimode boost driver for 445nm

I also had bad experience with one of these drivers ordered from KD.



These two chips almost exploded when I connected driver to dummy load.
But second driver works just great, giving more than 1200mA.

I hate to be the bearer of bad news . . . .,

but the D1 SS14 Schottky diode in this circuit is rated for 1 amp maximum average current.

That means for reliable operation, the output should be no more than 1000ma.

(Original circuit design was 700ma output)

I hope that saves some LD's.

LarryDFW

 

[DTR]

Re: NJG-18, multimode boost driver for 445nm

Just thought I would post up a really neat unit I built with this driver this week. It is a 1.2/1.4W Jayrob Pocked Mini.



Here is a run I did with an Aixiz lens and after I show off some of the modes.

The driver replaces the stock one perfectly in this host. And allows very easy access to the pot every time you go to change the battery.

Direct press copper heatsink.:drool: