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

I am not sure this is definite but according to Kaidomain the NJG has been discontinued. I see they are sold out on DX as well. If they really are gone I wonder if they were pulled for exploding drivers?.:tinfoil:

Thanks for the tip, DTR. I just topped off my stock in case this is the end of the NJGs. Quite a few builds are now designed around them

Well this sucks. Though the cavity in my sipik's are big enough to stuff most drivers in. So at least I don't have to redesign. the NJG-18's were certainly convenient and cheap though, even if they weren't optimum for the application. Maybe I should try to develop my own boost/buck driver for them. Shouldn't be extremely hard, Not like trying to build something micro flexdrive size.

Time to put the squeeze on Jib to get crackin on the JibBoost.

rocket689 said:

Time to put the squeeze on Jib to get crackin on the JibBoost.

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ouch, don't count me out. Ordering parts for mine in the next day or so for first protobuild. =)

random person said:

ouch, don't count me out. Ordering parts for mine in the next day or so for first protobuild. =)

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Ok, bring it on! The more the merrier. :beer: I don't want to see another boost driver famine ever again.

I'll likely attempt one as well but that's fairly low on the to do list for me. I need to get a large stock of my sipik hosts finished so I won't have to spend every night standing in front of the lathe.

LOve the use of the PIC 12f629 microcontroller in the the driver, albeit I'd use one also just because they are easier to set a frequency up with then some other oscillator, at any rate if someone has either the reverse engineered schematic for one or a broken one, I'd be more then happy to try and see what I could do to either design or make boost drivers for LPF, but since I'm new and DX is out and so are some of the others I'm sort of stuck with only the knowledge of how to make a boost converter which isn't all that great for small builds due to larger current draws.

If your going to the trouble of designing a boost driver for laser use.. there is ZERO point in trying to make a clone of the NJG-18. It's a CV driver and from looking at the datasheet of the regulation IC it uses.. it'd be extremely difficult to convert it to a CC driver.

And boost drivers will ALWAYS have large current draws. Even if it was possible to manage 100% efficiency, the lower the source voltage, the more current it would need to maintain the output.

Here's an example.

Say you had a diode that draws 1A at 5V (just for easy math) That's 5W of total power. Even with a 100% efficiency driver.. which isn't possible.. The input would still require 5W. So if your source was say.. 4.2v.. The driver would have to pull 1.2A to maintain that same 5W output.

As source voltage drops.. it will get worse.. Say you wanted to run the same driver off a some type of single alkaline or lithium primary.. at 3V input, it would need 1.66A to maintain the output.. at 1.5V input, it would need a whopping 3.33A to maintain a 5W output.

The fact that it's impossible to make a 100% efficient driver also compounds the problem greatly. 'good' drivers generally run in the 70-90% range across their tolerated voltage input range.. And some drivers are much much less efficient.

I was just making the suggestion since everybody liked them plus with the fact that it is using a microcontroller means, as long as theres code space and pins available we could ad as many features in as allowable.

It is not that we like them so much but more that they are our only real boost based alternative to the flexdrive.:undecided:

The microcontrollers these use, even if they're PIC's, are generally cheap single write flavors. IF you want to modify one you usually have to replace it with something else. Besides, the modes are just negative side PWM anyway. It really has nothing to do with the actual regulator, which is why they're easily disabled. If your driver is able to be disconnected from the diode even momentarily without it going poof or it causing the diode to fail.. modes can be added fairly easily.

If they work ok, does everyone tend to like the idea of modes provided they're not stupid? Personally, i love the thought of being able to change my laser between low and high powers, and i really like the idea of a strobe.

JaiNobeZ said:

If they work ok, does everyone tend to like the idea of modes provided they're not stupid? Personally, i love the thought of being able to change my laser between low and high powers, and i really like the idea of a strobe.

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Do you mean modes in a newly designed CC driver? I love having the modes when I use a njg on a build. Its just a PITA when setting them up.
As long as the new drivers have the option of disabling modes, id be all for it.

I think most people are ok with modes as long as they aren't overboard. I think my ideal would be a 'low-med-high-variable rate strobe' That way people could set the strobe rate to whatever they wanted it to be.

qumefox said:

I think most people are ok with modes as long as they aren't overboard. I think my ideal would be a 'low-med-high-variable rate strobe' That way people could set the strobe rate to whatever they wanted it to bed.

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That would be perfect! I would love to have a programmable strobe rate.