NUBM44 6W+ 450nm Laser Diode

[ED KLINE]

I am always looking to see what I might have done wrong, and have no problem openly admitting fault, regardless of how dumb the mistake was. Lol. But I can't see anything at all that I could have done differently with any of the ones that failed or otherwise acted up.

That does look like a quality driver. But I don't see any way of heatsinking the IC easily?

Hello. Looking at the pot in question, could the circuit be sensitive to current spikes as the pot is turning? Ed.

 

[TaterMay]

Not sure about the ones that stopped working but shoot them over to me or Lazeerer and I am sure we can get them replaced as long as they have not had reverse polarity or any obvious damage.

On getting it to go over 4.68A. I am commonly seeing people hitting the limits of their test loads with these. On mine I have to use 14V and the lowest setting on the test load to keep the test loads forward voltage under the voltage from the power supply. I would bet this is the issue. If you are hitting a hard ceiling and the pot can turn more it is probably going up you just cant read it as the unit is falling out of regulation.

No, it wouldn't go up OR down. Lol. I actually didn't want it that high, but that one hit 7.79 watts, so I was alright with it.

I don't use a standard test load for these. I use a 100 watt 1 ohm resistor when going over 3A or so. I don't think I can get them out without damaging them, as they are attached to the copper MX900 heatsink with thermal adhesive. They do have to come out regardless, but I'm not sure they'll be intact. I got one out, and it appears that something overheated and burnt out. I'll send you and Lazeerer a picture.

How can you tell if someone has damaged a driver with reverse polarity? Is there something specific to look for? I had a 3 watt laser that I sold that died inexplicably that I was curious about. I replaced it for him for free anyways.

Hello. Looking at the pot in question, could the circuit be sensitive to current spikes as the pot is turning? Ed.

I don't adjust it while supplying power to it. It's not a spike, it is simply stuck at that current and will not go up or down at all.

 

[DTR]

No, it wouldn't go up OR down. Lol. I actually didn't want it that high, but that one hit 7.79 watts, so I was alright with it. \.

Oh check and see if when the range resistors were bridges you might have overshot to the one next to it that has a zero on it and all three are now bridged. It will get stuck in high if that happens.

 

[TaterMay]

Oh check and see if when the range resistors were bridges you might have overshot to the one next to it that has a zero on it and all three are now bridged. It will get stuck in high if that happens.

It's already heatsinked in that very small space, no chance of doing anything with it now. I didn't touch the range resistors. I don't believe it's one I got from you because almost all of the SXDs I've gotten from you have been fixed current for a while now. It might be a replacement Lazeerer shipped me. But that one is perfectly fine with me. Like I said, 7.79 watts was way higher output than I've gotten from any others at 4.5A.

 

[RedCowboy]

I messaged X-wossee and he replied back that it is sufficient to use heat tape or heat sink compound to bond the flat backside of the driver to your heat sink.

6A Adjustable Buck LED Laser Diode Driver for NDB7A75 NDB7K75 NUBM44 445nm | eBay

 

[TaterMay]

Nice. It looks a little big for my application, but it looks to be a solid driver.

 

[rhd]

I messaged X-wossee and he replied back that it is sufficient to use heat tape or heat sink compound to bond the flat backside of the driver to your heat sink.

6A Adjustable Buck LED Laser Diode Driver for NDB7A75 NDB7K75 NUBM44 445nm | eBay

If it was me, I'd think that heatsinking the top of the inductor to your heatsink would do a better job of dissipating heat. It looks like the switch is integrated into the large IC (the two smaller ICs are probably too small to be external switches on this driver). That means you'll have quite a few pins on the large IC connecting to the inductor with thick traces and able to dissipate heat through that route if the inductor is sinked. Conversely, I don't see very many vias to move heat from the topside to the bottom of the driver if that's your heat escape route.

If this were me, I'd take a thin piece of copper or aluminum and arctic silver it across those two smaller ICs and the one larger IC, without touching other components. Then, assuming the inductor is still higher from the board, I'd arctic silver the inductor to the heatsink. If you're lucky enough and can find metal that is the right thickness to bridge across the 3 ICs and also raise the height to be on par with the inductor, you could do that, and then arctic silver both the inductor and IC bridge to the heatsink, and you'd be laughing.

 

[Cyparagon]

I'd think that heatsinking the top of the inductor to your heatsink would do a better job of dissipating heat.

That's a No-No. Having large masses of conductive materials adjacent to inductors will cause losses from eddy currents, degrade the performance of the inductor, and change the inductor's value. If the inductor is too hot, the wrong inductor is being used.

 

[TaterMay]

That's a No-No. Having large masses of conductive materials adjacent to inductors will cause losses from eddy currents, degrade the performance of the inductor, and change the inductor's value. If the inductor is too hot, the wrong inductor is being used.

Exactly what I was thinking. I knew that heatsinking the inductor was a no-no, but I couldn't remember exactly why. That's why I originally asked about heatsinking this driver because on the component side, the inductor sticks up much higher than all other components.

 

[zoeid]

hey gy i discoverd now this diode. (ye sorry for not meeting laser hobby everyday)

now i'm gonna selling my unused logitech g25.. to buy this. (i feel like a monkey are telling me to must do.. :yh
but one quest:
as of DTR picture.. more than 4.5a is useful..
but i've seen many user here reaching more than 7w

is 5amp option in dtr's shop good?

i have an Ehgemus host (2x18650) so not problem with heat XD

 

[ricktrent4]

hey gy i discoverd now this diode. (ye sorry for not meeting laser hobby everyday)

now i'm gonna selling my unused logitech g25.. to buy this. (i feel like a monkey are telling me to must do.. :yh
but one quest:
as of DTR picture.. more than 4.5a is useful..
but i've seen many user here reaching more than 7w

is 5amp option in dtr's shop good?

i have an Ehgemus host (2x18650) so not problem with heat XD

I have tested a lot and 4.5A is the best spot, did not get more going over that!

 

[RedCowboy]

I agree, 4.5 amps is as high as these should be driven, some may take 5.0 without dimming back, but it will shorten it's life significantly.

 

[Isaac Clarke]

those thing have horrible divergence but nowhere close to the divergence of those red multi mode diodes.

 

[Shakenawake]

those thing have horrible divergence but nowhere close to the divergence of those red multi mode diodes.

if you mean the diode that is the subject of this thread and say, a mitsubishi or oclaro 638 multi-mode, yeah they are just as bad

 

[zoeid]

but at 5amp will i jet better power? or not?

 

[ricktrent4]

but at 5amp will i jet better power? or not?

I tested 6 and did not get any more power over 4.5A