574nm 36 mW Yellow Laser

[ultimatekaiser]

Sounds pretty solid to me. I used to have a laser with a similar driver when I was first starting out. What I ended up doing was just putting little passive heatsinks on the transistors for more surface area and then took some aluminum roofing sheeting (since it's thin and easy to cut with scissors even) and stuck that to the driver and wrapped it around into an L or U shape, cutting a hole at the top for a small lightweight DC fan to mount to it and then wired that into the 12VDC input so it blew down on to the driver. It brought the temps down quite a bit. I also tuned the current output so the output to the diode was self regulated to about 1.8V as that's usually where most pumps are rated. most 1W pump c-mounts are rated at 1.8V at around an amp. if it's drawing 2VDC+ or so that means it's likely being over-driven and will greatly cut into its' lifespan. Definitely don't go beyond 2.2V! Especially as I'm sure these probably don't have a TEC for cooling inside..it might be prudent to go easy on them.

Just my 2 cents.

 

[paul1598419]

With your mod it should be able to work on 2x18650. I think I'll try that once mine arrives.

Mine runs fine with heat sinks just the way it is. I let it run for ten minutes while watching it on my spectrometer and it didn't flicker or move at all. There is an 8 pin SMD IC that has not been addressed here. I have not seen the underside of the board as it is sealed all the way around with glue. I might pull this one apart as I have more of these drivers on the way to me now.

 

[ZRaffleticket]

Just chiming in, I wouldn't call it flickering so much as turning off for 3 seconds then back on, on repeat. It'll shut off around 300-310F and turn on again around 245-255F.

I have two fans plugged in the fan port to cover both the driver and head. No problems to speak of doing it that way

 

[Alaskan]

I wanted to put a fan on the driver too, that should take care of it, I thought, need to get another fan.

 

[paul1598419]

Just chiming in, I wouldn't call it flickering so much as turning off for 3 seconds then back on, on repeat. It'll shut off around 300-310F and turn on again around 245-255F.

I have two fans plugged in the fan port to cover both the driver and head. No problems to speak of doing it that way

These look very much like the same laser. I wonder if the Aussie just over drove them too much. That would make more sense than anything else I can think of. I increased the current on mine by about 400 mA, but only after heat sinking the output transistor and driver IC.

 

[Alaskan]

I didn't touch my current pot, the unit was marked 35 mw and is drawing about 1 amp from my power supply at 9.0 VDC.

 

[paul1598419]

Jees! No wonder. Mine draws 550 mA at 12 volts at startup and drops to 500 mA in about 90 seconds. And that was after I increased the current. Have you tried using the plug next to the one you are using to input 12 volts?

Even when I was trying to decrease the voltage into it, the driver never pulled anywhere near an amp.

 

[Cyparagon]

With your mod it should be able to work on 2x18650. I think I'll try that once mine arrives.

If someone can get the readings I asked for, it may even be fine on a single 18650 if we can bypass the DCDC converter. The 358 is rated down to 3V for instance.

 

[Alaskan]

I haven't tried that plug, can't now, at work, 6 in the morning here. I lowered my voltage into the white port with the yellow and black wires (re: my photo) to 5 VDC and it started to dim too much, but was still putting out collimated light.

 

[paul1598419]

If what I suspect is true......that your driver has been increased to the point that it is over driving the diode to get more power out, it may fail on you prematurely. You might want to back the current down a bit for the sake of the head. You decrease current by turning the pot CW.

 

[ultimatekaiser]

like i said, I'd suggest finding a way to measure the voltage to the diode. if it's truely an 808-ish pump, it'll only draw about 1.8V-2V. 2.2 tops. if it's a GaN of sorts it'll be about 6V.

 

[RedCowboy]

If someone can get the readings I asked for, it may even be fine on a single 18650 if we can bypass the DCDC converter. The 358 is rated down to 3V for instance.

Yep, you could possibly just use the current regulator and an 18650, you may want to remove the step down to prevent any back feed, granted the regulator may still need the extra heat sink, but there is also the fan....they will run on 3 cells separately, it's probably easier to just use some heat sinks with taller fins.

I expect the head maker bought the driver trusting the overrated peak specs.

Has anyone seen the higher output units yet ?

 

[Alaskan]

If what I suspect is true......that your driver has been increased to the point that it is over driving the diode to get more power out, it may fail on you prematurely. You might want to back the current down a bit for the sake of the head. You decrease current by turning the pot CW.

My thought was the driver wants 12 VDC the way it was built and pulls more current (as I saw, when I dropped the input voltage) to make up for having the lower voltage input, but the heat produced by the regulator causes the device to shut down to protect itself, so it's a loop. Once I get the overheating problem fixed, I should be able to have much lower current when driven at 12 VDC, God knows if the diode isn't being over driven to make the 35 mw output and that is part of it, if the crystal setup I have is less efficient than normal. I will play with the current adjustment after I get the heat problem solved.

 

[paul1598419]

The Vf on my diode sits right around 1.53 volts. I suspect that Australian ones are higher than that because the current has been increased passed where it should be for a long life.


And, No. I tried decreasing the voltage to the driver and even at 9 volts in, it never pulled anywhere near a full ampere.

 

[Alaskan]

1.53, I don't see that low of a voltage for the shorter wavelength NIR laser diodes, so that matches the longer wavelength findings for the diode.

 

[diachi]

like i said, I'd suggest finding a way to measure the voltage to the diode. if it's truely an 808-ish pump, it'll only draw about 1.8V-2V. 2.2 tops. if it's a GaN of sorts it'll be about 6V.

Speculation puts it somewhere around 970nm IIRC.

Still, shouldn't be more than 2.2V or so.

If what I suspect is true......that your driver has been increased to the point that it is over driving the diode to get more power out, it may fail on you prematurely. You might want to back the current down a bit for the sake of the head. You decrease current by turning the pot CW.

Have you verified it's the same driver? If earlier posts about a switching stage before the linear regulator are accurate then I'd expect to see those drivers show a lower current vs one without that.