Anyone use this driver for the new Mitsubishi diodes? 635nm 300mw-500mw Laser Diode Driver

I've bought from qualifound and they are good folks to deal with, but personally I would not use that driver.

I just did not like the way the specs read: IE, it's pretty large in size and might be difficult to make room for in a handheld, and I didn't like the explaination for this: constant current at 6.5V input, but later states recommended voltage to be 3.7V, so what's the current at a 3.7V input?

Then again, I'm not an electronics engineer or even a tech, and it might be perfectly acceptable to the other members here.

It is... a bit big, but looks like a buck driver to me.
BTW, nice avatar, Mark.

^based on what?

8-pin IC: check.
big transistor: check.
big schottky: check.
three caps: check.
potentiometer paralleled with a smaller resistor: check.
OVP zener + resistor: check.
6.5V input: check.
poorly designed driver board: check.

diagnosis: a cheap chinese buck driver.

Dont buck drivers need inductors?

I'm pretty sure the inductor is that big white resistor looking thing... The way it is connected corresponds to it.

lm 317 driver ftw

That big white thing is a Resistor Flip Upside down.

If you scroll up to the main Picture next to the Price you can see it.

1R0 could mean 1uH... there are inductors made in 1206 or 0805... But even if it's not a coil, that would mean it's some weird design and not a switched one... But why the schottky and transistor then?

Yup, it doesnt look like any buck driver ive ever seen?

Seems like we have a couple of options here.

• Weird switched design that doesn't have an inductor
• The inductor is hidden somewhere (the big "resistor"?)
• Weird ULDO linear design that uses schottky and transistor

Guys, this is a regular old linear driver. Where's the mystery?

That white thing IS a resistor, there's no ambiguity on that point. No inductor, so not a boost/buck. It requires 6.5V input to drive an LD with a Vf of 3, so it's a step-down, and a fairly inefficient one.

This is linear. Why they need 3 ICs to accomplish this is beyond me.

Wait! Maybe it's just the LM317 type regulator, built without the IC? That would explain the 8-pin(op-amp) and the transistor. Then we could just call the diode a protection diode, and it would be all explained.

There's one IC... The DPAK type is marked Q1, thus it is a transistor of some sort, and that small little three pin thing is marked D, so it is a (double) diode, possibly used for making the 1.25V ref voltage.

probably just an opamp comparator switching a fet.

Again, a fairly poorly designed one if it drops 3+ volts. Given that, I don't know why they wouldn't have just used an LM1117 instead of the complexity they went with.

That. My buck driver prototype does around .45A with a red load at single li-ion voltage. With minimal heatup. I will see how it preforms in my single li-ion 635 build.

EDIT: Build finished, but I have no lens... I'll order some red coated lens then report.