Heatsinking X-Drive Driver? For continuous operation/100% Duty Cycle?

[simonb]

Dear 445nm Forum,

Please can you help me with a question about the excellent X-Drive driver modules that I'm hearing good things about?

I am about to undertake my first build of a 445nm laser using a 1.7W~2W M140 laser diode supplier by a chap known as DTR.

It going to be the blue in a lasershow system I am building. (I'm new to solid state lasers, but worked in the field using 4W Spectra-Physics Argon lasers back in the 80s. I cannot believe the power available with laser diodes! 30 years ago this would need a £40,000 Argon laser weighting half a ton that required 3 phase power & water cooling! And don't even mention the exploding power supplies; if the cooling water was too cold then condensation would form in the pass-bank & boom!).

DTR is supplying one of his combos which normally include an X-Drive driver inside the 12mm housing, but as I want continuous duty cycle he suggests using longer wires so I can have the driver outside the housing & heatsink it.

My question is how should I heatsink the driver?

It doesn't have a typical TO220 style regulator or MOSFET device to bolt a vaned heatsink to!!

I guess it's the surface mount IC that needs heatsinking, but I have no idea how to do this. I read somewhere that I could epoxy a piece of copper plate to it, but I thought I would check to avoid an expensive mistake!

I need to heatsink the diode case also, but I think this is easier, as I've found various mounting blocks for sale, which are effectively blocks of aluminium with a 12mm hole & Allen screw to hold the case securely.

Any help or advice would be greatly appreciated.

Many thanks,

Simon Bond.

[m0f]

You definitely need a driver that supports analog modulation. The x-drive is more designed for pointer use and simple on and off. The flexmod p3 is a popular one, and also dave at lasershowparts.com makes a nice reasonably priced dual driver, and also someone here named lasertack (i think) also has a line of drivers.

In the very least you need ttl modulation, which is on and off, but controllable with a 5v input for laser projector use. But analog modulation will allow for 0-5v range of dimming which is important for an rgb build, but also good feature to have in general when setting them up / aligning.

As well these drivers are a little more robust, designed for continuous use. Still need to be heatsinked though.

[The_Doctor]

If you're into DIY electronics, Sam's Laser FAQ has some diode driver circuits. There are one or two FET-based designs known to Google, but I'm not sure if the ones I remember are still known to it.

[simonb]

Thanks for the advice.

I'm going to have to stick with the X-Drive for now as its on order!

My question was rather more on the specifics of heatsinking the device on the driver itself, rather than the benefits of analogue mod/RGB; in fact I'm only able to build a blue system at the moment due to funding.

It appears to be a surface mount device, so if I can find the package type I could search for a suitable heatsink.

LPF made mention of gluing a piece of copper onto the device with epoxy. That doesn't sound a robust technique & could epoxy such as Araldite conduct the heat away? Or am I missing something (perhaps its a special epoxy with similar thermal conduction properties to thermal compound?

I read suggestion of mounting the driver onto the mounting block which holds the diode case.

Any ideas?

Thanks again,

Simon.

[m0f]

Well if you plan to use it for scanning of any type (ie a laser projector), you need some sort of blanking or modulation. The x-drive is not suitable for that.. So if you try to modulate fast with that you'll likely either damage the driver, the diode, or both in the process.

Even if you don't plan on building a laser projector with it (using it for scanning in any way), continuous use is just something that driver isn't built for, so it's going to be a challenge to get the heat away. Thermal epoxying it to a big chunk of aluminum, or heatsink / fan is probably all you can do.

Arctic Silver makes a 2 part thermal epoxy, that works pretty good for that type of thing. But it is permanent, so once it's hardened it's very difficult to break it loose without damage.
http://www.arcticsilver.com/arctic_s...l_adhesive.htm

I'm of the mindset of do something once and properly, it saves a lot of money and headaches in the long run. Basic drivers that can be easily heatsinked / built for continuous use aren't that expensive, probably not much more than the cost of some thermal epoxy..

[The_Doctor]

...could epoxy such as Araldite conduct the heat away?

m0f is right, to do this well you need an analog modulated driver, and to start from that point, but for a quick and dirty test device Araldite will work if the areas to be bonded are broad, and the glue is very thinly spread. Arctic Silver is obviously better, but a slab of cured unused Araldite feels cold to initial touch, meaning that while it's not an ideal thermal conductor, it's far from useless. Be wary of heat flow. Make it like a river delta, it's lousy if it can't spread out fast into ambient conditions. Sticking some small bit of copper on it might end up reducing thermal coupling to air instead of increasing it. Also, Araldite will go soft if it gets close to the upper limit of safe temperature for silicon electronics.

Your best bet is to keep the X-drive intact and find a use for it closer to its original purpose. And look at the drivers in the Laser FAQ because DIY can save you money if you don't have to design and test it yourself.

[steve-o]

I doubt if we're going to be much help with a pointer type driver. Try LPF or google "X-driver" I found a multi page thread here:
http://laserpointerforums.com/f52/x-...rer-66687.html
or email/PM the manufacturer "lasereer" for heatsinking instructions. From what I briefly read said " needs no heatsinking " on the 1st post ..

[TechJunkie]

This is a great driver for continuous use. No heat sinking needed. I have 8 X-Drives running various diode configurations up to a 2.4W 445nm diode. What's great is he can custom make your driver with a pot, and resistors so you can adjust the current to the max, or down to the lasing threshold of the diode without damaging the diode. Makes it great for color blending a RGB setup. It might not be the best driver for a high-end projector, but it has more applications than just a pointer driver.

The X-Boost is the one that needs the heat sink. Its a single cell driver (4.2v).

[m0f]

Modulation ? (15 chars)

Edit : Modulation / blanking capability is pretty important for a projector build. Any projector, even single colour needs some kind of blanking. Without modulation support, maybe still good for a lumia.

Other blanking options would be mechanical such as a blanking galvo, or aom, but either of those would end up costing far more than a driver with direct modulation

My bad if it supports modulation, but my understanding is that it does not.

Just wanted to add, in re-reading my post, sorry if I sounded a bit snippy, was not my intent. I'm on day 4 without a cigarette now and what I type seems to naturally come out that way now

But the op mentioned the plan was to build a projector with it. Perhaps clarifying exactly what you want to build will help us give a proper recommendation. But if it a scanning type laser projector, some sort blanking is needed (the ability to turn the laser on and off at high speed in time with the scanners).

In looking at the specs of the x-drive I don't see mention of that, which is typical of the pointer style drivers, and just makes them not suitable for that type of build. I wish more did include that as a feature..

[TechJunkie]

I didnt think you were snippy, so no worries. My girlfriend can only handle day 3 of me quitting till she throws a pack of stogies at me.

No, the X-Drives do not support modulation. My point only being they are a great driver for continuous use without heat sinking. Good for Lumia, Spiro, IR tripwire, 7 color laser, Star field generator, ect. If you wanted to create one of those cheap Chinese disco lasers this would be the better driver.