17mm/22mm MTN-MAXlp - Low-Profile 1A-4A Programmable Buck Driver + 22mm MTN-MAX

I saw a Cray II running once. There is one at the computer museum in Mountain View, but it doesn’t look so impressive turned off. When it was running, there were streams of tiny bubbles rising from the components. It ran in an aquarium full of freon.
A cooling liquid should be low viscosity and preferably have its boiling point below the highest component temperature. The main practical requirement, though, is that it not affect the components. Water probably won’t do, because it holds ions that make it conduct and it hydrolyzes. The ideal fluid would also have a high heat conductivity, high heat capacity, low surface tension and large thermal expansion.

Can the 22mm version of this driver be used with an electronic switch?

Yes, if it is programmed to use one. The quiescent current drain isn't super high (lower than zener mod), but it still isn't ideal for use as a momentary driver without a lockout of some sort.

I finally read this thread since back when the OP was just getting built. Exciting driver for sure.

Have you let the laser folks at LPF know about this driver? I think it would get a lot of attention. They spend big money on drivers that don't seem nearly as nice as this one. Especially considering the ability to customize the UI.

Does 4 layer mean thicker copper in one layer or 4 separate layers that are isolated from each other for more tighter layout of components?

Thanks RMM. I was going to use it in conjunction with a tailcap switch so it would be locked out. Its a little late now though as the driver is in the mail somewhere. I should of asked the question at the time.

^ I imagine you could wire a momentary switch to the Reset Pin (Pin 1) with just about any FW. I don't know if the OTC feature will work that way though.

It would work, except that you can't even hardly see that pin on that MCU unless it is specifically broken out.

I haven't talked to anyone at LPF about the driver. Honestly, I don't know much about the laser diodes and what specific requirements they may have. I know that they are expensive devices in comparison to our LEDs.

The Oshpark 4-layer boards are the same thickness (1 oz.) on the outside layers, and half thickness (0.5 oz) on the inside layers. The advantage is that you can run a complete pour in the middle layers to take better advantage of thermal vias by using the vias to spread heat directly to the copper in the middle layers which can then more easily transfer the heat into the fiberglass PCB and to the exposed copper around the edges of the driver. I had drivers that were dying after extended use with the two layer board that are still kicking despite lots of extended full power runs without a timer in the same light at the same power level with otherwise the same components. With my thermocouple I measure a 10C-20C difference in the component temperature and a corresponding increase in PCB temperature. I wanted to build a driver that was tough enough to handle lots of use and abuse as long as it had a decent thermal connection to the pill--it had better, given the price of the components alone.

^ I haven't been active at LPF in quite some time. I'll post a link to this thread over there and also to your complete build product page and just tell them I don't know how well it would work with most laser diodes, but it sounds promising. It does sound interesting. I have a couple laser diodes I've been wanting to use. I will probably use this driver for them.

Not sure I understand the 4 layer thing, but I sounds like a very good thing. Thanks for developing it. Definitely the way I will go when I get or make one of these neat drivers.

RMM wrote:

ImA4Wheelr wrote:

^ I imagine you could wire a momentary switch to the Reset Pin (Pin 1) with just about any FW. I don't know if the OTC feature will work that way though.

It would work, except that you can't even hardly see that pin on that MCU unless it is specifically broken out.

Well, hopefully MRsDNF will have enough of the board's contact pad exposed to solder a thin wire to. Momentary switches can use very thin wires.

When I get the driver I'll have a look and see if I can nut out what you guys are talking about. Thanks for the help.

OK guys, here is the 4-Layer PCB at Oshpark; from MTN.

Parts kit. The parts needed are the same, except I can only recommend using Coilcraft XAL6060 inductors at these drive levels and there are 2x diodes instead of one. The second diode basically just heatsinks the first, but it works. The second input capacitor is optional. After reflow, fill the exposed copper on the FET's drain pad with solder for increased thermal conductivity and decreased electrical resistance.

Ordered.

Here are some pictures for those you looking to build your own. The regular (non-HP) version is pretty much the same, so you can use these to guide you with it as well.

Thanks once again Richard!

Wow that looks like a tough build!! :slight_smile:

Hey folks. RMM added a parts kit for the 4-layer board. Pretty excited about this little buck that could so I had to order.

Remember if you order the parts kit it isn’t an SOIC8 Attiny, so it’s a little harder to flash. I made the mistake of ordering the mcu bare

What would one’s “Ideal build” be with this driver? Host? LED? Battery config? Looking for some idea’s?

UF 1405. That light rocks with a good driver in it. 5A constant current until the two 26650s are dead.

Thanks Richard, sounds like a winner!! :wink: