Sweet…
This fills the buck driver gap.
Sorry… got a little excited there.
Been waiting for this one.
May just have to try my hand at building a driver soon.
Jim
subscribed and waiting on the higher amperage one too! Good work Richard.
Been waiting for something like this for years. Keep up the hard work! Did you ever consider going to school to be an EE?
Richard, thanks.
Let us know when (we the build challanged) can buy this/these from your store?
I have three s7 hosts which I want to get drivers for along with incidentals.
- a triple using the XP-E 660nm Photo Red emitters (probably a different driver)
- a MT-G2 with 2x 18350 (this driver)
- a (other)
You shouldn’t need this buck driver for #2. MT-G2 runs off 6V which you have with the 2 18350 batteries. Any of the Zener modded drivers should suffice for that. This buck is going to drop the voltage of multiple cells down to 3v so that you could run something like a XM-L2 off multiple cells in series.
I’ve been waiting this for too long! Thanks for bringing this 17mm high current capable buck driver to us Richard! 
I am waiting for the release of the 6A version for my 1405… and nope, I’m not gonna build this driver by myself but I will order one from mtnelectronics directly. I hope you will offer them as a complete driver in the future Richard. 
Ordered, along with one of those mmu programming boards.
Still looking forward to your other versions. This is good stuff Richard.
Richard does sell a 20mm 6 volt 3 amp buck driver. I bought one to try on a XHP50 upgrade on one of my lights that can’t take the heat of a fet driver. Also I was too lazy to zener mod a 105E driver. :bigsmile:
LD-2D 2 or 3 Cell Driver - 20mm - For 6V LEDs - 3A
At this point in my life I think I'm about ready to be done with school! I have a biology degree where I did learn a little bit about basic electronics in physics, and now I'm finishing up law school. I did consider going back afterwards to get an EE degree or CS degree because those are very desirable in the patent law field, but after I decided not to pursue patent law I decided not to go back.
Besides, I just do this stuff mainly because I enjoy doing it. I don't know if I'd enjoy it as much if it were a "real job". I'm sure that a real EE would just laugh at some of my attempts, because these drivers are really simple compared to some of the products we use every day. I design these drivers at lunch time and when I get a few spare minutes, so I usually move pretty slow.
crap! we need an EU warehouse!!!
thanks Richard. I appreciate you putting this out there for the BLF community. Ordered the boards and the MMU breakout board that pilotdog reminded me of!!
+1 :party:
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OSH spamers 
subscribed and waiting on the higher amperage one also! Kudos to Richard for this fantastic resource. Wonderful vendor.
cant wait for other versions! twenty and 22 mm versions would be cool
For 20~22mm size we already have the LD-29 (about 21mm) which is capable to handle and deliver high current.
i need more than 3a though. 6a would be good. or more
I wouldn't recommend using this with a contact board, as it relies on having a direct thermal path between the ground ring and the pill, either by use of a retaining ring or solder to transfer the heat from the driver. Any intermediate piece, especially another PCB, will limit the transfer to some extent.
Looks great RMM. You know much more about this stuff than me. So I apologize if this is a dumb suggestion. I find that the fly back diode to be a limiting factor in some buck drivers. Maybe the inductor size you are limited to space wise is more of a bottleneck, but it looks like you have room to add a parallel to D1.