Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

Need a Driver

Joined
Dec 23, 2007
Messages
2,494
Points
0
Not any driver, but a high current driver. Preferably up to 10A, but the kicker is it needs to be portable.

I've seen some people offering drivers for the SST's or whatever they are, but none of them ever seem to make it to production.

So, I have batteries lined up that can handle a draw way over 10A, but I just need a efficient driver that wont catch fire that will also fit in a mag sized host. I can build things, but I have no idea where to start.

This is for the 2.6Vf red phlat projector LED
 





Joined
Feb 1, 2008
Messages
2,894
Points
0
I was just about to start a thread about a driver for this thing as well! (Except not a portable solution).

Well... lets start with your cells. You say you have some that can handle to current, and I may have a solution for you, but what's the voltage on each of these cells? Are these rechargeable? Are they lithium?
 
Joined
Dec 23, 2007
Messages
2,494
Points
0
These are the cells, bask in the amazingness that is a 20A draw!

AW IMR 26500 2300mAh LiMN rechargeable lithium battery

For those of you that don't want to click the link, they are D cell sized (26500) rechargeable lithium batteries. They have a capacity of 2300mAh and a max sustained draw of 20A. They have the standard voltages (4.2 charged, 3.6 under load etc) of a lithium battery.

I was planning on machining a host to hold at least 2 in parallel (40A!) but possibly up to 4 of these. I would prefer a more efficient boost circuit so I don't have to deal with more heat than is necessary, but I was considering two LM138 circuits in parallel for a while. I am also aware of a LM317 powering a transistor, but I've been told that makes a lot of heat.

Basically, what is the easiest way to get the most efficient circuit? Heat is really not that much of a deal as long as it is nothing crazy, I can configure some way to handle it.

Thanks!
 
Joined
Feb 1, 2008
Messages
2,894
Points
0
Holy #### man. I like how big you think.

If those cells run at 4.2V (typical for a lithium) from a full charge, I recommend some of these 1050mA AMC7135 based drivers (7 to be exact) connected to each other in parallel for an AMC7135 based driver that supplies 7.4A of regulated current, and that would have to drop a maximum of (4.2V - Vf 2.3V) 1.9V on a full charge, which is good, as the chips won't get too warm. The driver would draw 7.4A from the battery, and let the LED take the 2.3V its wants.

Your duty cycle would be limited to either the heat dissipated by the LED, or the drivers - whichever is greater. The driver would shutdown when the battery reaches Vf, which in this case is 2.3V-----> Perfect for an unprotected lithium.

I have read good things about these circuits, and how they love to run in parallel.

This is the exact same setup I will be using, except I will be using the 3.3V rail of an ATX supply.

Be careful with those lithiums.... holy $#@ man.

PM me when you get something going.

Here's the driver: DealExtreme: $16.58 AMC7135 1050mA Regulated Circuit Board for DIY Flashlights 10-Pack
 
Joined
Dec 23, 2007
Messages
2,494
Points
0
Could I just hook all ten up and go
Physics+5.jpeg


:D

7.4A is good, but these are rated at 8A with a max of 16A. I was wanting to overdrive them a touch.

Stacking 10 of those things would probably be difficult though, especially when both of the contacts are on the bottom like that. Not to mention the space needed...

Are there any high current boost drivers around? If I am going to hook things up in parallel I might as well go for something that can push a little more than an amp :undecided:
 
Joined
Feb 1, 2008
Messages
2,894
Points
0
As far as I know, stacking switching boost drive like the flex drive would be a BAD plan. I'm sure there is a methodical way to stack those circuit boards together. If you're good a soldering, the parallel wiring between the drivers would be enough to hold them all together in a nice cylindrical stack, allowing for further expansion. Heck, the boards are less than 2cm in diameter, so sliding a cylindrical stack of drivers into a maglite won't be an issue at all.

These work in parallel because they are linear, and not to mention near 97% efficient at voltages >3.5V.

I'm going to be looking for a cardboard cutout that will insulate and stack several of these things up.

Post if you find any HIGH CURRENT boost drivers, I know they're out there, so it may just take a bit of googling...
 




Top