500mw Mits 635: X-Drive, single cell?

[arcaneinsomniac]

On the cajunlasers page of the 1.5A X-Drive it says two lithium cells would be good for the driver. I was hoping that since the diode does not seem to require more than 3V that a single 3.7V cell and a buck driver could be possible.

Is it that at 1.5Amps that this will be difficult to pull off? Has anybody tried this? Is it perhaps that the driver has limitations which amount to it unable to operate without at least the 5.6V input?

I want to put my new $75 diode in a 1x16850 (solarforce) host and I was hoping I could avoid going to 2xRCR123A *and* run a driver not in need of heatsinking.

I guess a proper solution considering the LD voltage in this case with the 635 is an AMC7135 based driver. I ordered several 1400mA ones of these but I have to wait for delivery from China.

 

[LarryDFW]

arcane;

A good linear design buck regulator should be able to deliver ~1 amp current from a quality #18650 cell with low resistance.

The 7135 circuit should work, but I would run at 1050ma for diode durability.

LarryDFW

 

[arcaneinsomniac]

Fiddy has a build driving this diode with one more AMC7135, 1750mA! I already have a Mits 300mw @775mA... I just know that 1050mA won't leave me satisfied.

Looks like my choices if I want to go single cell are:

AMC7135: modes, is linear so is efficient for this diode and single cell
Flexdrive: heatsink needed
Some other Linear or Buck driver: prefer something that doesn't require heat sinking

Are there some mini buck drivers that do 1.5A off a single cell? I suppose I have a lot of options since linear drivers are okay too. The benefit of buck is bigger input voltage range.

I am getting impatient and might take apart my 775mA 300mw Mits and max out the flexdrive on it. Maybe I'll build 445's using those AMC7135 drivers later. For the modes. But I feel like they'd need heatsinking at 8V in and LD V < 6V... Maybe I'll run lithium primaries.

 

[IsaacT]

Look at the IRON4D driver new from Benwmv(and friends maybe? I forget). According to him it only needs one Li-Ion cell and you could stack them to double the mA. So you stack two of the 700mA ones to get 1400mA. Should do well.

 

[jander6442]

Never gut a working laser for parts you will hate yourself later.

 

[arcaneinsomniac]

Never gut a working laser for parts you will hate yourself later.

Sounds like good advice. If only I had a bench-heatsink or something to mount the new diode in. I just want to witness its emission without waiting and waiting.

Look at the IRON4D driver new from Benwmv(and friends maybe? I forget). According to him it only needs one Li-Ion cell and you could stack them to double the mA. So you stack two of the 700mA ones to get 1400mA. Should do well.

:thanks: I will look into this. I suspect, though, that dual drivers isn't gonna be tremendously economical.

 

[IsaacT]

They are 10 bucks each. See here: Iron4d Info Guide. If you decided to buy one you can find them on page two of the drivers on Cajunlasers' site.

 

[arcaneinsomniac]

They are 10 bucks each. See here: Iron4d Info Guide. If you decided to buy one you can find them on page two of the drivers on Cajunlasers' site.

I love you for just handing me a link, and I love discovering well engineered solutions. That thread is filled with awesome. woot

The magic board sounds too good to be true (and at that price!!). Looks like somebody took a flexdrive, made it 10 times better and made it into an IC. At that ridiculously low voltage drop it seems to be the solution for everything. How to set output current though? Edit: Oh I'm an idiot. It performs no current regulation.

 

[arcaneinsomniac]

Since Iron4d is in fact using 7135... Could I not simply solder two more 7135's on top of the two 7135's on one board? Not that such an effort would be in fact "simple" enough to be worth $10 for me.

 

[LarryDFW]

Since Iron4d is in fact using 7135... Could I not simply solder two more 7135's on top of the two 7135's on one board? Not that such an effort would be in fact "simple" enough to be worth $10 for me.

You can solder the 7135 IC on top of another 7135.

Just be aware that the heat dissipation will be POOR . . .

and the stacked 7135 IC will go into thermal shutdown fairly quickly.

Just buy a board with four 7135 IC's on it.

LarryDFW

 

[Blord]

Since Iron4d is in fact using 7135... Could I not simply solder two more 7135's on top of the two 7135's on one board? Not that such an effort would be in fact "simple" enough to be worth $10 for me.

Stacking two 7135 for more current is almost standard procedure at the flashaholics. They add two more 7135 ic to the already crowded 8x 7135 board.
Use the top pin to connect to the other 7135. It has the same ground as the middle pin but the heat will transfer easier to the mass.