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



NEW! The Blitz-Linear: Very Low Drop Out, 1A Adjustable Linear Driver

Wolfman29

Well-known member
Joined
Jan 14, 2011
Messages
3,828
Points
63
Hey everyone.

In the last few months, I have been working on a new project - a cheaper, adjustable, lower-powered driver for just about everything that isn't a 445nm.

So what did I do? I made a linear driver!


So what's special about this driver? It's absolutely tiny, fully adjustable, has a very low drop-out, is easily heatsinked, etc. There is one thing everyone should know off the bat though - it's continuous positive, meaning that you have to make sure to either A) isolate the diode or B) isolate the battery (unless you are using an already isolated diode or a diode that is case positive, of course!).

So, the current ranges are:

High (default): 500mA-1A
Low (set w/ solder bridge): 70mA-500mA

Size: 8mm by 11mm.

Dropout: <.45V to .7V (at 1A)

Output voltage: <1.8V to 10V

Input voltage: (Output voltage + Vdo) to 10V

Heatsinking pad: The entire underbelly of the driver is componentless, with gold-plated padding for heatsinking. Note that this MUST be isolated from the driver and from the case!


I bet you're wondering what the ripple and start-up specs are like. Never fear, they're AMAZING.




Current plot at 1A upon start-up. Note the lack of inrush spike - just smooth sloping. In fact, if you'll notice, the ramp up may even be noticeable by eye if you're quick - it's about 150ms before it reaches near maximum power!









Ripple voltage of the driver at 1A. Notice that, even at a current as high as 1A, the ripple voltage is less than 5mA.









Current plot at ~70mA. Note the lack of inrush spike here, too! Unlike before, however, the start-up is quicker (basic consequence of capacitor current flow), so you won't see it with your eyes, but in electronics terms, a start-up time of 5ms is still very long, so long that you will never see an inrush spike!







For those of you who use sensitive diodes, fear no more! With less than 2mA current ripple at lower currents, you'll never damage your laser diode! Notice the tiny scale - 2mV per division. Yet, it doesn't even take up a full division.​

Anyway, so that's all I have for you guys. I hope you like the driver, I put a lot of hard work into it and I hope to see it improve the laser hobby!

Expect to see these at CajunLasers soon, but buy them up, they are expected to fly off the shelves. Pricing is probably going to be $15 (not sure - ask Clif!).

Thanks,

Sam
 
Last edited:



Seoul_lasers

Well-known member
Joined
Jul 4, 2008
Messages
2,566
Points
83
Interested. :drool: :beer:
I'd like to know more about using these when powering 405nm diodes.
Any additional info would be greatly appreciated!! You got my attention.
 
Last edited:

Wolfman29

Well-known member
Joined
Jan 14, 2011
Messages
3,828
Points
63
I would be very comfortable powering any 405nm diode with these. There is no ripple, no inrush current, and with 7.4V in, you can power anything up to 6.7Vf, which is more than any 405nm out there.
 

Seoul_lasers

Well-known member
Joined
Jul 4, 2008
Messages
2,566
Points
83
Have you a picture or video showcasing your driver yet?
Also giving this tiny driver 2x 18650 cells (8.4V) to power a 405nm diode cause heating of the comparator/regulator. Sinking is advised for a project like this?
 

Wolfman29

Well-known member
Joined
Jan 14, 2011
Messages
3,828
Points
63
For a lower current, I wouldn't actually say heatsinking is necessary. Again, the exposed pad is huge, so it already is pretty well heatsinked.

The oscope things ARE pictures :D Of it running, anyway.
 
Last edited:

n2stuff

Active member
Joined
Nov 4, 2011
Messages
812
Points
28
Good lord Wolfman don't you ever sleep:crackup: Man you just keep cranking these things out:beer: +1
 

Wolfman29

Well-known member
Joined
Jan 14, 2011
Messages
3,828
Points
63
Didn't know people thought that! Thanks for the kind words. I have a BlitzBoost and a BlitzBuck V4 to be testing out tomorrow ;)
 

n2stuff

Active member
Joined
Nov 4, 2011
Messages
812
Points
28
Boost drive. Oh Ya. I used your blitzbuck ( I think 1.7a) in my last build and it worked great.
 

jimdt7

Well-known member
Joined
Feb 5, 2011
Messages
1,899
Points
48
Very interesting driver, probably going to order 1 or 2 from Clif when they become available....:beer:

Jim
 

Wolfman29

Well-known member
Joined
Jan 14, 2011
Messages
3,828
Points
63
Yes you could run an LPC with a single cell with one of these. However, you have to remember to use the case-isolated version (there is one, right?) because these are continuous on the positive rail.

And I am glad to hear you are interested!
 

benmwv

Well-known member
Joined
Sep 10, 2010
Messages
1,389
Points
48
Not going to mention any specifics to protect your design, but if this is the chip I think it is then the minimum input is technically 4.5v right? Cutting the diode gives you a bit more slack but not much. I haven't actually tried one cell though so I can't say if it really will or wont work.

I might be completely wrong about the chip you are using though.

Also nice work on the adjustment. I have used the same method.
 




Top