Dc Dc Converters

[liebster]

Hi everyone, this is my first post so hope to not say anything too stupid.
I've been thinking that perhaps industry standard DC to Dc converter modules, could be used to drive most laser diodes from one or two cells.
You can have a 2 to 9 volt input and 4 to 6 volt output unit, (driven by a single Li-ion cell,) and followed by a simple linear LM338 constant current regulator.
This is just an idea, though maybe the CC regulator will not be too efficient.

Anyone else been down this path ?

 

[grainde]

Where will you be getting your 2 V or 9 V input? If you were thinking along the lines of 1 AA or 2x AA for 1.5 or 3 V, respectively, or a 9 V battery it wouldnt be worth the bother in terms of capacity and losses. You might as well just use a Liion that can supply the required voltage and current from the start.

Most of drivers we use can handle varying input voltages anyway. :beer:

 

[liebster]

Input might be from single Li-ion, 2.75-4.3 Volt; Driving maybe a Nichia 3.7 to 5.5 V blue diode. If the linear CC regulator input/output voltages are close, then efficiency is not too bad.
Guess a dedicated driver would be more convenient.
Maybe I am thinking everyone has a huge and messy electronic junkyard under the bed like myself :yh: ...maybe an LT3477 led driver would do same job too :thinking:

 

[grainde]

There are 3 main types of driver; linear, boost and buck. All of these can be used to run a 445, but with the linear and buck you need 2 batteries. The linear also wastes a fair bit of energy as heat, with the excess voltage.

You might already know all of this, but heres a thread you might find interesting: http://laserpointerforums.com/f67/how-laser-diode-drivers-work-explanatory-thread-71513.html

There are also loads of threads dealing with the design of drivers too, but youll have to do some searching. Try searching for Ben Boost or DIY driver etc :beer:

 

[liebster]

Yes that thread from Quack is excellent reading !
No doubt that laser dedicated drivers are best, but if like myself you have electronic bits lying around, you might find something that does the job.
A while back I played with LT3477 led drivers http://cds.linear.com/docs/Datasheet/3477fc.pdf
On page 17 there is an application note for a 2.7 to 10v input and 1 A output. Have not tried this on a laser diode but should work too I guess.