100~240v labby supply 445nm

anyone has a schematic for a 100~240v input, 4.2v output with adjustable current ?

or the already builded PCB for sell?

Thanks in advance, all.

If you mean an unit with a main transformer, then any power supply schematics with voltage and current regulation can be ok.

If instead you mean a PSU without a "main" transformer ..... this involves switching circuitry at 240V potential, and it's not easy, especially if you don't have a possibility to wind-up your own switching transformers ..... the easiest way that come in mind, is to get one of those switching type "wall" adapters, universal (mean, voltage variable), and 2000mA capable, and then modify the inside circuit for get the result you want (but the modifications depends from the type of circuit you find inside it)

Another alternative is to use one of these switching halogen lamp "transformers" in an inusual way (those things are very helpful when you need compact power sources for non standard uses, and usually none think about them ) ..... get one not dipped with resin, ofcourse, open it, unwind the 12V wire (don't touch the thin one) from the output transformer (count the wire turns and divide for 12, for get the voltage that you have as output for each turn), and then rewind it with the turns you need for that voltage, or a bit more (consider that if you rewind it for 6V, half of the original voltage, you can use double size wire and get the double of the power ..... as example, a 100W unit usually give you 8A at 12V, so you can use a wire with the double size and get easily 15A at 6V ), then build a current control circuit as output stage (after a diode bridge and filtering caps, ofcourse).

yeah, thanks HIMNL9, I have thinked about getting a transformer and rewind it. But i'm not familiar to it so I think I'll ruin it haha (I can get someone to do this for me, there is a 'rewinder' that lives near my house, dunno what is called someone that winds transformers for money lol). Lets suppose, I already have the transformer (any voltage you like) that is 110v + 220v (center tap) with a switch for changing the voltage, with 12v @ 3A lets say (change that if needed). The bridge rectifiers and capacitors are there. I want stabilized 4.2v @ 200mA up to 1.8A (or more.. 2W output from A140).

I would need a LM317 as voltage regulator (heatsinked) and LM350 as OP-AMP for regulating the current (with a N-MOS as power mosfet, heatsinked). I need the current regulator circuit I'm somehow busy now if you (or someone else) had this circuit would be so good (or a even better circuit)...

Thanks again!

I would strongly recomment not building a direct power supply connected to mains yourself, unless you are experience with line voltage electronics and are able to source the proper transformers etc.

The safest and easiest method is getting a mains supply like these ones: DC12V 2A Universal Regulated Switching Power Supply 25W - eBay (item 260708500967 end time Jan-13-11 21:38:48 PST)

Look around a bit for one that suits your needs, but in general these work fine and cost much less then the components inside bought individually.

If you can get a 9 volt unit that would be great, but you can do with a 12 volt one as well. Often they can be tuned down a little too.

After this switching power supply you can use any linear driver to make a good current source for your laser diode. If you are driving it to 1 amp, the driver will dissipate a fair amount of power (6 watts or so when on 12 volts), so its important to heatsink it.

I'm all for DIY electronics projects, but those power supplies are little life savers sometimes... for $10 you get a unit that does the dirty/dangerous work for you. All such power supply units i've come across are completely electrically isolated from both mains power leads, and accept between 100 and 240 volts AC without the need to adjust a switch or anything like that - worldwide plug and play

well well here in brazil a 12v 2A costs 50 dollars (80BRL), and making one can go as low to $4 plus transformer that I have many here.

Wow this one is free shipping? OMG

Well, if you can get one of those halogen transformers, also second-hand, you can still experiment (the transformer i said, it's a toroidal coil, and the output coil is usually just 10 or 11 turns, it can be done handy) ..... just remember that their output is AC from 50 to 100 KHz, not DC.

Starting with a 12V PSU gives you more possibility, but sometimes require the modification of the internal transformer, but there are similar units made for 5 or 6 V output too.

EDIT: just as example:

http://cgi.ebay.com/BRAND-NEW-6V-2A...ronics_Batteries_Chargers&hash=item4aa6df3de1

http://cgi.ebay.com/BRAND-NEW-6V-2A...519?pt=LH_DefaultDomain_0&hash=item20b01ec707

http://cgi.ebay.com/BRAND-NEW-6V-2A...891?pt=LH_DefaultDomain_0&hash=item20b2a51983

Leodahsan said:

well well here in brazil a 12v 2A costs 50 dollars (80BRL), and making one can go as low to $4 plus transformer that I have many here.

Wow this one is free shipping? OMG

Click to expand...

These power supplies are amazingly cheap on ebay indeed, but i've ordered a couple of them by now, and had no problems with them.

I prefer them over a standard transformer + bridge rectifier and capacitors since they are more compact and cheaper, unless you already have the components lying around somewhere.