Power several driver boards with one power supply

[tommylee333]

I am trying to Power several driver boards with one power supply. i can run 2 30mw green lasers with their own seperate driver boards already soldered onto the diode. i want to power them all at once but when i add a third one it doesn't work i am using a 3.3 volt 20 amp power supply any suggestions?
this is the drivers and the diodes i am using.
http://www.ebay.com/itm/141347504404...%3AMEBIDX%3AIT
i am running them in parael 2 of them works fine but when i add the 3rd one it doesn't shine the other 2 keeps on shining. the third one works because it is fine if i run it by itself.i am trying to run 5 of them off of one power supply.
thanks and God bless.

[tommylee333]

this is the power supply i am using.
http://www.mpja.com/33V-16A-and-5V-1...fo/18090%20PS/

[JohnYayas]

Makes no sense that when three are connected only two work. Unless connections are bad I would expect all or nothing. Verify your connections and use a voltmeter to see if there is a voltage drop when adding a 3rd. Maybe check current draw of each module, although I don't think you need to if voltage is solid.

Also, make sure you have that P/S configured properly if you are only using the 3.3V connection and not the others. I don't know about that one but I know some require a minimum load to work. I briefly checked the spec sheet for it and it had some notes for single voltage operation but I didn't look at in detail to know if it matters.

[tommylee333]

the specs says it requires a 0.5 amp to work, but it works fine when only one diode is attached, actually the one diode that doesn't work when you connect the three works fine when wired by itself, i also have a 20amp switching power supply like the ones everybody on here uses, and i tried it with that power supply and the same problem. i ordered a couple batches of these diodes but i ordered one batch of 3 from one company, and another batch of 3 from another company, could that have something to do with the problem, they all work fine if you connect them single.thanks for your reply.

[JohnYayas]

At this point I think you should hook up a voltmeter to see what is going on. It could be something funky like modules requiring different voltages (ie some 3.3 and some 5) and when you only have a couple the PS is floating a little high and powers them but when you add more it drops down to 3.3v and thus won't allow the 5v modules to work. This is an extremely wild guess, though. But, the voltmeter would help you know.

[tommylee333]

i tried running them all at 5 volts and they all worked fine,all 5 of them worked at the same time, but won't that burn up the ones that says 3 volts?

[JohnYayas]

It might shorten their lives. I can't really say.

[tommylee333]

is there anything i could do to prevent that?