Ok to add Switch After Driver Circuit for Dual Modules?

[blue laser research]

I was looking at the new 2w 445nm laser posted over in the review section. With that massive heatseak I saw no reason that both an IR and a 445nm laser could not be mounted in it at the same time.

To keep it simple since there would not be much room left on the back of the heatseak I would want to only have 1 driver circuit if possible. I have some nice micro rotary switches that could be applied after the driver and could send current to the desired laser modules.

Wondering if the switch could cause any voltage regulation problems that might ruin one of the diodes if they are being switched back and forth while the power is still on. Also wonder if both could be powerd at the same time from the single driver.

 

[Coherent Light]

NEVER put a switch between the driver and diode!

 

[Cyparagon]

The driver detects no current, and tries to compensate by raising the voltage. When you close the switch, the diode will see the full voltage and momentarily draw WAY too much current.

 

[blue laser research]

Thanks for the info :thanks:

 

[Mohrenberg]

i think the only way this could work is if the switch momentarily powered both the lasers before switching tot he next...

if you tried it with a switch that slid from left to right, as you slide the switch it's going to cut the current completely, ad when you finally get it slid all the way over it's going to hit the diode with much more current than it should...

however if you somehow had a switch that went from powering diode A and as you slid it over it was powering Diode A & B, then once it got slid all the way over it was only powering diode B.
you need a switch that would complete the circuit to Diode B BEFORE cutting power to Diode A
basicly to ensure that the driver is never powered without a load connected to it.

anyone know if a resistor could just be added to avoid the over-discharge when switching back and forth?
I'm not too electronic savvy..

 

[Coherent Light]

You could try a resistor and a 1F capacitor, because that in theory should protect the diodes from the spike.

Try it with cheap diodes 1st if you go this route.