[canteen234]

Hello, I just ordered this 1.5W 445nm blue laser and I am wondering if I would need something to step down the voltage since the input range is 6-8.4V and I believe the RAMPS 1.4 outputs 12V on D9. I have this buck converter in mind if I need to step down the voltage. Do you guys think this would work? Thank you.

[Downunder35m]

Don't use buck converters, use a voltage regulator and if you need more juice add a transistor to get amps you need.

[Louis_Cannell]

Disagree buck converter far more efficient and ideal for job without heat and 75% inefficiency.

A second opinion or the facts.
https://www.youtube.com/watch?v=giGRrODKJSE

[Downunder35m]

That might be ture but so far I have not seen a buck converter that is able to provide a clean DC.
And for sensitive electronics I simply don't use converters that produce more interference than output.
I agree they are really efficient and have a purpose but not when it comes to running sensitive electronics with them.

[Louis_Cannell]

I have been running 2.8w laser on same one without problems for last 12 months, certain sensitive electronics I may well agree and advise not to use a buck converter, but this is not one of those cases.

[Cromaglious]

Buck converters are fine, if you take precautions as required.. like adding a inductor to filter noise, several different caps to smooth, chokes to isolate other noise.

[wmgeorge]

That's about all they use on Diode power supplies.

[dharmic]

Yeah, sorry, a buck converter gets my vote too. Especially if it's the LED PSU type which are designed to regulate current instead of voltage, which is the critical thing on an LED.

Better, get a laser diode with a photodiode on the third pin and a switch mode regulator with a current limiter but normal regulation based on the light output of the diode. But then you're into $$$ town.