Diode not drawing more than 100mA of current

[Wurdene]

Hi all, I recently purchased an Osram PL520 inside of heatsink assembly, and when I power it via my adjustable power supply, it is drawing ~105mA max @6.9V when I am allowing ~200mA. I have been working with basic electronics for a while, but am entirely new to lasers. Datasheet is specifying a typical operating current of 150mA. This may be a moronic question, but I am too afraid to experiment and burn this $40 diode.

 

[Cyparagon]

Double check polarity, heat sinking, and be sure light is coming out the front. Assuming these are okay:

You must be new to bench PSUs, or at least new to constant current. You are operating your supply in constant voltage. If you are sure the current limit is at 200mA (digital set-point, for example), then simply increase the voltage. If you are not 100% sure the current set-point is 200mA, lower the current set-point to zero or near zero. Increase the voltage to what you're sure is over the operating voltage of the laser. 8V+ in this case. (Note, the voltage readout may or may not rise at this point. That's okay.) Then raise the current set-point to whatever current you need.

Between voltage and current, a bench supply limits to the lower of the two setpoints.

 

[Wurdene]

Thank you! This worked for me. I was having no problems previously but didn't want to go any further incase the diode was damaged or something.

 

[Pman]

Nice of you to jump in and help a very new member Cyp