Pioneer 112D open can laser diode V-I-P plot

[Benm]

I agree about definitely keeping it below 480mA. My duration test does cycle the diode on and off every 10 minutes, so the thermal stresses do play a role in verification at a power level. So far, it has survived over 6 hours at 250mW!

Nice!
Is that 6 hours of on-time, or 6 hours of 50% duty?

 

[chimo]

That should flatten the V curve a bit as well. I look forward to you next plot.

I wonder if LDs have the same Vf drop that many high power LEDs (such as the Luxeon) experience after burn in.

Paul

[Also, those of you who noticed the high forward resistance of the diode, you were right!  theres a series resistance in my setup of 0.336 ohms that was unaccounted for in the plots.  This amounts to an increase in Vd of 0.168 at the 500mA mark, that should be subtracted to find the true Vd.  This will be compensated for in future plots, and previous data will be corrected.

 

[CHP]

drlava,

Thanks for posting a picture of your heatsink! Nice setup!

 

[CHP]

If anyone if using pspice to design a driver, the LD data from drlava (accounting for the 0336 ohms) can be modeled by a 1n4001 diode in series with a 2.36 ohm resistor, in series with a 1.1 volt voltage source. The + of the source faces the cathode of the diode.

 

[amkdeath]

it is surprising how different some 20x LDs can be: my lite-on one has Ith of about 56mA and much higher Vf /2.60V at 170mA/ compared to 20x LGs with Ith =75-77mA and Vf=2.43V at 200mA. the lite-on's power curve is probably steeper, but i dont know how far up it would extend compared to the seemingly cooler at lower currents LG.
drlava, it would be interesting to also record the Ith in this life test at a fixed temperature. If Ith goes up with time, this is a sign that the LD is due south....

the liteon diodes are the "short chip" open cans. that may be a reason why you get different results...

 

[phenol]

If anyone if using pspice to design a driver, the LD data from drlava (accounting for the 0336 ohms) can be modeled by a 1n4001 diode in series with a 2.36 ohm resistor, in series with a 1.1 volt voltage source.  The + of the source faces the cathode of the diode.

those LDs have Cjo is excess of 100pF, whereas 1n400x has only 20pF. this hardly matters unless one intends running high-speed time-domain simulations

 

[chido]

Hey DL, any chance you'll be doing the same test with the short open cans??
Just wondering since I ordered one from TheMonk and I want to know the differences between the two.

 

[jake21]

same here it would benice to no,sence i got one to

 

[phenol]

me 3! i'd like to know if its power curve is steeper than those long open cans.

 

[drlava]

Plot updated with lead resistance comp.

I don't have any short cans right now, but if I get one, or one appears in my mailbox, I'll throw up a comparison.

 

[CHP]

Thanks guys, yes I will be running a 4/6x BR through this, it should have arrived the same day Mike's did.

I agree about definitely keeping it below 480mA.  My duration test does cycle the diode on and off every 10 minutes, so the thermal stresses do play a role in verification at a power level.  So far, it has survived over 6 hours at 250mW!

Test was with a glass lens.

Any updates on the mini life testing?

 

[drlava]

not so far, I've been having too much fun playing with the 100mW blu-ray diode

 

[thesk8nmidget]

any updates now? andrew what do you recommend setting the current at for longest life running cw

 

[robjdixon]

400mA is about right for a long life - it is an open can iirc