opinion on this LM2596 based driver

[cyclonite]

Hi DTR and Bionic-Badger,

Thanks. I just want to add 2 things:

1) DTR, I did not heatsink this. Reason being, this was a free diode that was of the same Ampere and Voltage specs as the one that I will be using. The housing module has not arrived hence I could not press it into it to heatsink. I just wanted to use this as a 'dummy load' to calibrate the driver. Thinking back, it was slightly brighter at the start and now it's dimmer. Might have killed it.

2) Bionic-Badger, I was too tired/sleepy to elaborate on my dummy load set-up. Yes I'm aware that the 1N4001 diodes are rated at 1A. What I actually have here is 6 of those diodes. To I've got 2 in parallel to increase the rating to 2A and then I hook 3 of these sets up. The other reason I decided to do this is because I found that these diodes have different voltage drops across them hence by running 2 in parallel I get to average out the voltage drop.

So would the current/voltage draw change when a diode dies and becomes an LED?

Thanks

 

[Bionic-Badger]

Short of ESD-death, when a laser diode "LEDs" the facets on its lasing medium are destroyed, so it'll still operate--electrically--the same, but just can't lase. That's why those LEDed laser diodes make fine--if not expensive--dummy loads.

As for your dummy load setup, the best thing to do with your current setup is to just measure the actual voltage drop across your diodes. Then you'll get an idea of what the driver is dealing with.

 

[cyclonite]

gotcha. I'll measure the voltage across the LED and the 1N4001 diodes tonight and report. Cheers.

 

[cyclonite]

Hello Hello experts....

So I've hooked the driver up to my dummy load and to my 100mW diode (now I'm not sure if it's an LED or if it's still alive). Here are my findings:

1) Voltage drop across the Laser Diode is indeed 1.9v - 2.0v the diode's spec = 2.0v - 2.2v.

2) Current flowing through the Laser Diode = 1.1A which is also bang on target.

I'm now very happy that I've calibrated the driver and it's ready for the main primary Laser Diode. I'm now waiting for a drill bit, slide switch, Flaminpyro's diode press and most importantly the diode's house + glass lens to arrive. I've for everything else that I need for the build.

Here is a question. I've taken these 2 photographs with my iPhone 4's rear camera. Would you say that this 100mW diode is still alive or has become an LED? I guess those familiar with IR diodes would know. For comparison I've taken a 3rd picture of the LED on my CD Transport's remote control transmitter to show how dim a normal LED is.

1 more question, the seller has told me that the primary diode which is rated between 1000mW - 1500mW has the same current draw and voltage drop as this free 100mW diode. How is this possible? I don't understand this bit so could someone please elaborate? Thanks.

Thanks.

 

[Cyparagon]

Running laser diodes without a heat sink works about as well as running a modern CPU without a heat sink, except laser diodes don't have auto-power-down on overheat.

If it wasn't dead before, it's probably dead now.

 

[swkaise]

Running laser diodes without a heat sink works about as well as running a modern CPU without a heat sink, except laser diodes don't have auto-power-down on overheat.

If it wasn't dead before, it's probably dead now.

They heat up that quickly? Good info!

 

[cyclonite]

Beam pattern from my diode w/o lens. LEDed or still good?? Thx!

 

[ApexProxy]

It doesn't look fully dead but it looks damaged. It really is a very bad idea to run a diode without any heatsink....

 

[cyclonite]

ok thanks. yeah thankfully I learned this the cheap way as this was a free diode . The main one is rated at < 1500mW but draws the same Amps and Volts as this one. Anyone knows how this is possible? i.e. same power draw but puts out 15x more output?

Thanks.

 

[ApexProxy]

Sounds like one of the diodes was overrated or underrated or maybe the specs were off on one of them.

 

[cyclonite]

I thought so too but I've seen similar spec sheets for both the diodes and the V / A draw are indeed identical :S

Thanks anyway.

Sounds like one of the diodes was overrated or underrated or maybe the specs were off on one of them.