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I fried my Diode... twice

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scottypres

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I have been following a tutorial for a 1W 445nm build. I have the aurora cree c6, heatsink, and driver pill along with the 1.99 dx driver. I have wasted an incredible amount of money and should have started with an easier build first. First time, I loosened a diode pin accidentally by applying soldering heat too long. Next time I bought preattached leads. However, after completing the build and short circuiting the leads, I burnt the 2nd one out. Upon clicking the switch, the diode lit for about half a second and then turned off. It did that twice in succession and now is burnt out. Im not entirely sure why, but there could be a few reasons. I have been reading about different things and Im not sure what the output voltage should be. I have a 5w 1.25amp laser driver, without 1100mw output. My multimeter displays almost 7.4volts output from the driver with 2 880mah 3.7v cr123's. I know the drivers are supposed to regulate current and keep it stable, but should the input voltage equal the output voltage? I need to figure this out before I fry another $50 diode. Thanks
 





chipdouglas

chipdouglas

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it looks like to me that you are probably using a boost driver... so 2 3.7v batts are too much. you only need 1... that seems to be the problem.
 
Eudaimonium

Eudaimonium

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How exactly are you measuring those 7.2 V from driver?

I hope you're not simply measuring it with DMM on the output.

Switching drivers of any kind (DC/DC converters), both buck and boost, will burn out and destroy themselves if they are ran without anything on their output, even for a milisecond. And a LOT of those miliseconds happen if you do not have your output connection permanently soldered.

And perhaps you just wired the entire thing wrong. Maybe you're bypassing entire laser driver, resulting in that reading.

You should have started with a crude host-less build with easy to build driver, instead of immediately going for Aurora C6 host which requires some amount of skill to complete, and 445nm diodes when ran at high powers are among the most dangerous diodes to pick when trying out your first build.

Baby steps, as we say. Start small, try a bluray PHR-805 diode or maybe LPC-815 red.
Why?
Because of the exact reason you want your advice here - not to burn a $50 diode in exchange for learning experience.

Those diodes I've named are $5-10 a piece. Learning on those first is a much better idea than just going for power you've seen on Youtube videos.
 
Cyparagon

Cyparagon

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scottypres said:
My multimeter displays almost 7.4volts output from the driver with 2 880mah 3.7v cr123's
Click to expand...

If we're thinking about the same driver, it's bad to run them without a load. The problem is it's trying to maintain 1.2A (or whatever it's set to) and it can't, so it sends more voltage to increase the current. They're constant current devices, not constant voltage.

Short answer: it's a BS measurement.
 
S

scottypres

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Eudaimonium said:
How exactly are you measuring those 7.2 V from driver?

I hope you're not simply measuring it with DMM on the output.

Switching drivers of any kind (DC/DC converters), both buck and boost, will burn out and destroy themselves if they are ran without anything on their output, even for a milisecond. And a LOT of those miliseconds happen if you do not have your output connection permanently soldered.

And perhaps you just wired the entire thing wrong. Maybe you're bypassing entire laser driver, resulting in that reading.

You should have started with a crude host-less build with easy to build driver, instead of immediately going for Aurora C6 host which requires some amount of skill to complete, and 445nm diodes when ran at high powers are among the most dangerous diodes to pick when trying out your first build.

Baby steps, as we say. Start small, try a bluray PHR-805 diode or maybe LPC-815 red.
Why?
Because of the exact reason you want your advice here - not to burn a $50 diode in exchange for learning experience.

Those diodes I've named are $5-10 a piece. Learning on those first is a much better idea than just going for power you've seen on Youtube videos.
Click to expand...

i received in the mail today a second cree c6 from DX. with 2 cr123s it outputs around 4 volts at the LED leads. Is this what I want? I did feed power to the other without a dummy load. How can I be sure I blew my driver? Can I use this driver for my 445nm?
 
Eudaimonium

Eudaimonium

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scottypres said:
i received in the mail today a second cree c6 from DX. with 2 cr123s it outputs around 4 volts at the LED leads. Is this what I want? I did feed power to the other without a dummy load. How can I be sure I blew my driver? Can I use this driver for my 445nm?
Click to expand...
You can totally be sure you blew the other one.

About the second one, you don't need to order an entire flashlight for just one driver. You can find plenty of 445nm diode suitable boards that fit in 17mm holders:
18V 5W Cree Circuit Board for Flashlights (16.8mm*5.5mm) - Free Shipping - DealExtreme

And you do not want a voltage measurement of the output. You need a current output information, and to get that, you need to use a test load, or dummy load as you say.

You can find a lot of info about those and how to use them. If you get confused, ask me via PM anything, I'll do my best to help you.
 
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mattco2

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linear drivers are the best for beginners since they are the easiest to set up and use.
they don't burn out if you don't have them hooked to something
 
Hiemal

Hiemal

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Only buck/boost and boost drivers burn out with no load attached.

Bucking and linear drivers do just fine with no load.

The reason why buck/boost and boost drivers burn out is because they keep trying to boost up the voltage until they get current.....and, because there's nothing pulling current away, the voltage keeps going up and up and up until something gives, and thus it destroys itself.

With a buck converter, you'd just see supply voltage on the output.

Same with a linear driver as well.
 
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flucero28

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Be sure you are soldering your negative connection on the driver board after the sense resistor, which sounds like an R20 on your board if it's a 1.2A output board. Soldering the negative connection before the sense resistor will result in overdriving your diode to 2+ Amps depending what your power source is capable of. Test the driver with a dummy load and DMM to be sure, but it should still be fine. Test the current output, not voltage as this is a constant current driver.
 
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