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Recommendation on driver to use for TTL with BDR-209

zakelectric

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Nov 2, 2015
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Hi guys,

I figured out that I destroyed my BDR-209 by pulsing the ground to my ACS1500SE driver(Lesson learned). The reason I was doing this was to achieve TTL and it worked for about 6 hours before burning out.

I'm hoping someone can recommend a driver to use with the BDR-209 where I can safely use a TTL signal. Any ideas?

Thank you!
 



FireMyLaser

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Jan 12, 2008
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I made this circuit for a white laser I'm making. Mabe it is what you can use. I don't know how high frequency you intend to switch at or how critical the rise and fall time is, but this works for at least 300Hz PWM.
The main limiting factor for max frequency is set by the LM317 characteristics (not all regulators are made equally), and the protective capacitor over the laser diode. You may experiment with other values if it is an issue at much higher frequency.

You may switch out the transistors for whatever suits you, as long as they are rated for the task.

12V for supply voltage is fine, but can be lower to minimize waste heat in the regulator. Assume 4V is needed for the regulator, plus the voltage drop for the laser diode.

R1 is for supplying a low current to the laser diode at all times, so it doesn't switch off completely. It should be near the lasing threshold. You have to experiment to find out what works for your diode. There is no resistor value which will destroy your diode when experimenting.

R2 sets the max constant current for the laser diode. The following potentiometer is for adjusting intensity, but it can be omitted.

Test point 1-2 should measure 1.25V.
Test point 2-3 measure the current set to the laser diode.
Test point 3-4 measure the voltage drop over the laser diode.
 

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zakelectric

New member
Joined
Nov 2, 2015
Messages
5
Points
3
Wow thank you very much. I was hoping to find a pre-built driver board since I'm so busy to build one, but if I can't find anything I certainly will give that a try! Doesn't seem too complex. Thanks again!
 




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