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How Important Is Soft Start?

Captain Sid

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As the title asks, is soft start important in a 1W 525? I'm looking to buy another 1W laser for our tours we do here in Myrtle Beach. The first one has worked fine, but is not soft start. Does soft start add longevity to the diode? We use the laser to point out wildlife and fauna, avoiding wildlife eyes of course. How long can one expect a laser to last under those circumstances? The laser is on for no longer then 15 seconds at a time.
 



Lifetime17

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Hi,
Soft start is always a plus in any high power build, I prefer a 5 sec. delay this way the diode doesn't get smacked with all the current at once.
The SXD drivers years ago had this option how I miss them.
Rich:)
 

steve001

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As the title asks, is soft start important in a 1W 525? I'm looking to buy another 1W laser for our tours we do here in Myrtle Beach. The first one has worked fine, but is not soft start. Does soft start add longevity to the diode? We use the laser to point out wildlife and fauna, avoiding wildlife eyes of course. How long can one expect a laser to last under those circumstances? The laser is on for no longer then 15 seconds at a time.
I always start soft.
One accident at work and the tour company is looking at a law suite.
 

WizardG

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Does your tour company have a variance to use a 1W laser pointer.........didn't think so. That alone can get you shut down by the fed's.

As Steve said above, one tiny miscalculation, moment of inattention, simple accident, and the tour company will be out of business or at least under new management. A 1 watt laser will cause serious permanent damage if it winds up pointed (or reflected) into someone's eyes even for just a moment.
 

Lifetime17

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Hi, I built a PL520B / 520 in a EDC at 134mW's and that is very bright, never mind a 1W of 525nm. Yes way to powerful for pointing out birds and fauna might even scare the birds .
Rich:)

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paul1598419

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It really depends on the diode used. For the 525nm 1 watt, this is not so necessary. Now, the temperamental nature of the single mode 405nm diodes makes having this option more likely to help as these diodes tend to fail and deserve all the help you can give them.
 

CurtisOliver

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Forget soft starting. You need to not use a 1W laser for the purpose you are intending to use it for. A 5mW 532/520 is the safe option, however for your purposes not 35-50mW is probably more ideal. But care still needs to be taken even at those low power levels.
 

Cyparagon

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Now, the temperamental nature of the single mode 405nm diodes makes having [soft-start] more likely to help as these diodes tend to fail and deserve all the help you can give them.



Paul, you forgot the part where single mode 405nm is the standard in blu-ray devices, where 1x speeds are upwards of 36,000,000 on/off cycles per second, and 16x speeds are upwards of 576,000,000 on/off cycles per second. This is a rise-time in the f:)cking nano-second range, and it happens trillions of times per disk. Even a "non-soft-start" driver is going to be tens of thousands of times slower than that. And no one is going to turn on a pointer more than a few thousand times.

Try to keep things in perspective.
 

paul1598419

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Sure, but we drive them so much harder than they are ever driven when used to burn DVDs. That was what I was talking about when it comes to using soft start on these blue ray diodes. At drive current ~500 mA these same diodes still tend to fail and people drive them harder than that. Is that perspective enough for you?
 

Captain Sid

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Forget soft starting. You need to not use a 1W laser for the purpose you are intending to use it for. A 5mW 532/520 is the safe option, however for your purposes not 35-50mW is probably more ideal. But care still needs to be taken even at those low power levels.
I started with one of those 303's you get off Ebay and those did not work at all. Could not see the spot. Remember from a previous post I'm using this in broad daylight. A member here then built one at 150-200mW and that one was not effective either in daylight. Then I ordered from a member here a 1W and that one worked great in daylight. Yes, we are very careful and mindful of the beam. I would be happy to use a 500 or 700mW if it would work, but still there is potential for damage.
 

Cyparagon

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we drive them so much harder
"When I power my 20W LED at at 50W, it burns out. So clearly the best solution for longevity is turn up to 50W very slowly. The fact that PWM with fast rise times doesn't affect LED longevity in the slightest does not dissuade me from this recommendation."

Are you even listening to yourself? Knock off the groupthink and show some data to back this up.
 

paul1598419

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"When I power my 20W LED at at 50W, it burns out. So clearly the best solution for longevity is turn up to 50W very slowly. The fact that PWM with fast rise times doesn't affect LED longevity in the slightest does not dissuade me from this recommendation."

Are you even listening to yourself? Knock off the groupthink and show some data to back this up.
I'm glad you wanted to take this further. I'm guessing you have not seen many of these BDR diodes fail. I have seen about half a dozen fail personally and when they do it is at powered on. Now, one could say that maybe they failed during turn off on the last cycle, but that makes little sense. You can ask Jordan, DTR, if you think my assertions are baseless, but these do tend to fail right at turn on making the slower current increase a better way of powering these on. When they fail it is from catastrophic optical damage as can be seen in microscopic observation on the OC mirror at the front of the die. I obviously don't have data because who spends time trying to show that the immediate high current is the major cause of their failures. But, since I started using larger heat sinks and using drivers with slower current highs I have had very good results. I have spent a great deal of time trying to mitigate these failures and I have done so.
 
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Coonie

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I'm not sure if a soft start would solve the problems with the single mode 405s. I'd love to see some testing done to determine whether or not that could be the cause. I know that high power Cmount 660 diodes need soft start. Those can be super sensitive. I guess it depends on what diode. I mean having the feature can't hurt anything but not all diodes require it. I know for certain the m140 doesn't need it. Those things can be tough to kill
 




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