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Need Help Finding a Laser Driver

Supreminator

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Hello,
I am building two 80mW laser pointers using 450nm and 520nm Osram laser diodes. More specifically, they are the PL 450B and PL 520B models respectively. I know all the parts that I need to purchase (you can find the list below if it helps), except the drivers for the laser diodes. I plan on powering both pointers using 3.7V 18650 Lithium-Ion batteries. Since there are many people on this forum who have experience building laser pointers, I thought I'd ask for help getting a good driver that fits my project.

Here are my problems and the information I have:

According to the datasheet, the 450nm laser diode has a typical forward voltage of 5.2V, but can take up to 6.5V as well. Its typical operating current is 75mA but it can take up to 125mA as well. However, all the drivers that I can find for this wavelength - that take an input voltage that matches my battery - are designed for much more powerful diodes and deliver current that is at lowest, one amp.

As for the 520nm laser diode, the datasheet states that the laser diode has a typical forward voltage of 6V, but can take up to 8V as well. Its typical operating current is 200mA but it can take up to 240mA as well. However, I cannot find any drivers that match the voltage of my battery, and on the rare case that they do, they are again too powerful.

Again, since there are a lot of people here that have experience building laser pointers, I thought this is the perfect place to bring up this issue. If any of you have any links or knowledge you could share with me, I'd more than appreciate it.

Here is the list of all the parts I have so far, if it helps:

80mW 450nm Osram PL 450B laser diode:
https://www.ebay.ca/itm/LD-PL450B-OSRAM-445nm-450nm-80mW-3-8mm-TO-38-Blue-Laser-Diode/163772865291

80mW 520nm Osram PL 520B laser diode:
https://www.ebay.ca/itm/Osram-520nm-80mW-Green-Single-Mode-3-8mm-Laser-Diode-PL520B-515nm-Semiconductor/132985370641

Laser diode housing module:
https://www.ebay.ca/itm/Housing-1211-3-8-BL-12x11mm-3-8mm-T0-38-Laser-Diode-Heatsink-Holder-M9x0-5/263742315486

G-8 Aspheric Glass Collimation Lens:
https://www.ebay.ca/itm/DTR-G-8-Bro...Lens-WHY-COMPROMISE-HAVE-IT-ALL-/173828377573

Laser pointer host:
https://www.ebay.ca/itm/12mm-laser-...laser-parts-laser-host-for-18650/331194747510

Thank you!
 
Last edited:



Philipnzw

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driver for your 450nm


driver for your 520nm

Not 100% sure if they will fit your host but i think there shouldn't be a problem. Using taobao as i'm in SEA and i usually source from that website, finding the same exact drivers on Ebay shouldn't be an issue.

Since your host doesn't look like it is the kind that uses circular drivers, i assume these drivers will be okay for you.
However you will need to solder some mini springs to the inputs of the driver to act as contact for the battery.

If you wanna cheap out on the driver for your 520nm laser i think you could just use the driver for 405-450nm lasers, they might have enough Vf to drive the green diode.
I used a 5.5V driver meant for 405-450nm diodes for my SHARP 505nm laser and it worked wonderfully. Better yet it was very low powered so the heat output was very tame, be it at the expense of brightness.

Good luck on sourcing your parts.
 
Last edited:

Alaskan

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DTR LPF google shop has some lower current drives here:


This one might work and only needs one Li-ion battery:

 

Supreminator

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A huge thank you to both of you for such fast and info-packed replies! Honestly I posted this last night hoping to have a reply by the end of the week and I come back today to see two amazing responses to my question.


driver for your 450nm


driver for your 520nm

Not 100% sure if they will fit your host but i think there shouldn't be a problem. Using taobao as i'm in SEA and i usually source from that website, finding the same exact drivers on Ebay shouldn't be an issue.

Since your host doesn't look like it is the kind that uses circular drivers, i assume these drivers will be okay for you.
However you will need to solder some mini springs to the inputs of the driver to act as contact for the battery.

If you wanna cheap out on the driver for your 520nm laser i think you could just use the driver for 405-450nm lasers, they might have enough Vf to drive the green diode.
I used a 5.5V driver meant for 405-450nm diodes for my SHARP 505nm laser and it worked wonderfully. Better yet it was very low powered so the heat output was very tame, be it at the expense of brightness.

Good luck on sourcing your parts.
I really appreciate your rapid response to my problem, all the time that you spent looking to find the drivers AND to see if they fit my host, as well as your tip at the end. Unfortunately though I was not able to find the product names / IDs or find them on a source that delivers to where I live :( Thank you very much again, I was very happy to see your reply and I learnt a lot, too.



DTR LPF google shop has some lower current drives here:


This one might work and only needs one Li-ion battery:

Thank you for this great find! I was able to find it on ebay where it can ship to me. This is probably the one I'll end up using, however, I have two questions. Apparently, this product regulates current, but what do I do about the voltage? My two diodes operate at different voltages, and the product info says that the driver can play around with voltage too, but I only see one potentiometer. Also, as my battery drains, will the current / voltage provided by this driver change as well?

Thank you very much.
 

paul1598419

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If you are planning on using the Micro Flex Driver, it has four settings for current ranges depending on how you solder the resistors in the setting bridge. You can get anywhere from 100 mA up to 1500 mA, but you are limited to a Vf of 5.5 volts, or there about. Since these drivers are constant current, you only need to concern yourself that the forward voltage does not exceed 5.5 volts. The driver will take care of the rest.
 

DTR

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Thank you for this great find! I was able to find it on ebay where it can ship to me. This is probably the one I'll end up using, however, I have two questions. Apparently, this product regulates current, but what do I do about the voltage? My two diodes operate at different voltages, and the product info says that the driver can play around with voltage too, but I only see one potentiometer. Also, as my battery drains, will the current / voltage provided by this driver change as well?
Thank you very much.
The most basic features that will be common to every "laser driver" which is a circuit that was designed to drive laser diodes is operating in only in constant current, applying this fixed current source in a way that is non abusive during switching and is extremely clean compared to the tolerances for noise, over/under shoot and inrush during switching that other similar electronics like LED's for example can tolerate. They will not add an extraneous voltage limiting feature. To understand how to look at the forward you would look at the load range of the driver and match that with the laser diodes and use a power source that is in that range of he drives voltage input. The difference on a buck/boost style driver like the flex will either buck or boost any difference between the power source and load. That is a basic way of explaining it but basically it is not a concern you will need to deal with beyond the above voltage ranges you will make sure the input and load fall into.🍺

If the circuit has the ability to limit voltage then it was not designed to safely power laser diodes. Unfortunately there are many circuits that are repurpused for this and sold as a laser driver like LED drivers which most have one similar feature of being a constant current circuit but did not add extraneous features and complexity that is unnecessary to driving a LED maintain full rated life expectancy.

Anyway the PL520B will be very borderline for the max load voltage that the Flexdrive can deal with. Also if you have the diodes already maybe shoot some pics of them as there have been a lot of issues with sellers sending lower cost diodes that are of a similar wavelength and power and on these if you receive a PL520 the voltage drop is higher and the flex will not handle it at all. The most common I am seeing is the cheap sharp diodes being sent in place of most the available Oclaro diodes. They have been flooding with cheap units with similar power and wavelength but do not have the very clean output of the Osram diodes.

Anyway for the 520's the LDSE500 or ACS500SE would be the units I would recommend for powering with a single LI-ion. It can also power the PL450B or some of the "close it good enough" very cheap Sharp 80mW 450nm diodes that is commonly sold as the PLT5 450B Osram 80mW 450nm which I have a customer that uses them for holography that was going mad with all suppliers sending them unusable Sharps.




Received these from a suppler that was supposed to send PL520B round base vs the slotted base of the Osram.
https://laserpointerforums.com/threads/tbd-520nm-mw-3-8mm-single-mode-laser-diode.104704/
 
Last edited:

Supreminator

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If you are planning on using the Micro Flex Driver, it has four settings for current ranges depending on how you solder the resistors in the setting bridge. You can get anywhere from 100 mA up to 1500 mA, but you are limited to a Vf of 5.5 volts, or there about. Since these drivers are constant current, you only need to concern yourself that the forward voltage does not exceed 5.5 volts. The driver will take care of the rest.
I see. I plan on using the ACS500SE driver, though.



The most basic features that will be common to every "laser driver" which is a circuit that was designed to drive laser diodes is operating in only in constant current, applying this fixed current source in a way that is non abusive during switching and is extremely clean compared to the tolerances for noise, over/under shoot and inrush during switching that other similar electronics like LED's for example can tolerate. They will not add an extraneous voltage limiting feature. To understand how to look at the forward you would look at the load range of the driver and match that with the laser diodes and use a power source that is in that range of he drives voltage input. The difference on a buck/boost style driver like the flex will either buck or boost any difference between the power source and load. That is a basic way of explaining it but basically it is not a concern you will need to deal with beyond the above voltage ranges you will make sure the input and load fall into.🍺

If the circuit has the ability to limit voltage then it was not designed to safely power laser diodes. Unfortunately there are many circuits that are repurpused for this and sold as a laser driver like LED drivers which most have one similar feature of being a constant current circuit but did not add extraneous features and complexity that is unnecessary to driving a LED maintain full rated life expectancy.

Anyway the PL520B will be very borderline for the max load voltage that the Flexdrive can deal with. Also if you have the diodes already maybe shoot some pics of them as there have been a lot of issues with sellers sending lower cost diodes that are of a similar wavelength and power and on these if you receive a PL520 the voltage drop is higher and the flex will not handle it at all. The most common I am seeing is the cheap sharp diodes being sent in place of most the available Oclaro diodes. They have been flooding with cheap units with similar power and wavelength but do not have the very clean output of the Osram diodes.

Anyway for the 520's the LDSE500 or ACS500SE would be the units I would recommend for powering with a single LI-ion. It can also power the PL450B or some of the "close it good enough" very cheap Sharp 80mW 450nm diodes that is commonly sold as the PLT5 450B Osram 80mW 450nm which I have a customer that uses them for holography that was going mad with all suppliers sending them unusable Sharps.




Received these from a suppler that was supposed to send PL520B round base vs the slotted base of the Osram.
https://laserpointerforums.com/threads/tbd-520nm-mw-3-8mm-single-mode-laser-diode.104704/
Thank you for your amazing reply!

About the driver, I plan on using the ACS500SE to power both of my pointers because I was able to find it for 1.33 Canadian rubles less than the LDSE500, and they appear to be pretty much the same thing. However, I just want to clarify - my two diodes operate at different voltages - but when configuring the driver, do I only have to look at the current that I'm setting it up to and everything will be fine?

As for the diodes, I haven't bought them yet, but I looked at the pictures from the sources I want to buy them from. None of them had any numbers on the diode that I could use, but I did notice one thing:
On Osram's website, the diodes are shown to have two flat sides on the brass part of the diode:
1568725217227.png
But the diodes pictured on my source have circular brass bases:
1568725388177.png

Does this mean that they are not Osram diodes that I was looking for?
If it would help, I have the links to my sources in my original post on this thread.

Thank you very much.
 

DTR

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I see. I plan on using the ACS500SE driver, though.
Paul's advice still holds with the ACS500SE just you do have more headroom on the max load voltage with that driver so it can accommodate any variation we discussed above.🍺

Does this mean that they are not Osram diodes that I was looking for?
If it would help, I have the links to my sources in my original post on this thread.

Thank you very much.
It is possible or it is possible they have put generic pic up. That is why I mentioned it. I am sure I have a picture up somewhere that I had not realized was a different but close variation although I try to make sure that does not happen. Looking at most the ebay "drop shippers"(which probably themselves have no clue about these items and swaps are occurring upstream in the supply chain and there are several new ones that have just plastered the place with listings and generic pics that just don't even make sense. One or two(if they are actually different sellers) which I know to be selling the "close is good enough" with the cheapest cost from at least a few listings. When they are actually caught sending the wrong item they will use feedback extortion to keep the scam going by offering to refund and you keep the item. Compare that with spending from the US $50-65 to send it back with tracking and signature to be able to get refunded via ebay or pp protection but require you to give positive feedback first. One reason I think if people are getting sent the wrong stuff it would be nice to document it here. 🍺
 

NSFJojo

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DTR, if I was to order one of your drivers and needed it set for 2.4v at 1w could you do it before you ship?
 

DTR

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DTR, if I was to order one of your drivers and needed it set for 2.4v at 1w could you do it before you ship?
Might be a little confusion do you mean set a driver to 2.4A aiming to produce with some combination of diode and lens a 1W optical wattage output?

Which laser driver were you looking at? What laser diode were you wanting to power with it? Most drivers I do offer to set before sending out with a few exceptions of ones that are not as simple as setting a range resistor and putting on a breadboard with pegs to do a quick setting on the test load for instance the Blackbuck 8M.

let me know the specific items and I will try to better answer your question.🍺
 
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