TTL driver has a variable voltage pot(and of course current)??

I am trying to purchase a TTL compatible driver for a m140 2w 445nm diode, and any help would be much appreciated as I am new to laser building and this is my second build after killing another diode due to improper handling of the driver and module connection.

I found this driver and it confuses me. It (and a few others i have found) seems to have variable output current and output voltage
acording to the pictures and labeling.

12V TTL 1W 2W 3W 445nm 450nm Laser Diode LD Driver Power Supply Stage Light | eBay

I have seen the usual constant current based drivers, but I have no experience with ones with variable voltage and variable current in the same circuit, and I have no Idea how I would set the voltage.

1. Is this normal or should I find another TTL driver for my M140 diode?

2. How would I go about setting up this driver? (I have a 10 diode variable test load from Survival laser and a multimeter to do so, but i only know how to use it for current check)

Also here is the diode I will be purchasing
2W 445nm M Type M140 Blue Laser Diode | eBay

I plan on using this for a CNC Laser engraver/cutter.

Thanks!!

EDIT: is the variable output voltage for the fan maybe?

Usually I suggest staying away from the china drivers. They are typically cheap but you usually get what you pay for. If you need a driver with modulation there are a few community recommended options.
Flexmod P3. Pretty much the standard but usually on backorder.
FlexMod P3 Laser Driver

Lasertack drivers.
https://www.lasertack.com/en/laser-diode-drivers

J Tech a full service solution driver
High Current Laser Drivers | Product Categories | J Tech Photonics, Inc.

Lasershowparts drivers very good driver but only available in dual channel.
Lasershow Parts - 2 channel analogue diode driver

Check out this thread with some other options.
Are FlexMod P3's still available or is there an equivalent that is ready to ship?


Also check out this thread on CNC with these diodes. Lot of great info.
CNC Laser Engraving 8bit Shades of Grey 445nm

And my page as well.:beer:
https://sites.google.com/site/dtrlpf/home/laser-cnc-engraving

Thanks very much for the help and the links! I am actually purchasing the diode from you I think!

1 .So does the fact that there is a variable voltage knob make this a "shady" laser driver? Like maybe it is actually an LED driver?

I cannot find ANY documentation on laser drivers with an additional voltage potentiometer (on top of already having the current pot).
This has got me really confused, as i thought a constant current driver adjusts voltage to keep a steady current.

2. Is this an adjustable voltage limiter maybe(to prevent voltage going to high)? or maybe the voltage setting for the fan output?

I do not currently have the funds for a high end TTL driver, so If there is a cheap ebay alternative than I am willing to risk it at the moment. (I take full responsibility)

3. I was also looking at this TTL laser driver from techhood, but it seems very similar, and also has a variable voltage potentiometer.
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2W TTL 445nm Blue Laser Diode Driver 8 14V Step Down Circuit w 2 5A Output | eBay
Although I still don't understand how I would adjust the voltage pot for the m140 or any diode for that matter.

Has anyone had any experience with either of these drivers?

4. Would running the m140 off of a 1w laser driver be OK for the driver and diode? ( i have one of these already)
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Industrial 445nm Blue Laser Diode TTL Driver 12V 1 2A | eBay

Only reason I can think of to want to adjust voltage in a CC circuit, would be to ensure that the input voltage to the current regulator stays rock steady, yes?

-G

All of the drivers I have seen which have both a voltage and a current adjustment aren't tailored for use with a laser diode, more commonly for LED's and never have a TTL input. The only reason I can think of to have a voltage range adjustment on a laser diode constant current regulator is to allow it to be used with different diodes; IR, red, blue and green which require different voltage ranges to operate, from lower to higher in that order of color.

I like the idea of a driver which has adjustment for voltage as well as current because then it can be set for use with any laser diode made, if the supply voltage is high enough and the driver components will handle the demand. However, I believe all of the drivers designed for laser diodes leave this adjustment off because they can be designed to automatically set the voltage to what ever it needs to be, within its design and supply limits, to produce the current you set the output to remain at but then these drivers usually can't drive all of the different color laser diodes available, not just because of the different current demands depending upon whether high or low power, but because it is more difficult to design a single driver in a small package which has the needed voltage and current ranges for all of the available laser diodes we use in pointers. Due to this, we have ended up with are drivers which are designed for the type of diode you will use, if you buy the correct driver for your diode you don't need to concern yourself with the actual output voltage, just the current, as the voltage will take care of itself depending upon the current set point and the diodes resistance, some diodes higher, some lower requiring more or less voltage for a given amount of current, but all of that taken care of through the regulator.

Some drivers are not designed for IR diodes, some are not designed for green diodes because the voltages needed for the two different technologies are so different, infrared requiring about 2 volts, green up to ~8 volts, for blue about midway between the two extremes. The choice for the kind of driver you need becomes more complex when using just one, or two of the common Li-On batteries we use for pointers because their single cell voltage ranges are 3 to 4.2 volts. Some diodes require more voltage than a single cell can produce and because of this, you either need to use two batteries in series, or a special "boost" driver which will increase the voltage beyond what a single cell can provide, through the magic of electronic circuitry, but at a cost, more current draw from the battery. Because high power blue and green diodes require over 4.2 volts, the maximum you can get out of a single celled Li-On battery, a single battery won't work to drive one of those laser diodes unless you buy a boost driver which can produce a higher voltage than one battery cell can provide.

So, now we have two basic types of driver designs, a regular or normal linear driver called a buck driver, and a boost driver. Buck drivers throw voltage away in the form of heat to keep too much current from flowing into your laser diode, boost drivers use more current from the battery to produce a higher voltage so you can supply enough current to your laser diode, two different methods of producing the voltage and current you need, depending upon whether your batteries are supplying too little voltage, or too much voltage for the device you want to regulate the current to. You do not need a boost driver for most of the laser diodes we use if the battery supply is two cells in series inside a pointer, as two cells usually produce enough voltage to drive just about any laser diode we use. In that case, why have a voltage adjustment when the driver can be designed to supply what ever voltage is needed to produce the amount of current a diode will draw? So, they leave the voltage control off, at a price, that pricing being some drivers are suited for IR, red and perhaps blue, but can't reach enough voltage to drive a green diode, so then you buy a different design.

I'd prefer all of the constant current regulators we use for laser diodes were designed for both a voltage as well as a current adjustment, that way all I would need to know is the min-max voltage and current ranges for both the input and outputs and be able to understand which driver I need just by a quick glance at their numbers. In the world of laser pointer drivers the designers of these devices approach things differently than I do, I want these input and output voltage and current figures but try to find them on any web page selling them, they aren't there. When I ask why not, I'm told most people just know what kind of driver they need for the battery and diode they want to drive... I base my choices upon knowing DC theory, as an electronics technician in my trade, so not having the figures right there seems uber stupid to me. If I had the figures, I wouldn't need to know which driver is better suited for which laser diode, I could figure it out myself from the specs. To make things even more confusing, the individuals selling these drivers often won't even put information showing which laser diodes they are good for, let alone color or whether you can use one or two batteries in series with them if you want to do so, such as I need to know for my tri-color laser diode pointer which uses red, green and blue laser diodes in it which operate across a large range of voltages, not to mention the next one I want to build which will also include an IR diode. Of course, my thinking it's stupid not to include this information is taken as being stupid not to be more familiar with the drivers offered. Their prices are high enough as it is to take a risk I'm buying the wrong driver, especially since my projects usually require lots of them, my next project over 24 of them so I want specs man, gimmie the specs!

OK, so there's some info I hope is helpful, thank you for bearing with my rant regarding the laser driver industry, they need to standardize their specs so we can figure things out easier, I've been working in electronics over 40 years now and find buying laser drivers too confusing, maybe because I'm a tech and know the possible gotcha's, not wanting to guess about any of the parameters.