Author Topic: lt3080 lt1965 laser diode driver, feedback?  (Read 1324 times)

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Offline CopperConeTopic starter

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lt3080 lt1965 laser diode driver, feedback?
« on: April 26, 2018, 07:11:54 pm »
I have these two IC's, I know its ridiclous, but I wanted to use them to drive this 100mW green laser diode. Right now it has a simple little driver, but I was gonna add a trimpot and a switch that can be used to regulate it, and a steel enclosure, so I figure I might as well replace the chinese IC's  and deadbug a little power circuit directly on the heat sink with the diode.

Benefits would be it could run up to 20V or more (depending on the vreg I use) depending on ambient temperature

Anyway, I was thinking of power vs current control. The diode I have does have a feedback diode.

I noticed some commercial lasers have a selectable current mode or power mode. Current mode is easy, I just use the LT3080 as a current source.

Power mode would mean I would need to get the diode output voltage and route it back into the feedback pin on the LT3080 with a scaling network (voltage divider I guess?) to set the setpoint.

Any thoughts on this?
 

Offline elecom

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Re: lt3080 lt1965 laser diode driver, feedback?
« Reply #1 on: May 30, 2018, 04:51:50 pm »
Any updated information?
 

Offline CopperConeTopic starter

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Re: lt3080 lt1965 laser diode driver, feedback?
« Reply #2 on: May 30, 2018, 06:45:48 pm »
The diode I had was built like a piece of complete shit and minor rotation caused supposedly strain relief bond wires to break so I gave up on the project.

The mechanical design on those is garbage, I don't really even want to deal with one until I figure out some kind of nice tidy way to make a socket-like connector for them.

And im broke as fuck so I can't go forward. And some how oil got on my optics, and it was all fuzzy.

Word of advise : If you are doing machine work for lasers that involves cutting fluids or tapping fluids, I would recommend getting a ultrasonic cleaner (which I don't own) to clean them up afterwords. I did what I could with acetone but not enough.
« Last Edit: May 30, 2018, 06:47:47 pm by CopperCone »
 

Offline CopperConeTopic starter

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Re: lt3080 lt1965 laser diode driver, feedback?
« Reply #3 on: May 30, 2018, 06:51:30 pm »
and that laser had some kind of ridiculous fucking thread, for which I don't have the tools to tap, and the body was positive.

I cannot tolerate a positive body. I wanted to earth the chassis.

But I did design something using one of those LTC protection circuits thats real nice.

I kind of don't want to attempt this project again until I have the money to replenish my welding supplies and make a custom box for it (instead of trying to hack a junction box), and get some kind of laser that has a earthed or floating body.

And for power mode, it turns out that the solution commercial manufacturers have is to just use a thermistor on the heat sink, to prevent thermal runaway, which can happen.

It's like a tiny thread, meant for like 1/8 inch screws, on a god damn 1/2 inch

not worth my time unless I can make it right, otherwise it will just come out like some cheap garbage
« Last Edit: May 30, 2018, 06:55:51 pm by CopperCone »
 


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