Joined Jan 14, Messages 1, Likes Points This might not do what you want, anyway. Constant current doesn’t mean constant output from the laser. The LM is not a low-dropout type of linear regulator. I built a driver that combines both, using 2 LM’s, the first configured as a variable voltage regulator to feed the one configured as a current regulator, which is also set up as variable.

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To push less current, best to put a shunt resistor across the laser; currents from LM output must be over 5mA, preferably 10mA, for internal bias.

Markos Loizou 9 1. So here he traced out the voltages to find the second culprit. And there is no probably in “probably a small heatsink on the s is a good idea too” about it. With a 6V input and 5V output, the regulator won’t be regulating at all, it’ll just behave like a big diode.

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If you use a pot to make it variable like I did, make sure that you include an extra one ohm resistor in series with the lasdr so that you can’t make that value zero, it will always be the pot’s value plus one ohm. The discussion just reminded me of anti-Stokes phosphors. Thanks for all the answers.


Ok, I was on mobile. I used to have one.

Homemade Laser Driver with LM317

You can confirm that this works with your phone by trying it with your TV remote. I’ve built several LM based drivers for my lasers over the years.

This can useful for a number of applications including driving Laesr and laser diodes. Here is a driver I made: You might have to be careful with this circuit to be sure it can exit the DISABLE state without kaser applying the whole V3 voltage across the laser.

Help with LM laser driver | Laser Pointers

Mon Jan 16, 4: That seems pretty good for something like a laser diode. My basic idea was to provide a regulated clean DC power supply to the Vdd and Vlda as mentioned above to my laser driver.

Would be fine with a laser, I think. Would you like to answer one of these unanswered questions instead? The laser diode requires 7 mA and it will drop a maximum of 2.

You will need 1W resistors, and heatsinks for the s. You need to supply it with a higher voltage or use a regulator that can work with less difference between input and output. Do you have a reliable way to confirm the laser is still working? This power is dissipated on the regulator, the sense resistor and the diode.


Any other regulator with a low noise and paser drop out voltage This might not do what you want, anyway. Thanks Trevor, I completely forgot the diodes. If the regulators can respond that fast you will initially have close to 10V across each regulator at a whopping 5W each.

Help with LM317 laser driver

From wifi routers, to high spec lab equipment. As well as puzzling over the some of the design decisions in the radios construction, before identifying the final issue. Laseg thought I had to be as follow to limit correctly: The total dissipated power will be Thread starter Matrhis Start date Mar 14, Perhaps something like this.