Constant current laser driver circuit

The board should have also 12V available on it. The interface should be also PWM. Regards Milen. Excuse me for this question if you find it kind of off-topic. Some time ago I bought a bunch of step-up and another handful of step-down buck converter modules for possible future projects. Now the time has come that I need to replace a broken driver from a green laser pointer.

The LD is ok since I have tested it and worked. I'm talking about a cheapo laser pointer, so I don't want to spend much time neither money in repairing it. That's why I thought the step converter could be a handy option. Reply 11 months ago. Hi, Normally the lasers are driven by current generators, but in the cheap pointers batteries from the type are used.

I think that you can adjust one of your converters to give such voltage as in the original. Good Afternoon Milen. Thank you for the walk through, it has been very informative. I was just wondering how you choose which transistor to use for Q1? Im new to electronics and transistor selection is still a little beyond me. Reply 2 years ago. Hi, The choice of the transistor in this case depends mainly on how much current you want to pass through it and what supply voltage you will use.

In this case you have to check the max DC Ids current which the transistor can pass and the breakdown voltage drain-source this shall be not a problem at all, because it is always higher than the max supply voltage of the op amp.

Please read also above about the input capacitance gate capacitance. In this case you will nit have a problem with the capacitive overloading of the op amp. Keep in mind that it can create a lot of heat if high currents are flowing. Question 2 years ago. My Laser diode operates at 2. Thank you very much in advance. Answer 2 years ago. Hi, This circuit works in DC mode. It wound be too slow to try to modulate it. I would suggest to use some dedicated laser diode driver chip.

I have a chinese 5. I don't what is the problem. I tried turning the pot on the board but it is not burning, can this be a problem with the board or something that I need to adjust. Reply 4 years ago. Dear Milen, I need to find diagram and circuits of electronical board of a printer to understand better how circuit control laser patterning generation. Can you give me some pdf reference or diagrams, I don't understand well how current intensity is controlled exactly so if some is wrong final picture could be distorted.

How you laser modulation is controlled by circuits? Reply 5 years ago. Hi Franco In my circuit you could remove R4,D2,C2 and instead them to connect a digital signal which would modulate the laser light. The problem here is that the used parts does not have enough bandwidth to guarantee the high speed modulation.

But in all cases the main principle for laser modulators remains similar. One possible technology of the pattering could be the use of DLP. MAX is slow opamp, you have to use faster. You have to reduce also C1 significantly or to remove it. Mpandya91 yahoo. By Milen Follow. More by the author:. About: Thank you all for following me. More About Milen ». Attachments V2C. Did you make this project?

Share it with us! I Made It! Remote Control Light Switch by alanmerritt in Arduino. Reply Upvote. It can also be used for driving nm and nm laser diode. Battery: It is recommended to use 3. Note: If you are driving a mW nm diode, you only need to remove the R resistor. If you are driving a mW diode, you only need to remove the two R resistors.

List of Laser Diode Driver Boards. Previous Next. Why R4? What value? What's the nominal operating voltage of the laser-LED mA? Confirming what Klaus stated: You lose 0. I'm not sure what that 1 Ohm resistor is for, you should be safe to remove it, it buys you a little extra voltage back. Hi, sorry for the confusion. The laser I am using is not concerned with the voltage as long as the voltage is below it's rated value 2.

I added the 1 ohm R5 to keep track of the amount of current to the edfa. I understand the voltage drop but since I am not worrying about the voltage, I could add R5 there. The problem I am having is with the LMT.

I have tried several chips, but I am not getting 1. The circuit is exactly as shown in the schematic. This is the thing confusing me. What can be the reason for me not getting 1. I have tried with several LMTs and the result is same for all of them. I have checked the passive components as well and they seem to be fine. I am really at a loss about what the problem may be.

So, I would really appreciate any suggestions on this matter. Thank you for your time. I hope my explanation clears the confusion. Hi, What can be the reason for me not getting 1. Click to expand I have also checked by increasing the input voltage from 5V to 10V DC by connecting it to a test load, nothing changed. Also, since I am making a constant current circuit, the change in load shouldn't affect the circuit. Hi, thank you for clearing my confusion.