Why are green laser drivers more complex than Red Laser Drivers?

[blue laser research]

Copyright © 1994-2004, Samuel M. Goldwasser

So, many led and laser diodes seem to only have a voltage regulator and a diode for reverse battery protection. Some have current regulators, but all the green ones seem way more complex.

I'm interested in using the following laser in a project but want to simply the board if possible.

 

[Encap]

A 532nm laser driver is not more complex --the driver is the same as for any diode .
In the case of a 532nm output DPSS laser the driver is powering an 808nm diode.

 

[diachi]

A 532nm laser driver is not more complex --the driver is the same as for any diode .
In the case of a 532nm ourput DPSS laser the driver is powering an 808nm diode.

Often times drivers designed for red lasers will work just fine with DPSS green too, the forward voltage for typical 650nm red diodes and 808nm diodes is fairly close.

 

[blue laser research]

So lets say I have a voltage regulator that outputs the needed voltage to the diode and I run this through 7135 current regulators. Would I have a direct driver that worked? Does the diode need anything other than the proper voltage and current?

 

[diachi]

So lets say I have a voltage regulator that outputs the needed voltage to the diode and I run this through 7135 current regulators. Would I have a direct driver that worked? Does the diode need anything other than the proper voltage and current?

You just need the current regulator and the proper supply voltage.

The current regulator adjusts the output voltage to maintain a set current.

Laser diodes are current devices, not voltage devices.

 

[blue laser research]

You just need the current regulator and the proper supply voltage.

The current regulator adjusts the output voltage to maintain a set current.

Laser diodes are current devices, not voltage devices.

It's been awhile since I made my last driver but I think my 7135's were overheating above 3.7v, so I was going to use the voltage regulator before the current regulators to give me a wider range of batteries. Other than added complexity would this work?

 

[diachi]

It's been awhile since I made my last driver but I think my 7135's were overheating above 3.7v, so I was going to use the voltage regulator before the current regulators to give me a wider range of batteries. Other than added complexity would this work?

Would it work? Sure. But you'd still be producing the same amount of heat, all you'd be doing is moving some of it from your current regulator to the voltage regulator. You're not solving the problem, you're just moving it around. Assuming you're using a linear voltage regulator that is. If you're using a switching voltage regulator first then that'd be better.


With linear regulators you want your input voltage to be as close as possible to your output voltage.

The difference is turned into heat.

Pin=Vin*Iin
Pout=Vout*Iout
Pd=Pin - Pout

Pd being the amount of power dissipated as heat.

Options:

1) Use a switching regulator instead
2) Lower your input voltage
3) Pick a regulator that can handle the power dissipation
4) Add a heatsink to your regulator

 

[lasersbee]

So, many led and laser diodes seem to only have a voltage regulator and a diode for reverse battery protection. Some have current regulators, but all the green ones seem way more complex.

Would be great if you included your Global
location in your Profile so member now what
part of the planet you are from...:beer:

Jerry

 

[Encap]

"What is a laser diode driver? In the most ideal form, it is a constant current source, linear, noiseless, and accurate, that delivers exactly the current to the laser diode that it needs to operate for a particular application. The user chooses whether to keep laser diode or photodiode current constant and at what level"
see: https://www.teamwavelength.com/info/laserdiodedrivers.php

 

[paul1598419]

I have to admit that I thought this was a thread about 520nm green lasers. All the pertinent questions have been answered by others here. The main take away is that ALL laser diode drivers are constant current sources.