Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



Diode voltage?

Anthony P

Active member
LPF Site Supporter
Joined
Oct 7, 2018
Messages
318
Points
43
I am designing adjustable current power supply for RGB module.

It uses 3 diodes: red HL63603TG, blue PL459B, and green PL530. All have different power requirements. I intend to power them all from a single wall adapter. Each will have its own LM317 current regulator with in line current meters.

My question is about voltage. I have searched LPF and found much info on current, but little on voltage. Should I build a multi-rail power supply with 3 separate voltage regulators? red 2.7-3.0v, blue 5.3-6.5v, and green 2.2v (plus a heater voltage reg).

This project is still in the design stage. I haven't even done a breadboard yet, so nothing is etched in stone... open to suggestions.
 



DashApple

Well-known member
Joined
Jan 14, 2009
Messages
1,463
Points
83
Since the currents are low , I would Just use one power supply to cover them all if your not worried about total power dissipation , When running the LM317 in CC any difference in voltage will just be lost as heat in the regulator .
 

paul1598419

Well-known member
Joined
Sep 20, 2013
Messages
16,062
Points
113
I would also use just one supply for all your drivers. Since you are not using a direct diode green, you don't need a high voltage rail as the PL530 only needs a little over 2 volts Vf. There are some ready made drivers for RGB lasers that aren't terribly expensive. You might want to look into one of them.
 

WizardG

Well-known member
LPF Site Supporter
Joined
May 9, 2011
Messages
723
Points
63
Should I build a multi-rail power supply with 3 separate voltage regulators? red 2.7-3.0v, blue 5.3-6.5v, and green 2.2v (plus a heater voltage reg).

NO! Whether you go with one power supply or three the output to your lasers must not be from a 'voltage regulated' driver circuit. Laser diodes need current regulated drivers.
 

Anthony P

Active member
LPF Site Supporter
Joined
Oct 7, 2018
Messages
318
Points
43
Should I build a multi-rail power supply with 3 separate voltage regulators? red 2.7-3.0v, blue 5.3-6.5v, and green 2.2v (plus a heater voltage reg).

NO! Whether you go with one power supply or three the output to your lasers must not be from a 'voltage regulated' driver circuit. Laser diodes need current regulated drivers.
To clarify, I meant a voltage regulator in addition to mandatory current regulator. My concern was/is that the blue requires about 6v. If I run the other 2 at 6v they will be damaged... right? If I understand DashApple correctly, all could run 6v and cc regulator would just get hot. Fan and heatsink.
 

WizardG

Well-known member
LPF Site Supporter
Joined
May 9, 2011
Messages
723
Points
63
"I understand DashApple correctly, all could run 6v and cc regulator would just get hot. Fan and heatsink. "

You do understand correctly. LM317 regulators configured for CC would (in theory) let you run with any input voltage up to about 36 volts with more waste heat the higher the input voltage is.
 

Anthony P

Active member
LPF Site Supporter
Joined
Oct 7, 2018
Messages
318
Points
43
Thank you, gentlemen. I will start bread-boarding this week and do a review of rgb module with pics when completed.
 

kecked

Active member
Joined
Jun 18, 2012
Messages
442
Points
43
Since your not modulating it why not grab an off the shelf rgbw led driver. Add voltage reg before it to supply the 5v. Will not work for higher Vf diodes as they need more voltage but should work for your needs. That’s just an example there are hundreds of chips to pick from and p,entry prebuilt.

64303
 

Anthony P

Active member
LPF Site Supporter
Joined
Oct 7, 2018
Messages
318
Points
43
Since your not modulating it why not grab an off the shelf rgbw led driver. Add voltage reg before it to supply the 5v. Will not work for higher Vf diodes as they need more voltage but should work for your needs. That’s just an example there are hundreds of chips to pick from and p,entry prebuilt.

View attachment 64303
I will look into that approach. The hobby for me is in the building of laser projects. Don't care too much for owning or collecting them. Thank you for the circuit diagram.
 

kecked

Active member
Joined
Jun 18, 2012
Messages
442
Points
43
Same here. Circuits a random example. Just search rgbw led driver circuit. There are tons of chips to pick. Point is if you are not modulating you can do constant current will little fear of issue so long as your circuit is well behaved on turn on and turn off and the supply is stiff.
 




Top