A few driver questions..

[Amply]

Alright,

I am working on building a 445nm 2w blue laser driver
I have some questions about some of the items i have purchased.

The laser diode i'm using from DTR's laser shop
http://www.amazon.com/445nm-Diode-C...&redirect=true&ref_=oh_aui_detailpage_o03_s00

The plan is to make a constant current linear driver using these parts:

RCL12251R47FKEG Vishay / Draloric | Mouser

--1.47ohm resistor 2W power dissipation (going to be in parallel to get the desired .735ohm resistance I'm looking for (i think))--

TEXAS INSTRUMENTS LM1085IT-ADJ/NOPB IC, ADJ LDO REG, 1.2V TO 15V, 3A, TO-220 (1 piece): Rf Transistors: Amazon.com: Industrial & Scientific

--The voltage regulator (LM1085)--

http://www.amazon.com/gp/product/B01CU8CBV0/ref=crt_ewc_title_dp_1?ie=UTF8&psc=1&smid=A3RD7YW5IJU8WP

--The power supply 7.4v 400mAh (going to hook 4 of them up in parallel to get the desired 1.6A (i think))--

Now of course i'm going to be adding capacitors to the circuit as well but have yet to figure out that part. I also have a heat sink for the diode and heat sink for the LM1085 and a small computer fan.

My desired output to go into the laser diode is 4.6V and 1.6A

Now for my questions

Is the power source i chose viable?

Will the resistor i chose work? (if so how would i go about soldering that?) first time using a resistor that does not have pins.

Am i going about this correctly?

 

[Lifetime17]

hi Why go through all of that just buy one of DTR's1.8A bucking drivers made by lazeerer they are the best .. thats all i use for any of my 2W diodes never a problem..

Rich

 

[diachi]

Alright,

I am working on building a 445nm 2w blue laser driver
I have some questions about some of the items i have purchased.

The laser diode i'm using from DTR's laser shop
http://www.amazon.com/445nm-Diode-C...&redirect=true&ref_=oh_aui_detailpage_o03_s00

The plan is to make a constant current linear driver using these parts:

RCL12251R47FKEG Vishay / Draloric | Mouser

--1.47ohm resistor 2W power dissipation (going to be in parallel to get the desired .735ohm resistance I'm looking for (i think))--

TEXAS INSTRUMENTS LM1085IT-ADJ/NOPB IC, ADJ LDO REG, 1.2V TO 15V, 3A, TO-220 (1 piece): Rf Transistors: Amazon.com: Industrial & Scientific

--The voltage regulator (LM1085)--

http://www.amazon.com/gp/product/B01CU8CBV0/ref=crt_ewc_title_dp_1?ie=UTF8&psc=1&smid=A3RD7YW5IJU8WP

--The power supply 7.4v 400mAh (going to hook 4 of them up in parallel to get the desired 1.6A (i think))--

Now of course i'm going to be adding capacitors to the circuit as well but have yet to figure out that part. I also have a heat sink for the diode and heat sink for the LM1085 and a small computer fan.

My desired output to go into the laser diode is 4.6V and 1.6A

Now for my questions

Is the power source i chose viable?

Will the resistor i chose work? (if so how would i go about soldering that?) first time using a resistor that does not have pins.

Am i going about this correctly?

As Lifetime said - you'd save yourself a lot of trouble by buying a driver already built and set at the right current.

Anyway - onto your parts.

Not sure why you're going for an SMD resistor? You'd be much better off with a radial resistor - or a a few radial resistors in series/parallel if you can't find the correct value in one resistor.

As for the regulator - I'd go for an LM338 if I'm going linear and need that much current - it's pretty much the same as the very common LM317 that we all know and love - just has a higher current limit (5A instead of 1.5A). Stick to what you know right? Keep in mind you want to use it in a current regulating configuration, not a voltage regulating one. Laser diodes generally like to be current regulated.

On to batteries - I think you lack an understanding of battery ratings. 400mAh means that the battery can supply 400mA for 1 hour - it's a measure of capacity, not how much current it can provide at any given time. Those batteries should be able to provide a much larger amount of current than 400mA. That said, you'd best put several in parallel because you're probably only going to get less than ~15 minutes of run time out of one at those currents. I'd be more inclined to go for something like a couple of 18650s (In series) and a battery holder for those. Higher capacity than what you're looking at.

 

[Pman]

How many lasers have you already built? If you are just getting into the hobby I would HIGHLY recommend you start off building a few with components that have already been proven to work together. It seems far better to get a couple working builds done so you can see what you are getting into than possible big dissapointment by overreaching and dropping out before you give it a chance. Just my opinion. Have no idea where you are coming from since you are very new here.

 

[Amply]

This would be my first laser built other than a few 5mW lasers used for visual effects. I know that i could buy DTR's driver and just hook that up to a power supply (although i guess i misunderstood how power supplies work) and run the laser like that but i feel like that's cheating (not saying that's bad to discredit people who do that) but I'm trying to make something i can kinda call my own (although greatly influenced by help received on here and research I've done myself). From what I understand linear drivers are awful and buck drivers are in all ways superior? I know it's a terrible idea for a novice to be attempting to make his own driver from scratch and start off with 2w laser diode....

Is there any page you can link me to that explains how power supplies work?

Is there really any benefit of having a linear driver over a buck?

 

[Cyparagon]

"how do power supplies work?" that REALLY depends on what kind of power supply.

Where did you read that buck drivers are in all ways superior? Linears are more reliable, simpler, cheaper, much less electrically noisy, much faster, and more stable.

 

[Amply]

I did not read any articles or specific text saying that buck drivers are in all ways superior but a lot of the posts i read about people asking for help with a linear drivers people tell them to go with a buck converter rather than linear so i assumed their was good reason for that.