Labby Driver Options? Please Help :D

[KRNAZNBOY]

Hey guys i am in prgress in building a labby style laser for prolonged duty cycle. However, i have run into an issue, which is power source and a driver. I want to use a power supply that can be plugged into a wall. Like a 12v power supply on ebay or something like that. What are my driver options for this build (DIY is OK) and for those options, what kind of power supplies would i have to use?

BTW guys i need to get AT LEAST 2.4 amps.

Thanks guys, really appreciate it!
-Matt

 

[bdgreenb]

you could run 2 of any of our current(meaning the ones we have now, not A) drivers in parallel to get the added total. and just get a wall wart that = their combined necessary input

 

[KRNAZNBOY]

you could run 2 of any of our current(meaning the ones we have now, not A) drivers in parallel to get the added total. and just get a wall wart that = their combined necessary input

Well thats the thing, im looking at $40 plus with that setup. Are there any other options, like DIY or something? Or a super x-boost?

Also, how can i figure out the input if all i know is the output i want (2.4 amps)?

Thanks

 

[ARG]

A DIY LM317 driver with a beefy heatsink will do.

That or wait for the P3's to be in stock @ illumination supply.

 

[KRNAZNBOY]

Ok great, how does an LM317 driver work, does anyone have a schematic? Where can i get those lm317 chips in the 3-prong version? Sorry, looked at digikey and i couldn't find the square 3-pronged one

 

[ARG]

Read this: Laser driver - It can be done

Also, I checked and there are no LM317's that can do 2.4A, user an LM1085 then.
Such as digikey P/N LM1085IT-ADJ/NOPB-ND

Don't mess around with pots either, just use a set resistor.

 

[KRNAZNBOY]

Awesome, thanks for the helps m8s. I'm guessing the LM1085 work sin the exact same way. What about the math? is is the same?

 

[ARG]

Not sure about the math, pinouts may be different as well, best to check the datasheet.

 

[KRNAZNBOY]

The pinout is the same, but how can i find out the math and resistors

BTW for anyone else, here is th chip i plan on using: Invalid Request


Also, i plan on using a fan with this build, that can i use to get the right 12 output for the fan?

 

[jayrob]

The formula is voltage divided by ohms = Amps.

The chip has a constant regulation of 1.25 volts between the sense pins.

To get 2.5 Amps, you can use 2 X 1 Ohm resistors together, which would be the same as .5 ohms.

1.25 divided by .5 = 2.5 Amps. (you will need 2 X 1 ohm resistors rated at 3 Watts)

http://www.ebay.com/itm/1-OHM-3-WAT...2B-DALE-NEW-Qty-5pcs-/130762995994#vi-content

Getting to 2.4 Amps can be done with a 1.1 ohm (if available) resistor together with a 1 ohm.

If you can find a 1.1 with a 1, that will be about 2.4 Amps. They need to be rated at 3 Amps...

1.1 and 1 will be .5238 ohms.

1.25V / .5238 = 2.38 Amps...

Here's an ohms law calculator:
http://www.ohmslawcalculator.com/ohms_law_calculator.php

 

[KRNAZNBOY]

Would this work jay?

Power Supply Adapter Balancer Charger AC 100 240V DC 12V 3A FOR Laptop LED Strip | eBay

 

[jayrob]

It should work yes, but I'm thinking that since the C-mount diode is asking for around 3 volts, you may be ok with a 6 volt supply as long as you can find one that can put out 3 Amps...

 

[KRNAZNBOY]

Whats a C-Mount diode. I am planning to use a 9mm is the understanding right? Sorry if i dont know this stuff

 

[jayrob]

Oh... I had red C- Mount in mind...

Yeah for a 445, go for a 9 volt supply if available.

 

[KRNAZNBOY]

Last questions, will i be able to test this driver with Jufran's test load?

2) is it smart to heatsink the resistors to prevent them from heating up and lowering resistance?

:beer:
-Matt

 

[jayrob]

Last questions, will i be able to test this driver with Jufran's test load?

2) is it smart to heatsink the resistors to prevent them from heating up and lowering resistance?

:beer:
-Matt

Any 445 test load that can handle the current.

Heatsink the main chip. The LM1085...