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ArcticMyst Security by Avery

please, should i choice lm317 or acm7135 for driver laser

Joined
Oct 18, 2014
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546
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i have bought at DTR's shop a diode:
- 1 x ocalor red 1W 638nm
- could you please show me that which is better for diode laser red 1w? lm317 or amc7135?
- and the capacitor which is better? 10uf 35v or 47uf 35v!
- Thanks all!:yh:
 





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Aug 30, 2008
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Depends on what you're putting the laser in.
If the diode is case positive, you have to be careful with how you wire and set everything up.

if i recall correctly, the lm317 doesnt use the negative to regulate, so if you set up a case positive diode in a host, and you have positive case (battery + pointing towards the tailcap), and then the diode accidentally picks up the battery + from the case of the host, you'll bypass your driver and kill your diode.
So if you use the lm317 you'll have to isolate the module from the heatsink, or the heatsink from the host to keep it from getting power directly from the battery.
 
Last edited:
Joined
Oct 18, 2014
Messages
546
Points
63
Depends on what you're putting the laser in.
If the diode is case positive, you have to be careful with how you wire and set everything up.

if i recall correctly, the lm317 doesnt use the negative to regulate, so if you set up a case positive diode in a host, and you have positive case (battery + pointing towards the tailcap), and then the diode accidentally picks up the battery + from the case of the host, you'll bypass your driver and kill your diode.
So if you use the lm317 you'll have to isolate the module from the heatsink, or the heatsink from the host to keep it from getting power directly from the battery.

Oh, thanks, i known that, ;) but in here I want to talk about: the diode lifetime and stability between 2 ICs that I said, lm317 and amc7135 Which is help laser diode lifetime longer than? and capacitor 10uf and 47uf,too. ^^ thank you!
 
Joined
May 20, 2013
Messages
358
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The capacitor will only drain current when the driver is starting, helping to smooth the voltage spike that the driver does when starting, and will not have an effect during the actual working of the driver.

I also recommend adding a 470R resistor in parallel to the capacitor, it will discharge the capacitor automatically every time you turn off your laser, letting you able to reconnect the LD without the risk of connecting it to a charged capacitor.

I think both will work, but I'll go with the 47uF/35V.
 
Joined
Oct 18, 2014
Messages
546
Points
63
The capacitor will only drain current when the driver is starting, helping to smooth the voltage spike that the driver does when starting, and will not have an effect during the actual working of the driver.

I also recommend adding a 470R resistor in parallel to the capacitor, it will discharge the capacitor automatically every time you turn off your laser, letting you able to reconnect the LD without the risk of connecting it to a charged capacitor.

I think both will work, but I'll go with the 47uF/35V.

Thanks very much,i knew important of capacitor.
- but between lm317 and amc7135? which is better for the diode's lifetime?
- and if i adding a 470 ohm resistor inparallel to the câpacitor,it redution current to diode ?
 
Joined
May 20, 2013
Messages
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Points
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Thanks very much,i knew important of capacitor.
- but between lm317 and amc7135? which is better for the diode's lifetime?
- and if i adding a 470 ohm resistor inparallel to the câpacitor,it redution current to diode ?

The AMC7135 is a fixed current regulator, at 350mA, it is more efficient but you will not reach 1W with this driver. So, I recommend the LM317 that regulates up to 1,5A. Both will perform the same and there's no change in diode's lifetime.
The current consumed by the resistor will be very little, if you have the Vdrop of the LD, you can calculate the current consumed by the resistor with Ohm's Law: I=V/R.
 
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You can actually use AMC7135 in parallel. If you use AMC7135N Use 2 in parallel will give you 700ma whereas 3 will give you 1050ma and so on

Btw, which diode did you buy? I dont think dtr has a 1w 638nm diode. He only has 700mw 638nm diode
 
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yes it is 700m 638nm, but it have been run at 1A or 1,2A ~1W red.
Thanks for reply!^^
-Do you sure 3 amc7135 parallel give me 1050mA?
- So, if i use 2 x lm317 parallel give me 3A???
 
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yes it is 700m 638nm, but it have been run at 1A or 1,2A ~1W red.
Thanks for reply!^^
I would recommend run it at the most 1.1A, which will giveabout 800mw.
-Do you sure 3 amc7135 parallel give me 1050mA
if I am not, I wouldn't have answered

- So, if i use 2 x lm317 parallel give me 3A???
Will but why would you do that? Just use Lm338 or lm350. They are similar to lm317 with a higher max current output
 
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thank you very much for show me that! I am going to do that you said!
Thanks all because help me! ^^
 




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