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What driver do you recommend for 1.5W?

itsmei

itsmei

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Hi, i am going to be building a 1.5W 445nm laser, i will be powered the diode at 1.5A and i want to know what driver you recommend for it. Can i have a link too please.

Thanks
 





A

anselm

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That depends on which and how many batteries you are planning to use.
And that in turn depends on the host you are planning to use....
So, once you have that figured out, a driver recommandation can and will be made.
 
itsmei

itsmei

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well, i am making a "lab" style laser. I am getting a box which can fit a nice big heatsink in. Size is not a problem, so i can use any batteries. I was thinking of 1 or 2 18650 3.7v batteries. If i used a flex drive maybe? I am not sure really what i am talking about though with drivers that why i have asked you.
 
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anselm

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Well if you have a lot of free space and hence freedom in your choice of batteries,
you can just whip up a LM317 driver, it is the cheapest and works fine.
Have you visited the 2n link in my signature?
 
itsmei

itsmei

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Yes, my first idea was to build a LM317 driver which can power up to 1.5A but i really didn't want to risk destroying the diode. I'm getting a A-140 so it is capable of 2w which is probably about 2A. I want to power it at about 1.5W with 1.5A. Maybe i should consider the LM317 driver. The idea is that i will have the LM317 driver set to 1.5A and i will have another pot extra which will come out of the box so i can adjust the power to my likings. Thanks for the inspiration again! What ohm resistor should i use for 1.5A?

Thanks
 
DTR

DTR

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If the diode can hit 2W which will depend on its efficiency it will do so with 1.8A.;)

I have thought about a labby with a flexdrive sinked running @ Max with this beast. 10,000mAh. Or two in parallel for 20,000mAh.:eg:

It is a little wider than a D cell and twice as long as an 18650.
LiFePO4 38120P (M size) Cell: 3.2V 10 Ah, 100A Surge Rate, 32Wh with 6M screw Terminal - UN Approved (3.0)


Or you could go for the gold. 16,000mAh.:beer:

LiFePO4 40160S Cell: 3.2V 16 Ah, 160A Surge Rate, 51.2Wh with M3.4 screw Terminal
 
itsmei

itsmei

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If i build my own, the LM317 can go as high as 1.5A. If i just put 1.5A through does that mean i do not need a resitor?

Sorry if this seems like a really stupid question!
 
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anselm

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DTR said:
LiFePO4 38120P (M size) Cell: 3.2V 10 Ah, 100A Surge Rate, 32Wh with 6M screw Terminal - UN Approved (3.0)

LiFePO4 40160S Cell: 3.2V 16 Ah, 160A Surge Rate, 51.2Wh with M3.4 screw Terminal
Click to expand...
OMG I almost wet my pants just now..... holy battery!

itsmei said:
If i just put 1.5A through does that mean i do not need a resitor?
Click to expand...
You do need a resistor. I tried bypassing the resistor, and it did work for a few
seconds, making the poor litle LM317 push over 1.8Amperes, but it was
scary, overheating and shutting itself down....
 
123splat

123splat

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LM317 has a 'Design Load' of 1.5A for the big cases, less for the smaller cases. It is quoted as capable of delivering in excess of 1.5A (with adequate heatsinging),,But that don't mean you are supposed to design for that. if you look at the data sheet, the formula for calculating the resistance in the current source application is Vref/Resistance= Iout. Vref is always 1.25V. Anything less then 0.8 Ohms makes the regulator try to supply OVER 1.5 amps ( so, that's what you need minimum). A short, theoretically, tells the regulator to try to supply infinite current and is real hard on the thermal shutdown circuitry.
 
rhd

rhd

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I slightly disagree-

Hop over to digikey and grab:

- A two-18650 battery holder
- 1084 or 1085 Adjustable Positive Voltage regulator
- 2x 10uF ceramic capacitors
- 1N500x diode
- Resistor 2W, 0.81 Ohm (I think that's the closest common value)

(in reality, you may want to order a couple extra of the cheap componants... they're cheap)

Then basically build the normal LM317 DDL circuit, but do it with the 1085, and add an additional capacitor accross the battery outputs (driver input).

Why?

- The 1084 or 1085 are low dropout, so they'll work better for blue diodes, especially as the batteries start to run out of juice. The 1084/1085 needs ~1 to 1.5V, instead of ~2.5V
- You can wire the 1084 or 1085 exactly like an LM317 (pin for pin), don't need to rethink anything.
- The 1084 / 1085 can handle 3 or 5 amps, instead of ~1.5A of the LM317. That's important here, because you're trying to actually run at 1.5 A, which is just about the borderline for an LM317, but well UNDER what either a 1084 or 1085 can handle.
 
HIMNL9

HIMNL9

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^ only if in your country can be found Axelite products ..... as example, here in Italy they does not have any distribution, and no shops sells their products, including AX1804 ..... (i know this, cause are some weeks that i'm exchanging emails with their sales office, trying to get some of their boost converters ICs ..... damn crappy Italian distribution system :p)
 
Seoul_lasers

Seoul_lasers

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anselm said:
OMG I almost wet my pants just now..... holy battery!


You do need a resistor. I tried bypassing the resistor, and it did work for a few
seconds, making the poor litle LM317 push over 1.8Amperes, but it was
scary, overheating and shutting itself down....
Click to expand...

Yup, RC batteries have deep cycle of about 8000mA/hr @ 7.4v.
They can discharge 80A to 200A through a brushless motor.

I would strongly advise using a Die4driver 445nm version (V1.3) or a Dr.lava flexmod P3
Both of these are EXCELLENT drivers! Die4driver allows real time current monitoring in addition to TTL modulation!
Me.. I am thinking about a making a 445nm lab laser, next project using a 3000mA/hr 7.4v RC cell.
 
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