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Drivers for 445

Lumify

Lumify

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oic0 said:
Anyone else try a flexdrive at 1.5amps on this diode?
Click to expand...

I would love to know this as well. It seems that 1100mA works, and I'm looking for something that can buck and boost at 1.5A for a 445nm LD from a Vin of 3.0-8.4V. I've been looking all over the place for something like that, and the flexdrive is the only thing that comes close.
 





BShanahan14rulz

BShanahan14rulz

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vegasf6 said:
There are pages and pages on Candlepower forums about using the 7135 with multiple leds to drop the voltage (as opposed to zener diodes or other silicon diodes) but you are still burning battery power elsewhere.
Click to expand...
I was thinking about using a silicon diode on the Vin pin of the regulator to drop the extra voltage. I've seen download's work a while back, and what I'm planning is similar, except instead of putting a diode before the input on the whole system, it will only be on the 7135's Vin. This only pulls a very tiny amount of current, and the diode will drop the supply voltage that might be too high for the 7135.

vegasf6 said:
I believe the output voltage will be as stable as your input voltage pretty much, with the exception of any noise picked up by long leads, which aren't being used here. The suggested cap on the output, .1 to 1uF is a bypass cap to eliminate signal noise, I don't believe not using it will allow any significant amounts of current that would damage laser diode. At least not with batteries as the power source.
Click to expand...

Ok, that's cool. I don't think it was until recently that they added the diode and capacitor to the datasheet. Before, they were touting the "no external compnents needed" line.

vegasf6 said:
But, the voltage requirements of the LD and the max input voltage of the 7135 make them a poor match for lithium battery. Best bet would be 4xnimh. That will net the maximum efficiency.
Click to expand...

Alas, so I hear. I was hoping to run this off a single Li-Ion, but I guess I'd need a boost driver to do that if these 445nm diodes are 4.2V Vf.
 
V

vegasf6

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BShanahan14rulz said:
I was thinking about using a silicon diode on the Vin pin of the regulator to drop the extra voltage. I've seen download's work a while back, and what I'm planning is similar, except instead of putting a diode before the input on the whole system, it will only be on the 7135's Vin. This only pulls a very tiny amount of current, and the diode will drop the supply voltage that might be too high for the 7135.
Click to expand...
Current draw of the circuit will be determined by the regulator. If you plan to use 3 7135s it will be ~1 amp at the diode no matter where you put it in the circuit. To keep below the max supply voltage of 6V will require 4 diodes, but battery voltage will sag quickly so you can get away with 3. E*I=P so 2.1*1=2.1 watts turned to heat in the diodes.
BShanahan14rulz said:
Ok, that's cool. I don't think it was until recently that they added the diode and capacitor to the datasheet. Before, they were touting the "no external compnents needed" line.
Click to expand...

I don't know if, or when the datasheet was changed to include that, but there are different datasheets, as well as different makers of the IC, both Taiwanese and Chinese. The micro-bridge one I don't see the output cap. Addtek has it in theirs. LPF user Renno reports here having trouble with output cap but no details of what capacitance he tested. Or if he put it to ground.
BShanahan14rulz said:
Alas, so I hear. I was hoping to run this off a single Li-Ion, but I guess I'd need a boost driver to do that if these 445nm diodes are 4.2V Vf.
Click to expand...
Depending on drive current, yes. You could try a GD1000 but max Vin is only 5.4.
 
nospin

nospin

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My 1.5Watt 445 is running at 1.5 amps from the flexdrive
and can light a magazine page on fire in usually 1 second



A140 diode
1.5 amps at diode
4.35 volts
1.6 watts at 5 seconds
1.485 watts at at 30 seconds
2.25amps at 18650 battery
4171 host
405-G-1 lens
Micro flex drive V5
about 30 min on time in 6 days
 
midias

midias

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nospin said:
My 1.5Watt 445 is running at 1.5 amps from the flexdrive
and can light a magazine page on fire in usually 1 second



A140 diode
1.5 amps at diode
4.35 volts
1.6 watts at 5 seconds
1.485 watts at at 30 seconds
2.25amps at 18650 battery
4171 host
405-G-1 lens
Micro flex drive V5
about 30 min on time in 6 days
Click to expand...

Did you have to heatsink the flexdrive?
 
nospin

nospin

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I have done no tests but I guess >1000ma

regulating that much current generates heat

and sinking the driver will make it work better

The flex is the way to go, why limit yourself
 
BShanahan14rulz

BShanahan14rulz

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Everybody seems to think the flex is the best way to go. I'm curious why the microboost isn't a better choice. I've been thinking of using a microboost with a single li-ion. If the flexmod would be a better driver for me, could someone explain why?
Thanks
 
jayrob

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They both work good... I've been using mostly the Micro BoostDrive for up to 1 Amp. And 1100mA's by one request...

But the same for the FlexDrive. I have set it at 1100mA's too. (by request)
 
Alexizupinhea

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So just to double check, you can't use a microboost maxed out w/ a RCR123a correct? The RCR123a wouldn't be able to put out enough current?

And I don't think I read it much but I'm using a LM317 in my POINTER - yes, a pointer i made which uses 3x 18650s and the LM317 circuit is set up to 1.25A

Edit: Also, I have another quick question if anyone can answer. Can I just set the microboost to the highest range setting and then turn the pot all in one direction without having to use a test load? Like, I'm guessing the pot stops and so which direction do I turn it for max? As you can tell, I never used one before, and only used a flexdrive v2 once a longg time ago.
 
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jayrob

jayrob

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It just depends on the quality of the battery I think...

Plus the capacity is a big concern at high current demand...

I just set and tested a V5 FlexDrive at max... 1.5 Amps.

An RCR123 did not hold current. Nor did a 14500. But an AW 18650 held steady...
 
SHIN

SHIN

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Hi. Jayrob.

Didn't it start flickering at near 1.5A?

SHIN
 
jayrob

jayrob

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I did not test with a diode...

I tested with a red test load. The driver was good with the red test load.

But the test was just a few seconds.

I will be putting a flat piece of aluminum the same size as the driver on the 5 pin chip to heatsink the driver per drlava's documentation:

http://www.sonic.net/~jayrob/V5 FlexDrive.pdf

I will just use some thermal adhesive...
 
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