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Is there an "average current" yet?

ReNNo

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If you plan to use AMC7135 then you need 2xLi-Ion batteries and if you have 18650 host then you can use 2x18350.
But you most know that AMC7135 is going to boil on that voltage and you need to use heatsink.
But I think that is the cheapest driver for that diode.
 



Flaminpyro

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It could be the cheapest but the next best will be a custom DDL if you are going to use two 18650's


If you plan to use AMC7135 then you need 2xLi-Ion batteries and if you have 18650 host then you can use 2x18350.
But you most know that AMC7135 is going to boil on that voltage and you need to use heatsink.
But I think that is the cheapest driver for that diode.
 

Solonar

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Someone posted that they ran at 1A on the 50% duty cycle and 1.4A on the 66% cycle.


So many posts about these, I don't remember who or where.
 

ReNNo

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It could be the cheapest but the next best will be a custom DDL if you are going to use two 18650's

Yes, DDL can also be the cheapest but you need LM1117 in TO220 package (not Lm317) for these lasers and chip must be heatsinked and also you need at least 1.25W 1.25ohm resistor (If you want 1A current).
AMC looks like easier solution.
 

mikeeey

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Is it possible to safely make the flexdrive pulse? I remember when Jason (Gooeygus) helped me build a PHR and it PULSED! lol, we were somewhat amazed. It turned out a tiny tiny resistor had fallen off, and my PHR only lived a day. It also made a not very noticeable high pitch noise (I'd imagine some people probably can't even hear it).

So without breaking the driver, is it possible to make it safely pulse, does it really help duty cycles + lifetime, and how does it affect burning?
 

siqueirah

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If you plan to use AMC7135 then you need 2xLi-Ion batteries and if you have 18650 host then you can use 2x18350.
But you most know that AMC7135 is going to boil on that voltage and you need to use heatsink.
But I think that is the cheapest driver for that diode.

Got it ! Well, it says that the input voltage is between 3.6~4.5v If I use 2 cells (7.2~9v) would it really work ?
 

billg519

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The 7135's would get very hot and might thermal shutdown, or even desolder themselves. You could use several voltage dropping diodes (1N5408's would do) so that the 7135's see less battery voltage and therefore generate less heat. You would need to experiment to determine the optimum number of diodes.
 

ReNNo

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For now we can say it is.
Because none of diode has died yet
 

ReNNo

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I've just tested AMC driver.

I used only one AMC7135 chip powered by 8V and with dummy load that has forward voltage of 3.4V on 300mA.

And used one of these UF 501B heatinks just to cool down one AMC chip.


I tested for over 63 minutes to see if AMC is stable at these voltages.
And AMC survived :)

Current starts at about 315mA and lowers down to 300mA very quickly.
And current becomes stable at about 295mA.

I calculated power dissipation and it's 1.38W by one chip.

But with real blue diode forward voltage is even higher that means less heat dissipation on AMC.
And if we want to use 3xAMC there will be more voltage drop on batteries that also means less heat dissipation.
All that says that AMC can work as driver for these diodes but there will be much more heat dissipation than if we would use boost driver.

After 63 minutes this heatisnk for UF host was pretty warm an that caused only one AMC chip.
If we use 2 more chips , plus diode then there will be a lot of heat dissipation.
That means short duty cycle.
Or we can use bigger heatsink.
 

Benm

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I'd go for something a bit beefier than a couple of AMC chips. They sure are easy to use, but that much power dissipation in such small packages is asking for trouble.

You'd probably be better off with a 2 transistor current sink (or source), with the driver transistor being something like a BD139. Those offer a lot more contact area to fit a heatsink, if even required.
 

ReNNo

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Why to use that?

I can use Lm317 in TO220 package but heat dissipation will be the same because I have to use 2x Li-ion batteries. All needless voltage has to be converted to heat.

Only way to decrease heat is to use 1x18650 battery , but then you need boost driver. And that costs :)
 

HaloBlu

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Is it possible to safely make the flexdrive pulse? I remember when Jason (Gooeygus) helped me build a PHR and it PULSED! lol, we were somewhat amazed. It turned out a tiny tiny resistor had fallen off, and my PHR only lived a day. It also made a not very noticeable high pitch noise (I'd imagine some people probably can't even hear it).

So without breaking the driver, is it possible to make it safely pulse, does it really help duty cycles + lifetime, and how does it affect burning?

You mean safely pulse a flexdrive without an external circuit? I wouldn't think so. What rate did you want the pulsing? Visible or more PWM?
Pulsing should be less helpful to the lifetime then just turning it down. Lasing threshold is ~200mA.
 

Kevlar

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I've just tested AMC driver.

I used only one AMC7135 chip powered by 8V and with dummy load that has forward voltage of 3.4V on 300mA.

And used one of these UF 501B heatinks just to cool down one AMC chip.


I tested for over 63 minutes to see if AMC is stable at these voltages.
And AMC survived :)

Current starts at about 315mA and lowers down to 300mA very quickly.
And current becomes stable at about 295mA.

I calculated power dissipation and it's 1.38W by one chip.

But with real blue diode forward voltage is even higher that means less heat dissipation on AMC.
And if we want to use 3xAMC there will be more voltage drop on batteries that also means less heat dissipation.
All that says that AMC can work as driver for these diodes but there will be much more heat dissipation than if we would use boost driver.

After 63 minutes this heatisnk for UF host was pretty warm an that caused only one AMC chip.
If we use 2 more chips , plus diode then there will be a lot of heat dissipation.
That means short duty cycle.
Or we can use bigger heatsink.

I've been wondering about this and the AMC7135 chip. Thank You for your testing, it has been very helpful!!! +1
 




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