FREE DIY open source BOOST driver!!! Tested & working!!

DTR · Feb 20, 2012

Wolfman29 said:
Ah, very nice ^_^

As does my FlexDrive build with my 445 in it... of course, I turned the pot all the way up, so efficiency is certainly lower. In this case, I am drawing about 2.3A at 3.7V and putting out 4.5-4.6V at 1.5A or so.

Also from what I understand results often do differ slightly from the data sheets values when tested in with real world conditions. I am sure RHD could give us an idea what one of them set close to 1A is actually doing in the real world with an actual 445 diode and 4.2V from the power source.:beer:

Wolfman29 · Feb 20, 2012

Well, yeah. That's assuming "typical" values for the components. Obviously, you could get some that are slightly more or less efficient than normal. But ~88% is a good ballpark range - I am sure we should be getting anywhere from 80-90% efficiency.

rhd · Feb 20, 2012

LuxorLasers747 said:
Well, It´s not very common to use linear drivers on a LOCs with one cell right? There arent alot of options and it doenst take long for the batt to drop in voltage and not being able to supply what`s needed. I mean people use boost drivers on locs all the time..

I thought you could figure that out right after you made the driver

Regarding Linears:
It's common (for me). You just need a good linear driver, that's all. For example, my Mosquito driver has a dropout of about 0.2 or 0.25V. So even with a Li-Ion at a voltage that represents the bottom of its safe discharge, you've still got enough clearance.

Regarding Boosts:
I'm not sure about "all the time". I can't say that I very often see boost drivers used for REDs. People will often use a buck driver, or the buck functionality of a flexdrive, but I don't see a lot of boosting happening. I mean, with Vfs that are around 2.5V to 3V, what would you be boosting from? Basically 2x AA or AAA cells. That's the only thing I can think of that would be boosted to hit a RED diode's Vf. Not very often do I see 2x Alkaline builds.

DTR said:
Not bad at all if right. My very loose estimate on the flex puts it @ 81% efficiency.

The 1W 445 modules I build are set to 1040mA and pull 1.3A from the power supply @ 4.2V. So I am figuring (100%/1300)*1050=80.76%

It would be real easy for me to just figure out the efficiency thing. I can hook a driver up to my bench psu, and put a DMM in series with the output and the test load (in current mode), while putting a second DMM in voltage mode across the test load.

TestLoad(A*V) / BenchPSU(A*V) = efficiency

tsteele93 · Feb 20, 2012

rhd said:
Regarding Linears:
That's the only thing I can think of that would be boosted to hit a RED diode's Vf. Not very often do I see 2x Alkaline builds.

This is something that I am still confused about. I understand that current is what the diode wants. So we build constant current drivers to supply them with a fixed current.

But how does voltage factor in? I know we basically are limited in our supply voltage to roughly 1.2v-8.4v unless we get real exotic and run three batteries.

If I am understanding correctly, the laser diode doesn't care what the batteries are though, as long as it is seeing enough current to lase?

Something seems off to me there. Am I overlooking something? Does the driver have to have a voltage-out that stays within a certain range, or is it really just current, current, current?

benmwv · Feb 20, 2012

The output voltage of a boost driver must be higher than the input voltage or the driver will die.

Also:
The output voltage of a buck driver must be lower than the input voltage.
The output voltage of a Boost-Buck can be higher or lower than the input voltage.
The output voltage of a linear is always lower than the input.

Wolfman29 · Feb 20, 2012

The thing about laser diodes is that they DO take a voltage. For instance, red diodes typically take between 2.2V and 3.3V, depending on the type. However, if we regulated to that voltage, then A) the power would fluctuate with a given temperature and, more importantly, B) would be much harder to control.

You see, laser diodes follow Ohm's law to a certain point, generally. But, once you hit that point, the voltage starts increasing very slowly compared to the current. So, you could increase current like 200mA and only increase voltage by .05V.

So, current regulators make sure that the CURRENT is constant and that the voltage that the diode sees is whatever voltage it needs in order to meet that current that is being outputted. So, drivers take an input voltage (in a boost driver from a li-ion battery to a 445nm diode), and runs, lets say 1.3A to the diode. Because of the 445nm diode's characteristics, it will probably require 4.4-4.6V at that current. But, when a diode heats up, it will require less voltage per amp, so the output voltage of the driver will decrease but the current will stay the same. This is important because, say, if we were regulating it to output 4.5V because lets assume, on a cold start, it requires 1.5A at that voltage, once the diode heats up, it may only require 4.4V at that voltage. Then, because the current/voltage slope is so high, it will drastically increase the output current in order to meet the 4.5V output, which would probably kill your diode.

Sorry if something there was unclear - I will explain if you have any more questions.

Dave934 · Feb 20, 2012

:bowdown:Way to go guys.:gj:I like it when people combine brains and talent to work as team to benefit the whole Forum.
DTR when are the H-series diodes going to be available to buy:drool:

rhd · Feb 20, 2012

Dave934 said:
DTR when are the H-series diodes going to be available to buy:drool:

DTR - I didn't know you were getting an H-series?

Not withstanding the fact that I've gotten some real gems out of mine, I tend to think that you'd get a few real gems out of an M-series if you just looked as hard as I did with the H.

You really think the H-series is going to yield better diodes?

DTR · Feb 20, 2012

rhd said:
DTR - I didn't know you were getting an H-series?

Not withstanding the fact that I've gotten some real gems out of mine, I tend to think that you'd get a few real gems out of an M-series if you just looked as hard as I did with the H.

You really think the H-series is going to yield better diodes?

I am not. I don't believe they will yeild any better results and the cost would go up so unless someone bins a few of them and they have way better averages than the M140's I will stick with the M140's. Was of those gems a 3W diode.

tsteele93 · Feb 20, 2012

Wolfman29 said:
The thing about laser diodes is that they DO take a voltage. For instance, red diodes typically take between 2.2V and 3.3V, depending on the type. However, if we regulated to that voltage, then A) the power would fluctuate with a given temperature and, more importantly, B) would be much harder to control.

You see, laser diodes follow Ohm's law to a certain point, generally. But, once you hit that point, the voltage starts increasing very slowly compared to the current. So, you could increase current like 200mA and only increase voltage by .05V.

So, current regulators make sure that the CURRENT is constant and that the voltage that the diode sees is whatever voltage it needs in order to meet that current that is being outputted. So, drivers take an input voltage (in a boost driver from a li-ion battery to a 445nm diode), and runs, lets say 1.3A to the diode. Because of the 445nm diode's characteristics, it will probably require 4.4-4.6V at that current. But, when a diode heats up, it will require less voltage per amp, so the output voltage of the driver will decrease but the current will stay the same. This is important because, say, if we were regulating it to output 4.5V because lets assume, on a cold start, it requires 1.5A at that voltage, once the diode heats up, it may only require 4.4V at that voltage. Then, because the current/voltage slope is so high, it will drastically increase the output current in order to meet the 4.5V output, which would probably kill your diode.

Sorry if something there was unclear - I will explain if you have any more questions.

This does help. In my mind, I keep wanting to think of the diode as a resistor because it FEELS like we are powering a resistor-like component (in MY mind) and I'm expecting it to follow Ohm's law.

So that leads me to another question... You say that a 445 may require ~4.6v and a red might only need 2.2v - then does each diode have a voltage that it is needing to see? Is there a list or easy way to know what the driver needs to be doing as far as voltage?

I understand that the current needs to be below max for the diode or it will die, and higher currents equal shorter lifespans.

Will a laser driver work for ANY diode as long as the current is right? Or are there drivers specifically for reds and others for blue/violets and others for ir/green?

I know that I could just buy pre made modules and be happy, and I probably will never build or design a driver, bit I really would like to wrap my ahead around this a little better.

Thanks so much for all of you taking the time to do this!

:thanks:

Wolfman29 · Feb 20, 2012

Typically, IR diodes run slightly below 2V at whatever current they need for operation, red diodes between around 2.5-3.3V, 445nm are generally between 4.4-4.6V (for high current operation) and Blu-ray diodes are typically between 5.5 and 6.5V.

So, that in mind, you need a driver capable of outputting the highest of whatever voltage you need while still sustaining the current output and regulating CURRENT. So, obviously, a red diode will generally always have less voltage than a typical li-ion, so one would use either a low voltage drop linear regulator like the STCS1/2 or the AMC7315 IC or a buck driver, which is much more efficient, typically (buck drivers drop voltage but draw less current from the battery by converting excess voltage into more current). For 445nm diodes, if you are running it from one li-ion battery, you need a boost converter. From two li-ion batteries, you need a buck converter or a linear regulator because they require in the mid-4-volts. For blu-rays, its the same deal - you need a boost converter for 1 li-ion or a buck converter for 2 li-ions. Typically, linear regulators will not work with blu-rays because, even with 8.4V, if you are using an LM1117-based linear regulator, that drops 1V on the regulator and 1.25V on the resistor, so you are already below the 6.5V maximum output voltage necessary. Buck converters, on the other hand, can generally give voltages only .2-.3V less than the input voltage.

rhd · Feb 24, 2012

I built something neat. It's like the tiniest 445 I've ever made.

Basically, it uses the world's smallest (supposedly) AAA host. I put in one of these boost drivers, set to, I believe, around 575mW. I didn't know if this would work, so I used an A-series diode. I wish I had used one more efficient. Even still, I'm able to get 250mW+ from a single 10280 cell, using this boost driver.

But that's not what's cool about this video. What's cool about this video is how low the driver will boost from. It basically starts boosting at about 2.2V, and hits regulation at around 3V.

Boost - YouTube

The implication, is that it could probably run from 2x AA cells - at least alkalines, maybe not NiMH.

In terms of stability, as you watch the video, keep in mind that this entire laser build weighs 21 grams (host, lens, diode, module, driver), which is about half as much as a single 18650 battery.

Jubathoph · Feb 24, 2012

rhd said:
I built something neat. It's like the tiniest 445 I've ever made.

Basically, it uses the world's smallest (supposedly) AAA host. I put in one of these boost drivers, set to, I believe, around 575mW. I didn't know if this would work, so I used an A-series diode. I wish I had used one more efficient. Even still, I'm able to get 250mW+ from a single 10280 cell, using this boost driver.

But that's not what's cool about this video. What's cool about this video is how low the driver will boost from. It basically starts boosting at about 2.2V, and hits regulation at around 3V.

Boost - YouTube

The implication, is that it could probably run from 2x AA cells - at least alkalines, maybe not NiMH.

In terms of stability, as you watch the video, keep in mind that this entire laser build weighs 21 grams (host, lens, diode, module, driver), which is about half as much as a single 18650 battery.

http://laserpointerforums.com/
attachment.php?attachmentid=36723&stc=1&d=1330043132

Dude that is awesome. Can you provide a link to that host?

lasersbee · Feb 24, 2012

I can't see what does the weight of the Laser has to do
with this "DIY Open Source" Driver's operating characteristics....:thinking:

Am I missing something...:undecided:

Jerry

You can contact us at any time on our Website: J.BAUER Electronics

rhd · Feb 24, 2012

lasersbee said:
I can't see what does the weight of the Laser has to do
with this "DIY Open Source" Driver's operating characteristics....:thinking:

Am I missing something...:undecided:

Jerry

Yep, you're missing the fact that laser components (both laser diodes, and drivers) are impacted by heat (Heat - Wikipedia, the free encyclopedia). The ability of a laser diode + driver to function efficiently for a prolonged period of time, depends in large part on the host's ability to conduct heat (Thermal conduction - Wikipedia, the free encyclopedia) away from the components.

Thermal conduction is impacted by mass (Heat transfer - Wikipedia, the free encyclopedia), and the less of it there is, the less heat can be moved away from the components.

Thus, if you see 21 gram laser setup hold a stable output period for 1 minute, this is more impressive than if you see a 28 pound setup with a 14 inch heatsink on the diode and driver, do the same.

Glad I could help walk ya through that!

lasersbee · Feb 24, 2012

The total weight of a Laser has nothing to do with the
heat dissipating properties of said laser...
One could make a lighter (or same weight) Plastic Host
Laser and the heat dissipating properties would be atrocious...
Pure weight means absolutely nothing... It's all about thermal
dissipation...(getting rid of the LDs's and Driver's Heat)

Jerry

You can contact us at any time on our Website: J.BAUER Electronics

FREE DIY open source BOOST driver!!! Tested & working!!

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