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Old 03-06-2015, 03:14 AM #1
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Default Some previews of Quack's Drivers...



^^^Some nice previews of what's to come...




^^^7 x 7 mm boost drivers... Should be capable of 1.8 amps+. Dubbed the MicroDrive V2.
------------------------------------------------------------------------------


^^^7.75 x 7.15 mm boosts... Potentially capable of 2.3A+ boosts. Dubbed the MicroDrive BGA.
------------------------------------------------------------------------------


^^^New version of the Lo-D driver with blank copper pads on the back for super heatsinking...
------------------------------------------------------------------------------


I also have the experimental buck boost boards coming too. They should be, if they end up working properly, potentially capable of 2.3+ boosts and even more current bucking. They are sized at 12 mm by 12 mm. Called the BD-D.


Oh, all of these are adjustable, too.


Everything listed I should be able to sell for under $19, each of them will obviously have individual pricing but nothing should be above $19.


I will edit this thread as I test and create each of these boards in the coming weeks. Each driver will have a separate post in this thread, and this thread is where I will constantly maintain and update information for all of these drivers.


Can't wait to finally release these all.


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Old 03-06-2015, 03:14 AM #2
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Default Re: Some previews...

Ah, the BD-D. I was probably most excited for the prospect of this driver but unfortunately, actually testing it it did not seem to behave or work properly as anticipated.


The BB-D was going to be an open source experimental buck-boost driver, discussed here: Experimental BB-D Driver (Open Source)

It does seem to kind of work. Bucking it behaves as it should, regulating properly but producing more heat than it should given the output currents.

Boosting it just does not seem capable of doing without producing an audible squeal and the output seems to be a pulse of sorts, in the audio frequency range and ridiculous amounts of heat. I'm unsure if this is a heat related issue, or if it's some sort of protection that's kicking in on the driver. Either way the heat it's producing does NOT make sense given the output current, so I'm unsure where to go with this. Additionally the driver's board design actually has a minor error which I've fixed in a new version of the driver board.
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Old 03-06-2015, 03:14 AM #3
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Default Re: Some previews...

So, I finally got around to testing these boards, and the testing still isn't quite done but I wanted to go ahead and give some updates on them.

Basically, both of them work, but with some minor changes to the designs of the boards. I've also found some very odd quirks about the BGA version of the microdrive, which I will mention in its respective section in a few.

The MicroDrive V2 is a fully adjustable, 7 x 7 mm boost driver. The BGA version features almost all of the same things as the V2, (slightly larger, however at 7.75 by 7.15 mm) however it can handle more current and has some very odd, yet interesting quirks to it. When I was designing these two boards I was always trying to make them as small as possible while still maintaining safety and capability to the best I could.

They feature overtemperature protection as a baseline. You cannot kill either of these drivers with heat, it's simply not possible.

They also feature generous soft starts; very much like the Lo-D driver the voltage rises extremely slowly to make sure your laser diode does not experience any dangerous output spikes.

I have not figured out the maximum current capabilities of either driver just yet unfortunately. I will have to do more testing to figure it out but I will report back once I do.

At 1.1 amp output to 5.2 volts, boosting from a nominal 4 volt li-ion battery the output ripple of both drivers was around 50 mA. The V2 was capable of boosting well into the 17 volt range, however the BGA version seems to be limited to a max output of 5.6 volts before the overvoltage protection kicks in. This means the BGA version will NOT be capable of running 405 nm diodes without tripping its overvoltage protection. HOWEVER...

This is where it becomes quirky, and interesting.


Just out of my own curiousity I lowered the forward voltage of the test load below what the input of the driver was.

And oddly enough, it still regulated the current. It genuinely seemed to be bucking. The output current was, at times, (it depends heavily on the forward voltage and output current) LOWER than the actual output current meaning it was truly behaving like a buck converter. However, yet again oddly enough when I tried to switch it back over to a boost converter (IN between I also changed a part on the regulator) it seemed to had lost the ability to boost, so I'm unsure if making it behave like a buck converter somehow kills an internal switch, or if I accidentally destroyed something when I was changing parts. Still, though, this behavior seems quite interesting and I will look into it further to see if it's repeatable, and safe for the driver to do. A buck boost driver, theoretically capable of 2.3 amp boosts and even more bucking? Hell yeah.
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Old 03-06-2015, 03:15 AM #4
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Default Re: Some previews...

The LO-D Driver is a low dropout linear regulator designed for extremely low to extremely high currents.

They can handle up to 3.3 amps constantly, but require a heatsink in order to run at 100% duty cycle.

The dropout is typically 1 volt, but it may be slightly lower or higher depending on the output current you use (higher currents = slightly more dropout)

You can use this regulator with either one cell (for red diodes) or two cells with any type of diode.

Because it is a linear regulator the greater the difference is between the output voltage and the input voltage, the more heat is generated.

This driver features overtemperature protection; when the regulator gets too hot the output of the regulator slowly drops until it reaches an equilibrium between heat generated and current output by the driver. Once it cools down it will automatically go back to the current you have it set at. There's a large, blank pad on the back of the regulator for superior heatsinkability. This pad is connected to ground.

It is also fully adjustable, from 330 mA to 3.3 amps, no soldering or anything required. You just have to adjust a potentiometer on the back of the regulator board.

The output of the regulator has a very long soft start to make sure no spikes are produced. The lower the output current of the regulator, the longer the soft start is (with really low currents the effect is actually visible on the output of the laser!)


Picture of the output:


Sidenote: The ripple on this is nonexistent. Perfect for sensitive diodes.


Pictures of the drivers:









I am selling these drivers for $14 each, plus $2 shipping. For sale thread is here: Lo-D Drivers

Check that thread to see if I have these in stock.
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Old 03-06-2015, 03:19 AM #5
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Default Re: Some previews...

The Diode Savior is a simple 6.5 by 7.1 mm board that is designed to be connected between a driver and a laser diode to produce a soft start that is visible in the output.

These boards produce greater amounts of heat the LOWER the forward voltage of your diode is, so as such I cannot recommend their use for high current red, or IR builds without heatsinking.

Anything else, these boards work great and produce nearly no heat. They may also be capable of PWMing your diode, I will be testing this in the near future.
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Old 03-14-2015, 04:15 AM #6
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Default Re: Some previews of Quack's Drivers...

Some updates;

Got basically everything I need today, except my new oscilloscope which will be coming Monday. I'll be putting together a bunch of different boards this weekend and doing some prelim testing on each of them to see how they behave, and take some pictures of the finished products.

Once I get the o-scope I'll be able to post some start up and ripple pictures for each of them as well.

I'm pretty dang excited myself, I'm kind of disappointed no one's posted anything here yet.
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Old 03-14-2015, 08:52 AM #7
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Default Re: Some previews of Quack's Drivers...

I'm excited to see what comes of this.

One lesson I've learned though, is not to get too excited about *boards* or *designs* until they're *working drivers*. I have hundreds of boards that *should have been* great earth shattering drivers, but just didn't work in real life.

Here's my concern with the 7x7 boost that you expect to hit 1.8A of output (and I say this having designed a LOT of really tiny drivers - most of which didn't work the first 5x times I tried) -

Even if you're just targeting 1.8A at nominal li-ion voltage (3.7) and not all the way down to safe discharge, that still implies input cell current of (5.2/3.7)*1.8 = 2.5A to drive a 445 @ 1.8A in an ideal boost without considering diode or inductor drop. Applying an inductor saturation current "margin" of 1.4x (which I can't find a citation for, but is the figure I've often seen cited as a minimum and usually follow), that implies a saturation current of 3.5A minimum. The highest inductance you're likely to find in a 3x3mm (which is what your pads look like) inductor with that saturation likely has a DCR of 150 mOhm +

That DCR @ 2.5A is another 375mV drop. Add the shottky, and you've got another 450mV. Say that's an additional 800mV to feed into the equation, and adjust, and you now need to calculate for 6V of output. The non-ideal (real world) formula becomes (6/3.7)*1.8*1.4 = 4.1A, and what you actually need is an inductor with a saturation current above 4.1A.

The highest inductance you're likely to find in a 3x3mm inductor with that revised, real-world, saturation current target, is going to be 3.3uH. While 3.3uH isn't the end of the world, it's pretty low, and means that you need to be using a 2 mhz switch (or pretty damn near it) with lots of good caps, or you're going to see deadly voltage spikes. Regardless, you're certainly going to be burning a lot of heat.
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Old 03-18-2015, 12:31 AM #8
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Default Re: Some previews of Quack's Drivers...

Quote:
Originally Posted by rhd View Post
I'm excited to see what comes of this.

One lesson I've learned though, is not to get too excited about *boards* or *designs* until they're *working drivers*. I have hundreds of boards that *should have been* great earth shattering drivers, but just didn't work in real life.
Well, of course. I wasn't expecting any of these to necessarily work straight out of the oven (except the Lo-D driver, which I've done testing and necessary changes to beforehand). I did get pretty frustrated and upset for a few days because the drivers simply were not working as planned. Not boosting properly, heat, spikes, the works. However I've already fixed the problems that were presented in each of the drivers, save for the BB-D, which I cannot figure out what's wrong. However that's why it's open source so maybe people will be able to help figure out what's up?

Quote:
Originally Posted by rhd View Post

Here's my concern with the 7x7 boost that you expect to hit 1.8A of output (and I say this having designed a LOT of really tiny drivers - most of which didn't work the first 5x times I tried) ....
I totally hear what you're saying. However, funnily enough the BGA boost regulator actually has a 2.6 mhz switching frequency. It's honestly probably the highest frequency SMPS IC I've ever had the luck to work with, so the output ripple (even with just 0.68 uH of inductance!!) is actually really manageable. Of course the V2 is only a 1.2 mhz switch so the inductance on it is higher at 1 uH, though I may switch over to the 2.2 uH inductor in the same pad size to reduce ripple.

The 0.68 uH inductor has a saturation current of 4.5 amps, the 1 uH inductor 3.9 amps and the 2.2 uH 2.7 amps. Their DCR's are 0.043 ohms, 0.057 ohms, and 0.102 ohms respectively,

I was pretty surprised at how capable these little inductors are and that's why I chose them. Their only downside, however is they produce a decent amount of heat at their rated currents but that's stated to be normal in their datasheet.

I still haven't figured out their maximum currents and will do so once I receive the new, fixed designs.

-----------------------------------------------------------------------------

Also, the posts I reserved have been updated for a number of them, please read and comment what you think.
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Old 03-18-2015, 03:13 AM #9
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Default Re: Some previews of Quack's Drivers...

Quote:
Originally Posted by Le Quack View Post
The 0.68 uH inductor has a saturation current of 4.5 amps, the 1 uH inductor 3.9 amps and the 2.2 uH 2.7 amps. Their DCR's are 0.043 ohms, 0.057 ohms, and 0.102 ohms respectively,

I was pretty surprised at how capable these little inductors are and that's why I chose them. Their only downside, however is they produce a decent amount of heat at their rated currents but that's stated to be normal in their datasheet.
Holly crap. Those inductances are tiny. That terrifies me. Please scope them before you attach diodes They may be fine, but I generally consider it "danger zone" to go under 3.3uH on a 2 Mhz switch.

Required Inductance = (((Inductor Voltage x Duty Cycle) / Freq) x 1000) / Target Ripple
Freq = 2,600
Input V = 8.4
Output V = 5.2
Duty Cycle = Output V / Input V = 5.2 / 8.4 = 0.62
Inductor Voltage = Input V - Output V = 8.4 - 5.2 = 3.2
Target Ripple = 0.2 A

Required Inductance = (((Inductor Voltage x Duty Cycle) / Freq) x 1000) / Target Ripple
= (((3.2 x 0.62) / 2600) x 1000) / 0.2
= 3.8 uH

That suggests that you need a 3.8 uH inductor, just to keep ripple under 200mA (of course it doesn't account for some helpful caps).
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Old 03-18-2015, 03:42 AM #10
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Default Re: Some previews of Quack's Drivers...

Don't worry about spikes on the outputs, I've already scoped them with these inductances and the ripple is actually about 50 mA (at 1.3 amps) and no voltage spikes to speak of.

But hey, I've actually got two new versions of the non-BGA coming, one with an additional space for a cap on the output that stays at the same size, and one I'm calling the SLR (super low ripple) that's a bit bigger (8.84 mm by 8.66 mm) but supports a larger inductor, and 5 output capacitors. Theoretical max capacitance on the output, about 88 uF. Also because of its bigger size it should be able to handle more heat without triggering the protection. Could be the compliment to your edge driver

The BGA version also got a slight overhaul by changing an internal connection. I couldn't fit any additional caps on it though, unfortunately (it has a 0805 spot and 0603 spot, but I can get the output capacitance to about 44 uF, so it /should/ be okay). I'm really interested in figuring out what's going on with that bizarre bucking mode I experienced today.
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Last edited by Hiemal; 03-18-2015 at 03:45 AM.
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Old 03-20-2015, 12:45 AM #11
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Default Re: Some previews of Quack's Drivers...

It's great that you have your own scope
now. I'm sorry it has been taking so long
to test the diode savior boards. I had to
find my buck driver, and then realized I
don't have the right size resistor to get
it to output exactly 3A. All of this is
slowed down even even further by my health
and the fact that I cannot do anything
except video games and the computer when
someone is watching TV. It sounds
ridiculous, I know, but my health problems
are prettymuch ridiculous by definition.
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