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FrozenGate by Avery

Teaser: The BlitzBuck - A 2A+ Switching Buck Driver

Joined
Jan 14, 2011
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Introducing...

The BlitzBuck!

The BlitzBuck is a switching, buck-driver with a capability of driving over 2A of output current between 2.5V and 10V input.

The board I have developed for this driver is nearly exactly the size of the FlexDrive with tiny dimensions of 9mm x 12.2mm.

I have tested this driver and on a test load with varying input voltages. Above regulation, the driver will regulate to within 4mA of current. The IC itself is very efficient, but the whole circuit, overall, has an efficiency based on what your input voltage is. For the 445nm diodes, the whole board has an estimated efficiency of approximately 75-80%. This may seem very inefficient, but compared to the linear drivers we have been using to drive 445nm diodes, this is much better over the comparable 60%.

With just a small heatsink on the main IC and a small heatsink on a resistor, one is capable of nearly continuous duty-cycles, assuming reasonable output current.

At the moment, I have no pictures of completed circuits. The reason for this is not that I have never tested this in real life - rather, after having completed the initial test board, I immediately set it to output 1.6A (my test load showed an output of 1.576A) and placed it in a host with a very efficient 445nm diode, powered by two 18650s. I was hasty in this decision because I was very excited. Further, I wanted to see if the current ripple or startup current spike would kill the diode. It didn't! Not proof that it works perfectly, but very good evidence.

Nonetheless, I have placed an order for thirty improved boards (double the output capacitance, better heatsinking for the IC, better ground plane) from Laen. I will be taking a prototyped board (one that has wires in weird places and cut traces - it's not perfect so I didn't want to take a picture to put it here) to my physics department here at Arizona State to be tested on an o-scope to be certain that it is nearly ripple-free, but I am fairly certain of the results.

Assuming the o-scope test goes according to plan, I will begin to start producing these in quantity.

I plan to sell these for approximately $18 shipped.

Enjoy the wait ;)

Oscilloscope Results!

(Note that each division is .2A on the y-axis and 1uS on the x-axis.)

When in regulation:
2012-04-04%2014.11.52.jpg


When just entering regulation or getting to the extremes of the operating range (high voltage):
2012-04-04%2014.13.01.jpg


As you can see, even with the tiny output cap (the production run will have twice the output capacitance), the ripple when in regulation is typically under 100mA. Just on the edges of operating conditions, it will typically have higher ripple, but that's quite common. Anyway, these ripples occur at such a high frequency that really, the diode is simply seeing the average - this is occuring much, much faster than 1MHz - my estimate is probably around 10MHz.

So good results!
 
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what would you need a driver set at 2A for? Not trying to be rude, just a noob. Ill go review over diodes and capabilities now to try and answer my own question:D
 
Glad to see more drivers out there especially when the elusive Flexdrive's went AWOL on us. And being Flexdrive size, great job Wolfy!
 
That is the absolutely "minimum" maximum. I.e. every one of these drivers will be CAPABLE of pushing 2A of current. That doesn't mean you can't set it lower :D
 
I was just curious to see what can run at 2A+. Cant wait to see some pics of this new bad boy.
 
Well, it may be capable of driving multiple diodes in parallel. Further, with new diodes coming out all the time, as well as high-powered IRs (which bucks are perfect for), you never know. Always a good idea to leave your options open!
 
You could potentially use this to run LEDs at 2A if you wanted....Some IR diodes can handle it too...
 
Well, it may be capable of driving multiple diodes in parallel. Further, with new diodes coming out all the time, as well as high-powered IRs (which bucks are perfect for), you never know. Always a good idea to leave your options open!

Ahh, there we go! Thats what i forgot about. I totally forgot about the recent 3W+ build someone did using 2 diodes in parallel. Would LOVE to see more of those projects. Thanks for the help, i was just curious.
 
Yup. The actual upper limit on the IC is about 3A, but I haven't pushed it that far yet. :P

I just realized that I posted this on April Fools' Day. It may seem like it is a jest, but it's actually not :O I will be releasing this soon ^_^ Just waiting on boards and testing tomorrow!
 
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what would you need a driver set at 2A for? Not trying to be rude, just a noob. Ill go review over diodes and capabilities now to try and answer my own question:D

The H1600 diodes can handle 2A IIRC.
 
Congratz!!
Good luck :beer:
No wonder i have to spread some more love +3
 
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Yup ;)

That first run of 30 boards will just be essentially a test run. Going to send a few out to DTR, Cyp, and the like to be tested. Gonna mass produce if I can though, because soldering by hand a few hundred of these would take a while XD
 
People will demand them if they prove to be as good as described, and the regular high capacity li-ion's would be sufficient.. Dtr's testing h1600 didoes can handle upto 2.3Amps as far as i remember so in future it should be the next best thing to a mastech power supply!!
 
Yeah, these should be capable of driving up to 3A, but I dunno. May test them.
 
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How are the current set, by a pot or smd resistors ? And did you tested for red diodes on one 3.7V battery ?
I wouldn't mind take high-resolution photo's of these :)
 
Very nice, can't wait to see the results.

We rather needed a somewhat cheap buck driver... seems most people just opt for linears with their nasty voltage drops. :p

With a buck driver you'll get much longer runtimes with two cell builds; the extra voltage is converted into "extra" current so to speak. It'll draw less current with more voltage, whereas a linear driver will draw whatever the output current is.

It should work for a red diode as long as the voltage drop of the driver is low enough. Which, being a buck driver it shouldn't have any issues!

They'll also work well for 12x builds too with two cell builds, I'd think. What's the forward voltage on 12 blu rays? 6 -7 volts?
 
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