PREVIEW: "Pico" - A really tiny 2.4A+ buck driver.

[rhd]

Just a preview. I haven't decided what the future of this guy is (if any). It's so painful to reflow the IC (not pictured) that I can't imagine it ever being a useful driver for anyone else - it's more of a curiosity.

6.35 x 6.35 mm, which is 41 square mm (for comparison, the FlexDrive is 108 square mm). That's the smallest board that Oshpark can create - though the version on the photo was actually fab'd by iTead, because I wanted the cool red color.

I don't have much more to say about this guy until I've experimented a bit more, which could be a while. But as a starting point, it does 2.4A just fine, and I think it may do 3.7A for the new 3W diodes. I'll report back on this in the future.

 

[sinner]

Another awesome driver. Your expertise are very useful for the forum. +rep If I can.

Please do make some arrangements with some veteran member(s) or yourself to make them available for the masses , and the boost driver too. I can think of many people that could simply start building lasers again if these drivers become more common.

 

[dubious speculation]

Wow! another awesome driver from Rhd

It is hard to believe that this driver has a much smaller footprint compared to a flexdrive. I can see these being widely
used by many members if they where readily available. It would open up a whole new realm of small applications.

Your expertise and contribution to the forum deserves everyone's praise, +1 :beer:

 

[crazyspaz]

Wow, ANOTHER tiny, useful, and (correct me if im wrong) cheap driver. Will this be open source as well?
Also, why is soldering the IC so hard? Because its so tiny?

 

[ARG]

Must be a TQFN or BGA

 

[sinner]

Why all the good things in life have to be TQFN or BGA!

:scared:

 

[IsaacT]

Must be a TQFN or BGA

What is a TQFN or a BGA?

My guesses:
The Quilt Feels Nice
Big, Glorious Ass

In response to the OP: this is fantastic, but would show my soldering skills for what they are, an awful blundering about with some luck lol.

 

[ARG]

My guesses:
The Quilt Feels Nice
Big, Glorious Ass

BGA = Ball grid array

TQFN = Thin quad flat no sides

 

[rtp3955]

That's amazing one which I ve ever seen.

 

[offroadfreak8582]

Awesome work RHD. Future is now! :beer:

 

[Sigurthr]

Very interesting! I'm curious what the dropout voltage and thermal aspects are. My money is on BGA.. TQFN's can still be bodged somewhat easily if you are determined.

 

[RayJay]

One word... WOW!
I would definitely use these!

 

[rhd]

Here's an approach for even tighter builds:

On-diode 2.4A buck driver for 9mm diodes.
Just under 12mm diameter.
Two or three cell input.

 

[andrewb]

Amazing work.

So if you don't mind me asking, what's the magic sauce?

(i.e., what is the advancement that is allowing such smaller layouts compared to existing drivers?) Are you disclosing what part you are using? (Ok if not.)

 

[crazyspaz]

Awesome. 2 questions though:
1) what happened to the big inductor?
2)if you use this on the back of, say, a 5W NDB7A75 build, wont a significant amount of heat from the diode transfer to the driver? So really, what kind of overheating issues could/would you run into?

 

[rhd]

Awesome. 2 questions though:
1) what happened to the big inductor?
2)if you use this on the back of, say, a 5W NDB7A75 build, wont a significant amount of heat from the diode transfer to the driver? So really, what kind of overheating issues could/would you run into?

The big inductor is a small inductor this time around.

This particular driver is pushing some of the limits of smart design (intentionally - but it's pushing the limits nonetheless). Most notably, I'm using a bit lower inductance than I'd be comfortable with normally.

It was more a proof of concept than anything else.