I'm looking to convert power from a 19.5V power brick to 12V, with up to 10-12A draw. Looking around, it seems like I would want to make a buck converter. An all in one solution would be nice. I'm no electronics expert but I can learn. Thanks.

 

You can probably buy a ready-made 12v 10A regulated SMPS module that will work from 19.5v input.

 

If you want to hobby this, ask again. If you just want results, it's so much easier, and often cheaper, to buy one retail than to build one out of parts.

 

I'm looking for something small form factor. Something between these two mini box solutions.
http://www.mini-box.com/PicoPSU-120-WI-25-12-25V-DC-DC-ATX-power-supply

http://www.mini-box.com/M4-ATX-HV?sc=8&category=981

My available space is a little over 120mm x 64mm. The picoPSU doesn't support enough amperage(less than 8a). The m3-atx is too long. The m4-atx is too fat.

I think it would be fun to make this but I've never put together anything like this before. Texas Instruments did have an online platform that made up a schematic for me, but it had about 39 parts and I have no idea what kind of form factor could be pulled off at home.

 

You wouldn't be able to make one at hobby level with the same specifications in a smaller package. It most surely wouldn't be near the same price if a one off was made to match the size of those linked.

You could get close, if you understand how to build a SMPS system from scratch, which components you'll use, layout the PC board for both electrical noise reduction and thermal/heat management.

You may be able to produce one that is physically larger without as much protection and tight regulation, though this would be a switching power supply as well.

 

Think this'll do it?
http://www.prodctodc.com/high-power...r-power-supply-module-p-160.html#.UTQeRsrn_IU

The card actually draws less than 7A on load.

How much heat would this thing dissipate?

 

efficiency is likely 85% ballpark. If load power is about 90W, then 15% is maybe 13W of internal dissipation.