I have prototyped some DC-DC converter modules, and they work well. However due to size, I don't have a huge amount of copper pour for them to dissipate their heat. I have used 2oz copper but the bottom layer copper pours get really hot at higher current. Even through the solder mask!
I experimented with adding a heatsink to this bottom side of the PCB with some thermal grease and the results were surprisingly good. The heatsinks get hot under heavy load. The buck-boost-inverter went from maxing out at about 1.5A to being stable at 2.5A! This is my current setup:
However I can't help but think that I can improve this. I am thinking of removing the bottom solder mask around the heatsink area for better heat transfer. Also I want to use a Sil-pad instead of thermal grease for easier assembly, and because I don't want to risk shorting different copper pours when the solder mask is gone. Like this:
So my questions are:
- Is this a good way to do this? (given my limitations)
- is there anything that could affect the long term life of my PCBs with this setup?
- Are there any other suggestions people have?