> Would love to hear what the expert solution is to this that isn't just a massive heatsink.
A smaller heatsink with active cooling and parallel MOSFETs. At a certain power level, it's just physically impossible to rely on convection cooling alone - just look at audio amps or your average CPU/GPU... banks of MOSFETs, caps and inductors it is. While the BOM part count may be higher, you need lower-capability parts.
The danger is, you need to carefully grade and match the MOSFETs, otherwise you risk them failing sequentially in a very short time if you're operating too close to their rated current - one burns out, the load distributes to the others, and then they fail because they cannot handle the additional load (or one fails into dead short instead of open, which instantly kills all of the others).
A smaller heatsink with active cooling and parallel MOSFETs. At a certain power level, it's just physically impossible to rely on convection cooling alone - just look at audio amps or your average CPU/GPU... banks of MOSFETs, caps and inductors it is. While the BOM part count may be higher, you need lower-capability parts.
The danger is, you need to carefully grade and match the MOSFETs, otherwise you risk them failing sequentially in a very short time if you're operating too close to their rated current - one burns out, the load distributes to the others, and then they fail because they cannot handle the additional load (or one fails into dead short instead of open, which instantly kills all of the others).