Thermal Design Comparison of Various Natural Convection Cooling Concepts of Discrete SiC-MOSFETs

In power converters, the choice of semiconductors presents one with many options. Considering discrete semiconductors in standard packages, the semiconductor housing and resulting mounting technology have great influence on the overall cooling, cost, current load and converter performance. One decisive parameter is the thermal resistance of the complete cooling design. By now, the total design impact of the semiconductor package choice (surface-mounted and through-hole-mounted) is not thoroughly dis-cussed in literature, thus, we present a comparison of five cooling assemblies for discrete SiC-MOSFETs with equal chip area. The naturally cooled arrangements differ in packaging (TO-263 and TO-247), the presence and absence of isolation, and PCB technology. The validated results provide information on the total thermal resistance, maximum achieved load current, and cost of the full cooling assemblies. Up to 48 % greater DC load current can be achieved in the THT package compared to using an SMT package. The THT arrangements also show significantly lower cost. In addition, the used analytical calculation method can be used for sufficiently accurate estimation of thermal resistances, demonstrated by results with less than 10 % deviation compared to the conducted measurements.