Thermal Analysis and PCB design for GaN Power Transistor Pedro A. Rivera, Daniel Costinett Universidad del Turabo, University of Tennessee A more reliable, efficient and interconnected grid system is what we are heading towards. Most of modern power system technologies like wind, solar and electric vehicles depend on power inverters. Making them smaller and more efficient brings many challenges, but at the same time improvements that can revolutionize our electric driven world. One of the most important aspects in power inverter is the management of heat to improve performance, life, and reduce part failure. Semiconductors play an important role in power inverters and the use of gallium nitride power transistor offer many advantages such as high dielectric strength, operation in high temperature, high current density, fast switching speeds and low resistance. This poster shows three different PCB cooling configurations for the power transistor inside the inverter in figure 1. Two 30Ω surface mounted resistors (PWR163S-25-30R0J) in series replace the GaN power transistors inside the power inverter. The use of a thermometer and thermal camera was used to obtain the temperature values for the resistor and heat sink at different power dissipation stages (figure 2). To corroborate the experimental findings, FEMM (Finite Element Method Magnetics) software was used to simulate the experimental model as well as two new PCB configurations (figure 3). Thermal resistivity for each PCB configuration was also calculated to further support the finding of the simulation and experiment (see figure 4). GaN die Heat sink Figure 2: Thermometer and Thermal image of PCB Three different PCB configurations were compared, design #1 with the thermal vias and the heat sink on the bottom, design #2 with no thermal vias and heat sink on top, and design #3 combining the thermal vias and the heat sink on top. The width and thickness for each design was kept the same to see the advantages and disadvantages of each. As seen in figure 5, the simulation and theoretical results for design #1 follow the trend of the experimental results. This lets us know that the simulation and hand analysis are accurate. Figure 6 and 7 reveal that neither design 2 or 3 dissipate heat as well as design # 1. This was to expect because of the resulting high thermal resistivity of the design. Method Abstract Discussion & Results Figure 1: Experimental power inverter (right) Figure 3: FEMM simulation Figure 4: Theoretical analysis Design #1 Design #2Design #3 Figure 5 Figure 6 Figure 7 This work was supported primarily by the ERC Program of the National Science Foundation and DOE under NSF Award Number EEC Other US government and industrial sponsors of CURENT research are also gratefully acknowledged. The use of thermal vias in design #1 is the most suitable cooling configuration for the GaN power transistor. When theoretically analyzing designs 2 and 3, it was revealed that geometry affected the conductivity of heat through them. The more area or volume of heat spreading material there is closer to the heat source, the better the cooling will be. Adjustments to design 2 and 3 could be made to reduce their thermal resistivity, but would imply additional space and cost to the power inverter design. Conclusion Big Small