System Level Transient Thermal Performance of High-Power Dynamic Microelectronics

System-level thermal transient analysis of High-Power Dynamic Microelectronics System is performed using numerical simulations. The SmartMOS-type device is packaged in 20 lead SOIC module with exposed copper slug. The package is attached to 4-layer PCB with embedded thermal vias. The challenge resides in the transient thermal interaction between the dynamic heat sources (high/low side motors), activated simultaneously at different powering profiles. Several operating steps are simulated, and the transient thermal behavior for each source is analyzed then optimized during the process. The low side motor reaches a peak temperature of ∼126.1°C at 2.25s, while the final temperature reached by the motor after one cycle (2.565 s) is ∼75.9°C. The DC current limit study indicates that the current over 1A exceeds the thermal budget. The case with 0.5A current limit reaches 135°C after 4 cycles, satisfying the thermal budget. Additional studies for an equivalent system were performed with only the high side driver actively dissipating 120W for 2.56 ms. The peak temperature reached by the system during the first cycle (2.56 us) is ∼65°C. Analytical study was performed to evaluate the steady state (final) temperature after a large number of dynamic powering cycles, based on heating/cooling behavior and superposition principle. The peak temperature reached by the IC will not exceed 92°C (using the steady state value and the temperature fluctuations per transient cycle). A correlation to predict the peak temperatures reached by the dynamic system after a long number of powering cycles is provided.