Actually the need to design more and more reliable power electronic devices for several different applications has focused the designer interest on thermo-structural problems, in order to control the heat generated by the electronic components integrated on a Printed Circuit Board (PCB).
In order to completely describe a such system it is necessary accounting for the different physics of the device, dependently on each other, involved in the problem. The multi-physics analysis concerns the evaluation of stresses and deformations on the device and they are strictly correlated to the temperature distribution on each component and to the electric current flow into the device. So, the electric analysis gives the ohmic loss and the thermal analysis provides the temperature distribution as function of the geometry and the thermal conductivity of components. Finally the structural analysis allows to evaluate the stresses and the deformations depending on the constraints and the thermal loads, in order to detect possible faults. Since the complexity of the investigated systems, the numerical simulation is one of the best approach to handle all different physical variables determining the behavior of the device. From this point of view, ANSYS Workbench 12.1 is an important designer support in the multidisciplinary analysis whereas several physics are involved in the same phenomenon.
In the following paper, developed in collaboration with STMicroelectronics, the electro-thermal-structural analysis of a Power-SO10 device has been presented in order to prove the effectiveness and efficiency of a multiphysics approach. Power-SO10 is a surface mounting device having inside a chip made using a VIPower technology and its market applications are specially automotive.
In the case taken into account it was calculated the final structural behavior of the device upon a reliability test that consists of thousands current cycles (on/off). ANSYS analysis results put in evidence the integrity of the device at the end of test.
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