Cooling simulation model: Expanding the number of Simplified CFD Models for three-dimensional thermal fluid analysis in MOSFETs

Importance of thermal analysis

In recent years, the size reduction in electronic equipment, high-density mounting, and severe operating conditions such as high ambient temperatures have caused a variety of heat issues when selecting, placing electronic components to be used and designing boards. Therefore, the importance of thermal design using cooling simulation with three forms of heat transfer: thermal conduction, thermal convection, and thermal radiation, is increasing.

Thermal models, such as the enclosure, the board, and the mounted components are required for cooling simulations. Toshiba Electronic Devices & Storage Corporation ("Toshiba") has created the Simplified CFD Model that is suitable for cooling simulations, focusing on MOSFET, and has started releasing this model. Simplified CFD Model can be used with thermal fluid analysis tool to visualize three-dimensional behavior (temperature distribution and flow velocity).

Simplified CFD Model

  • CFD is the abbreviation for Computational Fluid Dynamics. In this page, it means three-dimensional thermal fluid analysis.
  • The device model is a three-dimensional model for this CFD. It simplifies actual components shapes that affect the heat-flow path to the block-shaped structure. (Refer to the left side of Figure 1.)
  • Material properties of components provided together with the device model are adjusted from the general values. (Refer to the right side of Figure 1.)
  • Model file formats are ISO standard STEP formats, so they are compatible with many 3D CAD tools. They are available in a variety of thermal fluid analysis tools.
Figure 1: Component structure of Simplified CFD Model
Figure 1: Component structure of Simplified CFD Model

Please refer to the application note for the usage of the Simplified CFD Model.

Example of analysis using Simplified CFD Model

Figure 2: Surface temperature distribution (overall, mold surface and inside)
Figure 2: Surface temperature distribution (overall, mold surface and inside)

Figure 2 shows a simulation result of which losses are applied to a MOSFET and heat is generated. It shows heat spread to the board and heatsink as MOSFET temperature rises.

Figure 3: Fluid display around the board (flow velocity and heat-flow path in the chamber)
Figure 3: Fluid display around the board (flow velocity and heat-flow path in the chamber)

Figure 3 shows the air velocity and heat flow in the chamber set during the analysis. The flow velocity and path of fluid (air) around the board can be checked. 

Please refer to the following web page for the list of MOSFETs with Simplified CFD Model.

Thermal Management for Designs Using Discrete Semiconductor Devices

Thermal Management for Designs Using Discrete Semiconductor Devices

There are several effective ways to manage the high temperatures of today’s discrete semiconductors in your design.

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