Simple Simulation with Power Stepping

thermalex06.in : Simple Simulation with Power Stepping

Requires: DevEdit 3D/Thermal 3D
Minimum Versions: Atlas 5.22.1.R

This example runs thermal simulation of a 2 transistors. The main sequential tasks are:

  • Specification of two neighboring transistor regions in DevEdit 3D
  • Specification of heat sinks in in DevEdit 3D
  • Interface to Atlas
  • Selection of thermal models and material parameters
  • Specification of the power stepping parameters
  • Solution of temperature distribution at different thermal powers

The structure in this example is defined using DevEdit 3D. Initially the structure was defined using the graphical mode of DevEdit 3D. After the mesh was created, a command file was saved from DevEdit 3D enabling the structure to be re-created in DeckBuild.

The structure used here consists of two neighboring transistors embedded in a substrate material. For thermal modeling the transistors are considered only as heat sources. No internal details of the transistors are considered. An Aluminum region is defined as an electrode on the bottom of the substrate material. This will act in Atlas as a thermal rather than an electrical boundary condition.

The go atlas statement automatically interfaces DevEdit 3D to Atlas. On reading the three dimensional mesh file, Atlas will automatically enter 3D mode.

The material statement is used to define the thermal conductivities of each region using the tc.const parameter. This parameter sets a constant value for thermal conductivity. Later examples show regions with temperature dependent thermal conductivities. The power parameter sets the thermal output of the region. This naturally defines these regions at heat sources. The region thermal power can also be defined in the solve statement for power stepping as shown below.

The command models thermal is all that is required to enable the 3D thermal calculations. The final stage sets solve t1=300 . This defines the temperature of the heat sink (or electrode) number 1. The region thermal power can be specified by adding the POWERx parameter where x is the region number. This has the same effect as in the material statement and will override the value if already set. In this example the thermal power of region 2 is stepped by adding the POWERSTEP NSTEPS and STEPREGION parameters.

POWER2 defines the initial thermal power for region #2. POWERSTEP determines the size of the power step, NSTEPS sets the number of power steps to be performed and the STEPREGION option determines which region to step as the thermal power of any region may be specified on the solve statement.

The final 3D thermal distribution is saved to the file specified by the outfile parameter. The output file name rightmost characters will be incremented alphanumerically so a different file will be saved for each step. These can be viewed in TonyPlot 3D.

To load and run this example, select the Load example button in DeckBuild. This will copy the input file and any support files to your current working directory. Select the run button to execute the example.