Thermal Simulation of Linear RegulatorsParameter Settings and Thermal Simulation Models

Initial Setting for Simulation

The simulation time, convergence options, and other simulation conditions can be set with the Simulation Settings icon introduced in the previous article. The table below shows the initial simulation settings. When there are issues relating to simulation convergence, these can be resolved by modifying detailed options. Simulation temperatures and various parameters for electrical circuits are defined in “Manual Options”.

Temperature Parameter Setting

Definition of component parameters

The component shown in blue in the figure above is a component for which the ambient temperature must be set; for this reason, the parameter is defined in “Manual Options”. The table below shows the initial value of the parameter. Enter the ambient temperature in the Manual Options box under the Simulation Settings as shown below.

Definition of parameters

Thermal Simulation Models

In the figure below, the”BD433M2EFJ“ symbol is a thermal simulation model of the BD433M2EFJ-C linear regulator. The terminals of the model are described in the table below. The node in red (BD433M2EFJ_TJ) can be used to monitor the junction temperature.

BD433M2EFJ-C thermal simulation model

Selecting a Thermal Simulation Model

The components shown in the table above are available for use in thermal simulation models; any of these can be selected. The figure below shows how to select a thermal simulation model.

How to select a thermal simulation model

First, right-click on the BD433M2EFJ component and select “Property” to open the Property Editor. Set the “SpiceLib Part” in the Property Editor to the name selected from the table above. The thermal simulation model will be changed. Next, run the thermal simulation, and the temperature graph of the linear regulator under the set conditions will be updated. For details of the models, refer to “User’s Guide: Thermal Simulation of BD4xxMx Series Linear Regulators.”
Similarly, the values of voltage source, capacitors, resistors, and other components can be changed by using the Property Editor. Input boxes that can be changed in values are white, while those that cannot be changed are gray.

This article is based on the following “User’s Guide: Thermal Simulation of BD4xxMx Series of Linear Regulators.”

https://fscdn.rohm.com/en/products/databook/applinote/ic/power/linear_regulator/bd4xxmx_thermal_simulation_ug-e.pdf