Quick Tutorial: How to Efficiently Resolve Convergence Errors in OrCAD PSpice

March 28, 2022 Team EMA

When performing a simulation, errors and warnings can sometimes occur and result in a failed analysis. While most errors can be easily resolved, convergence errors can be difficult with no indication of what exactly went wrong. Solving a convergence error involves a trial-and-error approach of loosening component tolerances, but it’s difficult to achieve the correct balance; loosening enough for a successful simulation while still retaining accuracy and producing realistic results. Quickly determine the best tolerance settings for a successful and accurate simulation with automatic convergence in OrCAD PSpice Designer.

This tutorial will provide step-by-step instructions for utilizing Autoconverge functionality in OrCAD PSpice. To follow along with this tutorial, use the included design file in ConvergenceError.zip.

Step 1: Open the provided file, ConvergenceError.opj, in OrCAD PSpice Designer.

Step 2: Select PSpice > Run from the menu or the Run button on the toolbar.

Note: The simulation will produce a convergence error and the PSpice Runtime Settings window will be activated. A convergence error occurs when the calculations performed in the simulation cannot be made to fall within the set tolerances.

Step 3: View the PSpice Runtime Settings window.

Note: In this window, you can loosen the available tolerances to allow for the simulation to converge, but it is very difficult to determine which option(s) to loosen.

Step 4: Check Autoconverge and click OK & Resume Simulation.

Note: Autoconverge determines how to loosen the tolerances by the smallest amount and achieve convergence.

Step 5: The Simulation Messages window will appear. Select No to view the simulation results.

Step 6: Close out of the simulation window.

Step 7: Back in the schematic canvas, select PSpice > Edit Simulation Profile from the menu.

Step 8: Select Options from the menu on the left.

Step 9: Select Analog Simulation > Auto Converge.

Step 10: Check AutoConverge and click OK.

Note: This will activate automatic convergence for the active simulation.

Step 11: Select PSpice > Run from the menu or the Run button on the toolbar.

Step 12: Select No when the Simulation Messages window appears.

Step 13: View the results.

Note: The simulation was completed successfully by activating AutoConverge from the start of the simulation.

Manually resolving errors or warnings when they occur in a simulation can be time-consuming and ambiguous. Efficiently adjust simulation tolerances responsible for convergence errors and achieve a successful, accurate simulation with the AutoConverge functionality in OrCAD PSpice Designer.

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