SIMPLIS Diode Models

Show extracted PWL waveforms option

Beginning in version 8.2, there is now an option to plot the extracted parameters as a set of PWL curves. To enable this option, select the Show extracted PWL waveforms checkbox and extract the model. After the model is extracted, a set of curves will be generated comparing the extracted PWL curves against the simulated SPICE curves. The curves displayed will depend on the model level being extracted.

Below is a typical PWL approximation of the Forward Bias Current characteristic of the diode, with the SPICE curve in red and the PWL curve in blue.

Level 0 Model

Level 0 models a diode on/off resistance values only. This Level 0 model can be used  for almost every simulation you may encounter in SIMPLIS.

• The diode conduction region is modeled with a 2- or 3-segment resistor.
• There is no junction capacitance in a Level 0 model.

Below is a schematic view of Level 0 model:

Level 0 models these circuit elements	Level 0 Schematic
!R_D_POWER: Diode modeled by PWL Resistor

Level 1 Model

Level 1 models a diode with on/off resistance values and a junction capacitance with up to 4 PWL segments.

• The diode conduction region is modeled with a 2- or 3-segment resistor.
• The junctions capacitance is modeled with a variable number of segments, with a maximum of four.

Below is a schematic view of Level 1 model:

Level 1 models these circuit elements	Level 1 Schematic
!R_D_POWER: Diode modeled by PWL Resistor CJ: Junction Capacitance modeled by PWL capacitor

User-defined model

Models these circuit elements	User-defined Schematic
!R_D_POWER: Diode modeled by PWL Resistor CJ: Junction Capacitance modeled by a linear capacitor

Manually Generate and Customize Diode Models

You can customize or manually generate your own diode models using a parameter string with multiple PARAM_NAME=PARAM_VALUE key-value pairs. The parameter names and their functions are described in the Diode Model Parameters section below. You can interpret the SIMPLIS parameter values from device datasheet specifications and curves.

You can compose the parameter string in a text editor, spreadsheet, or script. The order of the parameter names in the parameter string and the capitalization of the parameter names are irrelevant.

You can include a PROTECTED=1 key-value pair to prevent from extracting a model and overwriting your manually generated parameters. The PROTECTED=1 key-value pair is not used in the simulation.  

Note: When you click on the device after adding the PROTECTED=1 key-value pair, the following message box appears to warn you that this is a hand-edited model.

To customize or generate your own diode model, follow these steps:

1. Create a parameter string of multiple PARAM_NAME=PARAM_VALUE key-value pairs using your preferred text editor, spreadsheet or script.
2. Add the PROTECTED=1 key-value pair to the parameter string.
3. Extract a diode model and place it on a schematic.
4. Right click on the symbol and select Edit/Add Properties....
5. Double click on the PARAM_VALUES property.
   Result: The Edit Property dialog opens. At this point, you can change individual parameters in the Value box, or replace the entire default properties with the parameter string that you created in Step 2.
6. To replace the entire string, follow these steps:
   1. Click in the Value box and type Ctrl A to select all of the existing parameter string, and press Delete.
   2. Copy the parameter string you completed in Step 2 and paste into the Value box.
   3. Click Ok.
7. To change the name of your customized model, double click the VALUE property in the Edit Properties dialog, and change the name in the Value box.
8. To return to the schematic, click Ok.

prop PARAM_VALUES parameter_string

Diode Model Parameters

The following tables detail the parameters which define the electrical behavior of the Diode model. Several other parameters in the PARAM_VALUES property have no effect on the electrical behavior of the model. These parameters are used to populate the Extract Diode Parameters dialog box.