In this topic you will learn how the SIMPLIS_TEMPLATE property defines the
symbol-to-subcircuit interface and allows you to pass parameters from the symbol to the
subcircuit. The symbol can be designed to use either the single property or multi-property
method, this topic focuses on the multi-property method which is also the preferred method.
The single property method is described in the Appendix B - Single Property Parameterization topic.
To download the examples for Module 5, click Module_5_Examples.zip.
This topic addresses the following key concepts:
- Parameters are passed to subcircuits on the SIMPLIS_TEMPLATE property.
- The multi-property method stores each parameter on an individual symbol
What You Will Learn
In this topic, you will learn the following:
- How to store parameters on the symbol using symbol properties and the multi-property
- How to use the SIMPLIS_TEMPLATE property, which defines the symbol-to-subcircuit
interface, to pass parameters into subcircuits
In this topic, you will learn the multi-property method for parameterizing a subcircuit
symbol. The multi-property method passes symbol properties through the
symbol-to-subcircuit interface where the symbol property values are used as model
parameters. In general, the multi-property method is the recommended method; however, in
some circumstances, the single-property method is a better choice. For more information,
see the Appendix B - Single Property Parameterization topic.
In addition to using the SIMPLIS_TEMPLATE property, you can pass parameters into a
subcircuit using the special PARAMS property. While this is not the preferred method, a
number of symbols exist which use this method. Using the PARAMS property is covered in
the Appendix - Passing Parameters into Subcircuits Using the PARAMS Property
For the rest of Module 5, a single-pole filter is used as an example. The single pole filter
uses three parameters to configure the filter:
Single-Pole Filter Parameters
||The filter pole frequency in
||The resistor value used in the
R-C filter in Ωs
||The gain of the filter in
The multi-property method uses a dedicated symbol property for each parameter. This has
the advantage that each symbol property can be displayed on the schematic or hidden from
view. In the next exercise, you will add properties using the multi-property method.
Exercise #1: Parameterize Using the Multi-Property
In this exercise, you will use the
symbol editor to add a symbol property for each parameter. Although it is not
strictly necessary, you will use the parameter name for the symbol property name. For
example, the FC parameter will be saved on a symbol property named
- Open the schematic 5.4_parametrized_rc_filters_multi_prop.sxsch.
- Select U2.
- Right click to bring up the context menu, and then select Edit Symbol...to
edit the symbol for the schematic component param_rc_multi_prop.sxcmp.
- To add a symbol property for each name in the following table, follow the steps
- From the Symbol Editor menu, select
, and then add a symbol property with the name and value from
the table above.
- To display the symbol property between the name of the schematic component
and the symbol, select Auto Normal =
Top in Text Location group.
- Check the Show name and Selectable check boxes.
Result: The configured dialog for the FC
parameter is shown below:
- Click Ok to save the symbol property.
- Repeat steps a through d for the R_VAR and GAIN symbol
Result: The symbol with the added
properties appears as follows:
- To add the SIMPLIS_TEMPLATE property to pass the symbol properties
FC, R_VAR, and GAIN through the symbol-to-subcircuit
interface, follow these steps:
- From the Symbol Editor menu, select
- Type SIMPLIS_TEMPLATE in the Name field, and add the following in
the Value field: <ref> <nodelist> <value> vars: FC=%FC%
- In the Text Location group, select Auto Normal =
Top for the symbol property.
- Check the Hidden check box on the Add Property Dialog.
Result: The configured SIMPLIS_TEMPLATE add
property dialog should appear as follows:
- Click Ok to add the SIMPLIS_TEMPLATE property.
Result: You have now configured the symbol to use the
multi-property method. The symbol editor should appear as follows:
- Press Ctrl+S to save the symbol.
- Click Ok on the Save Symbol dialog to save the symbol to the component
file, and then close the Symbol Editor window.
- To update the instantiated symbols on the schematic, follow these steps:
- Select U1.
- Press and hold the Ctrl key while selecting U2.
Result: Both symbols for U1 and U2 are selected:
- Right click to bring up the context menu and select Restore
Result: A dialog opens, for you to confirm
that you want to add the new properties to the instantiated
- Click Ok.
Result: The schematic
instances for U1 and U2 are updated with the new symbol
- Press F9 to run the simulation.
design simulates in SIMPLIS and two gain curves are output, one for each of the
two filters. The pole frequency is 10kHz for both filters as the passed
parameters are identical for both U1 and U2.
- Double-click on the FC property for U2, this will open the Edit Property
dialog. Change the FC value to 30kHz. The Edit Property dialog should
appear as follows:
- Click Ok on the Edit Property dialog and run the simulation.
Result: The blue output curve for the 30kHz filter now
reflects the change to the FC parameter.
You can now double click on any of the
symbol properties to edit the individual symbol properties. Since each symbol
property is passed as a model parameter, you are directly editing the model
parameters. This is one of the main advantages to the multi-property method. You can
also choose which parameters to show and which to hide.
Conclusions and Key Points to