Organization of the Input File

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SIMPLIS supports the concept of a main circuit and subcircuits in the definition of the system to be analyzed. A subcircuit can be nested within another subcircuit for up to 20 levels of nesting, with the main circuit considered as the first level of nesting. Since the definitions for the main circuit and a subcircuit are similar, the term general circuit is used here to represent either the main circuit or a subcircuit.

General Circuit

The general circuit is defined by the following statements:

  1. Start Circuit Statement
  2. Comment Statements
  3. Device Statements
  4. Model Statements
  5. Subcircuit Definition Statements
  6. Control Statements
  7. End Circuit Statement
Subcircuit Definition Statements defining a subcircuit follow the same pattern of statements outlined here for the general circuit. The forms of the Start Circuit Statement and End Circuit Statement depend on whether the general circuit is the main circuit or a subcircuit. The forms of the rest of the statements remain the same for both the main circuit and subcircuits.

Sequence of Statements

The scope of definition for a general circuit begins at the Start Circuit Statement and stops at the End Circuit Statement, inclusively. Statements within the scope of definition of a general circuit can be placed in any sequence without any effect on the reading of the input file, with the following exceptions:

  1. In the definition of a general circuit, the Start Circuit Statement and the End Circuit Statement must be the first and the last statements, respectively.
  2. Analysis statements are special control statements. The order in which analysis statements appear in the input file determines the order in which SIMPLIS performs different analyses.

Main Circuit

Title Statement (Start of Main Circuit Statement)

The first line in the input file is the Title Statement. This statement is the Start Circuit Statement for the main circuit, and it is copied to some of the data files generated by SIMPLIS for annotation purpose. The Title Statement must be only one line long. It cannot be extended over additional lines by using the line continuation character.

.END Statement (End of Main Circuit Statement)

The first statement in the input file that has the first field matching the keyword .END is the end of main circuit statement. This statement is the End Circuit Statement for the main circuit. Any input lines following this .END statement in the input file are ignored by SIMPLIS. Since .END is a keyword, its interpretation is case insensitive. No other fields are allowed in this statement. It cannot be extended over additional lines by using the line continuation character

Subcircuit

The details of the SIMPLIS subcircuit feature are explained in Subcircuit Definition. The following two subsections give a brief outline of how the subcircuits are defined.

.SUBCKT Statement (Start of Subcircuit Statement)

Any statement whose first field matches the keyword .SUBCKT starts the definition of a subcircuit. The .SUBCKT statement is the Start Circuit Statement for a subcircuit. The keyword .SUBCKT is followed by the name of the subcircuit and a group of node names.

.ENDS Statement (End of Subcircuit Statement)

A statement whose first field matches the keyword .ENDS is the end of the subcircuit statement. This statement is the End Circuit Statement for a subcircuit. The .ENDS statement can have two forms. In the first form, the .ENDS keyword is the only field in the statement. In the second form, the .ENDS keyword is followed by the name of a proper subcircuit.

General Statements

Comment Statements

See Comment Statements and In-line Comments for an explanation on the use of comments in the input file.

Device Statements

A device statement defines the parameter values of the device and indicates how it is connected to the circuit. When a model name or initial condition is required for a device, they are also defined in the device statement. Device Statements provides a detailed description of the syntax of device statements.

Model Statements

The model statement defines the parameters associated with a particular device model. Once a model is defined, it allows SIMPLIS to insert the model characteristics for every device associated with that model name. The Model Statement always starts with the keyword .MODEL as the first field in the statement. The following is a typical model statement for a diode, modeled as a piecewise-linear resistor:

. MODEL MD1M VPWLR NSEG=2 X0=0 Y0=0 X1=0.7 Y1=10U
+ X2=0.8 Y2=1

Model Statements describes the syntax for model statements.

Control Statements

Control Statements start with the period character ('.'), and can be classified into one of the following types:

  1. Options
  2. Initial conditions
  3. Resource limits
  4. Analyses
Although all control statements start with a period character, not all statements which start with a period are control statements. For example, statements beginning with keywords such as .MODEL, .SUBCKT, .END and .ENDS which start with a period character are not control statements. Control Statements explains the meaning and syntax of all control statements supported by SIMPLIS.

◄ General Rules for the Input File

Device Statements: Overview ▶