Modeling

The modeling of analog elements in pyams.lib is based on defining their behavior using the Python language while following a structured approach:

Declaring the required library;
Defining the model name;
Specifying parameters with initial values;
Defining signal types (current or voltage);
Adding sub-models if applicable;
Establishing relationships between signals and parameters.

The general structure for modeling an analog element in pyams.lib is illustrated in the following example:

from pyams.lib import model, signal  # Library declaration

class NameOfElement(model):          # Model definition

     def __init__(self, ports):      # Initialization function
                                     # Declare signals (analog or digital) and parameters

     def sub(self):                  # Sub-function
                                     # Define sub-circuit or sub-model

     def start(self):                # Start function
                                     # Initialize values at the start of simulation

     def analog(self):               # Analog function
                                     # Define equations or analog operations

     def digital(self):              # Digital function
                                     # Define digital operations

Initial and Analog Functions

The initialization function (def __init__) is used to create ports for connections, define signals (analog or digital), and set default values for variables and parameters. The analog function (def analog) or digital function (def digital) is responsible for defining the mathematical relationships between signals and parameters, representing the behavioral model of analog or digital elements .

The __init__ , analog or ``digital``functions are the core components of a model. Additionally, there are two optional functions:

Sub-function: Used to construct sub-circuits within the model.
Start function: Initializes values when starting a simulation.

Signals and Parameters in pyams.lib

Signals in pyams.lib represent electrical quantities (voltage or current) and define how connections are established within the model. Signal declaration follows this syntax:

signal([Direction, Type, Port_p, Port_n])

where:

Direction specifies whether the signal is in or out.
Type defines the signal as either current or voltage.
Port_p and Port_n indicate the positive and negative terminals of the connection.

Parameters in an analog model are constants or variables that influence circuit behavior. They are declared as follows:

param([Value, Unit, Description])

where:

Value is the default parameter value.
Unit specifies the measurement unit.
Description provides a brief explanation of the parameter.

Allowed Operations Between Signals and Parameters

The following table summarizes the mathematical and logical operations available in pyams.lib:

Operation	Description	Result
+	Addition	real
-	Subtraction	real
*	multiplication	real
/	division	real
**	exponentiation	real
==	test for equality	boolean
!=	test for inequality	boolean
<	test for less than	boolean
<=	test for less than or equal	boolean
>	test for greater than	boolean
>=	test for greater than or equal	boolean
+=	get value	real