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94 2. Tutorial
Model[
Name −> Diode,
Selector −> DC,
Ports −> {A, C},
Parameters −> {Is, Global[Vt]},
]
The Definition Argument
For behavioral model definitions, the Definition parameter must be of the form
Definition −> Equations[eq 1 , eq 2 , ]
where eq 1 , eq 2 , denote the symbolic device equations. (For compatibility reasons the right hand
side of the Definition parameter may also be a list of equations.) When specifying an arbitrary
set of equations we must tell Analog Insydes how the unknowns of the equations relate to the port
currents and voltages of a model object.
node+
Voltage[node+, node-]
Current[node+, node-]
node-
Figure 6.2: Voltage and current identifiers at a model port branch
Ports of behavioral models are defined in terms of electrical port branches. Every unique pair
of node identifiers [node+, node−] introduces an electrical port branch in between the model port
nodes node+ and node−. For the associated port voltage and current the positive reference direction
is defined to be oriented from node+ to node−, which is illustrated in Figure 6.2.
Port variables in behavioral model equations can be referred to by means of two special keywords
which are recognized by Analog Insydes and replaced by the corresponding global current or voltage
identifiers during model instantiation and expansion. The keywords provided to make references to
port currents and voltages are, respectively:
Current[node+, node-]
Voltage[node+, node-]
Note that the above definition of positive reference directions implies that Current[nodeA, nodeB] and
Current[nodeB, nodeA] are two different quantities and refer to different port branches. Similarly,
Current[nodeA, nodeB] and Voltage[nodeB, nodeA] do not refer to the same port branch.