Circuit Elements

  1. Primitives
  2. Circuit Elements

isource

isource :
A current source circuit element.

The isource primitive represents a current source stand-alone or controlled by an input signal across two circuit terminals. Note that this primitive is a pseudo-module to describe a structural netlist of electrical circuits and not a behavioral model by itself. The XMODEL simulator extracts an event-driven behavioral model at run-time based on the circuit network described by these circuit-level pseudo-modules.

The isource primitive can be used in two different ways: first as a dependent current source controlled by an xreal-typed signal from a signal-flow model (mode=”in”) and second as an independent current source supplying a constant DC current (mode=”dc”).

1) A dependent current source controlled by an input (mode=”in”)

The default behavior of the isource primitive (mode=”in”) is to drive a current controlled by the input signal in between two circuit nodes. For instance:

xreal       in, A, B;
sin_gen     #(.amp(5.0), .freq(30.0)) in_ac(in);
isource     iin(.pos(A), .neg(B), .in(in));

drives a 5A-amplitude, 30Hz AC current into a branch between A and B.

This primitive provides a way to create a wide variety of current sources by combining it with various stimulus generator primitives. In other words, the primitive isource serves as a gateway that propagates a signal from signal-flow models to a current in electrical models.

2) An independent current source supplying a DC current (mode=”dc”)

When the parameter mode is set to “dc”, the primitive works as an independent DC current source. For instance:

xreal A, B;
isource     #(.mode("dc"), .dc(5.0))
            iin(.pos(A), .neg(B), .in(`ground));

connects a 5.0A supply between A and B. The terminal connected to the port “in” is ignored. In fact, it is equivalent to:

xreal       in, A, B;
dc_gen      #(.value(5.0)) in_dc(in);
isource     iin(.pos(A), .neg(B), .in(in));

Input/Output Terminals

Name I/O Type Description
pos input xreal positive terminal
neg input xreal negative terminal
in input xreal input control signal

Parameters

Name Type Default Unit Description
mode string “in” None mode of operation
dc real 0.0 amperes DC current value
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