Voltage-Controlled Current Source (VCCS)

Symbol

Information

A Voltage-Controlled Current Source (VCCS) is a dependent current source whose output current is proportional to a reference (control) voltage applied across a separate circuit branch. The fundamental equation governing VCCS is:

\[I_{out} = G_m \cdot V_{control}\]

Where:

\(I_{out}\) is the output current (Amperes)
\(V_{control}\) is the controlling input voltage (Volts)
\(G_m\) is the transconductance gain (Siemens)

VCCS is widely used in analog amplifiers, active filters, and transistor models.

Ports

cp, cn: Control voltage terminals
p, n: Output current terminals

Symbol description

Field	Value
Symbol.name	VCCS
Symbol.file	VCCS.sym
Symbol.directory	Basic
Symbol.referance	`C`
Model.name	`VCCS`
Model.file	VCCS.py

Model

The VCCS model implements an ideal voltage-controlled current source.

A VCCS provides an output current proportional to the control voltage.

Attributes:

V_control (signal): Input voltage signal that controls the output current, defined between nodes (cp, cn).

I_out (signal): Output current signal delivered to the circuit, defined between nodes (p, n).

Gm (param): Transconductance gain (Siemens), default is 1.0 S.

Methods:

analog(): Defines the VCCS behavior using the equation:

\[I_{out} = G_m \cdot V_{control}\]

from pyams.lib import model, signal, param, voltage, current

class VCCS(model):
    """
    Voltage-Controlled Current Source (VCCS) model.
    Implements the equation: I_out = Gm * V_control
    """

    def __init__(self, cp, cn, p, n):
        # Signal declaration
        self.V_control = signal('in', voltage, cp, cn)
        self.I_out = signal('out', current, p, n)

        # Parameter declaration
        self.Gm = param(1.0, 'S', 'Transconductance gain')

    def analog(self):
        """Defines the VCCS behavior"""
        self.I_out += self.Gm * self.V_control

Command syntax

The syntax for defining a VCCS in a PyAMS simulation:

# Import the model
from pyams.models import VCCS

# VCCSname: is the name of the VCCS instance
# cp, cn: The control voltage terminals
# p, n: The output current terminals
VCCSname = VCCS(cp, cn, p, n)