ISIN - Sinusoidal Current Source Model

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Modified by Phil Loughhead on Mar 4, 2014

Model Kind

Current Source

Model Sub-Kind

Sinusoidal

SPICE Prefix

SPICE Netlist Template Format

@DESIGNATOR %1 %2 ?"DC MAGNITUDE"|DC @"DC MAGNITUDE"| SIN(?OFFSET/&OFFSET//0/ ?AMPLITUDE/&AMPLITUDE//1/ ?FREQUENCY/&FREQUENCY//1K/ ?DELAY/&DELAY//0/ ?"DAMPING FACTOR"/&"DAMPING FACTOR"//0/ &PHASE) #"AC MAGNITUDE"|AC @"AC MAGNITUDE"| @"AC PHASE"

Parameters (definable at component level)

The following component-level parameters are definable for this model type and are listed on the Parameters tab of the Sim Model dialog. To access this dialog, simply double-click on the entry for the simulation model link in the Models region of the Component Properties dialog.

DC Magnitude	DC offset used in an Operating Point Analysis. (Default = 0).
AC Magnitude	the magnitude of the source when used in an AC Small Signal Analysis. (Default = 1).
AC Phase	the phase of the source when used in an AC Small Signal Analysis. (Default = 0).
Offset	DC offset current of the signal generator (in Amps). (Default = 0).
Amplitude	peak amplitude of the sinusoid (in Amps). (Default = 1).
Frequency	frequency of the sinusoidal output current (in Hz). (Default = 1K).
Delay	delay time until the source current commences (in seconds). (Default = 0).
Damping Factor	the rate at which the sinusoid decreases/increases in amplitude (in 1/seconds). A positive value results in an exponentially decreasing amplitude; a negative value gives an increasing amplitude. A zero (0) value gives a constant amplitude sine wave. (Default = 0).
Phase	phase shift of the sinusoid at time zero (in Degrees). (Default = 0).

Notes

The image below shows an example waveform produced by a sinusoidal current source (connected to a 1Ohm load). The Amplitude has been set to 100mA, the Delay set to 500.0u and the Damping Factor set to 250 - to illustrate a decreasing sinusoid. All other parameters have been left at their default values.

The shape of the waveform is described by the following formulae:

I(t₀ to t_D) = I_O

I(t_D to t_STOP) = I_O+ I_A e^{-(t- t}D^)THETA sin(2πF (t + t_D))

where,

t is an instance of time
I_O is the DC offset current of the signal generator
I_A is the maximum amplitude of the output swing (excluding the DC offset)
F is the Frequency
t_D is the Delay and
THETA is the Damping Factor

The simulation-ready sinusoidal current source component (ISIN) can be found in the Simulation Sources integrated library (Library\Simulation\Simulation Sources.IntLib).

Examples

Consider the sinusoidal voltage source in the above image, with the following characteristics:

Pin1 (positive) is connected to net GND
Pin2 (negative) is connected to net INPUT
Designator is Iin
Amplitude = 1m
Frequency = 10k
All other parameters for the model are left at their default values.

The entry in the SPICE netlist would be:

*Schematic Netlist: Iin 0 INPUT DC 0 SIN(0 1m 10K 0 0 0) AC 1 0