LOGI - Logarithm of Current

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Modified by Admin on Sep 13, 2017

Model Kind

General

Model Sub-Kind

Spice Subcircuit

SPICE Prefix

Model Name

LOGI

SPICE Netlist Template Format

@DESIGNATOR %1 %2 %3 %4 @MODEL

Parameters (definable at component level)

None

Notes

The content of the sub-circuit file (LOGI.ckt) associated with this model is shown below. The formula/equation used to provide this function is declared as part of the netlist-specific entry, under the .SUBCKT line of the file.

*Logarithm of Current .SUBCKT LOGI 1 2 3 4 VX 1 2 0 BX 4 3 I=LOG(I(VX)) .ENDS LOGI

Examples

Consider the circuit in the image above. With respect to the LOGI component, the entries in the SPICE netlist will be:

*Schematic Netlist: XM1 IN 0 OUT 0 LOGI . . *Models and Subcircuit: .SUBCKT LOGI 1 2 3 4 VX 1 2 0 BX 4 3 I=LOG(I(VX)) .ENDS LOGI

The effect of the function can be seen in the resultant waveforms obtained by running a transient analysis of the circuit.

In this example, the following analysis parameters on the Transient/Fourier Analysis page of the Analyses Setup dialog have been used:

Transient Start Time - set to 0.000
Transient Stop Time - set to 50.00m
Transient Step Time - set to 200.0u
Transient Max Step Time - set to 200.0u