Bode Plot Load - Current Load

The Bode Plot Load - DC Current subcircuit models a dc current load with the AC small signal source and Bode plot probe that is required to generate Bode plots. This load is identical to the Bode Plot Load - Resistive Load, except this load uses a DC current to load the power converter. The BodePlot() Test Objective uses the resistive Bode Plot Load - Resistive Load, you can use the SubCkt() Function in conjunction with the BodePlot test objective to generate Bode Plots with this load. See the Testplan Entry section for testplan details.

Other similar loads include the following:

In this topic:

Model Name Bode Plot load
Simulator This device is compatible with both the SIMetrix and SIMPLIS simulators.
Parts Selector
Menu Location
  • DVM > Loads > DVM Output Load - 3 Terminal
  • DVM > Loads > DVM Output Load - 4 Terminal
Symbol Library None - the symbol is automatically generated when placed or edited.
Model File SIMPLIS_DVM_ADVANCED.lb
Subcircuit Name
  • SIMPLIS_DVM_ADVANCED_LOAD_3T_DC_BODE
  • SIMPLIS_DVM_ADVANCED_LOAD_4T_DC_BODE
Symbols
Schematic - 3 Terminal
Schematic - 4 Terminal

Bode Plot Load Parameters - AC Analysis

The following table explains the relevant parameters.

Parameter Name Default Data Type Range Units Parameter Description
LOAD_NAME LOAD String n/a n/a Name of the DVM load. This name cannot contain spaces.
DC_CURRENT 500m Real Min: 0 A Sets the load current of the load.
MEASURE_BODE 0 Real 0 or 1   A flag used by DVM to measure the Bode Plot for this output load. This flag also enables the small signal AC source. When both MEASURE_BODE and MULTI_TONE are equal to 1, the load is set to measure a Multi-Tone AC Bode plot.
MULTI_TONE 0 Real 0 or 1   Enables Multi-Tone AC analysis for this load. For small signal POP and AC analyses, this is set to 0.

Bode Plot Load Parameters - Multi-Tone AC Analysis

The following table summarizes the additional parameters used when a Multi-Tone AC Analysis is specified. The load uses these parameters only if the MULTI_TONE property is set to 1.

Parameter Name Default Data Type Range Units Parameter Description
DC_VOLTAGE 5 Real n/a V The common mode voltage seen by the Bode plot probe included in this load. This parameter is used only in Multi-Tone mode.
INJ_AMP 10m Real   V The RMS injection amplitude for the Multi-Tone AC source included in this load.
MEASURE_BODE 0 Real 0 or 1     A flag used by DVM to measure the Bode Plot response of this load. This flag also enables the small signal AC source. When both MEASURE_BODE and MULTI_TONE are equal to 1, the load is set to measure a Multi-Tone AC Bode plot.
MULTI_TONE 0 Real 0 or 1     Enables Multi-Tone AC Analysis for this load. For Multi-Tone AC Analysis, this parameter is set to 1.
N_PT 10 Real     The number of points per decade when the SWEEP_TYPE is 1 or 2. Unused when the SWEEP_TYPE is 0 or 1.
START_FREQ 1k Real   Hz The starting frequency for the Multi-Tone AC Analysis
STOP_FREQ 100k Real   Hz The ending frequency for the Multi-Tone AC Analysis
SWEEP_TYPE 1 Real 0, 1, 2 or 3     One of the following:
  • 0 = Single Frequency passed as START_FREQ
  • 1 = Linear Sweep
  • 2 = Decade Sweep
  • 3 = Decade sweep with linear first decade
TIME_DELAY 10u Real   s The time delay for the AC Multi-Tone injection. This time delay is converted into a phase delay and is used to ensure that the Multi-Tone AC injection starts at the same phase angle where the FindAcSteadyState() test ended.

Output Curves

The BodePlot graph is shown below.

Testplan Entry

The following testplan has two tests - the first, on line #6 is copied from the built-in DC/DC testplan. This test uses the Bode Plot Load - Resistive Load which loads the supply with a resistive load.

The second test which is defined on line #7, has an additional load column which uses the SubCkt() Function to change the load from the Bode Plot Load - Resistive Load to the current type Bode Plot load. When this test is run, the Objective sets the load to the Resistive Bode Plot Load, then the load column changes the subcircuit to the current-type Bode load.
Note: When you set the load value, e.g. its resistance or current using the Load() Function, both the DC_CURRENT and LOAD_RESISTANCE parameters are calculated from the DVM control symbol parameters and these values are written to the symbol.
1   ***          
2   *** bode_loads.testplan          
3   ***          
4   *?@ analysis objective source load load label
5   ***          
6   Ac BodePlot(OUTPUT:1) SOURCE(INPUT:1, Nominal) LOAD(OUTPUT:1, 50%)   Bode Plot|Resistive Load
7   Ac BodePlot(OUTPUT:1) SOURCE(INPUT:1, Nominal) LOAD(OUTPUT:1, 50%) SUBCKT( OUTPUT:1 , SIMPLIS_DVM_ADVANCED_LOAD_3T_DC_BODE ) Bode Plot|Constant Current Load

Collected links
BodePlot() Test Objective
Impedance Load