Ramp Input Source

The ramp input source applies a ramp or a step voltage to the input of the circuit under test. The rise time is controlled by the RISE_TIME parameter and the source includes probes for the source voltage and current. This source is used in the StepLine() Test Objective.

Other similar sources include:

Pulse Input Source - Single Pulse - a single pule
Pulse Source - Repeating Pulse - similar to the square waveform source but with configurable rise time, fall time, and duty cycle
Pulse Source - Single Pulse w/ Exponential Decay - a single pulse with exponential rise and fall waveforms
Pulse Source - Repeating Pulse w/ Zero Rise and Fall Times - a repeating pulse with zero rise and fall times

In this topic:

Model Name	Ramp Input Source
Simulator		This device is compatible with both the SIMetrix and SIMPLIS simulators.
Parts Selector Menu Location	DVM > Sources > DVM Input Source
Symbol Library	None - the symbol is automatically generated when placed or edited.
Model File	SIMPLIS_DVM_ADVANCED.lb
Subcircuit Name	SIMPLIS_DVM_ADVANCED_SOURCE_RAMP
Symbols
Schematic

Ramp Input Source Parameters

The following table explains the relevant parameters.

Parameter Name	Default	Data Type	Range	Units	Parameter Description
FINAL_VOLTAGE	12	Real	min: 0	V	The final voltage for the source
RISE_TIME	100u	Real	min: 0	s	The ramp rise time in seconds
SOURCE_NAME	SRC	String	n/a	n/a	Name of the DVM source. This name cannot contain spaces.
SOURCE_RESISTANCE	0.4	Real	min:0	Ω	Sets the source resistance of the source
START_VOLTAGE	5	Real	min: 0	V	The starting voltage for the source
TIME_DELAY	10u	Real	min: 0	s	The time delay before the ramp initiates

Testplan Entry

To set any managed DVM source to a Ramp Source subcircuit, place a Ramp() testplan entry in the Source column.

The Ramp() testplan entry has the following syntax with the arguments explained in the table below.

Ramp(REF, START_VOLTAGE, FINAL_VOLTAGE)
Ramp(REF, START_VOLTAGE, FINAL_VOLTAGE, OPTIONAL_PARAMETER_STRING)

Argument	Range	Description
REF	n/a	The actual reference designator of the DVM source or the more generic syntax of OUTPUT:`n` where `n` is an integer indicating a position in the list of DVM sources.
START_VOLTAGE	min: 0	The starting voltage for the source. This can be a numeric value or a symbolic value, such as a percentage of the nominal input voltage.
FINAL_VOLTAGE	min: 0	The final voltage for the source. This can be a numeric value or a symbolic value, such as a percentage of the nominal input voltage.
OPTIONAL_PARAMETER_STRING	n/a	Parameter string with timing parameters TIME_DELAY and/or RISE_TIME*

* If both parameters are specified, join the two parameter key-value pairs with a space, as shown in the example below. The order of the parameter names does not matter.

Timing

During a StepLine() test, DVM sets the input to use the Ramp Source subcircuit. Then DVM sets the TIME_DELAY and RISE_TIME parameters for the Ramp Source. You can change the timing with the Ramp() function call by providing the timing parameters as an optional parameter string, which is the fourth argument to the Ramp() function call.

Example

The following example sets the first DVM managed source to a Ramp Source, with a starting voltage of 1V and a final voltage of 5V. The optional parameter string in this example sets the time delay to 25us and the rise time to 100us.

Note: In this examples, the Source column is the first column in the testplan and, therefore, begins with the special three character sequence: *?@.

*?@ Source
Ramp(INPUT:1, 1, 5, TIME_DELAY=25u RISE_TIME=100u)

The results of this testplan entry are shown below:

Annotation	Parameter Value
X0	TIME_DELAY
X1	TIME_DELAY + RISE_TIME
Y0	START_VOLTAGE
Y1	FINAL_VOLTAGE