Pulse Source - Single Pulse w/ Exponential Decay

The Pulse Source - Single Pulse w/ Exponential Decay subcircuit models a single exponential decaying pulse voltage source. This source is not used in any test objectives, but you can set a source to use this subcircuit with an Exp() call in the Source column of your testplan.

Other similar sources include:

Pulse Input Source - Single Pulse - A single pulse with programmable rise and fall times.
Pulse Source - Repeating Pulse - similar to the square waveform source but with configurable rise time, fall time, and duty cycle
Pulse Source - Repeating Pulse w/ Zero Rise and Fall Times - similar to the square waveform source but with a configurable duty cycle

In this topic:

Model Name	Exponential Decay Pulse Voltage 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_EXP
Symbols
Schematic

Pulse Source - Single Pulse w/ Exponential Decay Parameters

The following table explains the relevant parameters for the Single Voltage Pulse w/ Exponential Decay Source.

Note: This source is different than the other sources in that the RISE_TIME and FALL_TIME parameters are interpreted as time constants, as opposed to literal rise and fall times. These two parameters are highlighted in red text in the table below.

Parameter Name	Default	Data Type	Range	Units	Parameter Description
FALL_TIME	u50	Real	min: 0	s	The time constant of the rising edge of the pulse in seconds
FINAL_VOLTAGE	750m	Real	min: 0	V	The pulse voltage for the source. This can be a numeric value or a symbolic value, such as a percentage of nominal input voltage.
IDLE_IN_POP	0	Real	0 or 1		If set to 0, the source voltage during the POP analysis is set to the START_VOLTAGE; otherwise the source will be active during the POP analysis.
SOURCE_NAME	SRC	String	n/a	n/a	Name of the DVM source. This name cannot contain spaces.
PULSE_WIDTH	200u	Real	min: 0	s	The pulse width in seconds. DVM considers the pulse width to be the duration of the pulse at the PULSE_VOLTAGE.
RISE_TIME	100u	Real	min: 0	s	The time constant of the rising edge of the pulse in seconds
START_VOLTAGE	0	Real	min: 0	V	The starting voltage for the source. This can be a numeric value or a symbolic value, such as a percentage of nominal input voltage.
TIME_DELAY	10u	Real	min: 0	s	The time delay before the pulse initiates

Testplan Entry for the Single Voltage Pulse w/ Exponential Decay

To set any managed DVM source to a Single Voltage Pulse w/ Exponential Decay subcircuit, place an Exp() testplan entry in the Source column.

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

Exp(REF, START_VOLTAGE, FINAL_VOLTAGE, TIME_DELAY, RISING_TAU, PULSE_WIDTH, FALLING_TAU)
Exp(REF, START_VOLTAGE, FINAL_VOLTAGE, TIME_DELAY, RISING_TAU, PULSE_WIDTH, FALLING_TAU, OPTIONAL_PARAMETER_STRING)

where:

Argument	Range	Description
REF	n/a	The actual reference designator of the DVM source or the more generic syntax of INPUT:`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 nominal input voltage.
FINAL_VOLTAGE	min: 0	The pulse voltage for the source. This can be a numeric value or a symbolic value, such as a percentage of nominal input voltage.
TIME_DELAY	min: 0	The delay before the rising edge of the Exponential Pulse. The model TIME_DELAY parameter is set to this time value.
RISING_TAU	min: 0	The time constant for the rising edge of the Exponential Pulse. The model RISE_TIME parameter is set to this time value.
PULSE_WIDTH	min: 0	The pulse width of the Exponential Pulse, including the exponential rising edge
FALLING_TAU	min: 0	The time constant for the falling edge of the Exponential Pulse. The model FALL_TIME parameter is set to this time value.
OPTIONAL_PARAMETER_STRING	n/a	Parameter string with any of the other parameters from the parameter table above*

* If more than one parameter is specified, join the parameter key-value pairs with a space, for example:

parameter_name1=parameter_value1 parameter_name2=parameter_value2

The order of the parameter key-value pairs does not matter.

Symmetric Rising and Falling Edge Tau Example

The following example sets the first DVM managed source to a Single Voltage Pulse w/ Exponential Decay source with a starting voltage of 1V and a pulse voltage of 5V. This example shows a pulse with symmetric rising and falling edge time constants.

Note: In the following testplans, the Source column is prefaced with the characters *?@ because it is the first column in the testplan.

*?@ Source
Exp(INPUT:1, 1, 5, 25u, 3u, 150u, 3u)

The results of this testplan entry are shown below:

Asymmetric Rising and Falling Edge Tau Example

Note: In the following testplans, the Source column is prefaced with the characters *?@ because it is the first column in the testplan.

*?@ Source
Exp(INPUT:1, 1, 5, 25u, 3u, 150u, 1u)

The results of this testplan entry are shown below: