DVM - Design Verification Module

Symbolic Values

From the very outset, DVM was designed to use symbolic values for reference designators, source voltages, and load currents. Why? Because using symbolic values, such as "100%" load allows a single testplan to be used on multiple schematics regardless of the load current magnitude. The same testplan can be used for a multi-phase synchronous buck converter with a 200A output or on a PFC converter with a 100mA output. By storing the full load current value (200A or 100mA for these examples) on the schematic, a single testplan can be used for both converters.

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Symbolic Reference Designators
What Symbolic Values are Supported?
Where are the Symbolic Values Stored?

Symbolic Reference Designators

DVM stores a list of Managed Sources and Loads on the Full Power Assist DVM control symbol. After you designate the managed sources and loads, an DC Input tab is added to the DVM Control symbol dialog for each input source and an Output page is added for each output load. You then enter the specifications for the sources and loads in the DVM Control Symbol dialog and the information is saved to the control symbol.

To refer to these sources and loads in a testplan using the symbolic reference designators, use the following syntax

INPUT:n for the sources, where n is the number in the list of managed sources
OUTPUT:n for the loads, where n is the number in the list of managed loads

Of course, you can enter the real reference designator, such as V2 or I1, into the testplan; however, using this approach makes the testplan specific to that schematic and, therefore, less portable.

What Symbolic Values are Supported?

DVM is reasonably flexible when it comes to evaluating a symbolic value. The following sections describe the supported symbolic values for each type of DVM source or load. Note that symbolic values are not supported for sources and loads which are not managed.

Loads

Example: Load(OUTPUT:1, 50%)

Symbolic Value	Description
%	For loads, this is the percentage of the Maximum Full Load Current entered on the Output page of the Full Power Assist DVM control symbol. The load current is 1E-2 times the number which prefixes the % sign.
Nominal, or Nom	The maximum, or 100% full-load current for the load
No	Sets the load current to the minimum value. The minimum value for Resistive Loads is 10Meg ohms.
ppm	Sets the load current to 1E-6 times the number which prefixes ppm. For example, 10000ppm is equal to 1% of the nominal full-load current.
Light	If the input source is set to the minimum value, the load current is the @ Input 1 Low Line value. For all other input voltages, the load current is set to the value of @ Input 1 High Line. Both values are entered on the Output page of the Full Power Assist DVM control symbol.

DC Sources

Example: Source(OUTPUT:1, Minimum)

Symbolic Value	Description
%	For sources, this is the percentage of the nominal input voltage as entered on the DC Input page of the Full Power Assist DVM control symbol.
Minimum, or Min	The minimum source voltage
Nominal, or Nom	The nominal, or 100% source voltage
Maximum, or Max	The maximum source voltage
No	Sets the source voltage to zero volts.
ppm	Sets the source voltage to 1E-6 times the number which prefixes ppm. For example, 10000ppm is equal to 1% of the nominal source voltage.

AC Line Sources

AC line sources have more parameters than DC sources and are, therefore, more complicated. The symbolic entries are divided into three categories:

Line Range
Voltage
Frequency

Example: AcFixed(INPUT:1, LL, Maximum, F_Low)

Line Range

Symbolic Value	Description
LL	Used in conjunction with the voltage specification to return the minimum, maximum, or nominal low line voltage.
HL	Used in conjunction with the voltage specification to return the minimum, maximum, or nominal high line voltage.

Voltage Values

Symbolic Value	Description
%	For sources, this is the percentage of the nominal input voltage as entered on the AC Input page of the Full Power Assist DVM control symbol.
Minimum, or Min	The minimum source voltage at the line range specified by the Line Range argument.
Nominal, or Nom	The nominal source boltage at the line range specified by the Line Range argument.
Maximum, or Max	The maximum source voltage at the line range specified by the Line Range argument.
No	Sets the source voltage to zero volts.
ppm	Sets the Source Voltage to 1E-6 times the number which prefixes ppm. For example, 10000ppm is equal to 1% of the Nominal Source Voltage.

Frequency Values

Symbolic Value	Description
F_Low	Used in conjunction with the voltage specification to return the minimum, maximum, or nominal low line voltage.
F_High	Used in conjunction with the voltage specification to return the minimum, maximum, or nominal high line voltage.

Where are the Symbolic Values Stored?

Each symbolic value is stored as a symbol property of the DVM Full Power Assist DVM control symbol. Each time a symbolic value is used, DVM calculates the numeric equivalent from the value stored on the Full Power Assist DVM control symbol. You can copy and paste a configured control symbol to new schematics and the values entered are preserved.