Power Supply Modeling

In general a Power Supply device provides a  voltage source in series to an inner resistance for a specified pair of power- and ground pins (or more general:  a pair of power and ground pin groups, see below). Similar to the I/O Device modeling the set up of a Power Supply model is done via a data table.

The central element for modeling power supply is the power pin. The following fields in the corresponding row of a power pin has to be filled:

A power supply device can have signal pins, too. They act as pure input pins and should be used to load signal nets, which are connected to the device.  The general circuit topology is shown in the figure below:

 

 

Table for Power Supply Modeling

The table consist of an upper and a lower part. The upper part consists of only two rows: the top row lists the available column types (Pin, Net, Pin Type, ...). The row below is the selection row and includes the data of the currently selected row inside the lower part. The lower part provides the actual data table. There are as many rows in the table as device pins. Whether a certain data field in a row is needed or not depends on the selected Pin Type.

The rows of the lower data table can be sorted in an alphabetic order (upwards / downwards) according to any of the available column types. For example, in order to sort the table data according to net names, the user has to double click on the Net field inside the top row!

The table provides a multi-selection feature. For details refer to Table for I/O Device Modeling.

 

 

Pin: The column lists all pins of the corresponding device.

 

Net: The column lists the nets the corresponding pins are connected to.

 

Pin Type: Three pin types are available. The type can be chosen by double clicking inside the corresponding field. A drop-down menu appears allowing to select either signal, power or ground. According to the chosen pin type some fields can be edited or not.

 

Ground Ref: A Ground Reference has to be specified for a power pin and optionally for a signal pin. As a prerequisite one ground pin has to exist at least. The combination power pin / ground reference pin builds a port to which a DC current can be assigned during an IR-Drop analysis (see IR-Drop). The combination power pin / signal pin /ground pin builds an I/O driver used to switch current from the power- to the ground conductors via the voltage on the signal pin (see SITD).

 

In order to have a ground reference pin assigned to all signal and all power pins automatically, the user can press the Ground Refs ... button at the top of the table. The corresponding dialog box proposes to assign the ground pin which is closest to a signal (or power) pin as reference.

 

 

The second option "Reference & group all pins in range" performs to actions in one. It first groups all ground pins within a certain range (see section Pin Group below). In a second step the ground pin group which is closest to a signal (or power) pin will be assigned as reference.

 

 

Power  Ref

A Power Reference can  optionally be specified for a signal pin. The combination power pin / signal pin /ground pin builds an I/O driver used to switch current from the power- to the ground conductors via the voltage on the signal pin (see SITD).

 

In order to have a power reference pin assigned to all signal pins automatically, the user can press the Power Refs ... button at the top of the table. The corresponding dialog box proposes to assign the power pin which is closest to a signal  pin as reference.

 

 

The second option "Reference & group all pins in range" performs to actions in one. It first groups all power pins within a certain range (see section Pin Group below). In a second step the power pin group which is closest to a signal  pin will be assigned as reference.

 

 

Pin Group: Pins of type power and ground can be grouped together. From an electrical modeling point of view this means all pins within a group will be shorted and will have the same electrical potential. For more details please refer to Pin Grouping for I/O device.

 

V-source: Enables the user to assign a voltage to the corresponding power / ground pin pair.

 

R-source: Enables the user to assign a resistance in series to the V-source of the corresponding power / ground pin pair.

 

R-pin: Enables the user to assign a parasitic series resistance.

 

L-pin: Enables the user to assign a parasitic series inductance.

 

R-Up/Down: Only available for signal pins. Enables the user to assign a termination resistance between the signal pin and 0V (ideal ground).

 

C-Up/Down: Only available for signal pins. Enables the user to assign a termination capacitance between the signal pin and 0V (ideal ground).

 

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