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Ixiasoft
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Ixiasoft
1.2.2.1.2. Power Rail Data and Configuration Section
- Enter the power supply voltage in the Voltage column for each power rail listed in Area 1 by selecting a value from the pull-down menu, or by manually entering your own value.
Note: You must enter the total dynamic current consumption of related power rails before you can use the system decoupling function.
You can optionally adjust the recommended number up or down slightly based on knowledge of the intended application.
- Enter the current consumption in the Imax (Maximum Dynamic Current) column for each power rail.
The earliest data from the Early Power Estimator (EPE) can provide good values for the current entries. The EPE delivers bulk data for the transceiver channels. Each bank of transceiver channels should be assigned the total EPE value divided by the number of banks. Later in the design cycle, the Intel® Quartus® Prime software power analyzer can derive much better data for each bank rail.
- Setup your device power sharing scheme in Area 2.
Figure 6. Power Rail Data and Power Sharing Scheme SectionThis configuration is an example of how this section of the spreadsheet should look. Every design varies depending on the device chosen and the power rail configuration selected.
The current usage for each rail should be entered in the Imax (Maximum Dynamic Current) column in Area 1. Note that, for the VCC rail, only the dynamic current usage should be entered from the Early Power Estimator.
Each column in Area 2 represents a power group in your system. Add or remove a power group using the Add Group or Remove Group buttons. The first row of each group is the Regulator/Separator type. Set the source type for the power group and available options from the pull-down list as switcher, linear, or filter.
The second row is the Parent Group type. The available options for this row are None and the number representing all listed power groups. Input your power sharing hierarchy in this column, and set the power rail connection using the remaining rows.
Note: The PDN tool 2.0 defines the power rail configuration using the Parent/Child power group. A power group is a child power group if it attaches to another power group at its input. The other power group is the parent group in this case. A parent group can have multiple child groups. A parent power group number is required for the child group. The parent group number of a parent power group is assigned to None because the group has no parent group.The available Area 2 rail options are:
- blank — Device rail does not connect to the power group.
- x — Device rail connects to the power group.
- x/related— Device rail connects to the group, and its activity is related to other rails that connect to the same group. You must select x/related if that VCCIO/VCCPT power rail is related to other rails within the same power rail group.
Note: Two I/O rails are related if their output activities are synchronous. For example, when two VCCIO rails are assigned to the same memory interface. The maximum current is usually reached at the same time for these related rails. As a result, the total current of related rails equals the sum of the current of all shared rails. The total current of unrelated rails is calculated using the root-sum-square (RSS) method.The PDN tool 2.0 sets the default power rail sharing configuration based on the selected Intel-recommended power rail configuration listed above. Make changes to better match your design.Note:In the rail connection matrix, you can change the voltage of a rail without disconnecting it from a regulator group. However, all other rails connected to the same group must be able to change to the new voltage.
Figure 7. Changing Voltage for All Rails in a Group