20/08/2025

How to decide power domain area?

o   Logical Grouping (UPF create_power_domain -elements): All instances specified as elements of a power domain ideally need to be placed together physically.

o   Area Estimation: Estimate the total area required for all the standard cells and macros belonging to the power domain. Add margin for internal routing, CTS buffers, and special cells (power switches, isolation cells often placed at the boundary).

o   Power Grid Considerations: The voltage area needs its own internal power grid distribution (stripes/rails) connected appropriately to either the global grid (for always-on domains) or through power switches (for switchable domains). The size and shape must accommodate this grid.

o   Based on above factors and required utilization of voltage area, we can determine domain area.

o   The voltage area (create_voltage_area): Associate the physical area with the logical power domain name from UPF. Use placement guidance features (regions, fences) to enforce that cells belonging to the domain are placed within the defined voltage area.


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