20/08/2025

How do you do power planning? Which power plan strategies do you follow? Command used for power plan?

o   Requirement Analysis: Understand the power consumption estimate of the design (static and dynamic), voltage levels required, number of power domains, IR drop targets, and EM limits.

o   Define Structure:  Design the hierarchy of the PDN, typically involving:

o   Power Pads/Bumps

o   Power Rings

o   Power Stripes:

o   Power Rails

o   Calculate Widths/Spacing: Determine the required width and spacing of rings and stripes based on current density requirements

o   Layer Assignment: Assign specific metal layers for rings, horizontal stripes, and vertical stripes.

o   Implementation: Use PnR tool commands to create the rings, stripes, rails, and connect them with power vias.

o   Verification: Perform IR drop (static/dynamic) and EM analysis to verify the PDN meets the design requirements.

o    Commands (Tool Specific): The exact commands depend on the PnR tool:

§  Innovus: addRing, addStripe, editPowerVia, setDesignMode -powerPlanning, sroute (special route for rails).

§  ICC2: create_pg_* commands (e.g., create_pg_ring, create_pg_mesh_pattern, create_pg_stripe_pattern), set_pg_strategy, compile_pg.

o   Rings, Stripes, Grids: https://vlsiweb.com/power-plan/

 

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