UPF
Beginner
A written plan that tells the design tools which parts of the chip can be switched off, and how.
Novice
The Unified Power Format (IEEE standard 1801): a file, kept separate from the design’s code, that lists which parts of the chip have their own power supply, which can be switched off, and what protects their neighbors while they are off.
Expert
Tcl-based power intent (domains, supply nets, switches, isolation, level shifting, retention) kept separate from RTL and refined through the flow. Simulation, synthesis, place-and-route and equivalence checking all read it, so mismatches between UPF and implementation are a classic bug source.
Explained in Personal and edge devices (Industries).