power gating
Beginner
Cutting off power to a part of the chip that isn’t being used, like switching off the lights in an empty room.
Novice
Disconnecting an idle block of the chip from its power supply through a transistor switch, so it stops wasting power on leakage. The block loses whatever it was storing unless that is saved first.
Expert
Header (supply-side) or footer (ground-side) switch networks between the global rail and a block’s virtual rail, controlled by a power-management unit. It requires isolation on the block’s outputs, retention or state reload, control of in-rush current at wake-up, and power-aware verification.
Explained in Personal and edge devices (Industries).
See also: isolation cell, retention flip-flop.