Dynamic power: definition · Chip Field Guide

Beginner

The power a chip uses each time its tiny switches flip. More switching, faster, means more power.

Novice

Power spent each time signals switch, as tiny amounts of charge fill and drain wires and transistor inputs. $P = \alpha C V^2 f$ : how often signals switch ( $\alpha$ ), how much capacitance they charge ( $C$ ), the supply voltage squared ( $V^2$ ) and the clock rate ( $f$ ).

Expert

The $V^2$ term makes voltage the strongest lever. Short-circuit current, which flows while both transistors of a gate are briefly on, adds a little more. Clock gating (stopping the clock to idle blocks) cuts $\alpha$ , smaller cells and shorter wires cut $C$ , and DVFS lowers $V$ and $f$ together when full speed isn’t needed.