Clocksharing

Clocksharing refers to a technique used in digital circuit design to reduce power consumption. Instead of having every flip-flop in a circuit receive a global clock signal, clocksharing selectively gates the clock signal to functional blocks or individual flip-flops. This means that the clock signal is only delivered to those parts of the circuit that are actively performing computations. When a flip-flop is not transitioning or its output is not needed, its clock input can be held in a stable state, preventing unnecessary switching activity. This reduction in switching activity directly translates to lower dynamic power consumption, as dynamic power is proportional to the switching frequency.

Implementing clocksharing typically involves the use of clock gating cells, which are specialized logic gates that control the flow of the clock signal. These cells are driven by enable signals that indicate whether a particular block or flip-flop needs to be clocked. The design of these enable signals is crucial for the effectiveness of clocksharing. Poorly designed enable signals can lead to glitches or timing issues. While clocksharing is an effective power reduction technique, it can add complexity to the design process and potentially impact performance if not implemented carefully. It is a common optimization employed in modern integrated circuits, especially in battery-powered devices and high-performance processors where power efficiency is critical.