Using Clock Enables (CEs) - 2023.1 English

Vivado Design Suite User Guide: Implementation (UG904)

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2023.1 English

The Vivado power optimizer takes advantage of the abundant supply of Clock Enables (CEs). Power optimization creates gating logic to drive register clock enables such that registers only capture data on relevant clock cycles.

Note that in actual silicon, CEs are actually gating the clock rather than selecting between the D input and feedback Q output of the flip-flop. This increases the performance of the CE input but also reduces clock power.