Unified Gated Flip-Flops for Reducing the Clocking Power in Register Circuits

Since the clocking power consumption in today’s processors is considerably large, reducing the clocking power consumption contributes to the reduction of the total power consumption in the processors. Recently, a gated flip-flop is proposed for reducing the clocking power consumption of flip-flop circuits. The gated flip-flop employs a clock-gating circuit which cuts off an internal clock signal if the data stored in the flip-flop does not need to be updated. Although this reduces the clocking power consumption, the power dissipated in the clock-gating circuit is still large. For reducing the power dissipated in the clock-gating circuit, this paper proposes a technique for unifying the multiple clock-gating circuits, which reduces the overhead of the clock-gating circuit. Post-layout simulation results obtained using a commercial embedded processor which employs our unified gated flip-flop demonstrate that our technique reduces the power consumption of a core part of the processor by 25% on average and 33% at the best case compared to the same processor with the conventional gated flip-flop.