XNOR-based double-edge-triggered flip-flop for two-phase pipelines

Abstract

The conventional approach of double-edge-triggered flip-flops (DET-FFs) is to have two similar edge-triggered latches. And the achieved faster speed is at the cost of double chip area and complex logic structure. By contrast, the XNOR-based approaches is difficult to reach the speed demand due to the delay of the XNOR -based clock generator. This paper proposes a new designed DET-FF based on an alternative XNOR gate. By utilizing the sensitivity to the driving capacity of the previous stage, we use this simplified XNOR gate as a pulse-generator. A modified transparent latch following the pulse-generator acts as an XNOR-based DET-FF, which accomplishes the almost same speed and less power dissipation as compared with two conventional DET-FFs under HSPICE simulation. We also implemented the XNOR-based DET-FF in a two-phase-pipeline system, and the HSPICE simulation in the TSMC 0.25 um CMOS process shows our proposed DET-FF is much faster than those two conventional DET-FFs.