dRail: A Novel Physical Layout Methodology for Power Gated Circuits

In this paper we present a physical layout methodology, called dRail, to allow power gated and non-power gated cells to be placed next to each other. This is unlike traditional voltage area layout which separates cells to prevent shorting of power supplies leading to impact on area, routing and power. To implement dRail, a modified standard cell architecture and physical layout is proposed. The methodology is validated by implementing power gating on the data engine in an ARM ⃝ Cortex-A5 processor using a 65nm library, and shows up to 38% reduction in area cost when compared to traditional voltage area layout.