Layout techniques supporting the use of dual supply voltages for cell-based designs

Gate-level voltage scaling is an approach that allows different supply voltages for different gates in order to achieve power reduction. Previous researches focused on determining the voltage level for each gate and ascertaining the power saving capability of the approach via logic-level power estimation. In this paper, we present layout techniques that make the approach feasible in a cell-based design environment. A new block layout style is proposed to support the voltage scaling with conventional standard cell libraries. The block layout can be automatically generated via a simulated annealing based placement algorithm. In addition, we propose a new cell layout style with built-in multiple supply rails. Using the cell layout, gate-level voltage scaling can be immediately embedded in a typical cell-based design flow. Experimental results show that proposed techniques produce very promising results.