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Active leakage current is much larger (∼10×) than standby leakage current, and takes a large proportion (30% to 40%) of active power consumption. Active mode power gating (AMPG) has been proposed to extend the application of basic power gating to reducing active leakage; it relies on clock-gating signals to cut the power off a part of combinational gates. The problem to select those gates while integrity of circuit behavior remains intact has not been solved yet. We identify three constraints to solve this problem, namely functional, timing, and current constraints. The problem of synthesizing AMPG circuits is then laid out, and synthesis algorithm is proposed; a group of gates that can be power-gated by each clock-gating signal and the size of footer that is attached to the group constitute a synthesis output. The layout methodology for standard cell designs is proposed to assess AMPG circuits in area and wirelength. Experiments in 1.1 V, 45-nm technology demonstrate that active leakage is reduced by 16% on average compared to clock-gated circuits. [ABSTRACT FROM AUTHOR]

Reducing the power consumption of memory elements is known to be the most influential in minimizing total power consumption, since designs tend to use more memories these days. In this paper, we address a problem of high-level synthesis with the objective of minimizing power consumption of storage using dual-Vdd. Specifically, we propose a complete design framework that starts from dual-Vdd scheduling, dual-Vdd allocation, and controller synthesis down to the final layout. Its main feature is dual-Vdd register allocation, which exploits timing slacks left in the data-path after operation scheduling. In experiments on benchmark designs implemented in 1.08 V (with Vddl of 0.8 V), 65-nm CMOS technology, both switching and leakage power were reduced by 20% on average, respectively, compared to data-path with dual-Vdd applied to functional units alone. Detailed analysis of slack histogram, area, wirelength, and congestion were performed to assess feasibility of the design framework. [ABSTRACT FROM AUTHOR]