Minimizing leakage power in aging-bounded high-level synthesis with design time multi-Vth assignment

Abstract

Aging effects (such as Negative Bias Temperature Instability (NBTI)) can cause the temporal degradation of threshold voltage of transistors, and have become major reliability concerns for deep-submicron (DSM) designs. Meanwhile, leakage power dissipation becomes dominant in total power as technology scales. While multi-threshold voltage assignment has been shown as an effective way to reduce leakage, the NBTI-degradation rates vary with different initial threshold voltage assignment, and therefore motivates the co-optimizations of leakage reduction and NBTI mitigation. This paper minimizes leakage power during high-level synthesis of circuits with bounded delay degradation (thus guaranteed lifetime), using multi-Vth resource libraries. We first propose a fast evaluation approach for NBTI-induced degradation of architectural function units, and multi-Vth resource libraries are built with degradation characterized for each function unit. We then propose an aging-bounded high-level synthesis framework, within which the degraded delays are used to guide the synthesis, and leakage power is optimized through the proposed aging-aware resource rebinding algorithm. Experimental results show that, the proposed techniques can effectively reduce the leakage power with an extra 26% leakage reduction, compared to traditional aging-unaware multi-Vth assignment approach.