IR-drop Reduction Through Combinational Circuit Partitioning

IR-drop problem is becoming more and more important. Previous works dealing with power/ground (P/G) network peak current reduction to reduce the IR-drop problem only focus on synchronous sequential logic circuits which consider the combinational parts as unchangeable [4],[5]. However, some large combinational circuits which work alone in one clock cycle can create large current peaks and induce considerable IR-drops in the P/G network. In this paper, we propose a novel combinational circuit IR-drop reduction methodology using Switching Current Redistribution (SCR) method. A novel combinational circuit partitioning method is proposed to rearrange the switching current in different sub-blocks in order to reduce the current peak in the P/G network, while circuit function and performance are maintained. Experimental results show that, our method can achieve about 20% average reduction to the peak currents of the ISCAS85 benchmark circuits.