Design of Ternary Content-Addressable Memories with Dynamically Power-gated Storage Cells Using FinFETs

Abstract

An independent-gate FinFET can operate in two modes: SG (shorted-gate) and IG (independent-gate) modes, and thus a FinFET-based circuit offers rich design options for lower power, better performance or reduced transistor count. In this paper, we present two novel dynamically power-gated FinFET TCAM cells, called DPG-17T and DPG-16T, which power-gate the prefix data storage unit when storing a ‘don't care’ value. With the dynamic power-gating mechanism, DPG 17T/DPG-16T achieve lower power dissipation by eliminating the switching power of the comparison FinFETs and suppressing the leakage power of the prefix data storage when storing a ‘don't care’ value. Moreover, the discharge path of the matchline in DPG-17T/DPG-16T can be constructed with only one FinFET instead of two FinFETs, greatly boosting the search speed. Simulation results have shown that a TCAM of 64-word×128-bit using DPG-17T/DPG-16T can reduce the worst-case search delay by 53.0%/53.6% and improve the energy-delay product by 68.5%/70.4% when operating under a search rate of 4.0 GHz.