A Novel SRAM Cell Design with a Body-Bias Controller Circuit for Low Leakage, High Speed and Improved Stability

Abstract

A dynamic threshold voltage control strategy is presented in this paper to minimize leakage power while enhancing the speed and stability. The threshold voltage of driver and access transistor are tuned dynamically through a novel body-bias controller circuit. The word line signal level controls the action of the proposed body-bias controller. In order to reduce subthreshold leakage current, the threshold voltage of NMOS access and driver transistors are adjusted to a high value by applying a reverse body-bias. On the other hand, forward body-bias lowers the threshold voltage of NMOS access transistor thereby enabling faster read and writes operation. Simulation results shows that the proposed design is much better than conventional and other SRAM cells such as, NC SRAM, PP SRAM, WRE8T. The amount of leakage power reduction is as high as 41.071 % over conventional 6T SRAM cell when tested on (8 × 16) SRAM array. Whereas, the improvement in read and write delay is 30 and 15.81 % respectively.