Standby Leakage Power Reduction Technique for Nanoscale CMOS VLSI Systems

Abstract

In this paper, a novel low-power design technique is proposed to minimize the standby leakage power in nanoscale CMOS very large scale integration (VLSI) systems by generating the adaptive optimal reverse body-bias voltage. The adaptive optimal body-bias voltage is generated from the proposed leakage monitoring circuit, which compares the subthreshold current ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SUB</sub> ) and the band-to-band tunneling (BTBT) current ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BTBT</sub> ). The proposed circuit was simulated in HSPICE using 32-nm bulk CMOS technology and evaluated using ISCAS85 benchmark circuits at different operating temperatures (ranging from 25°C to 100°C). Analysis of the results shows a maximum of 551 and 1491 times leakage power reduction at 25°C and 100°C, respectively, on a circuit with 546 gates. The proposed approach demonstrates that the optimal body bias reduces a considerable amount of standby leakage power dissipation in nanoscale CMOS integrated circuits. In this approach, the temperature and supply voltage variations are compensated by the proposed feedback loop.