Switching-voltage detection and compensation circuits for ultra-low-voltage CMOS inverters

Abstract

This paper describes a switching-voltage detector and compensation circuits for an ultra-low-voltage CMOS inverter. The switching voltage of an inverter is an important design parameters for a digital circuit, and is determined by the difference in threshold voltages between MOSFETs. However, switching voltage varies significantly with fabrication process conditions and temperature. To address this problem, we have developed a threshold voltage difference detector circuit. We have also proposed a possible compensation technique for the inverter. Monte Carlo simulations demonstrated that the threshold voltage detector circuit can monitor the threshold voltage difference between pMOSFET and nMOSFET, and that the proposed inverter can achieve 80% reduction in switching-voltage variation compared to a conventional CMOS inverter.