Current-Starved and Skewed Topologies of CNTFET-Based Ring Oscillators for Temperature Sensors

Abstract

Carbon nanotube field-effect transistor (CNTFET) is the best nanoscale device for replacing the existing technology, having excellent electrical properties and its similarity to the present CMOS technology. Current-starved and skewed topologies in 10-nm technology using virtual source CNTFET for different characteristics using driver, load, and current-controlled source for different ring oscillator characteristics are presented. In the current-starved (CS) ring oscillator, the output will act as feedback to the inverted circuits, whereas in skew topologies, it can be categorized into high-skew- and low-skew-based circuits. In high-skew-based circuits, the feedback will be connected to pull-up networks, and in low-skew-based circuits, the feedback will be connected to pull-down networks. Based on the characteristics, we introduce a new CNTFET-based CS-based frequency multiplier (C-IFLM). The ring oscillator characteristics exhibit a decrease in power dissipation while using the current-controlled source. By increasing the current and the size of transistors, the load capacitances increase. Cadence Virtuoso simulations show that the average power for current-starved, high, and low skew for the driver, load, and the current-controlled source is 26.73, 4.09, and 2.43 mW, respectively. The duty cycle of the reference signal is reduced due to the change in bias current, and it pulls the free-running oscillator to desired harmonics. The temperature sensors built with these ring oscillators are a perfect fit for use in smart buildings. The CMOS-based temperature sensors have less resolution as they operate with bandgap reference. The proposed sensors will occupy a relatively less silicon area.