A 16 ns, 28 fJ Wide-Range Subthreshold Level Converter Using Low-Voltage Current Mirror

Abstract

This paper proposes a high-speed and energy-efficient low-voltage current mirror-based level converter (LCM LC) which can perform a wide-range conversion of a subthreshold input signal (180 mV) to an above-threshold output signal (1.2 V). The proposed level converter utilizes low-voltage current mirror (LCM) circuit with high-threshold-voltage (hvt) PMOS devices in the pull-up network, which drives a switching current from high supply rail to output node during the high-to-low transition of an input signal to ensure wide-range conversion. The driving capability of the pull-down network in LCM LC is increased by employing inverse-narrow-width-effect (INWE)-aware low-threshold-voltage (lvt) NMOS devices in order to perform a high-speed operation. This level converter employs multi-threshold CMOS devices and is implemented in 45 nm technology using Cadence Virtuoso. The LCM LC exhibits a delay of 16.4 ns, energy per transition of 28.1 fJ and static power of 412 pW which are observed using Spectre circuit simulator for the target conversion from 0.2 to 1.2 V at a signal frequency of 1 MHz.