Self‐biased nano‐power four‐transistor current and voltage reference with a single resistor

Abstract

A generic nano-power voltage and current reference topology, which takes advantage of the unequal threshold voltage ( V TH ) of two MOSFETs in subthreshold region, is developed to provide reliable bias and reference signals for the analogue integrated blocks used in the Internet-of-Things applications. The new architecture is a self-powered four-transistor topology with a single temperature-insensitive resistor, generating both temperature-independent voltage and current without any operational amplifier or bias network. Instead, the resistor defines the absolute value of the current reference ( I REF ) which supplies the core devices. The circuit is designed and simulated for a target current reference of 7.50 nA in 0.18 µm CMOS process, and achieves a worst-case temperature coefficient (TC) of 59.47 ppm/°C over a temperature range from −40 to 125°C and 1.8 V voltage supply. The average voltage reference ( V REF ) is 346 mV, and the worst-case TC of different corners is 21.98 ppm/°C. The nominal current consumption is twice the I REF (15 nA) regardless of the supply and temperature, and can be scaled down by reducing the desired current reference.