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

A generic nano-power voltage and current reference topology, which takes advantage of the unequal threshold voltage ($V_{{\rm TH}}$VTH) 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 ($I_{{\rm REF}}$IREF) 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 ($V_{{\rm REF}}$VREF) is 346 mV, and the worst-case TC of different corners is 21.98 ppm/°C. The nominal current consumption is twice the $I_{{\rm REF}}$IREF (15 nA) regardless of the supply and temperature, and can be scaled down by reducing the desired current reference.