Low voltage current reference circuit with low temperature coefficient

Current references are necessary building blocks of every integrated circuit where they are used for biasing analog circuits such as filters, oscillators, phase locked loops, etc. This paper describes the design of a low voltage, low power 10 nA current reference. The proposed current reference circuit is based on a simple design methodology which uses the principle of subtraction of two positive temperature coefficient currents. The circuit is made to operate in sub-threshold region with a supply voltage of 0.5 V. The proposed circuit has been designed and simulated in Cadence Virtuoso with gpdk 180-nm CMOS process. The temperature coefficient of the reference current is 186 ppm/° C over a range from 0 to 80° C and the variation with supply voltage is 8.02%/V. The total power consumption of the circuit is as low as 45.887 nW.