A Novel Voltage Reference With An Improved Folded Cascode Current Mirror OpAmp Dedicated for Energy Harvesting Application

In this paper, a CMOS ultra-low voltage reference circuit with ultra-low power consumption of 220nW is proposed. The circuit, simulated in 65nm standard CMOS process technology, operates with a supply voltage of 1V. It is based on sub-threshold MOSFETs using the technique of compensating a PTAT-based variable with the gate source voltage of a subthreshold MOSFET. The novelty of circuit is the use of an improved folded cascode current mirror op-amp operating directly from a 1V power supply. The resulting voltage is equal to the extrapolated threshold voltage of a MOSFET at absolute zero temperature, which was about 435mV for the MOSFETs used. The proposed circuit achieves an average temperature coefficient of 30ppm/degrees C, 12ppm/V in line regulation for a supply voltage range of 0.6-1.2V, and a power supply rejection ratio (PSRR) of - 38dB at 100Hz. The overall power consumption is only 220nW.