Design and Analysis of Low-Voltage, MOS-only Bandgap Reference Circuit

This paper presents a novel MOS-only voltage reference with a very low-temperature coefficient (TC) and is immune to power supply variation. It uses a power supply of 1.2 V and can even operate on a voltage of more than 800 mV. The circuit is simulated using PTM 65 nm models on Cadence. Proportional to absolute (PTAT) current is generated by biasing MOS in the subthreshold region and generating thermal voltage (VTH). Similarly, complementary to absolute temperature (CTAT) current is generated using the threshold voltage (VT) of NMOS. Both CTAT and PTAT currents are scaled and combined to give temperature-independent reference voltage. As MOS operating in the subthreshold region uses very little current, therefore the proposed circuit consumes less power. A reference voltage of 500 mV is generated with a temperature coefficient of 287 ppm/ °C for the -40 to +120 °C range while ensuring low sensitivity to power supply variation.