Dynamic Averager Based Sub-1V Bandgap Voltage Reference

This paper proposes 'Dynamic Averager,’ a novel technique to eliminate the impact of opamp offset in a sub-1V current CMOS bandgap. This technique reduces the size of resistors by 4x and simplifies the design of startup circuitry by limiting the number of stable operating points to two. This paper also presents a theoretical analysis of the error sources and contrasts them with errors introduced due to chopping, which is traditionally employed to remove offsets in amplifiers. A prototype designed in 28nm TSMC LP CMOS technology for a nominal voltage of 502 mV demonstrates 24 ppm/°C temperature coefficient from −40 °C to 125 °C and occupies an active area of 0.003 mm
²
.