An Improved Bandgap Reference with Curvature-Compensated and High Power Supply Rejection

This paper presents a bandgap reference (BGR) with the characteristics of curvature-compensation and high power supply rejection ratio (PSRR). To achieve a better performance, the base current of BJT is injected to a small segment of resistor string to flatten the temperature variation, and a pre-regulator of the power supply is implemented to improve the PSRR. The circuits, designed in 0.18μm BCD technology, exhibit an average voltage of 1.212V with temperature coefficient of 2.0ppm/∘C in the range from −40∘C to 110∘C at typical condition, and a power supply rejection ratio of −175.7dB at low frequency. After 4-bit trimming, Monte Carlo simulation results show that the proposed design gets an accuracy of 0.29%, with a variation of ±3.5mV. The active design area is 160μm×206μm, and the power supply current is about 8.2μA.