Curvature-Compensated Bandgap Voltage Reference with Low Temperature Coefficient

Abstract

Resistance errors in bandgap reference (BGR) circuits often cause deviations in design indicators, and it is true that utilizing various compensation techniques mitigates the impact of resistance errors. In this paper, an original BGR circuit with 180 nm BCD processing is presented, which uses an improved high-order compensation and curvature compensation. The proposed BGR contains four main blocks, including a start-up stage, a first-order temperature compensation stage, a high-order temperature compensation stage, and a curvature compensation stage. Meanwhile, a trimming resistor array structure is designed to revise the temperature coefficient (TC) deviation of the test output voltage from the theoretical design value. Through wafer-level laser trimming technology, the measurement results are achieved with very little difference from the theoretical design value. The proposed BGR provides a stable reference voltage at 1.25 V with a low TC and strong power supply rejection (PSR). Within temperatures ranging from −45 °C to 125 °C, the measured TC shows an optimal value at 4.2 ppm/°C and the measured PSR shows −100 dB.