Curvature-correction in the bandgap voltage reference based on thermal compensation of beta and base-emitter voltage

Abstract

A novel current-mode bandgap voltage reference circuit is presented. The proposed architecture exhibits the curvature compensation ability. The curvature compensation is achieved by utilising the nonlinear behaviour of forward current gain (β) to compensate nonlinear temperature dependence of base-emitter voltage (VBE). The proposed voltage reference is analysed theoretically and compared with other existing methods. The circuit is designed and simulated in standard 180 nm mixed mode CMOS technology which gives a bandgap reference level of 1.243 V. The minimum required supply voltage is 1.5 V. The maximum current drawn from VDD is 3.8 µA. A temperature coefficient of 4.5 ppm/°C is achieved over −25°C to 125°C temperature range. Variation in reference voltage is ± 15 mV across process corners. The reference circuit exhibits −65 dB low-frequency PSNA at 10 Hz with line sensitivity of 5 mV/V.