A Curvature Compensated Bandgap Circuit Exploiting Temperature Dependence of β

Abstract

This paper proposes a technique for the curvature compensation in Bandgap references to obtain a better Temperature Coefficient (TC). The proposed method is based on the fact that the Bipolar junction transistors used in Bandgap references have finite Beta which is temperature dependent. As β of NPN transistors in CMOS process is very low, Darlington configuration is used to achieve larger β to achieve the desired curvature compensation. Designed and simulated in TSMC 180-nm CMOS process the proposed bandgap circuit achieves a temperature coefficient of 9.9 ppm/°C across a temperature range of −40°C to 125°C and a line regulation from 1.6 V to 4.0 V.