A Curvature Compensated Bandgap Circuit Exploiting Temperature Dependence of beta

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 beta of NPN transistors in CMOS process is very low, Darlington configuration is used to achieve larger beta 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/degrees C across a temperature range of -40 degrees C to 125 degrees C and a line regulation from 1.6 V to 4.0 V.