A novel curvature-compensated high accuracy CMOS bandgap reference

A novel curvature-compensated method is presented. The method is based on obtaining two CTAT (complementary to absolute temperature) voltages with identical non-linear term through control of the currents of PN junctions, which in theory can achieve an ideal non-linear compensation. Thus, this work focuses on the precise control of the collector current of P-N-P bipolar transistor, which makes the non-linear term of the base-emitter voltage of one bipolar transistor can be completely compensated by that of another bipolar transistor. This method significantly improves the temperature independence. The circuit is designed using SMIC 0.18 μm CMOS technology, and the simulation result shows that the temperature coefficient (TC) in the range of -20°C to 85°C down to 0.09ppm/°CC (average).