A Curvature Compensation Technique for Low-Voltage Bandgap Reference

Based on the standard 40 nm Complementary Metal Oxide Semiconductor (CMOS) process, a curvature compensation technique is proposed. Two low-voltage, low-power, high-precision bandgap voltage reference circuits are designed at a 1.2 V power supply. By adding IPTAT (positive temperature coefficient current) and ICTAT (negative temperature coefficient current) to the output resistance, the first-order compensation bandgap voltages can be obtained. Meanwhile, the third high-order compensation current is also superimposed on the same resistance. We make use of the collector current of the bipolar transistor to compensate for the nonlinear term of V-BE. The simulation results show that TC (temperature coefficient) of the first circuit reference could be reduced from 29.1 x 10(-6)/& DEG;C to 5.71 x 10(-6)/& DEG;C over the temperature range of -25 to 125 & DEG;C after temperature compensation. The second one could be reduced from 17 x 10(-6)/& DEG;C to 5.22 x 10(-6)/& DEG;C.