Superior-Order Curvature-Corrected Voltage References Using Double Differential Structures

Two original superior-order curvature-corrected voltage references was presented. In order to improve the temperature behavior of the circuits, double differential structures was used, implementing the linear and the superior-order curvature corrections. An original CTAT (complementary to absolute temperature) voltage generator was proposed, using exclusively MOS transistors biased in weak inversion for a low power operation of the voltage reference. The superior-order curvature-correction was implemented by taking the difference between two gate-source voltages of subthreshold-operated MOS transistors, biased at drain currents having different temperature dependencies: PTAT (proportional to absolute temperature) and PTAT². The SPICE simulations confirm the theoretical estimated results, showing temperature coefficients under 11 ppm/K for an extended input range 173K < T < 423K and for a supply voltage of 2.5V and a current consumption of about 1muA