Negative voltage bandgap reference with multilevel curvature compensation technique^*

A novel high-order curvature compensation negative voltage bandgap reference (NBGR) based on a novel multilevel compensation technique is introduced. Employing an exponential curvature compensation (ECC) term with many high order terms in itself, in a lower temperature range (TR) and a multilevel curvature compensation (MLCC) term in a higher TR, a flattened and better effect of curvature compensation over the TR of 165 °C (−40 to 125 °C) is realised. The MLCC circuit adds two convex curves by using two sub-threshold operated NMOS. The proposed NBGR implemented in the Central Semiconductor Manufacturing Corporation (CSMC) 0.5 μm BCD technology demonstrates an accurate voltage of −1.183 V with a temperature coefficient (TC) as low as 2.45 ppm/°C over the TR of 165 °C at a −5.0 V power supply; the line regulation is 3 mV/V from a −5 to −2 V supply voltage. The active area of the presented NBGR is 370 × 180 μm².