A HCI self-healing circuit of a bandgap reference circuit with curvature compensation

Abstract

In this paper, the performance degradation of a bandgap reference circuit with curvature compensation under the hot carrier injection (HCI) effect is studied, and a self-healing circuit is proposed. The intrinsic performance of the curvature compensation bandgap circuit achieved a temperature coefficient (TC) of 1.949 ppm/°C and an output reference voltage of 384.748 mV under a 1.2 V power supply voltage between −40 °C to 125 °C. The TC of the reference circuit will increase to 8.033 ppm/°C and the output reference voltage decreases to 384.318 mV after 50 years under the HCI effect. The study found that the gain decrease of the op-amp in the reference circuit leads to a decrease in the output voltage, and the decrease of the compensation current in the curvature compensation circuit leads to the degradation of the TC. A self-healing circuit is designed to mitigate the impact of the HCI effect. The simulation results show that the TC of the self-healing reference circuit is 3.934 ppm/°C and the output reference voltage is 384.655 mV after 50 years under the HCI effect.