A Low-Drift, High-PSRR Bandgap Reference Using Piecewise Exponential Compensation and Internal Supply Regulation

A bandgap reference based on high order temperature compensation and an integrated negative feedback voltage regulation technique has been designed. The proposed bandgap reference exhibits low temperature drift and high power supply rejection ratio (PSRR). By employing two pairs of MOS transistors operating in the subthreshold region, exponential compensation currents are generated in segmented fashion according to the operating temperature, thereby achieving high order temperature compensation and reducing the bandgap reference's temperature coefficient. Furthermore, leveraging the bandgap reference's output voltage, an integrated negative feedback regulation circuit is employed to enhance its PSRR. Using 0.18μm BCD process, the design, layout, and post-simulation verification of a low temperature-drift, high PSRR bandgap reference were completed. The layout area of the bandgap reference is 290μm×200μm. Post simulation results indicate that, over the temperature range of −45°C to 125°C, the temperature coefficient is only 1.15 × 10⁻⁶/°C, and the PSRR reaches 83.22dB. Under a supply voltage variation from 2.8V to 5.5V, the average reference voltage is 1.212V, with a line regulation of 0.015%.