A high-order compensated bandgap reference design with a buffer circuit

To address the issue of low power supply rejection ratio (PSRR) in traditional bandgap reference circuits, a novel bandgap reference scheme is proposed. This scheme employs a five-transistor unit and an emitter follower to form a two-stage operational amplifier, isolating the reference voltage from other modules and thereby ensuring the gain of the reference generation circuit. Additionally, a high-order compensation circuit is introduced to reduce temperature drift and enhance precision. Based on a $0.18 \mu \mathrm{~m}$ BCD process and validated through Cadence simulations, the results demonstrate a temperature drift of $\mathbf{T}_{\text {dit, REF1 }}$ $=20 \mathrm{ppm} /{ }^{\circ} \mathrm{C}$ and a power supply rejection ratio of -113 dB over a temperature range of $-40^{\circ} \mathrm{C}$ to $125^{\circ} \mathrm{C}$. This circuit is capable of generating high-precision reference voltages and bias currents.