关键词: 低压差线性稳压器, 高阶带隙, 斩波调制, 缓冲阻抗衰减, 低噪声

Abstract: The noise performance of low-dropout linear regulators (LDO) is largely dependent on their reference voltage. Based on TSMC 180 nm CMOS process, a high-order temperature-compensated bandgap reference circuit was designed to provide a low-noise, low-drift reference voltage for the LDO. Chopper modulation technology and a notch filter were employed to achieve low-noise performance. A super source follower circuit was designed as an impedance attenuation circuit to achieve circuit stability and further noise reduction. The above design elements work synergistically to ensure high purity from the reference source to the output stage while delivering low-noise performance. Simulation results show that at a supply voltage of 3 V and output voltage of 1.6 V, the temperature coefficient is 2.9×10^-6/℃ within the temperature range of -45 ℃ to 120 ℃. At a simulation frequency of 1 Hz, LDO noise is reduced from 159.671 µV/Hz before improvement to 3.692 µV/Hz after the innovative enhancement, with significant mitigation of operational amplifier offset and 1/f noise issues. Under both light and heavy load conditions, phase margin exceeds 60°, demonstrating excellent system stability.

Key words: Low-dropout linear voltage regulator, High-order bandgap, Chopping modulation, Buffer impedance attenuation, Low noise