Comparative Analysis of LDO Post-Regulation for Power-Supply Rejection and Ripple Suppression

초록

This paper analyzes a power management integrated circuit where a low-dropout regulator (LDO) acts as a post-regulator to suppress the buck converter’s switching ripple and slow transient response. LDO utilizes high power-supply rejection (PSR) to filter ripple and a fast feedback loop to improve load regulation. Simulation results show the settling time is reduced from 57.01 μs to 14.10 μs and the output ripple is suppressed from 10.16 mV to 0.75 mV with -25.17 dB PSR at switching frequency.