Low dropout regulator with double operational amplifiers based on FVF structure

Abstract

In this paper, low dropout voltage regulator based on Flipped Voltage Follower (FVF) is proposed. It is futured with fast transient response to load changes, high slew rate, and faster power-on time. The circuit proposed in the paper is adopted with double error amplifier and transient enhancement circuit. The major error amplifier can provide reference voltage for FVF structure and ensure flipped voltage stability. The auxiliary error amplifier is used to form a feedback loop at VOUT and VREF, improving the precision of output voltage, generating extra charge and discharge branch to provide greater slew rate, faster loop response, and faster power-on speed. The simulation results show that this LDO has output voltage jump less than 33mV and 150ns power-on time.