A Fast Transient Response Capacitorless LDO with Slew Rate Enhancement Design

This paper proposes a transient response enhancement method for low-dropout (LDO) regulator without off-chip capacitors. It’s based on a slew rate enhancement circuit that includes a tail current detection circuit and a pass transistor gate drive circuit. The voltage of the gate of the regulating tube is driven by detecting the change of the output voltage. This paper uses a 0.18 μm MOS process and shows that when the load current changes from 0 to 100 mA within 1 μs, the LDO proposed in this paper can reach a stable voltage within 1.6 μs. Its output voltage overshoot is 1.47 V and undershoot is 0.83 V.