This paper presents an output capacitor-less low-dropout regulator (LDO) with a fast transient response and high current efficiency. The proposed slew rate enhancement circuit is activated only when the output voltage is instantaneously changed due to the transient of the load current. This method cannot only instantaneously increase the bias current source current for rapid output voltage recovery in order to enhance the load regulation but also reduce power consumption. The proposed LDO was fabricated using the standard 0.18 μm CMOS process. Measurement results revealed that the proposed LDO can operate from 1.2 to 1.8 V at an output voltage of 1 V and can provide loading current ranging from 3 to 100 mA. The current efficiency of the LDO was determined to be 99.96% at the maximal load current of 100 mA.
