A novel output-capacitorless low-dropout regulator (OCL-LDO) with an embedded slew-rate-enhancement (SRE) circuit is presented in this paper. The SRE circuit adopts a transient current-boost strategy to improve the slew rate at the gate of the power transistor when a large voltage spike at the output is detected. In addition, a feed-forward transconductance cell is introduced to form a push−pull output structure with the power transistor. The simulation results show that the maximum transient output voltage variation is 23.5 mV when the load current ILOAD is stepped from 0 to 100 mA in 100 ns with a load capacitance of 100 pF, and the settling time is 1.2 μs. The proposed OCL-LDO consumes a quiescent current of 30 μA and has a dropout voltage of 200 mV for the maximum output current of 100 mA.
Keywords: low-dropout regulator (LDO); output-capacitorless; push–pull; slew-rate enhancement.