This chapter first discusses the working principle, equivalent model, and ripple analysis of switching LDO. Then, the classic hysteresis switching control LDO structure is introduced. While hysteresis switching control has a fast transient response, it results in a significant output ripple. Increasing the operating frequency and dynamically adjusting the power transistor strength can help reduce this ripple. Multiphase PWM control can effectively decrease the output ripple and reduce the output capacitor requirement. We cover multiphase PWM control circuits, including high-speed continuous comparators, ramp generation circuits, current balancing analysis, and both dual-loop and single-loop control methods. In addition, for digital LDO, part of the switches operating in switching mode can reduce the output ripple and extend the load current range. Finally, we present LDO examples utilizing switching assistance schemes.