The invention discloses a single-inductor multi-output DC-DC buck converter, relates to the technical field of DC-DC converters, and solves the technical problem that the performance requirements of transmission efficiency, cross modulation and output ripple waves are difficult to consider in an existing SIMO control method. The single-inductor multi-output DC-DC buck converter comprises a powerconversion unit and an i-path charge controller, and further comprises a phase-locked loop, a logic unit, a driving unit and an input trunk duty ratio generation unit, wherein the charge controller isconnected with the driving unit through the logic unit, the logic unit is further connected with the phase-locked loop, the phase-locked loop is connected with the driving unit through the input trunk duty ratio generation unit, and the driving unit is connected with the power conversion unit. Charge control is carried out for each output branch, and the phase-locked loop is used as period control, so that the cross modulation effect of each branch is effectively inhibited, the last branch is not required to have enough load, and the load range is widened; and meanwhile, other performance requirements are well considered.