An in-depth analysis on the load transient operation of a buck converter with auxiliary current control is presented in this article. The analysis quantifies the effects of nonideal characteristics, such as the equivalent series resistance, inductor current and output voltage ripples, time delay, and slew rate of the load current, on the fluctuation of the output voltage in a practical implementation. The analysis results reveals that some of the non-idealities may cancel each other out and become negligible in the implementation. A design considering the nonidealities can achieve the transient-wise capacitor charge balance of the output capacitor and minimize the output voltage deviation during the load transient. The agreement between the simulation and experimental results validates the effectiveness and precision of the proposed analysis and design.