<p>A high-efficiency tracking and tight output voltage control algorithm for a synchronous buck converter is proposed in this paper. Conventional output regulation only adjusts the duty ratio at a fixed switching frequency. However, the output voltage and efficiency of the converter depend simultaneously on the duty ratio and the switching frequency. To address this, the power losses of the components are mathematically modeled, and regression analysis is employed to formulate the optimal operating point in terms of the duty ratio and switching frequency for each output condition. The derived model is incorporated into the control loop, so the output voltage can be tightly regulated with high efficiency by modulating both the duty ratio and switching frequency. The proposed algorithm is validated using a 78&#xa0;W synchronous buck converter prototype. The proposed method shows power conversion efficiency enhancements of 4.01% and 0.17% under the light and full load conditions, with similar dynamic performances compared to the conventional method. Experimental results show that the proposed method can improve the power conversion efficiency under long-term operation, even when the aging of components changes the theoretical power loss model.</p>