Summary As for the traditional LLC converter, there is a problem in efficiency at light load. In order to keep the output voltage of this converter constant at a given value at light load, the switching frequency will be increased, and hence, the efficiency would be degraded. Consequently, based on the inherent frequency modulation and from the point of view of blanking time tuning, the efficiency at light load will be further improved due to circular current reduction, and at the same time, the efficiencies under other operating conditions are also enhanced. In this paper, the strategy for automatically adjusting the blanking time is described and analyzed. Afterwards, the digital signal processor (DSP) is used as a circuit control kernel, and an experimental setup, with input voltage of 400 ± 10 V, rated output voltage of 12 V, and rated output current of 20 A, is provided to demonstrate the effectiveness of the proposed strategy.