In this paper, a new gate driving method to improve light-load efficiency is proposed for the power conversion system with a standby converter. The proposed method reduces the gate driving voltage of power MOSFETs and operating voltage of controller ICs under light load conditions by adjusting the auxiliary output voltage of the standby converter. Therefore, the gate driving loss on MOSFETs and the loss on controller ICs are significantly reduced without the degradation of performance in the main power stage. To confirm the validity of this study, the DC/DC server power supply with 48V input, 12V/60A output for the DC/DC stage, and 5V/3A output for the standby stage is experimented.