LLC resonant converter is an attractive topology to achieve high power density with high efficiency. However, the high switching frequency and circulating current result the poor efficiency of a LLC resonant converter under light load condition. To improve efficiency further, a modified burst-mode control is implemented in the proposed controller. The switching frequency decreases gradually during burst-on time to reduce the number of switching cycles under the same output ripple. Moreover, in burst-on time, the first pulse drives the MOSFET at high side with limited pulse width to suppress the initial current in resonant tank. The last switching cycle in burst-on time must be complete to ensure that initial conditions of each burst cycle are the same. Consequently, the switching losses are reduced, and light-load efficiency is improved.