The FAN7631 is a pulse−frequency modulation controller for high−efficiency half−bridge resonant converters that includes a high−side gate drive circuit, an accurate current−controlled oscillator, and various protection functions. The FAN7631 features include variable dead time, operating frequency up to 600 kHz, protections such as LUVLO, and a selectable latch or A/R protection using the LS pin for user convenience. The Zero−Voltage−Switching (ZVS) technique reduces the switching losses and improves the efficiency significantly. ZVS also reduces the switching noise noticeably, which allows a small Electromagnetic Interference (EMI) filter. Offering everything necessary to build a reliable and robust resonant converter, the FAN7631 simplifies designs and improves productivity and performance. The FAN7631 can be applied to resonant converter topologies such as series resonant, parallel resonant, and LLC resonant converters.