A resonant converter includes: a transformer including a first primary winding, a second primary winding and a secondary winding, each primary winding having a first end terminal and a second end terminal; a first switch coupled to the first end terminal of the first primary winding; a resonant inductor and a resonant capacitor connected in series between the second end terminal of the first primary winding and the first end terminal of the second primary winding; a second switch coupled between the first end terminals of the first and second primary windings; and a third switch coupled between the second end terminals of the first and second primary windings.