Power supply device

A power supply device, comprising:

• a full-bridge circuit including first to fourth switches switching power input from a power input unit, the first and second switches being connected to both terminals of the power input unit in parallel and the third and fourth switches being connected to the terminals of the power input unit in parallel;
• a resonance unit connected between a first connection node between the first switch and the second switch and a second connection node between the third switch and the fourth switch;
• a transformer including a primary winding and a secondary winding connected to the resonance unit in series;
• a rectifying circuit rectifying and outputting a voltage transferred from the secondary winding;
• a sensing unit obtaining at least one of an output current and an output voltage output from the rectifying circuit;
• and
• a controlling unit controlling the first to third switches provided in the full-bridge circuit or controlling the second to fourth switches provided in the full-bridge circuit when the at least one of the output current and the output voltage obtained by the sensing unit has a predetermined value or less,
• wherein the controlling unit turns the first switch and the third switch on and turns the second switch off at a first interval, and turns the first switch and the third switch off and turns the second switch on at a second interval, and turns the fourth switch off at the first interval and the second interval, or
• wherein the controlling unit turns the second switch and the fourth switch on and turns the third switch off at the first interval, and turns the second switch and the fourth switch off and turns the third switch on at the second interval, and turns the first switch off at the first interval and the second interval.