Abstract: A load detecting device for detecting whether a load is connected to a power supply device includes a no-load condition detector configured to detect a no-load condition using a sensing voltage having a frequency variant with a switching frequency of the power supply device, a circuit configured to acquire a signal having a waveform differing according to a connection or detachment between the load and the power supply device after the no-load condition is detected by the no-load condition detector, and a detachment detector configured to detect whether the load is detached by sensing the signal acquired by the circuit.

Abstract: Disclosed is a planar transformer including a first planar core which is formed of a magnetic substance, a lower secondary winding which is disposed to enclose a first left sill of the first planar core between a first rear sill and a first front sill of the first planar core; a primary winding which is disposed on the lower secondary winding so as to enclose first left and right sills of the first planar core; an upper secondary winding which is disposed on the primary winding to enclose the first left sill of the first planar core; and a second planar core disposed on the upper secondary winding.

Abstract: Disclosed is a planar transformer including a first planar core which is formed of a magnetic substance, a lower secondary winding which is disposed to enclose a first left sill of the first planar core between a first rear sill and a first front sill of the first planar core; a primary winding which is disposed on the lower secondary winding so as to enclose first left and right sills of the first planar core; an upper secondary winding which is disposed on the primary winding to enclose the first left sill of the first planar core; and a second planar core disposed on the upper secondary winding.

Abstract: Disclosed is a planar transformer including a first planar core which is formed of a magnetic substance, a lower secondary winding which is disposed to enclose a first left sill of the first planar core between a first rear sill and a first front sill of the first planar core; a primary winding which is disposed on the lower secondary winding so as to enclose first left and right sills of the first planar core; an upper secondary winding which is disposed on the primary winding to enclose the first left sill of the first planar core; and a second planar core disposed on the upper secondary winding.