Integrated transformer and power supply using the same

1. An integrated transformer comprising:

a core part comprising:

first and second supports each having a predetermined length and separated from each other by a predetermined distance, the first and second supports each having one end, the other end provided at a side opposite to the one end, and a middle end provided between the one end and the other end; and

first and second outer legs and a center leg provided between the first and second supports and magnetically coupled with the first and second supports, the first and second outer legs connecting one set of ends and the other set of ends of the first and second supports to each other, the center leg magnetically connecting the middle ends of the first and second supports to each other; and

a coil part including a primary winding wound on the center leg, a secondary winding wound on the center leg and electrometrically coupled to the primary winding, and an inductor winding wound on at least one of the first and second outer legs to stabilize power by electromagnetic interaction between the primary and secondary windings,

wherein a cross-section of the first and second outer legs and a cross-section of the center leg have a width of the first support and a width of the second support in a longitudinal direction, respectively, and a width of each of the first and second outer legs exceeds 0.5 times a width of the center leg but does not exceed 2 times the width of the center leg.

2. The integrated transformer of claim 1 , wherein the core part is configured by coupling an EE core or an EI core.

3. The integrated transformer of claim 1 , wherein the primary winding, the secondary winding, and the inductor winding are wound in the same direction.

4. The integrated transformer of claim 3 , wherein the secondary winding is provided with a center tap electrically connected to the inductor winding.

5. The integrated transformer of claim 1 , wherein the inductor winding is divided and wound on the first and second outer legs.

6. A power supply using an integrated transformer, the power supply comprising:

a switching unit alternately switching input DC power to convert the input DC power into AC power;

a transformation unit converting a voltage level of the AC power from the switching unit according to a predetermined turns ratio;

a rectification unit rectifying the AC power from the transformation unit and outputting DC power; and

a control unit controlling a switching duty of the switching unit according to a voltage level of the DC power from the rectification unit,

wherein the transformation unit comprises:

a core part comprising:

first and second supports each having a predetermined length and separated from each other by a predetermined distance, the first and second supports each having one end, the other end provided at a side opposite to the one end, and a middle end provided between the one end and the other end; and

first and second outer legs and a center leg provided between the first and second supports and magnetically coupled with the first and second supports, the first and second outer legs connecting one set of ends and the other set of ends of the first and second supports to each other, the center leg magnetically connecting the middle ends of the first and second supports to each other; and

a coil part including a primary winding wound on the center leg, a secondary winding wound on the center leg and electrometrically coupled to the primary winding, and an inductor winding wound on at least one of the first and second outer legs to stabilize power by electromagnetic interaction between the primary and secondary windings.

7. The power supply of claim 6 , wherein a cross-section of the first and second outer legs and a cross-section of the center leg have a width of the first support and a width of the second support in a longitudinal direction, respectively, and a width of each of the first and second outer legs exceeds 0.5 times a width of the center leg but does not exceed 2 times the width of the center leg.

8. The power supply of claim 6 , wherein the core part is configured by coupling an EE core or an EI core.

9. The power supply of claim 6 , wherein the primary winding, the secondary winding, and the inductor winding are wound in the same direction.

10. The power supply of claim 9 , wherein the secondary winding is provided with a center tap electrically connected to the inductor winding.

11. The power supply of claim 10 , wherein the rectification unit rectifies the AC power from the transformation unit by using a full-wave rectification method or a half-wave rectification method.

12. The power supply of claim 11 , wherein the rectification unit comprises:

first and second switches rectifying the AC power from the secondary winding of the transformation unit; and

a capacitor forming an LC filter together with the inductor winding to stabilize the power rectified by the first and second switches.

13. The power supply of claim 12 , wherein the switch is formed of a diode or a semiconductor switching device including a metal oxide semiconductor field-effect transistor (MOSFET).

14. The power supply of claim 6 , wherein the inductor winding is divided and wound on the first and second outer legs.

15. The power supply of claim 6 , wherein the switching unit selects one from a full-bridge method, a half-bridge method, and a push-pull method.

16. The power supply of claim 6 , wherein the control unit controls a switching duty of the switching unit by using a phase shift pulse width modulation (PWM) method.

17. A power supply using an integrated transformer, the power supply comprising:

a switching unit alternately switching input DC power to convert the input DC power into AC power;

a transformation unit converting a voltage level of the AC power from the switching unit according to a predetermined turns ratio;

a rectification unit rectifying the AC power from the transformation unit and outputting DC power; and

a control unit controlling a switching duty of the switching unit according to a voltage level of the DC power from the rectification unit,

wherein the transformation unit comprises:

a core part comprising:

first and second supports each having a predetermined length and separated from each other by a predetermined distance, the first and second supports each having one end, the other end provided at a side opposite to the one end, and a middle end provided between the one end and the other end; and

first and second outer legs and a center leg provided between the first and second supports and magnetically coupled with the first and second supports, the first and second outer legs connecting one set of ends and the other set of ends of the first and second supports to each other, the center leg magnetically connecting the middle ends of the first and second supports to each other; and

a coil part including a primary winding wound on the center leg, a secondary winding wound on the center leg and electrometrically coupled to the primary winding, and an inductor winding wound on at least one of the first and second outer legs to stabilize power by electromagnetic interaction between the primary and secondary windings; and

a power factor correction unit rectifying commercial AC power, correcting a power factor of the AC power, and supplying the input DC power.