1. Field of the Invention
The present invention relates to a transformer, and more particularly, to a transformer capable of minimizing leakage inductance while satisfying a safety standard.
2. Description of the Related Art
Various kinds of power supplies are required in various electronic devices such as a television (TV), a monitor, a personal computer (PC), an office automation (OA) device, and the like. Therefore, these electronic devices generally include power supplies converting alternating current (AC) power supplied from the outside into a power required for each type of electronic appliance.
Among power supplies, a power supply using a switching mode (for example, a switch mode power supply (SMPS)) has recently been mainly used. This SMPS basically includes a switching transformer.
A switching transformer generally converts AC power of 85 to 265 V into direct current (DC) power of 3 to 30 V through high frequency oscillation at 25 to 100 KHz. Therefore, in a switching transformer, the sizes of a core and a bobbin may be significantly reduced as compared to a general transformer converting AC power of 85 to 265 V into AC power of 3 to 30 V through frequency oscillation of 50 to 60 Hz, and low voltage, low current DC power may be stably supplied to an electronic appliance. Accordingly, a switching transformer has recently been widely used in an electronic appliance that has tended to be miniaturized.
This switching transformer needs to be designed to have low leakage inductance in order to increase energy conversion efficiency. However, in accordance with the miniaturization of the switching transformer, it may be difficult to design a switching transformer having low leakage inductance.
In addition, when a compact transformer is manufactured, primary and secondary coils are disposed to be adjacent to each other, such that it may be difficult to satisfy a safety standard (such as Underwriters Laboratories (UL) safety standards) between the primary and secondary coils.