Power supply apparatus for light emitting diode

A power supply apparatus for Light Emitting Diode (LED) comprising:

• a transformer comprising a primary winding, a secondary winding receiving a power induced from the primary winding, and a tertiary winding receiving the power induced from the primary winding;
• a first output unit connected to the secondary winding of the transformer, and outputting a first power current to an LED;
• and
• a second output unit connected to the tertiary winding of the transformer, and outputting a second power current to the LED;
• wherein the LED is simultaneously connected to both the first output unit and the second output unit,
• wherein the first power current is applied to the LED in a first operating condition and the second power current is applied to the LED in a second operating condition, and
• wherein a turns ratio of each of the secondary and tertiary winding is set such that a first power induced to the secondary winding is lower than a minimum output power of the primary winding and a second power induced to the tertiary winding is higher than a maximum output power of the primary winding.