A light emitting diode (LED) lighting device comprising: an LED array ; a first control unit configured to control dimming of the LED array ; a second control unit configured to transmit a dimming control signal, which controls the dimming of the LED array , to the first control unit ; and a transformer including a primary coil (T1) and a secondary coil (T2) spaced apart from each other, wherein the first control unit is connected to the primary coil (T1) and the second control unit is connected to the secondary coil (T2), the primary coil (T1) and the secondary coil (T2) are isolated from each other, characterized in that the transformer is configured to transmit a pulse signal, which is repeatedly turned on and turned off at a predetermined interval, from the first control unit to the second control unit , that the second control unit is configured to transmit the dimming control signal from the second control unit to the first control unit through the secondary coil (T2) and the primary coil (T1) of the transformer when the pulse signal transmitted from the first control unit to the second control unit through the transformer is turned off, and that the first control unit is configured - to rectify (S430) the dimming control signal which is an alternating current signal transmitted from the second control unit to the first control unit through the transformer to a direct current signal; - to cancel an offset voltage from the rectified signal; - to control the dimming of the LED array using a signal from which the offset voltage is cancelled. an LED array ; a first control unit configured to control dimming of the LED array ; a second control unit configured to transmit a dimming control signal, which controls the dimming of the LED array , to the first control unit ; and a transformer including a primary coil (T1) and a secondary coil (T2) spaced apart from each other, wherein the first control unit is connected to the primary coil (T1) and the second control unit is connected to the secondary coil (T2), the primary coil (T1) and the secondary coil (T2) are isolated from each other, characterized in that the transformer is configured to transmit a pulse signal, which is repeatedly turned on and turned off at a predetermined interval, from the first control unit to the second control unit , that the second control unit is configured to transmit the dimming control signal from the second control unit to the first control unit through the secondary coil (T2) and the primary coil (T1) of the transformer when the pulse signal transmitted from the first control unit to the second control unit through the transformer is turned off, and that the first control unit is configured - to rectify (S430) the dimming control signal which is an alternating current signal transmitted from the second control unit to the first control unit through the transformer to a direct current signal; - to cancel an offset voltage from the rectified signal; - to control the dimming of the LED array using a signal from which the offset voltage is cancelled. - to rectify (S430) the dimming control signal which is an alternating current signal transmitted from the second control unit to the first control unit through the transformer to a direct current signal; - to cancel an offset voltage from the rectified signal; - to control the dimming of the LED array using a signal from which the offset voltage is cancelled. <EOS>