LED lighting device and dimming control method therefor

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 and a secondary coil spaced apart from each other,
• wherein the first control unit is connected to the primary coil and the second control unit is connected to the secondary coil,
• the primary coil and the secondary coil are isolated from each other,
• the transformer transmits 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,
• the dimming control signal is transmitted from the second control unit to the first control unit through the transformer when the pulse signal transmitted from the first control unit to the second control unit through the transformer is turned off, and
• the first control unit rectifies 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 and then controls the dimming of the LED array using a value in which an offset voltage is cancelled, wherein:
• the first control unit includes a rectifier, which includes a diode configured to rectify the dimming control signal and a capacitor connected between the diode and a direct current power source, and an offset voltage cancellation part configured to cancel the offset voltage from a signal output from the rectifier;
• and
• the offset voltage includes a voltage value of the direct current power source.