Ballast circuit for LED lamp

A ballast circuit for an LED lamp including a current limit unit that is constructed of a capacitor C1 and a resistor R1 connected in parallel with each other to be charged and discharged in 60 Hz of alternating power source AC 220V and to control LED used current, and a bridge diode BD that rectifies an alternating voltage passed through the current limit unit into a direct voltage, the ballast circuit comprising:

• a surge absorber circuit that includes a capacitor C3 and a resistor R3 serially connected between both ends of the bridge diode BD, a resistor R5 and a capacitor C4 serially connected with each other, and a silicon controlled rectifier SCR, the SCR being connected to the resistor R5 and capacitor C4 in parallel, the resistor R5, capacitor C4 and silicon controlled rectifier SCR being connected to the positive (+) terminal of the bridge diode BD, thereby protecting the LED from a surge occurring when power is turned on or off;
• LED arrays (DA1, DA2 . . . DAn) connected to an output terminal of the surge absorber circuit, each array having a plurality of forward LEDs, the forward LEDs being connected serially with one another;
• and
• LED arrays (DA11, DA12 . . . DA1n) connected to the negative (−) terminal of the bridge diode BD, each array having a plurality of reverse LEDs, the reverse LEDs being connected serially with one other.