Electronic ballast of high power factor for compact fluorescent lamp

An electronic ballast having a photocell circuit unit 100, a DC transformation unit 200 and a CF lamp driving circuit unit 400, being characterized in that the CF lamp driving circuit unit 400 comprises:

• a voltage divider 401 for dividing a DC power supplied from the DC transformation unit 200 into a lamp power and a circuit driving power;
• field effect transistors Q1 and Q2 for controlling a voltage of the circuit driving power supplied from the voltage divider 401 to provide it as a voltage for high frequency oscillation;
• a resistor R12, and diodes D7, D8 and D9 provided at the front stage of the field effect transistors Q1 and Q2, for preventing a voltage higher than a predetermined voltage from being applied to the field effect transistors Q1 and Q2;
• a triac TA2 for preventing line surge from being applied to the gates of the field effect transistors Q1 and Q2;
• Zenor diodes D12 and D13 for making the voltage through the field effect transistors Q1 and Q2 a constant voltage;
• a plurality of oscillation coils L3˜L5 that oscillate at high frequency according to the constant voltage produced by the Zener diodes D12 and D13 to generate a high frequency (25 Khz ˜30 Khz);
• a bulb BULB for receiving the high frequency generated by the oscillation coils L3 and L4 through a choke coil CT to turn on the CF lamp;
• and
• diodes D14 and D15 and condensers C10 and C11 connected to one side of the bulb BULB, for removing a surge voltage occurring when the lamp is connected to the socket in order to protect the lamp and the socket.