| 摘要 |
PURPOSE: An electronic ballast is provided to stabilize waveform output through a lamp even at the abnormal state, while preventing blackening, lengthening useful life of lamp and reducing power consumption. CONSTITUTION: An electronic ballast comprises a rectifier unit(200) for rectifying an input AC signal and supplying a DC voltage; a lamp driving unit(300') for receiving voltage from the rectifier unit, and turning on a lamp by oscillating the received voltage by a resonance frequency; and a lamp unit(400) for receiving the voltage from the rectifier unit and turning on the lamp by the oscillation of the lamp driving unit. The lamp driving unit includes a first bypass section and a second bypass section. The first bypass section and the second bypass section include third and fourth transistors(Q3,Q4), respectively, which are connected to bases of first and second transistors(Q1,Q2) and improve lamp output characteristics by partially bypassing the base current of first and second transistors, when the output from first and second transistors is higher than a predetermined level.
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