ELECTRONIC BALLAST HAVING A DIMMING-CONTROLLING PART DRIVEN BY A SEPARATE POWER SUPPLY

摘要

An electronic ballast having a dimming-controlling part driven by a separate power supply line is provided to operate the dimming-controlling part by forming an additional power supply voltage separately from a power supply line in order to control several ballasts in a group by separating the dimming-controlling part from a power supply circuit of the ballast. An electronic ballast has a power supply input part(1), a bridge rectification part(2) rectifying a voltage of the power supply input part, an inverter part(5) driving a lamp(14), a frequency oscillation part(4) applying an oscillation frequency to the inverter and a resonant part(8) forming a resonant circuit with the lamp. A frequency control part(6) controls the oscillation frequency of the frequency oscillation part. A dimming controlling part(9) generates a control signal of the frequency control part. A DC voltage generation part(13) generates a DC voltage and then applies a driving voltage separate from the power supply input part to the dimming controlling part.