| 摘要 |
PURPOSE: An apparatus for driving a lamp is provided to apply the high voltages to both ends of a lamp and controls the brightness of the lamp of by controlling a duty ratio within one period. CONSTITUTION: An apparatus for driving a lamp includes a duty control portion(10), a high frequency generation portion(20), a lamp driving control portion(30), and an inverter portion(40). The duty control portion(10) outputs a low-frequency square wave signal to vary a duty ratio according to a dimming control voltage. The high frequency generation portion(20) outputs a high-frequency oscillation signal. The lamp driving control portion(30) receives the low-frequency square wave signal and the high-frequency oscillation signal and outputs selectively a first and a second driving signals according to an active period and an inactive period of the low-frequency square wave signal. The inverter portion(40) is formed with a transformer including a first switching portion, a second switching portion, a first and a second coils of the primary side, and coils of the secondary side in order to turn on or off a lamp(50).
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