FLAT FLUORESCENT LIGHTING FIXTURE OF LOW VOLTAGE SWITCHING TYPE

摘要

A flat fluorescent lighting fixture of a low voltage switching type is provided to prevent an accident such as a fire due to a high voltage and an electric shock by forcibly breaking a driving of a PWM(Pulse Width Modulation) control unit in a protection circuit unit when a portion of lamps of a load part does not operate or is damaged. In a flat fluorescent lighting fixture of a low voltage switching type, a rectifier(15) receives an AC commercial power(10) and rectifies the power. A voltage dropping unit(20) connected with the rectifier(15) drops the rectified voltage. An inverter driving unit(25) switches the dropped DC power and drives an inverter(30). The inverter(30) transforms the dropped DC power to an AC power. A lamp(35) connected with the inverter(30) lights by the inverter(30). A PWM control unit(40) controls an output current by applying a control signal to the inverter driving unit(25). The inverter driving unit(25) comprises a first switching unit and a second switching unit outputting two switching signals mutually alternated to the inverter(30). The inverter(30) includes a DC/AC transformer which receives the signals of the first and second switching units and transforms the DC power to the AC power, a transforming unit including two transformers reversely connected to an output terminal of the DC/AC transformer, and a resonant unit consisting of a capacitor connected to a reverse phase output terminal of the transforming unit.