DRIVING APPARATUS FOR COLD CATHODE FLAT FLUORESCENT LAMP

摘要

A drive unit for the cold cathode flat fluorescent lamp is provided to interrupt power supply to frequency control unit and power factor circuit by sensing lighting failure and an abnormal current of lamp with auxiliary winding of the resonance inductor. In a drive unit for the cold cathode flat fluorescent lamp, a power factor circuit(14) improves the power factor of the rectifying power outputted from the rectifier and boosts voltage the input voltage. An inverter unit converts the DC voltage outputted from the power factor circuit into the high frequency AC with square wave. A frequency control unit(18) controls the oscillation frequency of the switching element equipped in the inverter unit. A high voltage generation unit(22) boosts voltage with AC square wave outputted from the inverter unit to the sinusoidal AC voltage and generates the driving voltage of the cold cathode flat fluorescent lamp. A protection circuit parts(26a, 26b, 26c) senses the abnormal current flowing in the high voltage generation unit and block the operation of the frequency control unit.