POWER FACTOR IMPROVEMENT CIRCUIT FOR ELECTRONIC FLUORESCENT LAMP BALLASTS

摘要

PURPOSE: A power factor improvement circuit is provided to adjust the power used in the electronic fluorescent lamp ballasts by joining the valley-fill structure and the charge pump capacitor by using the secondary part of the power transformer in a resonance inverter. CONSTITUTION: The power factor improvement circuit comprises an input rectifying circuit(1) for rectifying the input AC, a power supply capacitor for converting the output of the input rectifier circuit into the DC, a resonance inverter(2) connected in parallel with the power supply capacitor, a charge pump placed between AC source and the input rectifying circuit, a valley-fill DC power supply(4) connected between the input rectifying circuit and a DC capacitor, a high frequency wave rectifier circuit connected between the valley-fill and DC power supply. One pole of the DC capacitor is connected to the secondary part of the power transformer and the other pole is connected to the junction of a plurality of capacitors connected to in series with the load lamp.