POWER SUPPLY FOR FLUORESCENT LAMP HAS CAPACITOR BANK CONNECTED BETWEEN RECTIFIER INPUT AND OUTPUT TO REDUCE HARMONIC DISTORTION OF AC SUPPLY CURRENT

摘要

A power supply circuit for supplying power to a load, such as compact fluorescent lighting, the circuit being suitable for connection directly to an AC supply grid. The circuit comprises AC to DC rectifying means (30) having a pair of input terminals connected to the AC supply and a pair of output terminals. The circuit further comprises a filter capacitance means (31) and a non-capacitive impedance means (32) connected in series between the output terminals. The non-capacitive impedance means is adapted to increase conduction time of input current drawn from the AC supply. A bank capacitance means (35, 36) is connected between the output terminals and one of the input terminals (37) of the rectifying means such that the bank capacitance means further increases the conduction time of the input current to more closely approximate a sinusoidal form, thereby reducing unwanted harmonic distortion in the input current and reducing loss in the non-capacitive impedance means.