Elektronisches Leuchtstofflampen-Vorschaltgerät, um harmonische Stromschwingungen zu unterbinden

An arrangement for suppressing current harmonics for electronic power supplies of compact fluorescent lamps of the type comprising a "boost" type power supply circuit which includes a bridge rectifier that powers in succession an inductance (L1) for accumulating magnetic energy connected to a switch (Int, Mft) able to be driven to conduct to ground, followed by a diode (D1) and an accumulation capacitor Co, followed by a conventional power supply for fluorescent lamp. The switch (Int, Mft) is a semiconductor switch having a control electrode that is voltage-driven at higher frequency than mains frequency and having a predefined conduction threshold. The driving voltage of said switch (Int, Mft) is drawn from the fluorescent lamp power supply and the conduction period of said switch (Int, Mft) is modulated as a function of the rectified sinusoid of the mains voltage in such a way as to conduct for a longer time in correspondence with low instantaneous values of the rectified sinusoid and for a shorter time in correspondence with high instantaneous values of the rectified sinusoid.