Circuit arrangement for operating low-pressure discharge lamps

Abstract

Abstract To reduce network harmonics upon connecting a fluorescent lamp (LP1) with a power network rectifier (2) and a push-pull frequency generator (3) and a series resonance circuit (4) to the network, a harmonic filter is connected in the circuit with the fluorescent lamp (LP1) or lamps (LP1, LP2). The harmonic filter includes two diodes (D8, D9), connected in forward current passing direction to the power rectifier (2), and two capacitors (C7, C8) connected, respectively, between the serially connected diodes and a center tap (M1) between the push-pull transistors directly and beyond an inductance forming part of a series resonance circuit (4) for the lamps. In parallel to the two diodes, two further diodes (D10, D11) are provided, having a center tap (M4) which is connected over a capacitor (C9) also to the center tap between the transistors of the push-pull frequency generator (3). Preferably, the capacity value of the further capacitor (C9) is about 0.2 times the total capacity value in the harmonic filter circuit.

Inventors

• 👤 Hans-Jürgen Fähnrich
• 👤 Anton Zuchtriegel

Bibliographic Details