Current supply circuit for mains operated gas discharge lamps - has rectifier stage supplying support capacitor, and series connection of switching transistors with parallel charge capacitor

摘要

A switch set at a higher frequency than that of the mains, operates the rectified a.c. flowing across an inductance. The rectifying stage, supplied by the a.c., feeds its output to a support capacitor (6). A series connection of several transistors (8,9), switching in a time alternation, has a charge capacitor (10) in parallel. At the centre point (M) of the two series connected transistors is applied on one side the rectified alternating voltage, flowing across the inductance (7), and on the other side the supplied voltage for the consumer load, preferably across a coupling capacitor (19). A diode (12,13) each may be connected in anti- parallel to the collector-emitter paths of the two transistors. A series connection of two support diodes (14,15) is connected in parallel to the charge capacitor, these diodes being polarised in the blocking direction w.r.t. this capacitor.