Gas discharge lamp operable from DC source

摘要

The gas discharge lamp (10) is driven from a DC source (12) with a high voltage ignition circuit (130). There are four semiconducting switches (36 to 39) used for periodic polarity reversal. There is an inductance (132) in series with the lamp and a capacitor (134) in parallel with the lamp which form an LC resonant circuit for the ignition. The control circuit (54) activates the polarity reversal at a frequency that is close to the resonant frequency of the igniter circuit. The polarity reversal circuit is in the form of a bridge network, whereby the positive and negative lines from the DC supply are connected to the two diagonal points (40,44) via the semiconducting switches.