Inverter for a gas discharge lamp with stepwise variable frequencies

摘要

The invention relates to an inverter for feeding a gas discharge lamp, comprising: a direct voltage source; at least two switch elements incorporated in a bridge circuit; a control circuit for controlling the switch elements so that the bridge circuit continuously generates an alternating voltage; at least one ballast inductance connected to one of the output terminals of the bridge circuit; and at least one gas discharge lamp connected between the ballast inductance and the other output terminal of the bridge circuit, wherein the control circuit is adapted to apply at its output terminals a control signal to the switch elements of the bridge circuit so that the alternating voltage generated by the bridge circuit changes frequency stepwise in time between at least three frequencies. According to a preferred embodiment the time duration for which a signal of a determined frequency is generated depends on the value of the frequency. <IMAGE>