Method and control circuit for dimming a gas discharge lamp

Abstract

In a method of dimming a gas discharge lamp, a controllable switch is provided which is connected between terminals of the lamp receiving an alternating power supply voltage. The opening and closing of the switch is controlled. The switch is closed at least during a first closing time period and a subsequent second closing time period within a half period of the power supply voltage. The second closing time period is longer than the first closing time period. The switch may be closed during a plurality of closing time periods within a half period of the power supply voltage, each closing time period after the first closing time period being longer than a previous closing time period. The first closing time period is started after a delay time period after a first reignition of the lamp after a voltage zero-crossing of the power supply voltage.

Dependencies are inferred from the claim text.