Abstract: A discharge lighting assembly and a method of operating a discharge lamp 10 are described. The discharge lamp 10 includes a discharge vessel 20 with two electrodes 24 for forming an arc discharge. A driver circuit 12 supplies electrical power to the lamp 10 as an alternating lamp current IL and/or an alternating lamp voltage UL with a commutation between half periods of positive and negative values. The driver circuit 12 is controlled to be able to deliver at a predetermined delivery time tD of 10-100 ?s after commutation a voltage level Up which varies in dependence on the lifetime L of the lamp 10.

Abstract: A method of generating a measuring signal indicating arc straightness in a gas discharge lamp (L) comprises the following steps: in a first step, applying a first lamp current (IN) to the lamp; in a second step, adding a brief pulse current (Ip) to the first lamp current (IN), allowing the lamp voltage to regain a steady state, and measuring the resulting average value of the lamp voltage (V2) in this steady state; generating a measuring signal indicating arc straightness on the basis of said average lamp voltage (V2) measured in the second step.

Abstract: A lamp driver circuit for operating a gas discharge lamp (La) is proposed, which comprises a switched mode power supply circuit (SMPS) and a first and a second output terminal (OT1, 0T2) for supplying a lamp current to the gas discharge lamp (La). The lamp driver circuit further comprises an output capacitor (CO) connected between the SMPS circuit and a ground terminal (GT) and comprises a resistive shunt (Rsh) connected between the ground terminal (GT) and the second output terminal (0T2) for determining the lamp current. An output current sensing circuit for determining a SMPS output current is comprised in the lamp driver circuit instead of a further resistive shunt, which would require a differential voltage measurement. The output current sensing circuit comprises a sensing resistor (RS) connected in series with a sensing capacitor (CS), the series connection being connected in parallel to the output capacitor.

Abstract: A lamp driver circuit for operating a gas discharge lamp (La) is proposed, which comprises a switched mode power cc supply circuit (SMPS) and a first and a second output terminal (OT1, 0T2) for supplying a lamp current to the gas discharge lamp (La). The lamp driver circuit further comprises an output capacitor (CO) connected between the SMPS circuit and a ground terminal (GT) and comprises a resistive shunt (Rsh) connected between the ground terminal (GT) and the second output terminal (0T2) for determining the lamp current. An output current sensing circuit for determining a SMPS output current is comprised in the lamp driver circuit instead of a further resistive shunt, which would require a differential voltage measurement. The output current sensing circuit comprises a sensing resistor (RS) connected in series with a sensing capacitor (CS), the series connection being connected in parallel to the output capacitor.