Abstract: A light source comprises a discharge lamp (LA), a bridge circuit for driving the discharge lamp and a reflector (RE). The bridge circuit comprises a capacitor (C1) coupled between a lamp connection terminal (T3, T4) and an input terminal of the bridge circuit (T1). EMI caused by the discharge lamp is suppressed by connecting a further capacitor (C2) between the lamp connection terminal and the reflector, so that a conductive path exists between the reflector and the bridge input terminal formed by both capacitors.

Abstract: A method of electronic ballast protection including providing an electronic ballast having an AC/DC converter 104 with an electronic ballast input and a mains voltage connection 103 connectable to a mains voltage 102, an inverter 120 operably connected to the AC/DC converter 104 and having an electronic ballast output 125 connectable to a lamp 124, a control circuit 116 controlling the inverter 120, and a low voltage power supply 114 providing low voltage power to the control circuit 116; supplying power to the low voltage power supply 114 from the electronic ballast input when the mains voltage connection 103 is wired to mains voltage 102; and disconnecting the power to the low voltage power supply 114 when the electronic ballast output 125 is wired to the mains voltage 102.

Abstract: A method of electronic ballast protection including providing an electronic ballast having an AC/DC converter 104 with an electronic ballast input and a mains voltage connection 103 connectable to a mains voltage 102, an inverter 120 operably connected to the AC/DC converter 104 and having an electronic ballast output 125 connectable to a lamp 124, a control circuit 116 controlling the inverter 120, and a low voltage power supply 114 providing low voltage power to the control circuit 116; supplying power to the low voltage power supply 114 from the electronic ballast input when the mains voltage connection 103 is wired to mains voltage 102; and disconnecting the power to the low voltage power supply 114 when the electronic ballast output 125 is wired to the mains voltage 102.

Abstract: A driver for HID lamps includes four switches and generates a constant DC-current that is commutated at a low frequency. The driver includes a filter capacitor. The occurrence of peak currents due to the charging or discharging of the filter capacitor is prevented by driving one of the switches at a high frequency immediately after commutation.