Abstract: A circuit arrangement for igniting a high pressure discharge lamp includes a secondary winding of a pulse transformer which is at least partially capacitively shunted forming a tuned filter. The tuned filter preferably forms a band pass filter for passing the second harmonic of the signal produced by a pulse generator. An increase in the supply of current during take-over results thereby minimizing the time required for ignition.

Abstract: A circuit arrangement for igniting and operating a high intensity discharge lamp including a Buck converter. The Buck converter includes a switch, a rectifier and an inductor having primary and secondary windings. The secondary winding is part of an integrator for controlling the non-conductive state of the switch. A detector responsive to the flow of current through the rectifier produces a signal supplied to the integrator output during the non-conductive state of the switch. The integrator output remains proportional to the flow of current through the inductor regardless of the state of the switch. Consequently, the time duration that the switch is in its non-conductive state can be limited while maintaining the circuit arrangement in a reliable non-self oscillatory mode of operation.

Abstract: An arrangement for igniting and operating a high-pressure discharge lamp provided with a Buck converter for supplying the lamp through periodic switching of a switching device which is held alternately in a conducting state for a period t.sub.on and in a non-conducting state for a period t.sub.off. The arrangement further includes circuitry which produces fixed minimum and maximum time limits for the time duration t.sub.off.

Abstract: An arrangement for igniting and operating a high intensity discharge lamp including a Buck converter. The Buck converter includes a switch, a rectifier and an inductor. The converter is connected to input terminals for connection to a supply source and output terminals for supplying the lamp with a current through periodic swithing of the switch alternately into a conducting and a non-conducting state. The Buck converter operates in a self-oscillatory mode during stable lamp opertion. The arrangement further includes circuitry for causing the Buck converter to operate in a forced oscillatory mode in dependence on the lamp condition.

Abstract: A circuit arrangement for igniting and operating a high-pressure discharge lamp is provided with a switching device, inductive device and a rectifier which together form a Buck converter, connected to input terminals for connection to a supply source and output terminals for connection of the lamp. The lamp is supplied with a current through periodic switching of the switching device alternatively into a conducting and a non-conducting state by means of a switch-on and switch-off signal, respectively. The inductive device includes a primary and a secondary winding with the secondary winding forming part of an integration network for generating the switch-off signal. The secondary winding also forms part of a voltage divider network for generating the switch-on signal. A very simple circuit arrangement is thereby achieved.

Abstract: A circuit arrangement for igniting a high pressure discharge lamp includes a secondary winding of a pulse transformer which is at least partially capacitively shunted forming a tuned filter. The tuned filter preferably forms a band pass filter for passing the second harmonic of the signal produced by a pulse generator. An increase in the supply of current during take-over results thereby minimizing the time required for ignition.

Abstract: The invention relates to a switching arrangement suitable for ignition and operation of a high-pressure discharge lamp by means of a plulsatory current of changing polarity. For this purpose, the switching arrangement is provided with a bridge network (II), which includes a switching means (21) switched alternately to the conducting and the non-conducting state. The switching means is provided with a control electrode (215) and a main electrode (211), between which a shortcircuit is maintained by means of a shortcircuit switch (27) for the time in which the switching means is in the non-conducting state. According to the invention, the shortcircuit switch is controlled by means of a controlled current source (28).

Abstract: A switched mode power supply for ignition and operation of a high-pressure discharge lamp (5). The switched mode power supply comprises a switching device (1), an inductor (2), capacitive buffer (3) and a rectifier (4) for producing a current through the lamp from an input voltage. In order to supply a switching signal to the switching device, the switched mode power supply is further provided with a control circuit (I). A detector circuit (20) provides current detection of the inductor current and at the same time serves to produce the switching signal.