Koninklijke Philips Corporation N.v.

Roy Hendrik Anna Maria Van Zundert

Lukas Leyten

Gerlach Corne Pieter Maria Emmen

Oscar Jan Deurloo

Dolf Henricus Jozef Van Casteren

Subramanian Muthu

Christofher Daniel Charles Hooijer

Johannes Petrus Wernars

Thijs Oosterbaan

Hans Antonie Feijen

Wouter Edgard Koen Broeckx

John Evarist Karel Georges De Clercq

Marcus Cornelis Van Meel

A method of electronic ballast protection including providing an electronic ballast having an AC/DC converterwith an electronic ballast input and a mains voltage connectionconnectable to a mains voltage, an inverteroperably connected to the AC/DC converterand having an electronic ballast outputconnectable to a lamp, a control circuitcontrolling the inverter, and a low voltage power supplyproviding low voltage power to the control circuit; supplying power to the low voltage power supplyfrom the electronic ballast input when the mains voltage connectionis wired to mains voltage; and disconnecting the power to the low voltage power supplywhen the electronic ballast outputis wired to the mains voltage

Electronic ballast protection

A circuit arrangement for operating a high pressure discharge lamp comprises a down converter equipped with an output capacitor and a commutator equipped with lamp connection terminals. The amplitude of the DC current generated by the down converter is controlled by means of a control loop. Commutation of the DC current causes a periodical voltage to be present across the output capacitor. This periodical voltage can be an overshoot voltage and/or a voltage caused by resonance of the lamp with the output capacitor. To suppress the periodical voltage, the reference signal of the current control loop is adjusted in dependency of the amplitude of the periodical voltage.

Circuit arrangement for operating a high pressure discharge lamp

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.

Circuit arrangement for preventing high peak currents

A circuit arrangement for operating a high pressure discharge lamp comprises a down converter equipped with an output capacitor and a commutator equipped with an ignition choke. The amplitude of the DC current generated by the down converter is controlled by means of a control circuit. To suppress resonance of the ignition choke with the output capacitor caused by commutation of the DC current, the current reference signal of the current control is adjusted in dependency of the power consumed by the lamp and in dependency of the lamp voltage immediately before and after each commutation.

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Eindhoven, Netherlands

Roy Hendrik Anna Maria Van Zundert