The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 24, 2012
Filed:
May. 30, 2007
Engbert Nijhof, Eindhoven, NL;
Marcel Johannes Maria Bucks, Eindhoven, NL;
Jozef Petrus Emanuel DE Krijger, Eindhoven, NL;
Cong Khanh Pham, Eindhoven, NL;
Engbert Nijhof, Eindhoven, NL;
Marcel Johannes Maria Bucks, Eindhoven, NL;
Jozef Petrus Emanuel De Krijger, Eindhoven, NL;
Cong Khanh Pham, Eindhoven, NL;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
In a lamp driving circuit for operating a high intensity discharge lamp, an a commutation circuit comprises at least two switching devices. The switching devices are alternately switched active at a commutation frequency. The active switching device switches at a switching frequency. During an ignition mode, the switching frequency and the commutation frequency are substantially equal. A resulting commutation voltage is supplied to an inverter resonant circuit for generating a supply current. At a node of the inverter resonant circuit, a clamping circuit limits the generated voltage to a predetermined maximum voltage. The voltage at said node of the inverter resonant circuit is applied to an output resonant circuit. The output resonant circuit operates in the ignition mode as a resonator for generating a high ignition voltage; in a steady state operation mode, the output resonant circuit operates as a low-pass filter for reducing a high frequency current component in a lamp current.