Patent ID: 6100652
Filing Date: 2000-08-08
Classification: H05B,Y02B,Y10S

Abstract:
A ballast and high-intensity discharge lamp arrangement, comprising:an inverter having first and second input terminals adapted to receive a source of substantially DC voltage, and first and second output terminals, wherein the inverter is operable to provide a substantially square wave voltage between the first and second output terminals;a first series combination of a resonant inductor and a resonant capacitor, the first series combination being coupled between the first and second output terminals of the inverter;a second series combination of a DC blocking capacitor and a high-intensity discharge lamp, the second series combination being coupled in parallel with the resonant capacitor; anda lamp starting circuit operable to supply a charging current to the DC blocking capacitor so as to provide a high voltage thereacross for igniting the lamp, wherein:(i) during normal operation of the lamp, the charging current is at least an order of magnitude less than the root-mean-square alternating current that flows through the lamp; and(ii) the lamp starting circuit comprises:a starting winding magnetically coupled to the resonant inductor, and electrically coupled between a first node and the second output terminal of the inverter;a current-limiting capacitor coupled between the first node and a second node;a first rectifier having an anode coupled to the second output terminal of the inverter, and a cathode coupled to the second node; anda second rectifier having an anode coupled to the second node and a cathode coupled to a junction between the lamp and the DC blocking capacitor.