Electronic starter for igniting a discharge lamp
AssigneeU.S. Philips Corporation
InventorMichel Remery
Life of this patent
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Abstract
An electronic starter for a discharge lamp includes an SCR controlled by a temperature-sensitive element and an auxiliary switch arranged so that no current flows in the temperature-sensitive element when the lamp is in operation, whereby rapid restarting of the lamp occurs after a brief interruption of the AC supply voltage. The temperature-sensitive element may be thermally coupled to an inductor in series with the lamp ballast thereby to limit the ballast current in the event the lamp fails to ignite.
Claims19
An electronic starter for igniting a discharge lamp comprising, two input terminals adapted for connection to the lamp electrodes and interconnected by an electric circuit comprising at least a controlled semiconductor switch having first and second main electrodes defining a main current path through the switch and a control electrode for controlling the current flow in said main current path, a control circuit coupled between said control electrode and said first main electrode for controlling the operation of said semiconductor switch, said control circuit comprising a temperature-sensitive circuit element which, at an elevated temperature, inhibits the igniting function of the starter, the control circuit further comprising an auxiliary switch connected to the temperature-sensitive circuit element and a threshold voltage element coupled to the input terminals, the auxiliary switch being controlled by the threshold voltage element so that the auxiliary switch is open if the voltage across the threshold voltage element is lower than its threshold voltage.
An electronic starter for igniting an electric discharge lamp comprising, a pair of input terminals for supplying an operating voltage to the electronic starter, a controlled semiconductor switch connected across said input terminals, said semiconductor switch including first and second electrodes that define a current control for the switch, a control circuit coupled between said first and second electrodes for controlling the operation of said semiconductor switch, said control circuit including a temperature-sensitive element, a voltage threshold element and an auxiliary switch having control electrode means, means coupling the auxiliary switch to at least one of said first and second electrodes of the semiconductor switch so as to control the operating condition of the semiconductor switch, means including said threshold element for coupling the control electrode means of the auxiliary switch to one of said input terminals so that the operating condition of the auxiliary switch is determined by the voltage level of said one input terminal, and means connecting the temperature-sensitive element to the control electrode means of the auxiliary switch thereby to effectively inhibit the operation of the auxiliary switch and thereby the operation of said semiconductor switch when the temperature of the temperature-sensitive element exceeds a given temperature level.
Dependencies are inferred from the claim text.