High efficiency converter for discharge lamps
First Claim
1. An arrangement comprising a DC/AC converter for igniting and feeding a discharge lamp having preheatable electrodes, the converter including a starting circuit and in which, in the connected condition of the lamp, the ends of the lamp electrodes remote from the converter are connected to each other by means of a circuit comprising a relay make contact, wherein the starting circuit of the DC/AC converter comprises an energizing winding of the relay contact, the converter having a timing circuit which controls a switching element in the starting circuit, the time constant of the timing circuit being such that 0.2 to 5 seconds after the converter has been switched on, the switching element interrupts the starting circuit.
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Accused Products
Abstract
An energization arrangement for a discharge lamp includes a DC/AC converter to which a discharge lamp (81) is connected. The lamp is shunted by a relay contact (90) to obtain an electric circuit through which two electrodes (83, 84) of the lamp can be preheated. It is advantageous to insure that the relay contact is closed before a voltage occurs between the electrodes of the lamp. This prevents the lamp from exhibiting a transient flash at too cold electrodes. A timing circuit (40-47) ensures that the relay contact remains closed for about 1 second, after which the lamp ignites with warm electrodes. No electrical losses occur in the relay winding (30) during operation of the lamp.
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Citations
12 Claims
- 1. An arrangement comprising a DC/AC converter for igniting and feeding a discharge lamp having preheatable electrodes, the converter including a starting circuit and in which, in the connected condition of the lamp, the ends of the lamp electrodes remote from the converter are connected to each other by means of a circuit comprising a relay make contact, wherein the starting circuit of the DC/AC converter comprises an energizing winding of the relay contact, the converter having a timing circuit which controls a switching element in the starting circuit, the time constant of the timing circuit being such that 0.2 to 5 seconds after the converter has been switched on, the switching element interrupts the starting circuit.
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4. Apparatus for energizing an electric discharge lamp having preheatable electrodes comprising:
- a pair of input terminals for a source of DC supply voltage, a DC/AC converter coupled to the input terminals and having an output for supplying a high-frequency voltage to a discharge lamp via a ballast device, said DC/AC converter including a starting circuit coupled to the input terminals and having a relay energizing winding with a normally open contact connectable to the lamp electrodes so as to provide preheat current path for the lamp electrodes when the relay contact is closed, said starting circuit including a switching element for controlling current flow in the energizing winding so as to allow the relay contact to close when the apparatus is switched on, and a timing circuit coupled to the switching element for operating the switching element a given time after the apparatus is switched on so as to interrupt the current flow in the energizing winding and open said relay contact to promote lamp ignition.
- View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12)
Specification