Direct current power source for an electric discharge lamp
First Claim
1. A power supply for an electric discharge vapor lamp comprising, in combination,a source of a direct current potential,a ballast resistor,a VMOS insulated-gate field effect transistor having a gate electrode and a source-drain channel,first circuit means for serially connecting said channel and said vapor lamp across said source,second circuit means for connecting said ballast resistor in parallel with said channel,and regulating means responsive to variations in the magnitude of electrical energy delivered to said lamp for varying the potential applied to said gate electrode to control the conductivity of said channel.
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Accused Products
Abstract
A solid-state electronic ballast circuit for supplying direct-current power to an electric discharge vapor lamp is disclosed. The source-drain channel of a Vertical Metal Oxide Semiconductor (VMOS) Field Effect Transistor (FET) is connected in parallel with a fixed ballast resistor, the parallel combination being connected in series with the lamp across a DC source. A resistance network controls the conductivity of a bipolar transistor, which in turn controls the conductivity of the VMOS channel, in response to variations in both lamp voltage and current. The ballast circuit may be manufactured as a part of the lamp bulb assembly, the ballast resistor taking the form of an incandescent lamp filament mounted in the same outer bulb with the vapor lamp arc tube. A variable resistance may be employed to manually adjust the level of illumination delivered by the lamp, or a light-sensitive phototransistor may be employed to deliver constant illumination.
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Citations
32 Claims
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1. A power supply for an electric discharge vapor lamp comprising, in combination,
a source of a direct current potential, a ballast resistor, a VMOS insulated-gate field effect transistor having a gate electrode and a source-drain channel, first circuit means for serially connecting said channel and said vapor lamp across said source, second circuit means for connecting said ballast resistor in parallel with said channel, and regulating means responsive to variations in the magnitude of electrical energy delivered to said lamp for varying the potential applied to said gate electrode to control the conductivity of said channel.
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8. A ballast circuit for connecting a high intensity discharge lamp to a source of direct current energy comprising, in combination,
a VMOS insulated-gate field effect transistor having a gate-electrode and a source drain channel, a fixed ballast resistor connected in parallel with said channel, a current sensing resistor for connecting the parallel combination of said channel and said ballast resistor in series with said lamp, a voltage sensing resistance connected to said lamp, and a control transistor having an input circuit connected to said sensing resistors and having an output circuit connected to the gate of said field effect transistor.
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10. A self-ballasted HID lamp comprising, in combination,
an electric discharge vapor arc tube and a tungsten filament mounted within a glass bulb, a VMOS insulated-gate field-effect transistor transistor having a control electrode and a transconductive path, circuit means for connecting said transconductive path in series with said arc tube and in parallel with said filament, and means connected to said control electrode for increasing the conductivity of said transconductive path in response to increases in the vapor pressure within said arc tube.
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12. A self-ballasted lamp comprising, in combination,
a glass bulb, a lamp base having external conductive contact means adapted to establish electrical connections to an alternating current power supply socket, a neck section attaching said bulb to said base, an electric discharge vapor arc tube mounted within said bulb, a resistive filament adapted to be heated to incandescence mounted within said bulb, and an electronic control circuit mounted within said neck section, said control circuit comprising, in combination, a rectifier having an input circuit connected to said conductive contact means and an output circuit forming a source of a direct current potential, a transistor having a control electrode and a transconductive path, circuit means for connecting said transconductive path in series with said arc tube across said source, circuit means connecting said filament in parallel with said transconductive path, and means connected to said control electrode and responsive to the magnitude of electrical energy delivered to said arc tube for controlling the conductivity of said transconductive path.
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18. An improved power supply for operating an electric vapor discharge lamp comprising, in combination,
a source of a direct-current potential, a vertical Metal Oxide Semiconductor Field Effect Transistor (MOSFET) having a source-drain channel and a gate electrode, means connecting said source-drain channel in series with said lamp across said source, and means for supplying a control potential to said gate electrode to increase the conductivity of said source-drain channel in response to increases in the vapor pressure in said lamp as it is heated following ignition.
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24. A solid-state ballast circuit for supplying power to a high intensity discharge lamp from a source of an electrical potential which comprises, in combination,
a Vertical Metal Oxide Semiconductor Field Effect Transistor (VMOS FET) having a source-drain channel and a gate electrode, a current sensing resistor serially connected with said lamp across said source, a fixed resistor connected in parallel with said channel, a bipolar transistor having a collector-emitter path and a base-emitter path, means connecting said base-emitter path in parallel with said current sensing resistor, and means connecting said collector-emitter path to said gate electrode to control the conductivity of said channel.
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29. A solid-state power supply for a high intensity discharge lamp which comprises, in combination,
a fixed resistance connected in series with said lamp for limiting the amount of current flowing through said lamp after said lamp is first ignited and before said lamp is heated to its normal operating vapor pressure, a VMOS field-effect transistor having its source-drain channel connected in parallel with said fixed resistance, and a control circuit responsive to the magnitude of current flowing through said lamp for increasing the conductivity of said channel whenever said magnitude of current falls below a predetermined threshold level.
Specification