Claims
- 1. A gas-discharge lamp comprising:
a power supply interconnectable to a load; and an overvoltage-protection-and-ground-fault-interrupt (OVP/GFI) circuit interconnected with the power supply, the OVP/GFI circuit including
an overvoltage-protection (OVP) sub-circuit that deactivates the power supply when an overvoltage condition is detected, and a ground-fault-interrupt (GFI) sub-circuit that deactivates the power supply when a ground-fault condition is detected.
- 2. A gas discharge circuit as set forth in claim 1, wherein the OVP sub-circuit includes a voltage sensor, a storage device interconnected with the voltage sensor and a shut-down device interconnected with the storage device, and wherein the GFI sub-circuit includes a current sensor interconnected with the storage device and wherein the shut down device is also interconnected with the storage device.
- 3. A gas-discharge lamp as set forth in claim 2 wherein the power supply includes a transformer having a secondary winding and is operable to supply a first voltage to the load, wherein the voltage sensor generates a second voltage having a relationship to the first voltage, the second voltage having a first positive peak and a first negative peak, wherein the current sensor generates a third voltage having a relationship to a ground-fault current produced in the secondary winding, the third voltage having a second positive peak and a second negative peak, and wherein the storage device stores a fourth voltage, the fourth voltage being the combination of the larger of the first and second positive peaks and the larger of the first and second negative peaks.
- 4. A gas-discharge circuit as set forth in claim 3 wherein the shut-down device receives the fourth voltage and deactivates the power supply if the fourth voltage is greater than a fault voltage.
- 5. A gas-discharge lamp as set forth in claim 3 wherein the voltage sensor includes a sense winding mounted on the transformer and a voltage-doubler rectifier interconnected with the sense winding, and wherein the voltage-doubler rectifier produces the first voltage.
- 6. A gas-discharge lamp as set forth in claim 3 wherein the current sensor includes a winding tap interconnected to the secondary winding, a resistor interconnected to the winding tap, and a voltage-doubler rectifier interconnected to the resistor, and wherein the voltage-doubler rectifier produces the second voltage.
- 7. A gas-discharge lamp as set forth in claim 3 wherein the voltage sensor includes a sense winding mounted on the transformer, the sense winding having a winding tap interconnected with the secondary winding, and a first voltage-doubler rectifier interconnected with the sense winding, wherein the first voltage-doubler rectifier produces the second voltage, wherein the current sensor includes the winding tap, a resistor interconnected to the winding tap and a second voltage-doubler rectifier interconnected to the resistor, and wherein the second voltage-doubler rectifier produces the third voltage.
- 8. A gas-discharge lamp as set forth in claim 7 wherein the sense winding includes a second tap interconnected with the secondary winding.
- 9. A gas-discharge circuit as set forth in claim 2 wherein the shut-down device includes a diac, an opto-transistor interconnected to the diac, and a transistor interconnected with the opto-transistor.
- 10. A gas-discharge circuit as set forth in claim 2 wherein the shut-down device clamps the power supply from supplying power until power is removed from the power supply.
- 11. A gas-discharge circuit as set forth in claim 2 wherein the shut-down device includes a diac and an opto-silicon-controlled rectifier interconnected to the diac.
- 12. A gas-discharge lamp as set forth in claim 2 wherein the power supply further includes:
a terminal interconnectable to an alternating-current (AC) power source that provides AC power; a rectifier that rectifies the AC power to create direct-current (DC) voltages; a logic power supply that receives the DC voltage and creates a bias voltage; and a driver circuit operable to receive the bias voltage and to produce a driving signal that drives the load with a voltage having a frequency.
- 13. A gas-discharge lamp as set forth in claim 12 wherein the shut-down circuit prevents the bias voltage from being applied to the driver circuit when a fault condition occurs.
- 14. A gas-discharge lamp as set forth in claim 1 wherein the load includes a gas-discharge tube.
- 15. A gas-discharge lamp comprising:
a power supply including a secondary winding interconnectable to a load, the power supply being operable to supply power to the load; and an overvoltage-protection-and-ground-fault-interrupt (OVP/GFI) circuit interconnected with the power supply, the OVP/GFI circuit including
an overvoltage-condition-and-ground-fault-condition (OC/GFC) sensor that is operable to sense both an overvoltage condition being created by the power supply and a ground-fault condition being created in the secondary winding, and to generate a fault signal when either of the conditions occurs, and a shut-down device interconnected with the OC/GFC sensor, the shut-down device deactivates the power supply from supplying power to the load upon receiving the fault signal.
- 16. A gas-discharge lamp as set forth in claim 15 wherein the load includes a gas-discharge tube.
- 17. A gas-discharge lamp as set forth in claim 15 wherein the power supply further includes:
a terminal interconnectable to an alternating-current (AC) power source that provides AC power; a rectifier that rectifies the AC power to create a direct-current (DC) voltage; a logic power supply that receives the DC voltage and creates a bias voltage; and a driver circuit operable to receive the bias voltage and to produce a driving signal that drives the load with a voltage having a frequency.
- 18. A gas-discharge lamp as set forth in claim 17 wherein the shut-down circuit prevents the bias voltage from being applied to the driver circuit when a fault condition occurs.
- 19. A gas discharge circuit as set forth in claim 15, wherein the OC/GFC sensor includes a dual voltage-doubler rectifier and a storage device.
- 20. A gas-discharge lamp as set forth in claim 19 wherein the power supply includes a transformer having a secondary winding, wherein the OC/GFC sensor includes a sense winding having a winding tap, and wherein the winding tap is interconnected with the secondary winding.
- 21. A gas-discharge lamp as set forth in claim 20 wherein the sense winding includes a second tap interconnected with the secondary winding.
- 22. A gas-discharge circuit as set forth in claim 15 wherein the shut-down device includes a diac, an opto-transistor interconnected to the diac, and a transistor interconnected with the opto-transistor.
- 23. A gas-discharge circuit as set forth in claim 15 wherein the shut-down device clamps the power supply from supplying power until power is removed from the power supply.
- 24. A gas-discharge circuit as set forth in claim 15 wherein the shut-down device includes a diac and an opto-silicon-controlled rectifier interconnected to the diac.
RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional Patent Application No. 60/208,693, entitled GROUND FAULT AND OVER VOLTAGE FAULT SHUTDOWN CIRCUIT FOR NEON POWER SUPPLIES, filed Jun. 1, 2000.
Provisional Applications (1)
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Number |
Date |
Country |
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60208693 |
Jun 2000 |
US |