Ballast circuit for high intensity discharge (HID) lamps
AssigneeGTE Sylvania Incorporated
InventorWilliam C. Knoll
Life of this patent
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Abstract
An electronic ballast circuit includes a directly driven high frequency inverter circuit with a series resonant output circuit coupled to a load circuit having a high intensity discharge (HID) lamp and to a drive circuit dependent upon current flow in the load circuit. A starting circuit for the high frequency inverter is coupled to a DC source and to a charge storage and isolating circuit and provides initial energization to the high frequency inverter circuit. Also, a lamp starting circuit initiates increased conductivity of the high frequency inverter circuit which causes development of energy sufficient to "fire" an HID lamp whereupon a disablement circuit essentially removes the lamp starting circuit from the operational circuitry.
Claims15
In a direct drive ballast circuit for a high intensity discharge (HID) lamp having a high frequency inverter circuit coupled to a DC source and to a HID lamp load circuit;
- a drive circuit coupling the HID lamp load circuit to the high frequency inverter circuit;
- a charge storage and isolating circuit shunting the DC source;
- a high frequency inverter starting circuit coupled to the high frequency inverter circuit and to the DC source, the charge storage and isolating circuit, and to the high frequency inverter circuit;
- and a feedback rectifier circuit coupled to the HID lamp load circuit and to the charge storage and isolating circuit, the improvement comprising a lamp starting circuit coupled to said charge storage and isolating circuit and to said feedback rectifier circuit and a lamp disablement circuit coupled to said HID lamp load circuit and to said lamp starting circuit whereby conductivity in said HID lamp load circuit energizes the lamp disablement circuit which disables the lamp starting circuit.
In a direct drive ballast circuit for a high intensity discharge (HID) lamp having a high frequency inverter circuit coupled to a DC source, a charge storage and isolating circuit shunting the DC source, a high frequency inverter starting circuit coupled to the DC source and to the charge storage and isolating circuit and to the high frequency inverter circuit, the improvement comprising an HID lamp load circuit coupled to said high frequency inverter circuit, a high frequency inverter drive circuit coupling said HID lamp load circuit to said high frequency inverter circuit, a feedback rectifier circuit coupling said HID lamp load circuit to said charge storage and isolating circuit, a lamp starting circuit coupled to said charge storage and isolating circuit and to said feedback rectifier circuit and a lamp disablement circuit coupled to said HID lamp load circuit and to said lamp starting circuit whereby said lamp starting circuit alters said feedback rectifier circuit in a manner to cause said high frequency inverter circuit to energize said HID lamp load circuit in an amount sufficient to energize a HID lamp and energization of said HID lamp causes said lamp disablement circuit to disable said lamp starting circuit.
Dependencies are inferred from the claim text.