Abstract: According to the disclosed embodiment of the invention, a circuit and method for stabilizing an operating characteristic of a compact fluorescent lamp driven by a ballast circuit having an operating frequency controlled by a component value, may comprise a first circuit connected to said ballast circuit for applying the component value thereto; and a second circuit connected to the ballast circuit for changing the component value so as to stabilize the operating characteristic. The operating characteristic may be power, current, voltage or crest factor for example. The second circuit changes the component value in response to a bus voltage of the ballast circuit and includes a switching device such as a transistor responsive to the bus voltage.

Abstract: An integrated circuit controls a power converter that includes single stage buck-boost converter and a switching full bridge that may be used to drive an HID lamp. The single stage buck-boost converter reduces the complexity and parts count of the power converter, or electronic ballast, while permitting PFC and DC bus voltage regulation under control of the integrated circuit. The integrated circuit also provides all the drive signals to operate the switching full bridge circuit to maintain constant power on the HID lamp. A wait timer provides an interval of time between restart attempts for the HID lamp to permit the lamp to cool so that high hot restart voltages are avoided. The integrated circuit simplifies the design of power converters and electronic ballasts in particular, while contributing to reducing part count, complexity and cost in conjunction with the single stage buck-boost converter.

Abstract: A multi-function feedback sense input in an electronic ballast control indicates a number of lamp faults on the basis of lamp parameters exceeding specified thresholds. An end of life detection is achieved by conditioning a lamp feedback with a DC offset to provide a simple threshold comparison to determine if the lamp exceeds specified operational boundaries. An open filament, absent lamp or broken cathode is detected on the same feedback sense by detecting an open circuit in the lamp filament and driving the sense feedback to a shutdown state in the event of a filament open circuit. The ballast control includes a current sense feedback for detecting overcurrent conditions as well as lamp faults so that the control detects an end of life condition, lamp absence, broken lamp, open filament, broken cathode, overcurrent, hardswitching or failure to ignite fault with a minimum number of feedback sensors.

Abstract: According to the disclosed embodiment of the invention, a circuit and method for stabilizing an operating characteristic of a compact fluorescent lamp driven by a ballast circuit having an operating frequency controlled by a component value, may comprise a first circuit connected to said ballast circuit for applying the component value thereto; and a second circuit connected to the ballast circuit for changing the component value so as to stabilize the operating characteristic. The operating characteristic may be power, current, voltage or crest factor for example. The second circuit changes the component value in response to a bus voltage of the ballast circuit and includes a switching device such as a transistor responsive to the bus voltage.

Abstract: A multi-function feedback sense input in an electronic ballast control indicates a number of lamp faults on the basis of lamp parameters exceeding specified thresholds. An end of life detection is achieved by conditioning a lamp feedback with a DC offset to provide a simple threshold comparison to determine if the lamp exceeds specified operational boundaries. An open filament, absent lamp or broken cathode is detected on the same feedback sense by detecting an open circuit in the lamp filament and driving the sense feedback to a shutdown state in the event of a filament open circuit. The ballast control includes a current sense feedback for detecting overcurrent conditions as well as lamp faults so that the control detects an end of life condition, lamp absence, broken lamp, open filament, broken cathode, overcurrent, hardswitching or failure to ignite fault with a minimum number of feedback sensors.

Abstract: An integrated circuit controls a power converter that includes single stage buck-boost converter and a switching full bridge that may be used to drive an HID lamp. The single stage buck-boost converter reduces the complexity and parts count of the power converter, or electronic ballast, while permitting PFC and DC bus voltage regulation under control of the integrated circuit. The integrated circuit also provides all the drive signals to operate the switching full bridge circuit to maintain constant power on the HID lamp. A wait timer provides an interval of time between restart attempts for the HID lamp to permit the lamp to cool so that high hot restart voltages are avoided. The integrated circuit simplifies the design of power converters and electronic ballasts in particular, while contributing to reducing part count, complexity and cost in conjunction with the single stage buck-boost converter.