Abstract: A ballast to energize a lamp is provided. The ballast comprises a buck converter connected to an inverter via a switching component. The buck converter includes a transistor, a capacitor, a diode, and an inductor. The switching component has a predetermined breakover voltage value and is configured to provide a start up signal to the inverter when voltage at the switching component increases to the predetermined breakover voltage value. A control circuit is configured to monitor the voltage at the switching component while the voltage at the switching component increases to the predetermined breakover voltage, and is configured to generate a gate drive pulse at a gate terminal of the transistor when the voltage at the switching component reaches a predetermined voltage that is less than the breakover voltage of the switching component.

Abstract: A electrodeless lamp including a fluorescent discharge vessel, a tip, an amalgam, a lamp core, and a heater. The vessel contains a gas having a partial vapor pressure and a fluorescent material. The tip has an inner end engaging the vessel, and an opening in communication with the gas. The amalgam is positioned within the opening, in heat transfer relation with the tip. When the temperature of the amalgam decreases, mercury vapor in the gas condensates onto the amalgam, causing a decrease in the partial vapor pressure of the gas. The opposite occurs when the amalgam temperature increases. The lamp core generates a magnetic flux, causing an electrical discharge in the gas. The heater includes a positive temperature coefficient connected to a winding of the lamp core. The heater is in heat transfer relation with the tip and heats the tip when the electrodeless lamp is in a dimming mode.

Abstract: A lamp driver circuit to selectively energize one or more lamps is provided. The inverter circuit has a transformer with primary and secondary windings to provide voltage to the lamps. A filter is connected to the primary winding to receive a primary winding signal representative of the voltage across the primary winding. The primary winding signal has a frequency spectrum and the filter detects a particular characteristic of the frequency spectrum that is indicative of an end of life (EOL) condition of the one or more lamps. A control circuit is connected to the inverter circuit and to the filter. The control circuit is configured to discontinue energizing of the one or more lamps by the inverter circuit when the particular characteristic of the frequency spectrum of the primary winding signal is detected by the filter.

Abstract: A three light level electronic ballast, and methods of operating lamps at three light levels, are provided. The ballast includes a rectifier, a power factor correction circuit, an inverter circuit, a first circuit, a second circuit, and a control circuit. The rectifier receives an AC voltage signal and produces a rectified voltage signal, which the power factor correction circuit receives and uses to provide a corrected voltage signal. The inverter circuit receives the corrected voltage signal and provides an energizing signal to power at least two lamps. The first circuit selectively reduces the current applied to the lamps by the energizing signal. The second circuit selectively prevents the second lamp from being energized by the energizing signal. The control circuit controls the first circuit and the second circuit.

Abstract: A ballast that selectively operates multiple lamps is provided. The ballast includes a switching network, capable of operating in a number of switching configurations. The ballast also includes a control circuit, and two lamp control switches. The control circuit is connected to the switching network, and provides respective control signals via respective output terminals as a function of the switching configuration of the switching network. Each lamp control switch is in parallel with its lamp and is connected to a respective output terminal. The first lamp control switch is connected to a ballast power supply, and either provides power to the first lamp or does not, depending on the first control signal. The second lamp control switch is connected to the first lamp control switch and to ground, and either provides power to the second lamp or does not, depending on the second control signal.

Abstract: A ballast to energize a lamp at a selected lighting level is provided. The ballast includes a rectifier, a buck converter, and a controller. The rectifier produces a DC voltage with a substantially constant magnitude. The buck converter generates a lamp voltage output from the DC voltage based on a duty cycle. The output has a magnitude that is varied based on the duty cycle to energize the lamp at a selected lighting level. The controller receives a dim input signal indicating the selected lighting level, and provides an appropriate control signal to the buck converter. The appropriate control signal indicates a particular duty cycle corresponding to magnitude of the output to produce the selected lighting level. In response to receiving the control signal, the buck converter adjusts the duty cycle accordingly, producing the output having the magnitude to energize the lamp at the selected lighting level.

Abstract: A bi-level lamp ballast to selectively operate two lamps is provided. The ballast includes a control circuit having an input, connected to a switching network, and an output, which provides a particular control signal based on the state of the switching network. The ballast also includes respective lamp control switches, each having respective outputs. The first switch is connected to the output and a ballast power supply. In its first state, it connects the ballast power supply to its first output, and in its second state, it connects the ballast power supply to its second output. The second switch is connected to the output and a ground. In its first state, it connects the ground to its first output, and in its second state, it connects the ground to its second output. The state of each lamp control switch depends on the control signal generated by the control circuit.

Abstract: A multi-strike ballast to ignite an electrodless lamp is disclosed, and includes an inverter circuit, an output voltage detection circuit (OVDC), and an inverter shutdown circuit. The inverter circuit, upon activation, sends an ignition pulse to the electrodeless lamp. The inverter circuit shut downs upon receiving a deactivation signal, and activates upon receiving an activation signal, triggering another ignition pulse. The OVDC detects an output voltage across the lamp. The inverter shutdown circuit includes a multi-strike diac and receives the detected output voltage. The multi-strike diac breaks upon the output voltage reaching a predetermined level. In response, a deactivation signal is sent to the inverter circuit. The multi-strike diac turns off upon the output voltage falling below the predetermined level. In response, an activation signal is sent to the inverter circuit, triggering a further ignition pulse. The process repeats, providing multiple ignition pulses to the lamp.

Abstract: A lighting system converter circuit of a lamp power converter to selectively operate a plurality of lamps connected thereto is provided. The lighting system converter circuit includes a first impedance circuit and a second impedance circuit. Each impedance circuit includes an input terminal, an impedance component, and a switching network. The impedance components are each configured to connect in series with the lamps. Each input terminal is configured to receive a control signal that indicates a state of a switch. Each control signal has a first logic level, indicating the switch is non-conductive, and a second logic level, indicating the switch is conductive. Each switching network is connected to its respective input terminal and in parallel with its respective impedance component, and is configured to selectively operate between a conductive state and a non-conductive state, as a function of the logic level of its respective control signal.

Abstract: A two level lighting ballast is provided, which includes a self-oscillating inverter circuit and a control circuit. The inverter includes an input; an output to selectively provide current to energize a lamp; a switching circuit operating at a switching frequency; a feedback transformer; and an impedance component. The feedback transformer is connected to the output, and drives the switching circuit based on the lamp current. The impedance component is connected in parallel with the feedback transformer, and is operated by the control circuit. When the control circuit enables the impedance component, the switching circuit operates in a first frequency range, and a first lamp current is provided. When the control circuit disables the impedance component, the switching circuit operates in a second frequency range, and a second lamp current is provided. The first frequency range is lower than the second, and the first lamp current is greater than the second.

Abstract: An light emitting diode (LED) retrofit system for fluorescent lighting systems including a fluorescent lamp fixture is disclosed. The fluorescent lamp fixture includes a frame, an existing ballast configured to be coupled to an AC power source, and at least one connector coupled to an output of the existing ballast. The connector is configured to be coupled to a fluorescent lamp. The LED retrofit system includes at least one pin configured to be removably coupled to the connector, and to receive a high voltage AC signal from the existing ballast. The LED retrofit system includes at least one LED light source, transformer circuitry coupled to the pin and configured to receive the high voltage AC signal and to output a low voltage AC signal, and rectifier circuitry configured to receive the low voltage AC signal and generate a DC voltage to drive the LED light source.

Abstract: A restart circuit for causing an electronic ballast to perform a restart in response to reconnecting any lamp of a multiple lamp configuration of the electronic ballast to the electronic ballast is disclosed. The electronic ballast includes a filament health check circuit for providing a first current through a monitored filament of the lamps to a controller of the ballast. The controller restarts the electronic ballast when a determined ratio of the first current to a reference current indicates that the monitored filament has been disconnected or broken (i.e., the first current substantially decreases) and is subsequently replaced or reconnected to the ballast (i.e., the first current returns to a predetermined level). The ballast further comprises a dv/dt circuit for reducing the first current for a transient time period in response to reconnecting a filament other than the monitored filament to the ballast, causing the controller to restart the ballast.

Abstract: A ballast for driving one or more lamps includes a controller and a current reduction circuit for accelerating a controller reset. Upon detecting a fault, the controller disables the ballast for a preset period of time, and resets. The controller additionally resets when the ratio of a supplied second value to a supplied first value falls below a threshold value. The current reduction circuit reduces the supplied second value in less than the preset period of time, such that the ratio falls below the threshold value and the controller resets. An emergency lighting system includes the ballast as a primary ballast, a backup ballast, and a primary power source. The controller detects a fault if the primary power source de-energizes and the backup ballast disconnects the one or more lamps from the primary ballast. The current reduction circuit accelerates the reset of the controller when the primary power source de-energizes.

Abstract: A control circuit for use in a ballast configured for powering a first lamp set and a second lamp set. The second lamp set is operated via a controller and a second lamp driver circuit. The controller enables the second lamp driver circuit as a function of a monitored value corresponding to a current through a lamp of the second lamp set. The control circuit includes first and second input terminals for selectively connecting to the power supply. The control circuit reduces the monitored value as a function of a connection state of the first and second input terminals of the control circuit to the power supply. Thus, the control circuit causes the controller to selectively operate the second lamp driver circuit in order to energize the second lamp set in combination with the first lamp set.

Abstract: A lamp driver circuit to selectively energize one or more lamps is provided. The inverter circuit has a transformer with primary and secondary windings to provide voltage to the lamps. A filter is connected to the primary winding to receive a primary winding signal representative of the voltage across the primary winding. The primary winding signal has a frequency spectrum and the filter detects a particular characteristic of the frequency spectrum that is indicative of an end of life (EOL) condition of the one or more lamps. A control circuit is connected to the inverter circuit and to the filter. The control circuit is configured to discontinue energizing of the one or more lamps by the inverter circuit when the particular characteristic of the frequency spectrum of the primary winding signal is detected by the filter.

Abstract: A backup ballast used with a primary ballast for providing power to one or more lamps. The backup ballast includes an output switch and a delay circuit. The output switch has a first operating mode for connecting a primary power source via the primary ballast to a first set of the lamps and second operating mode for connecting a backup power source with a second set of the lamps. The output switch operates in the first operating mode when it is energized and in the second operating mode when said it is not energized. The delay circuit is adapted for connecting to the primary power source for receiving power therefrom. The delay circuit is connected to the output switch for energizing it while the power is being received and for a delay period thereafter. The delay circuit includes an energy-storage component for storing energy while the power is being received and discharging the stored energy when the power is not being received in order to energize the output switch for the delay period.

Abstract: A restart circuit for causing an electronic ballast to perform a restart in response to reconnecting any lamp of a multiple lamp configuration of the electronic ballast to the electronic ballast is disclosed. The electronic ballast includes a filament health check circuit for providing a first current through a monitored filament of the lamps to a controller of the ballast. The controller restarts the electronic ballast when a determined ratio of the first current to a reference current indicates that the monitored filament has been disconnected or broken (i.e., the first current substantially decreases) and is subsequently replaced or reconnected to the ballast (i.e., the first current returns to a predetermined level). The ballast further comprises a dv/dt circuit for reducing the first current for a transient time period in response to reconnecting a filament other than the monitored filament to the ballast, causing the controller to restart the ballast.

Abstract: A ballast for driving one or more lamps includes a controller and a current reduction circuit for accelerating a controller reset. Upon detecting a fault, the controller disables the ballast for a preset period of time, and resets. The controller additionally resets when the ratio of a supplied second value to a supplied first value falls below a threshold value. The current reduction circuit reduces the supplied second value in less than the preset period of time, such that the ratio falls below the threshold value and the controller resets. An emergency lighting system includes the ballast as a primary ballast, a backup ballast, and a primary power source. The controller detects a fault if the primary power source de-energizes and the backup ballast disconnects the one or more lamps from the primary ballast. The current reduction circuit accelerates the reset of the controller when the primary power source de-energizes.

Abstract: A control circuit for use in a ballast configured for powering a first lamp set and a second lamp set. The second lamp set is operated via a controller and a second lamp driver circuit. The controller enables the second lamp driver circuit as a function of a monitored value corresponding to a current through a lamp of the second lamp set. The control circuit includes first and second input terminals for selectively connecting to the power supply. The control circuit reduces the monitored value as a function of a connection state of the first and second input terminals of the control circuit to the power supply. Thus, the control circuit causes the controller to selectively operate the second lamp driver circuit in order to energize the second lamp set in combination with the first lamp set.

Abstract: A backup ballast used with a primary ballast for providing power to one or more lamps. The backup ballast includes an output switch and a delay circuit. The output switch has a first operating mode for connecting a primary power source via the primary ballast to a first set of the lamps and second operating mode for connecting a backup power source with a second set of the lamps. The output switch operates in the first operating mode when it is energized and in the second operating mode when said it is not energized. The delay circuit is adapted for connecting to the primary power source for receiving power therefrom. The delay circuit is connected to the output switch for energizing it while the power is being received and for a delay period thereafter. The delay circuit includes an energy-storage component for storing energy while the power is being received and discharging the stored energy when the power is not being received in order to energize the output switch for the delay period.