Abstract: A control device may comprise a plurality of buttons, a plurality of light sources located behind the respective buttons and configured to illuminate the buttons, a light detector circuit configured to measure an ambient light level around the control device, and/or a control circuit configured to control the light sources to adjust surface illumination intensities of the respective buttons in response to the measured ambient light level. Each button may comprise indicia indicating a function of the button. The control circuit set the first button as active and the second button as inactive in response to an actuation of the first button. The control circuit may, based on the measured ambient light level, control the light sources to illuminate the first button to an active surface illumination intensity, and to illuminate the second button to an inactive surface illumination intensity that is less than the active surface illumination intensity.

Abstract: A control device may comprise a plurality of buttons, a plurality of light sources located behind the respective buttons and configured to illuminate the buttons, a light detector circuit configured to measure an ambient light level around the control device, and/or a control circuit configured to control the light sources to adjust surface illumination intensities of the respective buttons in response to the measured ambient light level. Each button may comprise indicia indicating a function of the button. The control circuit set the first button as active and the second button as inactive in response to an actuation of the first button. The control circuit may, based on the measured ambient light level, control the light sources to illuminate the first button to an active surface illumination intensity, and to illuminate the second button to an inactive surface illumination intensity that is less than the active surface illumination intensity.

Abstract: A control device may comprise a plurality of buttons, a plurality of light sources located behind the respective buttons and configured to illuminate the buttons, a light detector circuit configured to measure an ambient light level around the control device, and/or a control circuit configured to control the light sources to adjust surface illumination intensities of the respective buttons in response to the measured ambient light level. Each button may comprise indicia indicating a function of the button. The control circuit set the first button as active and the second button as inactive in response to an actuation of the first button. The control circuit may, based on the measured ambient light level, control the light sources to illuminate the first button to an active surface illumination intensity, and to illuminate the second button to an inactive surface illumination intensity that is less than the active surface illumination intensity.

Abstract: A control device may comprise a plurality of buttons, a plurality of light sources located behind the respective buttons and configured to illuminate the buttons, a light detector circuit configured to measure an ambient light level around the control device, and/or a control circuit configured to control the light sources to adjust surface illumination intensities of the respective buttons in response to the measured ambient light level. Each button may comprise indicia indicating a function of the button. The control circuit set the first button as active and the second button as inactive in response to an actuation of the first button. The control circuit may, based on the measured ambient light level, control the light sources to illuminate the first button to an active surface illumination intensity, and to illuminate the second button to an inactive surface illumination intensity that is less than the active surface illumination intensity.

Abstract: A control device may comprise a plurality of buttons, a plurality of light sources located behind the respective buttons and configured to illuminate the buttons, a light detector circuit configured to measure an ambient light level around the control device, and/or a control circuit configured to control the light sources to adjust surface illumination intensities of the respective buttons in response to the measured ambient light level. Each button may comprise indicia indicating a function of the button. The control circuit set the first button as active and the second button as inactive in response to an actuation of the first button. The control circuit may, based on the measured ambient light level, control the light sources to illuminate the first button to an active surface illumination intensity, and to illuminate the second button to an inactive surface illumination intensity that is less than the active surface illumination intensity.

Abstract: A control device may comprise a plurality of buttons, a plurality of light sources located behind the respective buttons and configured to illuminate the buttons, a light detector circuit configured to measure an ambient light level around the control device, and/or a control circuit configured to control the light sources to adjust surface illumination intensities of the respective buttons in response to the measured ambient light level. Each button may comprise indicia indicating a function of the button. The control circuit set the first button as active and the second button as inactive in response to an actuation of the first button. The control circuit may, based on the measured ambient light level, control the light sources to illuminate the first button to an active surface illumination intensity, and to illuminate the second button to an inactive surface illumination intensity that is less than the active surface illumination intensity.

Abstract: A control device may comprise a plurality of buttons, a plurality of light sources located behind the respective buttons and configured to illuminate the buttons, a light detector circuit configured to measure an ambient light level around the control device, and/or a control circuit configured to control the light sources to adjust surface illumination intensities of the respective buttons in response to the measured ambient light level. Each button may comprise indicia indicating a function of the button. The control circuit set the first button as active and the second button as inactive in response to an actuation of the first button. The control circuit may, based on the measured ambient light level, control the light sources to illuminate the first button to an active surface illumination intensity, and to illuminate the second button to an inactive surface illumination intensity that is less than the active surface illumination intensity.

Abstract: A control device may comprise a plurality of buttons, a plurality of light sources located behind the respective buttons and configured to illuminate the buttons, a light detector circuit configured to measure an ambient light level around the control device, and/or a control circuit configured to control the light sources to adjust surface illumination intensities of the respective buttons in response to the measured ambient light level. Each button may comprise indicia indicating a function of the button. The control circuit set the first button as active and the second button as inactive in response to an actuation of the first button. The control circuit may, based on the measured ambient light level, control the light sources to illuminate the first button to an active surface illumination intensity, and to illuminate the second button to an inactive surface illumination intensity that is less than the active surface illumination intensity.

Abstract: A control device may comprise a plurality of buttons, a plurality of light sources located behind the respective buttons and configured to illuminate the buttons, a light detector circuit configured to measure an ambient light level around the control device, and/or a control circuit configured to control the light sources to adjust surface illumination intensities of the respective buttons in response to the measured ambient light level. Each button may comprise indicia indicating a function of the button. The control circuit set the first button as active and the second button as inactive in response to an actuation of the first button. The control circuit may, based on the measured ambient light level, control the light sources to illuminate the first button to an active surface illumination intensity, and to illuminate the second button to an inactive surface illumination intensity that is less than the active surface illumination intensity.

Abstract: An amount of filament voltage supplied by a reconfigurable ballast may be adjusted based on a lamp type with which the ballast is operating. The filament voltage may be reconfigured dynamically and/or may be reconfigured via a user-provided value. An electronic dimming ballast may include a control circuit configured to control generation of the AC filament voltage in accordance with a reconfigurable AC filament voltage value. Reconfiguring an electronic dimming ballast may include reconfiguring an AC filament voltage applied by the electronic dimming ballast to a filament of a lamp installed with the electronic dimming ballast. Reconfiguring the AC filament voltage may include computing a hot-to-cold cathode resistance ratio associated with the filament. Reconfiguring the AC filament voltage may include determining whether the computed hot-to-cold cathode resistance ratio is within a range specified for the electronic dimming ballast.

Abstract: A load control device, such as an electronic ballast, for controlling the power delivered from an AC power source to an electrical load, such as one or more fluorescent lamps, comprises a power converter having an inductor and a power switching device coupled to the inductor, a load control circuit adapted to be coupled to the electrical load, and a control circuit operable to calculate an average input power of the load control device. The control circuit may be operable to calculate a cumulative output power of the power converter while the ballast is preheating filaments of the lamps, and to subsequently determine a fault condition in the lamps in response to the calculated cumulative output power of the power converter. Further, the control circuit may be operable to transmit a digital message including the calculated average input power of the load control device.

Abstract: An amount of filament voltage supplied by a reconfigurable ballast may be adjusted based on a lamp type with which the ballast is operating. The filament voltage may be reconfigured dynamically and/or may be reconfigured via a user-provided value. An electronic dimming ballast may include a control circuit configured to control generation of the AC filament voltage in accordance with a reconfigurable AC filament voltage value. Reconfiguring an electronic dimming ballast may include reconfiguring an AC filament voltage applied by the electronic dimming ballast to a filament of a lamp installed in the electronic dimming ballast. Reconfiguring the AC filament voltage may include computing a hot-to-cold cathode resistance ratio associated with the filament. Reconfiguring the AC filament voltage may include determining whether the computed hot-to-cold cathode resistance ratio is within a range specified for the electronic dimming ballast.

Abstract: A load control device, such as an electronic ballast, for controlling the power delivered from an AC power source to an electrical load, such as one or more fluorescent lamps, comprises a power converter having an inductor and a power switching device coupled to the inductor, a load control circuit adapted to be coupled to the electrical load, and a control circuit operable to calculate an average input power of the load control device. The control circuit may be operable to calculate a cumulative output power of the power converter while the ballast is preheating filaments of the lamps, and to subsequently determine a fault condition in the lamps in response to the calculated cumulative output power of the power converter. Further, the control circuit may be operable to transmit a digital message including the calculated average input power of the load control device.

Abstract: A load control device, such as an electronic ballast, for controlling the power delivered from an AC power source to an electrical load, such as one or more fluorescent lamps, comprises a power converter having an inductor and a power switching device coupled to the inductor, a load control circuit adapted to be coupled to the electrical load, and a control circuit operable to calculate an average input power of the load control device. The control circuit may be operable to calculate a cumulative output power of the power converter while the ballast is preheating filaments of the lamps, and to subsequently determine a fault condition in the lamps in response to the calculated cumulative output power of the power converter. Further, the control circuit may be operable to transmit a digital message including the calculated average input power of the load control device.

Abstract: An electronic ballast for driving a gas discharge lamp comprises an inverter circuit, a resonant tank circuit, and a control circuit operable to determine an approximation of a resonant frequency of the resonant tank circuit and to control the inverter circuit in response to the approximation of the resonant frequency. The control circuit determines the approximation of the resonant frequency by adjusting an operating frequency of a high-frequency inverter output voltage provided to the resonant tank circuit from a frequency above the resonant frequency down towards the resonant frequency, measuring the magnitude of a lamp voltage across the lamp, and storing the present value of the operating frequency as the resonant frequency when the magnitude of the lamp voltage reaches a maximum value. The control circuit may control the operating frequency of the inverter output voltage in response to the approximation of the resonant frequency and a target intensity of the lamp.

Abstract: An electronic ballast for driving a gas discharge lamp comprises an inverter circuit, a resonant tank circuit, and a control circuit operable to determine an approximation of a resonant frequency of the resonant tank circuit and to control the inverter circuit in response to the approximation of the resonant frequency. The control circuit determines the approximation of the resonant frequency by adjusting an operating frequency of a high-frequency inverter output voltage provided to the resonant tank circuit from a frequency above the resonant frequency down towards the resonant frequency, measuring the magnitude of a lamp voltage across the lamp, and storing the present value of the operating frequency as the resonant frequency when the magnitude of the lamp voltage reaches a maximum value. The control circuit may control the operating frequency of the inverter output voltage in response to the approximation of the resonant frequency and a target intensity of the lamp.

Abstract: A load control device, such as an electronic ballast, for controlling the power delivered from an AC power source to an electrical load, such as one or more fluorescent lamps, comprises a power converter having an inductor and a power switching device coupled to the inductor, a load control circuit adapted to be coupled to the electrical load, and a control circuit operable to calculate an average input power of the load control device. The control circuit may be operable to calculate a cumulative output power of the power converter while the ballast is preheating filaments of the lamps, and to subsequently determine a fault condition in the lamps in response to the calculated cumulative output power of the power converter. Further, the control circuit may be operable to transmit a digital message including the calculated average input power of the load control device.

Abstract: An electronic ballast circuit for driving a gas discharge lamp is operable to control the lamp to avoid flicking and flashing of the intensity of the lamp during low temperature conditions. The ballast circuit includes an inverter circuit for receiving a DC bus voltage and for generating a high-frequency output voltage, a resonant tank circuit for receiving the high-frequency output voltage and generating a sinusoidal voltage for driving said lamp, and a control circuit operatively coupled to the inverter circuit for adjusting an intensity of the lamp between a minimum intensity and a maximum intensity. The control circuit receives a control signal representative of a lamp temperature of the lamp, and increases the minimum intensity of the lamp if the lamp temperature of the lamp drops below a cold temperature threshold. In addition, the ballast circuit may also include a temperature sensing circuit operable to generate the control signal representative of the lamp temperature of the lamp.

Abstract: The output current of a ballast is dynamically limited when an over-temperature condition is detected in the ballast according to one of (i) a step function or (ii) a combination of step and continuous functions, so as to reduce the temperature of the ballast while continuing to operate it.

Abstract: The output current of a ballast is dynamically limited when an over-temperature condition is detected in the ballast according to one of (i) a step function or (ii) a combination of step and continuous functions, so as to reduce the temperature of the ballast while continuing to operate it.