Abstract: A dimmer switch for controlling the intensity of a dimmable screw-in compact fluorescent lamp provides smooth dimming of the fluorescent lamp and prevents flickering of the lamp due to multiple re-strikes. The dimmer switch prevents multiple re-strikes by avoiding multiple firings of a controllably conductive switching device of the dimmer circuit by limiting the high-end light intensity of the fluorescent lamp. Specifically, the dimmer switch limits the length of a conduction interval of the controllably conductive switching device to less than approximately 75% of each half-cycle. The dimmer switch may include a user-accessible adjustment actuator for changing the dimmer switch between an incandescent operating mode and a screw-in compact fluorescent mode.

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: A load control system comprises a load control device for controlling an electrical load receiving power from an AC power source, and a controller adapted to be coupled in series between the source and the load control device. The load control system may be installed without requiring any additional wires to be run, and is easily configured without the need for a computer or an advanced commissioning procedure. The load control device receives both power and communication over two wires, and the controller generates a phase-control voltage that has at least one timing edge in each half-cycle, and transmits digital messages by modulating a timing edge of the phase-control voltage relative to a reference edge. The controller may be operable to receive inputs from a plurality of different input devices, and the load control device may be operable to control a plurality of different loads.

Abstract: A load control circuit, such as a light-emitting diode (LED) driver, for controlling the amount of power delivered to an electrical load, such as an LED light source, comprises a regulation transistor adapted to be coupled in series with the load, and a feedback circuit coupled in series with the regulation transistor, whereby the load control circuit is able to control the magnitude of a load current conducted through the load from a minimum load current to a maximum load current, which is at least approximately one thousand times larger than the minimum load current. The feedback circuit generates at least one load current feedback signal representative of the magnitude of the load current. The regulation transistor operates in the linear region to control the magnitude of the load current conducted through the load in response to the magnitude of the load current determined from the load current feedback signal.

Abstract: A method of striking a gas discharge lamp involves the steps of generating a high-frequency square-wave voltage having an operating frequency, generating a sinusoidal voltage from the high-frequency square-wave voltage, controlling the operating frequency to a low-end frequency, and increasing the amplitude of the sinusoidal voltage during successive pulse times and then decreasing the amplitude of the sinusoidal voltage towards the low-end amplitude at the end of each of the successive pulse times until the lamp has struck, where the length of each of the successive pulse times being greater than the length of the previous pulse time. A maximum amplitude of the sinusoidal voltage during each pulse time may be greater than a maximum amplitude of the sinusoidal voltage during the previous pulse time.

Abstract: A hybrid light source comprises a discrete-spectrum lamp (for example, a fluorescent lamp) and a continuous-spectrum lamp (for example, a halogen lamp). A control circuit individually controls the amount of power delivered to the discrete-spectrum lamp and the continuous-spectrum lamp in response to a phase-controlled voltage generated by a connected dimmer switch, such that a total light output of the hybrid light source ranges throughout a dimming range. The discrete-spectrum lamp is turned off and the continuous-spectrum lamp produces all of the total light intensity of the hybrid light source when the total light intensity is below a transition intensity.

Abstract: A ballasted lamp socket for a gas discharge lamp, such as a compact fluorescent lamp, is adapted to replace an Edison screw-in lamp socket in a ceiling mounted light fixture, or a table or floor lamp. The ballasted lamp socket comprises a lamp-receiving portion adapted to be coupled to the gas discharge lamp, an enclosure mechanically coupled to the lamp-receiving portion, a dimming ballast circuit electrically coupled to the lamp-receiving portion and housed within the enclosure, and first and second electrical connections. The ballast portion is adapted to receive an AC line voltage and to generate a high-frequency AC voltage for driving the gas discharge lamp and controlling the light intensity of the gas discharge lamp between a high-end intensity and a low-end intensity. The first and second electrical connections are operable to receive the AC line voltage and to provide the AC line voltage to the ballast circuit.

Abstract: A dimmer switch for controlling the intensity of a dimmable screw-in compact fluorescent lamp provides smooth dimming of the fluorescent lamp and prevents flickering of the lamp due to multiple re-strikes. The dimmer switch prevents multiple re-strikes by avoiding multiple firings of a controllably conductive switching device of the dimmer circuit by limiting the high-end light intensity of the fluorescent lamp. Specifically, the dimmer switch limits the length of a conduction interval of the controllably conductive switching device to less than approximately 75% of each half-cycle. The dimmer switch may include a user-accessible adjustment actuator for changing the dimmer switch between an incandescent operating mode and a screw-in compact fluorescent mode.

Abstract: A hybrid light source comprises a discrete-spectrum lamp (for example, a fluorescent lamp) and a continuous-spectrum lamp (for example, a halogen lamp). A control circuit individually controls the amount of power delivered to the discrete-spectrum lamp and the continuous-spectrum lamp in response to a phase-controlled voltage generated by a connected dimmer switch, such that a total light output of the hybrid light source ranges throughout a dimming range. The continuous-spectrum lamp is driven by a continuous-spectrum lamp drive circuit, which is operable to conduct a charging current of a power supply of the dimmer switch and to provide a path for enough current to flow through the hybrid light source, such that the magnitude of the current exceeds rated latching and holding currents of a thyristor of the dimmer.

Abstract: A dimmer switch for controlling the intensity of a dimmable screw-in compact fluorescent lamp provides smooth dimming of the fluorescent lamp and prevents flickering of the lamp due to multiple re-strikes. The dimmer switch prevents multiple re-strikes by avoiding multiple firings of a controllably conductive switching device of the dimmer circuit by limiting the high-end light intensity of the fluorescent lamp. Specifically, the dimmer switch limits the length of a conduction interval of the controllably conductive switching device to less than approximately 75% of each half-cycle. The dimmer switch may include a user-accessible adjustment actuator for changing the dimmer switch between an incandescent operating mode and a screw-in compact fluorescent mode.

Abstract: A hybrid light source comprises a high-efficiency lamp, for example, a fluorescent lamp, and a low-efficiency lamp, for example, a halogen lamp. A control circuit individually controls the amount of power delivered to each of the high-efficiency lamp and the low-efficiency lamp, such that a total light output of the hybrid light source ranges throughout a dimming range from a minimum total intensity to a maximum total intensity. The high-efficiency lamp is turned off and the low-efficiency lamp produces all of the total light intensity of the hybrid light source when the total light intensity is below a transition intensity. The low-efficiency lamp is controlled such that the correlated color temperature of the hybrid light source decreases as the total light intensity is decreased below the transition intensity. The hybrid light source is characterized by a low impedance throughout the dimming range.

Abstract: An electronic ballast for driving a gas discharge lamp comprises an inverter circuit that operates in a partially self-oscillating manner. The inverter circuit comprises a push-pull converter having a main transformer having a primary winding for producing a high-frequency AC voltage, semiconductor switches electrically coupled to the primary winding of the main transformer for conducting current through the primary winding on an alternate basis, and gate drive circuits for controlling the semiconductor switches on a cycle-by-cycle basis. The drive circuits control (e.g., turn on) the semiconductor switches in response to first control signals derived from the main transformer, and control (e.g., turn off) the semiconductor switches in response to second control signals received from a control circuit. The control circuit controls the semiconductor switches in response to a peak value of an integral of an inverter current flowing through the inverter circuit.

Abstract: A hybrid light source comprises a discrete-spectrum lamp (for example, a fluorescent lamp) and a continuous-spectrum lamp (for example, a halogen lamp). A control circuit individually controls the amount of power delivered to the discrete-spectrum lamp and the continuous-spectrum lamp in response to a phase-controlled voltage generated by a connected dimmer switch, such that a total light output of the hybrid light source ranges throughout a dimming range. The discrete-spectrum lamp is turned off and the continuous-spectrum lamp produces all of the total light intensity of the hybrid light source when the total light intensity is below a transition intensity.

Abstract: A dimmer switch for controlling the intensity of a dimmable screw-in compact fluorescent lamp provides smooth dimming of the fluorescent lamp and prevents flickering of the lamp due to multiple re-strikes. The dimmer switch prevents multiple re-strikes by avoiding multiple firings of a controllably conductive switching device of the dimmer circuit by limiting the high-end light intensity of the fluorescent lamp. Specifically, the dimmer switch limits the length of a conduction interval of the controllably conductive switching device to less than approximately 75% of each half-cycle. The dimmer switch may include a user-accessible adjustment actuator for changing the dimmer switch between an incandescent operating mode and a screw-in compact fluorescent mode.

Abstract: A dimmer switch for controlling the intensity of a dimmable screw-in compact fluorescent lamp provides smooth dimming of the fluorescent lamp and prevents flickering of the lamp due to multiple re-strikes. The dimmer switch prevents multiple re-strikes by avoiding multiple firings of a controllably conductive switching device of the dimmer circuit by limiting the high-end light intensity of the fluorescent lamp. Specifically, the dimmer switch limits the length of a conduction interval of the controllably conductive switching device to less than approximately 75% of each half-cycle. The dimmer switch may include a user-accessible adjustment actuator for changing the dimmer switch between an incandescent operating mode and a screw-in compact fluorescent mode.

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 that operates in a partially self-oscillating manner. The inverter circuit comprises a push-pull converter having a main transformer having a primary winding for producing a high-frequency AC voltage, semiconductor switches electrically coupled to the primary winding of the main transformer for conducting current through the primary winding on an alternate basis, and gate drive circuits for controlling the semiconductor switches on a cycle-by-cycle basis. The drive circuits control (e.g., turn on) the semiconductor switches in response to first control signals derived from the main transformer, and control (e.g., turn off) the semiconductor switches in response to second control signals received from a control circuit. The control circuit controls the semiconductor switches in response to a peak value of an integral of an inverter current flowing through the inverter circuit.

Abstract: A hybrid light source comprises a high-efficiency lamp, for example, a fluorescent lamp, and a low-efficiency lamp, for example, a halogen lamp. A control circuit individually controls the amount of power delivered to each of the high-efficiency lamp and the low-efficiency lamp, such that a total light output of the hybrid light source ranges throughout a dimming range from a minimum total intensity to a maximum total intensity. The high-efficiency lamp is turned off and the low-efficiency lamp produces all of the total light intensity of the hybrid light source when the total light intensity is below a transition intensity. The low-efficiency lamp is controlled such that the correlated color temperature of the hybrid light source decreases as the total light intensity is decreased below the transition intensity. The hybrid light source is characterized by a low impedance throughout the dimming range.

Abstract: An electronic ballast for driving a gas discharge lamp having first and second electrodes comprises an inverter circuit and a symmetric resonant tank circuit for minimizing the RFI noise produced at the electrodes of the lamp. The inverter circuit receives a substantially DC bus voltage generates a high-frequency AC voltage. The symmetric resonant tank circuit comprises a split resonant inductor having first and second windings magnetically coupled together. The first and second windings electrically coupled between the respective electrodes of the lamp and the inverter circuit. The symmetric resonant tank further comprises first and second capacitors coupled in series electrical connection between the electrodes of the lamp with the junction of the first and second capacitors coupled to the DC bus voltage at the input of the inverter circuit.