Abstract: An AC line voltage may be encoded with control information, such as dimming information derived from an output signal of a conventional dimmer, so as to provide an encoded AC power signal. One or more lighting units, including LED-based lighting units, may be both provided with operating power and controlled (e.g., dimmed) based on the encoded power signal. In one implementation, information may be encoded on the AC line voltage by inverting some half cycles of the AC line voltage to generate an encoded AC power signal, with the ratio of positive half-cycles to negative half-cycles representing the encoded information. In other aspects, the encoded information may relate to one or more parameters of the light generated by the LED-based lighting unit(s) (e.g., intensity, color, color temperature, etc.).

Abstract: A system for implementing mains-voltage-based dimming of a solid state lighting module includes a transformer, a mains sensing circuit and a processing circuit. The transformer includes a primary side connected to a primary side circuit and a secondary side connected to a secondary side circuit, the primary and second side circuits being separated by an isolation barrier. The mains sensing circuit receives a rectified mains voltage from the primary side circuit and generates a mains sense signal indicating amplitude of the rectified mains voltage. The processing circuit receives the mains sense signal from the mains sensing circuit across the isolation barrier, and outputs a dimming reference signal to the secondary side circuit in response to the mains sense signal. Light output by the solid state lighting module, connected to the secondary side circuit, is adjusted in response to the dimming reference signal output by the processing circuit.

Abstract: A two-stage light emitting diode (LED) driver for powering an LED load at a substantially constant current, and related methods and systems. The first or front end stage of the LED driver includes a buck topology power factor correction (PFC) circuit, the buck PFC circuit and a PFC controller. The second stage of the LED driver includes a conventional isolation and regulator circuit configured to receive the DC voltage and DC current output by the buck PFC and then to provide the substantially constant current to the LED load. By squaring the rectified input voltage sensed by the PFC controller, the input AC current drawn by the buck PFC circuit has a much improved total harmonic distortion (THD), which is achievable without the need for using an expensive PFC controller. The rectified input voltage is squared using a Zener diode ladder circuit.

Abstract: A light-emitting diode (LED) driving circuit includes a constant current module, a current follower module and a LED indicator. The constant current module is connected to a power supply output for stabilizing the output current from the power supply at a preset value. The current follower module is connected between the constant current module and the LED indictor for further stabilizing the current output from the constant current module. The LED driving circuit makes sure the current through the LED indicator invariable, thereby keeping brightness of the LED indicator invariable.

Abstract: New and useful methods and systems for providing lighting control are disclosed. For example, in an embodiment a lighting system includes one or more first solid state lights having a first aesthetic color, one or more second solid state lights having a second aesthetic color, the second aesthetic color having an appreciably longer wavelength than the first aesthetic color, and an amplitude correlation circuit configured to control a ratio of first light produced by the one or more first solid state lights to second light produced by the one or more second solid state lights as a function of a received dimming control signal.

Abstract: A driving apparatus configured to drive a light emitting device includes a driving current source module operable to supply current to the light emitting device via a node during operation. A protection module coupled to the node and the driving current source module selectively injects current to the node during operation. The driving current source module is controlled based on a detection result of a voltage on the node.

Abstract: One example includes a power-over-Ethernet (PoE) control system. The system includes a powered device (PD) that is configured to receive a voltage signal via an Ethernet connection and which comprises a PoE signal receiver configured to indicate a nominal power level via the received voltage signal. The system also includes a power sourcing equipment (PSE) device configured to generate the voltage signal and to measure a class current of the voltage signal to determine the nominal power level. The PSE device includes a PoE controller configured to provide a power setting command as a function of the nominal power level to the PoE signal receiver via the voltage signal, such that the PD can operate at a power level that is based on the power setting command.

Abstract: The present invention proposes an LED backlight driving circuit comprises voltage booster circuits parallelly connected and a constant current driving IC module. The voltage booster circuits are used for conversing an input voltage into a needed output voltage to supply to an LED unit. The constant current driving IC module is used for controlling the voltage booster circuits, so that the voltage booster circuits converse the input voltage into the needed output voltage to supply to the LED unit, driving the LED unit in a constant current. The constant current driving IC module generates driving signals at different frequencies to control the voltage booster circuits respectively. The invention can set up multiple driving signals operating simultaneously at different frequencies respectively and disperse resulting harmonic wave, hence reduce EMI signals of the backlight driving circuit effectively. The present invention also proposes an LCD using the LED backlight driving circuit.

Abstract: An electronic system for driving a lamp of a blinker of a vehicle may include a switch having a first input terminal configured to receive a battery voltage, a second input control terminal configured to receive a control signal for operating the switch, and an output terminal. The system may also include a change-over switch configured to connect, alternatively, the output terminal of the switch to the lamp and to a high impedance reference. The system may also include an electronic device connected to the switch and configured to detect a voltage drop between the first input terminal and the output terminal, and, based upon the voltage drop, generate the control signal to have a value to maintain the switch open for a time interval, and generate the control signal to have a second value to maintain the switch closed for another time interval.

Abstract: The disclosed multi-channel driver equalizer circuit matches currents in multiple strings of illumination devices at low current levels by using an analog equalizer to sequentially couple the output of a reference amplifier in series with each current source amplifier in a current limit loop of the driver equalizer circuit to correct the offsets of the current source amplifiers, resulting in the matching of string currents on average.

Abstract: A circuit (10), for causing a light source (30) to flash in correspondence to the peak amplitudes of an incoming sound signal, e.g. music (12), comprises an audio transducer (14), a band-pass amplifier (16), a peak detector section (18), and a filter (20) connected to a monostable circuit (24) via a capacitor (22). The light source (30) comprises one or more surface mount LED devices, and can be used to illuminate the contents of a container, e.g. a drinks bottle.

Abstract: In a lighting apparatus containing a high pressure discharge lamp, an alternating current supplied to the discharge lamp at the time of steady lighting of the frequency (basic frequency) selected from a range between 60 and 1000 Hz and a low frequency having a frequency selected from a range between 5 and 200 Hz lower than the basic frequency is generated alternately. The frequency of the low frequency wave is changed in response to the change of the lighting voltage of the discharge lamp. The supply period of the basic frequency is increased and decreased little by little by every predetermined time.

Abstract: The invention is directed to a method, apparatus, and system of illuminating a target area and space by providing continuous substantially controlled, concentrated, and aimed light downwardly towards the target area from an elevated position and providing temporary uplight relative to the target area upon a triggering event or condition. The triggering event or condition can be automatically sensed or manually initiated. Examples of automatic sensing include but are not limited to evaluating a sound, an image, or movement of an object. The uplight can be supplied by solid state light sources driven at or above rated operating power for a limited periods of time (e.g. 5-10 seconds for a triggering event in a baseball or football game), to save energy as compared to operating them continuously.

Abstract: An apparatus includes a bus configured to be coupled to a controlled current source and at least one light emitting device coupled to the bus. The apparatus further includes a voltage regulator circuit configured to regulate a voltage at the bus and a current regulator circuit configured to control a current through the at least one light emitting device. The current regulator circuit may be used to control a color output of the apparatus.

Abstract: A single wire serial interface for power ICs and other devices is provided. To use the interface, a device is configured to include an EN/SET input pin. A counter within the device counts clock pulses sent to the EN/SET input pin. The output of the counter is passed to a ROM or other decoder circuit. The ROM selects an operational state for the device that corresponds to the value of the counter. In this way, control states may be selected for the device by sending corresponding clock pulses to the EN/SET pin. Holding the EN/SET pin high causes the device to maintain its operational state. Holding the EN/SET pin low for a predetermined timeout period resets the counter and causes the device to adopt a predetermined configuration (such as off) until new clock pulses are received at the EN/SET pin.

Abstract: The present disclosure relates to a method and apparatus for controlling an illumination device, such as a light bulb, LED light, or the like. In one embodiment, a lighting control adapter is described, comprising a male base for physically attaching the lighting control adapter to a light fixture and for receiving power from the light fixture via a light switch connected to the light fixture, a female socket for receiving a base of an illumination device, a switching circuit for providing switchable power to the illumination device, and a processing circuit coupled to the switching circuit, for detecting one or more power toggles of the power received by the male base, and for controlling illumination of the illumination device based on the detection of one or more detected toggles.

Abstract: A light fixture includes a ballast and a plurality of lamps connected to the ballast in parallel. The ballast provides an output signal to the plurality of lamps as a function of a 1st steady state condition. When the ballast senses an end-of-life condition for a lamp of the plurality of lamps, the ballast increases the frequency of the output signal provided to the plurality of lamps until the lamp ceases to conduct current. When the lamp ceases to conduct current, the ballast decreases the frequency of the output signal to a frequency determined as a function of a 2nd steady state condition different from the 1st steady state condition. A total current of the 2nd steady state condition is proportional to a total current of the 1st steady state condition as a function of the number of lamps exhibiting an end-of-life condition.

Abstract: There is described a circuit for retro-lighting a display, comprising a group of white light-emitting diodes connected in series between a first node and a second node and a circuit for driving said group of series-coupled light-emitting diodes comprising: a power supply providing a positive voltage supplied to the first node; and a charge pump converter providing a negative voltage obtained from the positive voltage, said negative voltage being supplied to the second node.

Abstract: Systems and methods are provided for regulating a string current flowing through a string of one or more light emitting diodes. A system controller includes a first controller terminal, a second controller terminal and a third controller terminal. The first controller terminal is coupled to a base terminal of a bipolar junction transistor, the bipolar junction transistor further including an emitter terminal and a collector terminal, the collector terminal being connected to the string of one or more light emitting diodes. The second controller terminal is coupled to the emitter terminal of the bipolar junction transistor and to a first resistor terminal of a resistor associated with a resistance. The third controller terminal is coupled to a second resistor terminal of the resistor. In addition, the system controller is configured to receive a reference voltage, receive an emitter voltage, and output a base current.

Abstract: A transformer isolated LED lighting circuit supplies current from a secondary-side storage capacitor to one or more LED strings in conformity with one or more dimming values. The dimming values are communicated through the transformer by patterns or codes provided in pulses of a power converter circuit that charges the storage capacitor from the primary side of the transformer, or alternatively by a special modulated signal provided in addition to the switching pulses.

Abstract: A ballast includes a rectifier, DC to DC converter, a dimming sensor, and a light source driver circuit. The rectifier provides rectified power from an AC power source modified by a chopper dimmer. The converter includes a boost inductor having a primary winding and a detection winding. The converter receives the rectified power from the rectifier and provides a DC power rail. The dimming sensor monitors a voltage of the detection winding of the boost inductor and provides a dimming signal as a function of the monitored voltage. The light source driver circuit receives the dimming signal, receives the DC power rail, and provides power from the DC power rail to the light source as a function of the dimming signal. An amount of power provided to the light source by the light source driver circuit corresponds to a dimming level indicated by the dimming signal.

Abstract: A dimmable LED driver adapted to be operated with a dimmer that is configured to generate a predetermined conductive angle, wherein the dimmable LED driver comprises: a rectifier configured to convert an alternating current output by the dimmer to a direct current, a buck PFC block configured to adjust an output voltage of the direct current so as to obtain a stable output voltage, a second buck DC/DC block configured to realize output of a constant current after the stable output voltage is realized, a dimming block configured to, after realizing output of the constant current, accomplish a dimming function jointly with the second buck DC/DC block, and an MCU configured to control the buck PFC block, the second buck DC/DC block and the dimming block.

Abstract: A handheld device includes a backlight driving unit and a power supply circuit for powering the backlight driving unit. The power supply circuit includes a power management unit, a battery, a first electronic switch, a second electronic switch, and a control unit. When a voltage of a second terminal of the second electronic switch is less than a reference voltage of the control unit, the control unit turns on the first electronic switch and turns off the second electronic switch. The backlight driving unit is powered by the battery through the first electronic switch. When the voltage of the second terminal of the second electronic switch is more than the reference voltage of the control unit, the control unit turns off the first electronic switch and turns on the second electronic switch. The backlight driving unit is powered by the PMU through the second electronic switch.

Abstract: A PWM signal generation circuit according to the present invention includes a duty setting unit (10) configured to generate a duty control signal designating a duty ratio corresponding to each period of a PWM signal on the basis of an initial duty setting signal, a target duty setting signal, a slope setting signal, and a clock signal, a period setting unit (20) configured to output a period setting value, and an output control unit (30) configured to generate the PWM signal having a period corresponding to the period setting value and having a duty ratio corresponding to a value of the duty control signal. The duty setting unit (10) increases the value of the initial duty ratio to the value of the target duty ratio each time the number of a clock pulse of the clock signal reaches the period setting value reaches the slope setting value.

Abstract: A circuit for lighting a semiconductor light source is provided. The circuit includes: a switching regulator including a switching element and configured to generate a drive current for the semiconductor light source using the switching element; and a control circuit configured to control on-off of the switching element such that the magnitude of the drive current comes close to a targeted value. The control circuit includes: a comparator configured to compare the magnitude of the drive current with the targeted value; an up/down counter configured to count a digital value in a counting-up direction or counting-down direction, based on a comparison result of the comparator; a digital-to-analog converter configured to convert the counted digital value into an analog signal; and a drive circuit configured to control on/off of the switching element based on the analog signal.

Abstract: A light-emitting element lighting device includes: a step-down chopper circuit which outputs a current that flows to a light-emitting element; a current command circuit which selects between a rated mode for passing a rated current for turning ON the light-emitting element and a detection mode for passing an abnormality detection current, which is smaller than the rated current, for detecting an abnormality in the light-emitting element; a voltage detection circuit which detects a voltage across both ends of the light-emitting element; and a control circuit which causes the step-down chopper circuit to stop outputting the current to the light-emitting element, when the voltage across both ends detected by the voltage detection circuit in the detection mode is lower than or equal to an abnormality detection threshold voltage which is set lower than the rated voltage at the time when the light-emitting element is turned ON.

Abstract: A single wire serial interface for power ICs and other devices is provided. To use the interface, a device is configured to include an EN/SET input pin. A counter within the device counts clock pulses sent to the EN/SET input pin. The output of the counter is passed to a ROM or other decoder circuit. The ROM selects an operational state for the device that corresponds to the value of the counter. In this way, control states may be selected for the device by sending corresponding clock pulses to the EN/SET pin. Holding the EN/SET pin high causes the device to maintain its operational state. Holding the EN/SET pin low for a predetermined timeout period resets the counter and causes the device to adopt a predetermined configuration (such as off) until new clock pulses are received at the EN/SET pin.

Abstract: A circuit includes a dimming controller, an adjustable resistor connected downstream of and in series connection with the dimming controller, a driver connected downstream and in series with the adjustable resistor, and a light connected downstream and in series with the driver. Related methods are also provided. A light emitting diode (LED) light fixture has a wide adjustment range of wattage and lumen outputs. A variable output LED light fixture has adjustable lumen output. An adjustable LED light fixture is adaptable to multiple lighting environments and needs, including outdoor and indoor applications. A LED light fixture includes a LED driver with a device adjusting the maximum wattage and lumen output of LED array(s). The adjustment is not permanent and can be adjusted multiple times to tune the wattage and lumen output or as required due to changes at the installation environment.

Abstract: A driving device is adapted to drive a light emitting device with stable optical power, and includes a feedback driving circuit, and a pulse wave generating circuit. The feedback driving circuit provides a driving current that is associated with a pulse-wave signal to the light emitting device, and outputs a feedback signal. The pulse wave generating circuit includes an analog-to-digital converter outputting a digital feedback signal according to the feedback signal, and a controller outputting the pulse-wave signal according to the digital feedback signal.

Abstract: A controller for controlling the illumination state of a light source of solid state lighting devices such as LED or OLED assemblies, is presented. The controller controls the light source according to a plurality of illumination states subject to determine an event of a plurality of events. The controller controls a power converter that converts power derived from an input voltage waveform of line voltage power supply into a drive signal for the light source. The controller determines an event of a plurality of events encoded within the input voltage waveform of the line voltage power supply. A first state processor determines a next illumination state of the plurality of illumination states, based on the determined event and based on the current illumination state. Line voltage Switch event detection is performed while no power is available at the line voltage terminals.

Abstract: A light emitting unit driving circuit may include: an operating voltage supplying unit configured to supply a voltage input for the driving circuit; a driving unit coupled to the operating voltage supplying unit and configured to drive the light emitting unit to make the light emitting unit turn on or turn off; and a feedback control unit coupled between the driving unit and the light emitting unit, and configured to form a feedback loop together with the driving circuit and the light emitting unit to stabilize an operating current of the light emitting unit.

Abstract: A lighting system includes light fixtures not in communications with and not synchronized with one another, and one or more light sensors. Each light fixture separately emits data encoded visible light including light fixture information encoded therein in a manner that avoids visually perceptible flicker and enables light fixture information emitted by one light fixture to be distinguished from light fixture information emitted by other light fixtures. The light fixture information is encoded into data encoded visible light such that a difference between different levels of the data encoded visible light is indicative of an illumination capability of the light fixture and such that visually perceptible flicker is avoided. Each light sensor separately receives portions of data encoded light visible light emitted by multiple light fixtures and separately determines the identity of and the maximum and present illumination contributions for each light fixture.

Abstract: A ceiling lamp adopting a non-separating driver circuit includes a conversion module and a control module. The conversion module converts an input voltage into an operating voltage to drive the LEDs and forming a driving current, and the control module monitors the operating voltage and the driving current to adjust the operating cycle of the conversion module, change the output voltage value of the operating voltage, and linearly change the driving current at a constant current state. The conversion module just executes the power conversion for one time to provide the driving power of the LEDs instead of using the conventional driving method that executes a two-stage power conversion by a separating power converter and a negative booster of the conventional ceiling lamp. Therefore, the ceiling lamp adopting a non-separating driver circuit is capable of lowering the circuit cost and improving the operating efficiency.

Abstract: A Light Emitting Diode (LED) driver circuit and a Pulse Width Modulation (PWM) controlling circuit thereof is provided. The LED driver circuit includes a voltage detector connected to a plurality of LED arrays, the voltage detector being configured to determine a connection status of each of the LED arrays according to a level of a feedback voltage of each of the LED arrays, and detect a minimum feedback voltage from the feedback voltage of each of the LED arrays that are determined to be connected, a controller configured to output a control signal to control boosting of the LED arrays according to the detected minimum feedback voltage, a PWM signal generator configured to output a PWM signal corresponding to the outputted control signal, and a driving voltage generator configured to supply a driving voltage commonly to the LED arrays according to the PWM signal.

Abstract: System and method for dimming control. The system includes a system controller including a first controller terminal and a second controller terminal, a transistor including a first transistor terminal, a second transistor terminal and a third transistor terminal, and a resistor including a first resistor terminal and a second resistor terminal. The system controller is configured to generate a first signal at the first controller terminal based on an input signal and to generate a second signal at the second controller terminal based on the first signal. The first transistor terminal is coupled to the second controller terminal. The first resistor terminal is coupled to the second transistor terminal. The second resistor terminal is coupled to the third transistor terminal. The transistor is configured to receive the second signal at the first transistor terminal and to change between two conditions in response to the second signal.

Abstract: An enhanced control mechanism for an LED light string system is provided for switching between one of two DC output phases or polarities so as to actuate one or the other of two LEDs within the bulbs on the light string. The control mechanism is further configured to allow switching so as to pass through the input power provided by a high-to-low voltage converter that is plugged into its electrical power feeding end. The control mechanism may then provide rectified AC voltage, or DC voltage, of various switched values to the LED string according to the particular needs of the LED bulbs.

Abstract: An Alternating-current-Direct-current (AC-DC dual-use) Light Emitting Diode (LED) driving circuit includes an input power circuit, a buck-boost converter, and a Pulse Width Modulation (PWM) signal controller. The buck-boost converter, including a switching transistor and a feedback resistor, receives a current signal output from the input power circuit, and drives an LED with a driving signal. The PWM signal controller outputs a PWM signal according to the driving signal, so as to sequentially turn on and turn off the switching transistor. One end of the feedback resistor is coupled to the LED, and a floating ground terminal of the PWM signal controller is coupled to the switching transistor and the other end of the feedback resistor. Therefore, the AC-DC dual-use LED driving circuit is capable of dynamically adjusting the duty ratio of the PWM signal without connecting an external photocoupler.

Abstract: Disclosed is a variable power dimming control circuit for driving and linearly adjusting the illumination brightness of a plurality of light emitting diodes (LEDs), and the circuit includes a dimming stabilization unit and a control unit. The control unit is provided for detecting an input current of a circuit, and the dimming stabilization unit is driven for outputting a holding current when the input power is smaller than a standard, and stopping the output the holding current when the input power is greater than the standard. When the LEDs are dimmed to low luminance, a chip controls the operation of the dimming stabilization unit to assure the stability of the dimming operation of a TRIAC. When the LEDs are adjusted to high or full brightness, the chip stops the output of the holding current to reduce unnecessary power consumption and enhance the overall circuit performance effectively.

Abstract: A tunable light-emitting diode (LED) lamp for producing an adjustable light output is provided. In one embodiment, the LED lamp includes a drive circuit for driving LED dies in one of a plurality of light output configurations (e.g., a pre-sleep configuration, a phase-shift configuration, and a general lighting configuration). Further, the LED lamp may include an output select controller and/or input sensor electrically coupled to the drive circuit to select the light output configuration. As such, the LED lamp is tunable to generate different levels of spectral output, appropriate for varying biological circumstance, while maintaining a commercially acceptable light quality and color rendering index.

Abstract: The present invention discloses a current splitter circuit for splitting a supply current to multiple light emitting device strings of a light emitting device array. The current splitter circuit includes: a minimum selector circuit coupled to the multiple light emitting device strings to generate a minimum signal which indicates a minimum voltage of the light emitting device strings; and multiple current source circuits each including a first current source end coupled to a corresponding light emitting device string, a second current source end coupled to ground, and a current source control end receiving a current control signal related to the minimum signal, so as to control currents through the corresponding light emitting device string.

Abstract: In one example implementation in accordance with the present disclosure, a process is provided. The process includes entering a first mode of operation where a plurality of light sources are permitted to illuminate. The process further includes entering a second mode of operation where the plurality of light sources associated with the first switch are not permitted to illuminate, and where the entering of the second mode of operation is in response to not detecting a presence for a time period. The process still further includes entering a third mode of operation in response to receiving a command, where only a subset of the plurality of light sources are permitted to illuminate and the remainder of the plurality of light sources are not permitted to illuminate.

Abstract: A switchable constant current constant voltage supply unit outputs a constant current to drive a plurality of light emitting diode apparatuses when voltages of the light emitting diode apparatuses are not greater than a threshold voltage detected by a voltage detection unit. The switchable constant current constant voltage supply unit outputs a constant voltage to drive the light emitting diode apparatuses when the voltages of the light emitting diode apparatuses detected by the voltage detection unit are greater than the threshold voltage. Moreover, the light emitting diode apparatus includes a positive temperature coefficient thermistor or a polymeric positive temperature coefficient thermistor.

Abstract: The present invention relates to a driver device (30) for driving a load (32), in particular an LED unit (32) having one or more LEDs, comprising input terminals (45) for receiving an input voltage (V14) from an external power source (12) for powering the load (32), a current path (46) including a controllable switch (50) for connecting the input terminals (45) to each other, a measurement path (48) including a resistor (56, 58, 84, 86) connecting the input terminals (45) to each other for providing an alternating voltage corresponding to the input voltage (V14) and including a measuring device (64, 70) for measuring the alternating voltage (V15) at the measurement path (48), and a controller (54, 62) for controlling the controllable switch (50) on the basis of the measured alternating voltage.

Abstract: Provided is a light emitting diode (LED) driver. The LED driver includes a microcontroller for setting a level of an output current of the driver. The driver is configured to receive a prefix as an input, the prefix instructing the microcontroller to enter a programming mode. The microcontroller is responsive to a level signal representative of the level of the output current during the programming mode.

Abstract: A method controls the light exposure of an individual during a given time period. A control unit is provided for controlling lights. A first sensor is worn by the individual and gathers light exposure data including lighting intensity data and Kelvin temperature data experienced by the individual. Second sensors are disposed in a building for collecting emitted light data emitted in the building. The emitted light data and the light exposure data are transmitted to the control unit. The light data, along with desired data including desired light intensity and desired Kelvin temperature are stored. The optimal light exposure for the individual is determined based on the light data or the desired data, and an output signal is generated based on the optimal light exposure. The lights are controlled based on the output signal to produce an overall light intensity and Kelvin temperature pattern per day for the individual.

Abstract: Provided is an LED driver including an amplifier configured to receive a negative voltage input signal and produce a positive voltage output signal in response thereto. Also included is a microcontroller configured for sensing a value of the positive voltage output signal. The microcontroller (i) enters a programming mode when the value exceeds a threshold and (ii) produces an output current responsive to the value.

Abstract: A ballast comprises an inverter circuit for providing an oscillating current signal for energizing the at least one lamp. The inverter circuit comprises a first switching component and a second switching component each having a collector terminal, a base terminal, and an emitter terminal. And, each switching component is configured for alternately operating between a conductive state and a non-conductive state. A first collector-emitter circuit is connected between the collector terminal and the emitter terminal of the first switching component, wherein the first collector-emitter circuit has a first resistance of zero or more Ohms. A second collector-emitter circuit is connected between the collector terminal and the emitter terminal of the second switching component, wherein the second collector-emitter circuit has a second resistance of zero or more Ohms and the first resistance and the second resistance are unequal.

Abstract: To prevent biased consumption of electrodes in a discharge lamp and to prevent biased precipitation of the electrode material, a light source is provided. The light source device has a discharge lamp that emits light by discharge between a first electrode and a second electrode; and a driver that supplies alternating current to the first and the second electrodes so as to maintain the discharge, and changes duty ratio of the alternating current in accordance with predetermined pattern. The predetermined pattern includes a plurality of section periods for which the duty ratio maintains mutually different values for a predetermined period.

Abstract: A method is provided for controlling a power converter (220) to provide a uniform dimming range to a solid state lighting load (240) independent of a type of dimmer. The method includes detecting maximum and minimum phase angles of a dimmer (204) connected to the power converter (220) during operation of the solid state lighting load (240), and dynamically adjusting an output power of the power converter based on the detected maximum and minimum phase angles of the dimmer. The adjusted output power of the power converter adjusts a high end level of light output by the solid state lighting load at the maximum phase angle to match a predetermined high end value and adjusts a low end level of light output by the solid state lighting load at the minimum phase angle to match a predetermined low end value.

Abstract: A lighting system (100) includes light sources (110) and a user interface (130) configured to display an image of an environment including an object provided with a first illumination. The image may be provided by a camera (140) to a remote display device (260). A processor (120) may be configured to change the first illumination to a second illumination in response to a signal and to select at least one of the light sources to provide the second illumination based on attributes of the second illumination and availability and specifications of the light sources. The signal may be provided by a user viewing the image. Alternatively or in addition, the processor (120) may be further configured to generate the signal by detecting a change of the object using content analysis of the image in comparison with a previous image.