Abstract: An LED driving device has a first constant current source circuit and a voltage control circuit. The first constant current source outputs a first constant current to a first node and the first constant current flows into a first LED module disposed between a driving node and the first node; wherein, the first constant current source circuit has a first detection node for generating a first detection signal in response to the voltage level of the first node. The voltage control circuit is coupled to the first detection node, for outputting a control signal in response to the first detection signal to a voltage regulator circuit in order to control and modulate the voltage regulator circuit to output a driving voltage to the driving node.

Abstract: An illumination apparatus includes: a series circuit of a thyristor and at least one load circuit connected across an AC power source; a current control circuit for adjusting an input current to be maintained at a predetermined level during a part or the whole of an ON period of the thyristor; and a short circuit for short-circuiting input ports of the load circuit to have a predetermined resistance during a part of the ON period of the thyristor and a part or the whole of an OFF period of the thyristor. The current control circuit and the short circuit are connected in parallel to the load circuit.

Abstract: A switching current regulator controls a load current flowing through a load. The switching current regulator switches a switch to an ON state after applying a regulating signal to the switch. During an integration period while the switch is in the ON state, the switching current regulator integrates an output voltage based on a sense voltage based on the load current and a reference voltage; at the end of the integration period, the switching current regulator outputs an integrated output voltage. The switching current regulator compares the integrated output voltage to a predetermined value. Based on a result of comparing the integrated output voltage and the predetermined value, the switching current regulator adjusts the regulating signal.

Abstract: In one embodiment, an LED driving circuit can include: (i) a sense circuit configured to sense an inductor voltage, and to generate a sense voltage signal; (ii) a protection control circuit configured to activate a first protection control signal in response to a comparison of the sense voltage signal against a first reference voltage to indicate an LED device is in a first load state; (iii) the protection control circuit being configured to activate a second protection control signal in response to a comparison of the sense voltage signal against a second reference voltage to indicate the LED device is in a second load state; and (iv) a PWM control circuit configured to control a power switch according to the first protection control signal or the second protection control signal, based on the load state of the LED device.

Abstract: An optical lighting apparatus having a constant luminance with a drive current controlled by a controller unit. A temperature controlled photodetector indirectly monitors the luminance and informs the controller when a change in luminance has occurred so that the controller can make appropriate adjustments to the drive current. Also disclosed is a method of regulating the drive current to a light source to enable the luminance to remain fixed and independent of fluctuations in ambient temperature. A temperature compensated photodetector senses the amount of light reflected off a diffuser lens and feeds back the output to a controller circuit which regulates the drive current to the light source. The lighting apparatus has application in calibrating imaging systems, such as digital cameras, and for scanning devices.

Abstract: A method of operating a lighting fixture comprising a plurality of discrete illumination sources of distinguishably different color coordinates comprises determining target color coordinates and luminous flux at which to operate the lighting fixture, determining input electrical power values for each of the plurality of discrete illumination sources that substantially produce the target color coordinates and luminous flux by referencing a calibration data lookup table having calibration data based on measurements of the plurality of discrete illumination sources, determining a color mixing zone defined by three distinguishably different color coordinates of the plurality of discrete illumination sources within which the target color coordinates lie according to the calibration data, determining luminous flux ratios for each of the plurality of discrete illumination sources having one of the three distinguishably different color coordinates defining the color mixing zone that substantially produces the target

Abstract: A power supply circuit (4) is responsive to an activating signal by supplying a discharge lamp (2) with an operating voltage on which a high voltage is temporality superposed. An insufficient current detecting circuit (46) detects abnormality of an output current supplied to the discharge lamp (2) from the power supply circuit (4). A CPU (52) stops the operation of the power supply circuit (4) in response to detection of abnormality by the insufficient current detecting circuit (46). An output nullification time period timer (50) nullifies the output of the insufficient current detecting circuit (46) for a predetermined time period measured from the supplying of the activating signal.

Abstract: A flicker suppression system for a dimmable LED bulb. In one embodiment, the system includes a rectifier circuit having input terminals and output terminals. The rectifier circuit is configured to rectify a line voltage to generate a rectified voltage at its output terminals. A resistor and switch are also included and coupled in series. A switch control circuit is directly coupled between the output terminals and configured to control the switch only as a function of the rectified voltage.

Abstract: The present invention provides a protection circuit with low energy-consumption and a driving circuit thereof. The protection circuit includes a detection circuit and a switch circuit. The switch circuit is disposed between a power supply circuit and a peripheral step-down shunt. The detection circuit and the switch circuit are connected for controlling. The switch circuit includes a PNP triode or a P MOS transistor connected between the power supply circuit and the peripheral step-down shunt. A base of the PNP triode or the P MOS transistor is connected to a drain of another N MOS transistor through a resistor, and a gate of the N MOS transistor is connected to a status pin of the detection circuit. The present invention solves drawbacks of existent input voltage after the circuit entering a protection state causing unnecessary energy-consumption in peripheral small-signal circuit and voltage-dividing resistors.

Abstract: Electronic circuits provide an error signal to control a regulated output voltage signal generated by a controllable DC-DC converter for driving one or more series connected strings of light emitting diodes.

Abstract: Apparatuses, methods and systems for controlling a luminaire are disclosed. One embodiment includes a lighting control sub-system. The lighting control sub-system includes a luminaire, a controller coupled to the luminaire, and a sensor coupled to the controller. The sensor generates a sensed input. The lighting control sub-system further includes a communication interface, wherein the communication interface couples the controller to an external device. The controller is operative to control a light output of the luminaire based at least in part on the sensed input, and to communicate at least one of state or sensed information to the external device.

Abstract: In a single lighting device including a large number of light-emitting elements (LEEs), the LEEs are divided into separately powered groups, and different combinations of the groups are fully energized to achieve the desired overall brightness. In some embodiments, the number of LEEs in each group has a binary relationship to the other groups. The resolution of the dimming is the brightness of the smallest group. In one example of five binary weighted groups of LEEs, 32 brightness levels can be achieved while the LEEs in the energized groups are fully ON. Thus, since there is no high frequency switching, there is substantially no power dissipation by the dimming control system, and there is limited noise or EMI created. The dimming control can be easily implemented with a logic circuit controlling a transistor switch for each group.

Abstract: An illumination control system includes a signal detection unit for detecting a signal changed depending on an eye state of a person, an opening/closing determination unit for determining an opening/closing state of an eye of the person based on the detected signal, and a sight line detection unit for detecting a person's sight line direction with respect to an illumination device based on the detected signal. The illumination control system further includes a control unit for controlling the illumination device to reduce an illuminance when the opening/closing determination unit determines that the eye of the person is in a closed eye state, and to change an illuminance and a light color based on the sight line direction detected by the sight line detection unit when the opening/closing determination unit determines that the eye of the person is in an open eye state.

Abstract: A system including a selection module to select one of a plurality of templates corresponding to a plurality of light emitting diodes, where the selected template includes one or more of temperature, current, and voltage characteristics of the plurality of light emitting diodes. A control module measures a voltage across one of the plurality of light emitting diodes; determines a temperature of the plurality of light emitting diodes based on the voltage measured across the one of the plurality of light emitting diodes and the selected template; and in order to maintain a luminosity of the plurality of light emitting diodes at a predetermined luminosity, adjusts current through the plurality of light emitting diodes based on the temperature, the selected template, and calibration data. The calibration data include current through the plurality of light emitting diodes and corresponding luminosities of the plurality of light emitting diodes.

Abstract: A control circuit for light emitting diode (LED) of display includes a central processing unit (CPU), an AND gate, and a driving circuit. The CPU comprises a general purpose input output (GPIO) contact which outputs an instant high level voltage when a battery is installed into a portable electronic device. The AND gate includes a first input contact connected to the GPIO contact, a second input contact connected to a system power supply, and a first output contact. The system power supply outputs a low level voltage when the electronic device is powered off and outputs a high level voltage when the electronic device is powered on. The driving circuit includes a second output contact connected to an anode of the LED, a feedback contact connected to a cathode of the LED and an enable connected to the first output contact.

Abstract: A high intensity discharge lamp (HID) control circuit and method are provided in the present invention. The circuit includes a first winding and a second winding, both of which are coupled with a series-connected inductor of an HID lamp circuit; a current zero point detector for detecting an inductor current zero crossing signal in the HID lamp circuit; an inductor current signal generator for generating an inductor current signal in the circuit to indicate a current value of the HID lamp; a modulator having input terminals connected to the current zero point detector and the inductor current signal generator, respectively, and an output terminal connected to a driving circuit for the HID lamp; and the driving circuit for driving switches in the HID lamp control circuit.

Abstract: An LED drive circuit comprises a power supply unit, a first LED lamp string, a first voltage control unit, a second LED lamp string and a first power transfer unit. The power supply unit outputs a drive power to drive the first LED lamp string. The first voltage control unit gets the drive power and stabilizes and provides the voltage to the first LED lamp string. The first voltage control unit includes a power switch where the drive power generates a power loss. The second LED lamp string and first power transfer unit are coupled in series with the first voltage control unit so that the power loss is transferred and output to drive the second LED lamp string. Thus loss of the drive power is reduced and lighting efficiency of the LED improves.

Abstract: Techniques for controlled dimming of an illuminant such as, for example, a light-emitting diode (LED), an organic light-emitting diode (OLED) or gas discharge lamp are described herein. In one example, a control difference formed by subtracting actual values from desired values (dimming values) is smaller than actual values fed back by the lamp. Thus, without directly digitizing an analog feedback variable, the example digitizes a control difference (control deviation) determined in the analog domain, in order to process the latter in a digital control algorithm that determines a digital manipulated variable that influences power to the illuminant.

Abstract: A lamp includes a single string of light emitting diodes (LEDs), driven in common, configured to cause the lamp to emit a visible light output via a bulb. The lamp also includes a lighting industry standard lamp base, which has connectors arranged in a standard three-way lamp configuration, for providing electricity from a three-way lamp socket. Circuitry connected to receive electricity from the connectors of the lamp base as standard three-way control setting inputs drives the string of LEDs. The circuitry is configured to detect the standard three-way control setting inputs and to adjust the common drive to the string of LEDs to selectively produce a different visible light outputs of the lamp via the bulb responsive to the three-way control setting inputs. The lamp may also include nanophosphors pumped by emissions of the LEDs, so that the lamp produces a white light output of particularly desirable characteristics.

Abstract: A drive voltage generation circuit for an LED display device capable of increasing the input voltage range thereof is disclosed. The drive voltage generation circuit includes a booster that boosts an input voltage from an external source, to generate a boosted voltage, a protection switching element that controls whether or not the boosted voltage generated from the booster is to be output, in accordance with a switch control signal, a protection circuit that compares a level of the boosted voltage output from the booster via the protection switching element with a predetermined threshold voltage, selects one of a high voltage and a low voltage, based on a result of the comparison, and outputs the selected voltage as the switch control signal, and a discharger that discharges a low voltage node, to which the low voltage is applied.

Abstract: An LED assembly containing separately-controllable regions of LEDs with temperature sensing devices placed to measure the temperature within each region of LEDs. When the temperature difference between two regions becomes higher than an acceptable maximum, the system may adjust the power to one or more LED regions to maintain luminance uniformity. The regions can be arranged vertically or horizontally or both. A software processor may be used to interpret the data from the temperature sensing devices and control the power sent to the various LED regions. Embodiments can be used at least in LED backlights for LCD displays or for LED displays.

Abstract: This invention relates to a method of adjusting the fixture color emitted by a first and a second lighting fixture to a target color, each lighting fixture comprising at least a first and a second light source emitting light having different source colors, and said fixture color is obtained as a combination of said source colors, and said fixture color can be varied by varying the intensity of each light source; where the adjusting of said fixture color to a target color is performed by varying the intensity of said light sources based on both a first color gamut and a second color gamut respectively described by said source colors from said first lighting fixture and said second lighting fixture. The invention further relates to a light adapter and light system for adjusting the fixture color emitted by a first and a second lighting fixture to a target color and to a computer-readable medium having stored therein instructions for causing a processing unit to execute said method.

Abstract: A flash driver to limit a load current for a flash comprises a dc/dc converter (DCDC) having a first input (IN1) to receive an input voltage (Vin) and an output (OUT) to supply an output voltage (Vout). The dc/dc converter is designed to convert the input voltage (Vin) to the output voltage (Vout). Furthermore the flash driver has an adjustable current source (Iadj) connected between the output (OUT) and a load terminal (LT). A first control unit (CTRL—1) is connected to the first input (IN1) and coupled to the adjustable current source (Iadj), and is designed to compare the input voltage (Vin) to a threshold (Vth) and, if the comparison indicates the input voltage (Vin) being smaller than the threshold value (Vth), adjust the adjustable current source (Iadj) such that the input voltage (Vin) is equal or greater than the threshold value (Vth).

Abstract: An overvoltage protection method for backlight driver includes: providing an LCD device having 2D and 3D modes, comprising a backlight driver comprising a constant current supplying chip and a dimming control coupled to the constant current supplying chip, the constant current supply chip applying a first overvoltage protection level and a second overvoltage protection level as a overvoltage protection level; detecting a signal of the dimming control by using the constant current flow supplying chip, and applying the first overvoltage protection level as the overvoltage protection level based on the signal of the dimming control when the LCD device is in the 2D mode; and detecting the signal of the dimming control by using the constant current flow supplying chip, and applying the second overvoltage protection level as the overvoltage protection level based on the signal of the dimming control when the LCD device is in the 3D mode.

Abstract: The present disclosure discloses a light emitting element driving circuit. In one embodiment the light emitting element driving circuit may comprise a power conversion circuit and a current balancing circuit. In other embodiment the light emitting element driving circuit may further comprise other modules integrated and interacting with the power conversion circuit and the current balancing circuit, such as fault detection and protection circuits, status indication circuits and phase-shift PWM dimming circuits. In other embodiment, the present disclosure further discloses a current balancing circuit. In other embodiment, the present disclosure further discloses a fault detection and protection circuit. In still other embodiment, the present disclosure further discloses a phase-shift PWM dimming circuit.

Abstract: The invention relates to a detector circuit comprising a connection for a voltage supply (Vbat) and a connection for connecting a lamp (LED), said connection being connected to the connection for a voltage supply (Vbat) and to a first control component (I2C) of a first interface protocol and a second control component (PWM) of a second interface protocol. The detector circuit further comprises a first input node (In1) and a second input node (In2), wherein the first control component (I2C) is connected to the first input node (In1) and the second input node (In2) and the second control component (PWM) is connected to the second input node (In2). A detector (det) for ascertaining an interface standard is coupled to the connection for a voltage supply (Vbat) and the first input node (In1) on one side and to ground (GND) on the other side.

Abstract: A light emitting system includes a light emitting device having a forward voltage, and an optical power control device. The optical power control device includes a control signal module and a current controller. The control signal module generates a control signal according to the forward voltage, and the current controller permits flow of a driving current through the light emitting device according to the control signal.

Abstract: A semiconductor light source lighting circuit includes a voltage step-down unit configured to generate a drive voltage lower than an input voltage by turning on or off a first switching element in a voltage step-down mode, a voltage step-up unit configured to generate the drive voltage higher than the input voltage by turning on or off a second switching element in a voltage step-up mode, and a controller. The controller includes a charge pump unit configured to repeat charging from the drive voltage to a second capacitor and discharging from the charged second capacitor to the first capacitor in the voltage step-up mode, and a switch drive unit configured to apply a voltage higher than the voltage at the other end of the first switching element to the control terminal of the first switching element by using a voltage of the charged first capacitor.

Abstract: Systems and methods for preventing or otherwise reducing cyclic light output caused by failure modes are disclosed, which shut off a power supply to a lighting system susceptible to output cycling (also known as flashing, flickering, or strobing) in a non-latching fashion. A power supply and/or driver system includes a processor and memory arrangement configured to track failures and prevent cyclical behavior when detected. The processor can be implemented, for example, with an existing microcontroller already present in the power supply, or as a dedicated processor. Once a failure mode that exhibits cyclic behavior above a certain frequency is detected, the power supply can be turned off or otherwise prevented from attempting to source power to the lighting system.

Abstract: A LED driver comprising: a power switch; a transformer comprising a primary winding coupled to the power switch, a secondary winding and a third winding; a current sense circuit configured to sense a current flowing through the power switch and generates a current sense signal; a zero cross detecting circuit configured to detect a current flowing through the secondary winding, and generates a zero cross detecting signal; a compensation circuit configured to compensate the current sense signal based on the current flowing through the third winding; a control circuit configured to receive the compensated current sense signal and the zero cross detecting signal, and wherein the control circuit generates a control signal to control the power switch.

Abstract: An LED lamp is provided in which the output light intensity of the LEDs in the LED lamp is adjusted based on the input voltage to the LED lamp. A dimmer control unit detects a type of dimmer switch during a configuration process. Using the detected dimmer type, the dimmer control unit generates control signals appropriate for the detected dimmer type to provide regulated current to the LEDs and to achieve the desired dimming effect. The LED lamp can be a direct replacement of conventional incandescent lamps in typical wiring configurations found in residential and commercial building lighting applications that use conventional dimmer switches.

Abstract: A photoelectric sensing sensitivity adjusting device includes: an LED for emitting light by being supplied with energy (current or voltage); a regulator for LED driving for supplying the energy to the LED; a light receiving device for receiving the light emitted from the LED; a digital potentiometer for controlling increase or decrease of the energy to be supplied to the LED; a CPU for digitally controlling, according to a control program, the increase or decrease of the energy to be supplied to the LED; and a photodetection portion for detecting an optical signal, converting the optical signal to an electrical signal, and outputting the electrical signal.

Abstract: A lighting circuit according to embodiments includes: a self-hold element connected in series to an AC power source that generates power for lighting an illumination load, together with the illumination load, the self-hold element being configured to control supply of the power provided by the AC power source to the illumination load by the self-hold element being turned on/off; a noise prevention circuit connected in parallel to the self-hold element; and a damping circuit configured to connect a damping resistance to the noise prevention circuit parallely only for a predetermined period from turning-on of the self-hold element, thereby preventing the self-hold element from being repeatedly turned on/off during a period in which the self-hold element is on under normal conditions, due to a transient during power supply.

Abstract: A method of controller an AC/DC to converter is disclosed, the converter having a power factor correction stage and a signal indicative of a required power and operating with a switching cycle having a switching frequency being the inverse of a switching period. The method comprises switching on the PFC stage, in response to a signal indicative of an average switching frequency rising above a first threshold. The method further comprises switching off the PFC stage, in response to the signal indicative of an average switching frequency falling below a second threshold. The method may further comprise switching on the PFC stage, in response to a positive step change in the signal indicative of a required power, and switching off the PFC stage, in response to indicative step change in the signal indicative of a required power. A controller and an AC/DC converter operable according to such a method are also disclosed as is an LED lighting system comprising such a controller.

Abstract: According to one exemplary embodiment, driver circuit coupled between an AC line and a load includes a first semiconductor switch interposed between a bus voltage and a resonant circuit and a second semiconductor switch interposed between the resonant circuit and a ground, where the resonant circuit drives the load. In the driver circuit, the bus voltage has a shape substantially corresponding to a shape of a rectified AC line voltage, thereby increasing a power factor of the driver circuit. The driver circuit can further include a full-bridge rectifier disposed between the resonant circuit and the load. The load can include at least one LED.

Abstract: A light source apparatus includes a plurality of light source parts, a power supply part, a current selection part and a current control part. The plurality of the light source parts are connected in parallel and the power supply part provides power to a first terminal of each of the light source parts. The current selection part selects the current level of one of the light source parts as a reference current level. The current control part adjusts the levels of the currents flowing through the light source parts to be substantially equal to the reference current level. Selection of the light source part that provides the reference current level is dynamically changed.

Abstract: A two-wire load control device such as a dimmer switch for controlling the amount of power delivered from an AC power source to an electrical load such as a high-efficiency lighting load may be provided. The load control device may include a bidirectional semiconductor switch coupled between the source and the load and a controller operable to control the bidirectional semiconductor switch. The load control device may also include a front accessible trimming actuator to adjust a low end intensity setting of the load control device. The trimming actuator may be coupled to the controller such that the controller may control the bidirectional semiconductor switch appropriately. Additionally, the trimming actuator may include indicia to help a user readily identify the proper low end intensity setting.

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: 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 luminaire is provided, which includes a first light source for providing an illumination light and a second light source passing through at least one image pattern for providing a patterned light. The first light source and the second light source are coupled to a driving circuit and covered by a lamp cover. The driving circuit is used to selectively drive at least one of the first light source and the second light source for providing the illumination light and/or the patterned light. A user may turn on or switch different patterns by touching a casing of the luminaire.

Abstract: LED driver systems and associated methods of control are disclosed herein. In one embodiment, the LED driver system comprises a converter and a controller. The controller is responsive to the LED current feedback signal and a dimming signal, and operable to generate a continuous gate drive signal to control the primary side switch of the converter. Thus, the controller regulates the output current of the converter.

Abstract: A compensation method for a light emitting diode (LED) circuit including a first transistor, a second transistor, a capacitor, and a LED is illustrated. A first end as a control end of the first transistor is connected to one end of the second transistor and the capacitor, and a second end of the first transistor is connected to the LED. A width to length (W/L) ratio of the second transistor is less than one. An initial control voltage is applied to a control end of the second transistor, and the current output voltage of the LED is correspondingly measured. If a difference between the current output voltage and an initial output voltage exceeds a predetermined value, a compensation voltage, which is a summation of the initial control voltage and the difference, is applied to the control end of the second transistor.

Abstract: A method of utilizing a light replication luminaire to match the spectral characteristics of light that is output from the luminaire to the spectral characteristics of a target light spectrum is provided. In one example, the method permits the user to assign a weight to one or more characteristics of the target light spectrum to be replicated. A best approximation of the target light spectrum is then determined, taking into account the weight assigned to each characteristic. In another example, the target light spectrum is provided to the luminaire by the user through the specification of various characteristics of the target light spectrum.

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: 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 control device includes a plurality of LED arrays connected to a ground and connected in parallel to one another, each of the plurality of LED arrays including one or more LEDs connected in series and a resistance element connected in series to the LEDs, a first switching circuit disposed between each of the plurality of LED arrays and a power source, a second switching circuit disposed between each of the plurality of LED arrays and the power source, a capacitor having one end connected to the first switching circuit and another end connected to the plurality of LED arrays, a voltage detection circuit having an end connected to the other end of the capacitor, and a control circuit that controls switching of conduction states of each of the first and second switching circuits, and reads a voltage from the voltage detection circuit.

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: The present document relates to solid state lighting (SSL) devices. A driver circuit for phase-cut dimmable SSL based lighting assemblies is described. A control circuit for a power converter is provided. The power converter is configured to convert an input power derived from a mains power supply into a drive power for a light source. The control circuit comprises a dimmer mode detection unit to determine a first dimmer mode. The first dimmer mode indicates if the input power has been derived from the mains power supply using a dimmer. The control circuit comprises a state processor configured to determine a first operation mode of the power converter. The pre-determined first state information is dependent on the first dimmer mode. The control circuit comprises a first control unit configured to generate a first control signal for operating the power converter in accordance to the first operation mode.

Abstract: A light emitting element drive apparatus capable of outputting the lowest voltage satisfying drive conditions and having high light emitting efficiency and low power loss, and a portable apparatus using the same, comprising an LED drive apparatus to which LEDs of different drive voltages required for emitting light are connected in parallel and driving one or more LEDs, wherein the LED drive apparatus 10 has drive circuits connected to the corresponding LEDs among a plurality of LEDs and driving the corresponding LEDs with luminances based on set values and power supply circuits for deciding a drive voltage value required for the highest light emission among one or more LEDs driven to emit light based on drive states of drive circuits (for example terminal voltages of the current source) and supplying a drive voltage having at least the decided value to LEDs in parallel.

Abstract: A vehicle light control device mounted on a vehicle to control lighting of a light of the vehicle based on illuminance around the vehicle, has an infrared sensor that detects an infrared ray around the vehicle, an infrared illuminance detector that detects infrared illuminance from an output of the infrared sensor, a visible-light sensor that detects visible light around the vehicle, a visible-light illuminance detector that detects visible-light illuminance from an output of the visible-light sensor, a storage in which a first lighting threshold is stored, and a controller that controls the lighting of the light based on the infrared illuminance detected by the infrared illuminance detector, the visible-light illuminance detected by the visible-light illuminance detector, and the first lighting threshold stored in the storage.