Abstract: A system and method of controlling a lighting system having a ballast is provided. The ballast may be used in a lamp system that utilizes different types of lamps. The ballast may detect a lamp signal that indicates a change in state of at least one of the lamps in the lighting system. A voltage regulator signal can be modified based on the detected lamp signal and the light system controlled based on the modified voltage regulator signal.

Abstract: A light power compensation circuit includes a current source to be electrically coupled to a temperature-detecting light-emitting device and providing a working current for the temperature-detecting light-emitting device, a detector unit operable to detect a forward bias voltage across the temperature-detecting light-emitting device and providing a detector voltage proportional to the forward bias voltage, a compensation voltage converting module converting the detector voltage into a compensation voltage which has a negative relation to change in the detector voltage, and a driving module converting the compensation voltage into a driving current which is proportional to the compensation voltage and which drives operation of a controlled light-emitting device.

Abstract: A lighting device includes first and second power source lines supplied with a driving current, first and second switching portions that respectively allow or prohibit supply of the driving current to the first and second power source lines, first and second current application lines respectively coupled with the first and second power source lines, first and second light-emitting element groups respectively disposed on the first and second current application lines, a driving portion coupled with the first and second current application lines and allowing flow of the driving current to the first and second current application lines, and a control portion that controls the first and second switching portions and the driving portion.

Abstract: A light emitting device is provided which is capable of displaying in desired colors stably by controlling a change in luminance of OLED when an organic light emitting layer is degraded or there is a change in temperature of the surroundings. A reference value for the amount of current flowing into a pixel portion is calculated from data of a video signal. Then, the pixel portion displays an image in accordance with the data of the video signal and the drive current at the time is measured for all of OLEDs in the pixel portion. The two voltage values supplied from a variable power supply to the pixel portion are corrected such that the measured drive current approaches the reference value. With the above structure, lowering of luminance which accompanies degradation of an organic light emitting layer is prevented and a clear image can be displayed as a result.

Abstract: A user-actuated lighting effect device includes a housing, a light-generating lamp coupled to the housing, a power source, and a control circuit. The control circuit includes a user-actuated switch operably coupling the lamp and the power source. The lamp creates a lighting effect on or near the user when the first switch is on. The housing can be mounted in a use orientation on a pedal board. The lamp can create an upwardly directed lighting effect. An operational mode can be selected using a lighting mode switch.

Abstract: An LED lighting device includes: a power source unit for supplying the DC output voltage to a light-emitting diode; a control unit for adjusting the DC output voltage; and a control power source unit for supplying a control power to the control unit. The control power source unit generates the control power with the DC output voltage and has: a current-limiting resistor for limiting an electric current that flows from the power source unit to the control unit; a constant voltage unit for converting a voltage to be applied to the control unit through the current-limiting resistor unit to a constant voltage; and a switching unit for switching a resistance value of the current-limiting resistor unit among a plurality of resistance values.

Abstract: An LED display device providing current correction includes a number of LED modules, a microprocessor, and a storage unit storing a standard voltage value. The correction sequence begins with each of the plurality of LED modules entering a work state in sequence, outputting a feedback voltage indicating work current of one of the LED modules to the microprocessor in sequence, comparing the feedback voltage with the standard voltage, adjusting the current of the LED module if the feedback voltage does not equal the standard voltage.

Abstract: A cascoded current regulator, including: a first load circuit, having a first load and a current source unit; and a second load circuit, being cascaded with the first load circuit and having a second load and a current mirror unit, wherein a first current flowing through the first load and a second current flowing through the current source unit are controlled by a control voltage, and a third current flowing through the second load and a fourth current flowing through the current mirror unit are generated according to the second current.

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: An LED driving apparatus for suppressing harmonic components is provided. First and fourth portions 21 and 24 are in parallel to the first and second LEDs 11 and 12, respectively. The first portion 21 controls the current amount in said first LED 11. The fourth portion 24 controls the current amount in said first and second LEDs 11 and 12. The first and fourth controllers 31 and 34 control the first and fourth portions 21, respectively. A current detector 4 detects a signal based on the amount of a current flowing from the first and second LEDs 11 and 12. A signal providing portion 6 provides a voltage based on a rectified voltage provided from a rectifying circuit 2. The first and fourth controllers 31 and 34 compare the current detection signal with the signal voltage, and control the first and fourth portions 21 and 24 based on the comparison.

Abstract: An LED drive circuit is provided that can be connected to an alternating current power source via a phase-control light controller and drives an LED load.

Abstract: The present invention is directed to an electrical wiring device that includes a lighting assembly module disposed in the housing assembly and coupled to a set of line terminals. A control circuit is configured to provide a modulated lighting control signal to the lighting assembly module when AC power is being provided. The modulated lighting control signal is configured to adjust an intensity of the light emitted by a light emitting device such that the intensity is a function of the ambient light level. The control circuit is further configured to provide a second lighting control signal configured to turn the lighting assembly ON at a predetermined intensity for a predetermined period of time when AC power is not being provided by the source of AC power, the second lighting control signal being provided by a rechargeable electrical storage device.

Abstract: A control circuit (1) for light emitting diode arrangements (11), used particularly for backlighting LC flat screens. The circuit has a plurality of control channels (5, 5?) in each of which one or more light emitting diode arrangements (11) are disposed. The circuit has a balancing device (23) which allows currents in the individual control channels (5, 5?) to be balanced. Each control channel (5, 5?) has a separate dimming device (13) through which a brightness of the light emitting diode arrangements (11) in this control channel (5, 5?) can be changed separately from the other control channels (5, 5?). For this purpose, the control circuit has a compensation device (16) which allows a flow of current in the individual control channels (5, 5?) to be balanced when the light emitting diodes have different brightnesses.

Abstract: An operating device for operation of at least one illuminant, such as one or more LEDs, includes first and second converters and first and second logic circuits. The first converter is supplied directly or indirectly with mains voltage, with a first reference potential. The second converter is galvanically isolated from the first converter, with a second reference potential for supplying a load circuit with the illuminant. The first logic circuit is for controlling the first converter, and the second logic circuit is for controlling the second converter. The first logic circuit and the second logic circuit are connected to one another, with potential isolation, via an interface.

Abstract: According to one embodiment, an LED lighting device includes a DC source, a non-insulated step-down chopper and a light emitting diode. The non-insulated step-down chopper includes: a first circuit in which a switching element, a current detecting impedance element and an inductor are connected in series to each other; a second circuit in which the inductor and a freewheel diode are connected in series to each other; and a control portion for controlling the switching element. A power portion including the switching element and the control portion are constituted by a single package IC, and the current detecting impedance element and inductor are attached to the outside of the IC.

Abstract: A control circuit controls driving of an LED and a current-controlled device controls current through the LED. The current-controlled device has a control node. The control circuit has a driving circuit and a fault detector. In the driving circuit, a first comparator compares a current-setting signal with a sensing signal to generate a first comparison signal. Based on the first comparison signal, a buffer generates a driving signal to the control node and drives the current-controlled device. Within the fault detector, a second comparator compares the first comparison signal with the driving signal, generating a second comparison signal. A third comparator compares the driving signal with a threshold voltage, generating a third comparison signal. A fourth comparator compares the sensing signal with the current-setting signal, generating a fourth comparison signal. A decision maker enables or disables the driving circuit according to the second, third, and fourth comparison signals.

Abstract: A lighting system has a lighting fixture with a white light source and a color light source, a control circuit pulses the white and color light sources and changes relative duty cycles of the light sources to alter a color output of the lighting fixture, in response to a change in a control signal from a controller. A comparator compares a reference voltage relating to an aggregate current driving the light sources to a signal voltage relating to the periodic signal from a signal generator. The comparator controls a switch that controls one of the light sources. A duty cycle of the color light source can be vary inversely to a duty cycle of the white light source.

Abstract: The light emitting device control circuit device 100 in accordance with the disclosure includes a power source V1, a transistor TR1, a light emitting unit EU1, switches S1 to S17, constant current sources CC1 to CC17, and a controller 110. A switching voltage Vs1 is supplied from the controller 110 to turn ON or turn OFF the transistor TR intermittently, a pulse voltage is supplied to a pulse voltage supplying line Y1 connected to a drain terminal D of the transistor TR1. The driving signals SP1 to SP17 are sequentially supplied to the switches S1 to S17 to turn ON or turn OFF them (i.e., time division drive). The light emitting devices A1 to A17 are driven sequentially by a pulse current (i.e., time division drive) when a high voltage is supplied to the pulse voltage supplying line Y1 and when the driving signals SP1 to SP17 are turned ON.

Abstract: A lamp control circuit includes a first switch circuit receiving a voltage from a power supply after a control is turned on and outputs a first control signal, a count circuit receives the first control signal and outputs a second control signal, a gate circuit receives the second control signal and outputs a third control signal, a second switch circuit includes a number of electronic switches to receive the third control signal and controls the electronic switches to be turned on or turned off, and a lighting circuit including a number of light emitting diode (LED) groups. Each LED group includes an LED. When an electronic switch connected to an LED group is turned on, the LED of the corresponding LED group is lit. When an electronic switch connected to an LED group is turned off, the LED of the LED group does not light.

Abstract: A lighting device is provided, having at least one light emitting diode module, a power factor correction circuit, a non-regulated isolation DC to DC converter and at least one regulated non-isolation DC to DC converter. The power factor correction circuit performs a power factor correction on an AC power source and outputs a corrected DC voltage. The non-regulated isolation DC to DC converter generates an output voltage in a predetermined voltage range according to the corrected DC voltage, wherein the non-regulated isolation DC to DC converter is an open-loop controlled buck DC to DC converter. The regulated non-isolation DC to DC converter generates a fixed current or a fixed voltage according to the output voltage output from the non-regulated isolation DC to DC converter, thereby driving the light emitting diode module.

Abstract: A method for making a lamp wattage available for operating at least one gas discharge lamp depending on a dimming signal which is input into a wattage factor correction circuit, having a switch element that is switched on clocked by a switch-on time, wherein the wattage factor correction circuit emits an intermediate circuit voltage which in turn is input into a converter that makes the lamp wattage available, comprising the steps of: in an operating phase in which the dimming signal has no phase leading edge and no phase trailing edge, the wattage factor correction circuit and the converter are regulated independently of each other using a separate regulating circuit in each case; and in an operating phase in which the dimming signal has a phase leading edge or a phase trailing edge, the two independent regulating circuits are coupled to each other via a higher-order third regulating circuit such that the lamp wattage of the converter is adjusted such that the switch-on time of the switch element in the watt

Abstract: A load driving apparatus is disclosed. The load driving apparatus includes a driving signal generator and a controller. The driving signal generator is used for providing a driving signal to a load. The controller is used for generating and providing a control signal to the driving signal generator. The driving signal generator generates N integer signals and M fractional signals in a driving period to form the driving signal according to the control signal. N and M are positive integers, and an amplitude of the integer signals is greater than an amplitude of each of the fractional signals.

Abstract: A driving power control circuit and method for light emitting diodes (LEDs) are provided. The driving power control circuit includes a plurality of switch units and a control unit. Each switch unit is electrically coupled to one LED string whose end generates node voltage. The control unit includes a voltage selecting module, a subtractor, and an adjusting module. The voltage selecting module is electrically coupled to the node voltages and outputs one of the node voltages as a reference node voltage. The subtractor is electrically coupled to an output terminal of the voltage selecting module and generates a corresponding feedback voltage according to the reference node voltage and the node voltage. The adjusting module is electrically coupled to an output terminal of the subtractor and outputs a corresponding adjusting signal according to the feedback voltage to determine whether the corresponding switch unit is turned on.

Abstract: A method of estimating the output light flux of a light emitting diode, comprises applying a drive current waveform to the LED over a period of time comprising a testing period. The forward voltage across the LED is monitored during the testing period, and the output light flux is estimated as a function of changes in the forward voltage.

Abstract: A LED driving apparatus includes a rectifying circuit, first, second and third blocks, and first and second switching portions. The rectifying circuit is connected to AC power supply, and rectifies AC voltage of the AC power supply to provide pulsating current voltage. Each block includes a plurality of LEDs. The first, second and third blocks are serially connected to the output side of the rectifying circuit. The first switching portion switches ON/OFF of a first bypass path based on flowing current amount in the first block. The first bypass path bypasses the second block. The second switching portion switches ON/OFF of a second bypass path based on flowing current amount in the first and second blocks. The second bypass path bypasses the third block.

Abstract: A low-voltage DC distribution board for indoor LED lighting with multiple LED lamps, comprises: a power converting module (2), arranged within a box casing (7) and connected with a power input port (1), the power converting module (2) including a set of output ports (3) with different output voltages; a set of selection switches (4) connected between the set of output ports of the power converting module (2) and a plurality of current regulators (5) which are connected to load connectors (6).

Abstract: An apparatus for illuminating a target surface, the apparatus having a plurality of LED arrays, where each of the arrays has a plurality of individually addressable LEDs, and where at least one of the arrays is disposed at an angle of between about forty-five degrees and about ninety degrees relative to the target surface, where all of the arrays supply light into a light pipe, the light pipe having interior walls made of a reflective material, where light exiting the light pipe illuminates the target surface, and a controller for adjusting an intensity of the individually addressable light sources.

Abstract: In one aspect, protecting high frequency (HF) amplifiers of a plasma supply device configured to deliver >500 W at a substantially constant fundamental frequency >3 MHz is accomplished by: driving two HF amplifiers with two drive signals having a common frequency and a predetermined phase shift with respect to one another; generating two HF source signals using the HF amplifiers, the HF source signals coupled in a coupler to form a HF output signal; transmitting the HF output signal to the plasma load; measuring electrical variables related to the load impedances seen by the two HF amplifiers; determining whether the load impedance seen by one of the HF amplifiers lies outside a predetermined range; and adjusting the phase shift of the two drive signals, wherein neither of the load impedances seen by the HF amplifiers lies outside the predetermined range.

Abstract: An apparatus for driving a light emitting device (LED) is provided. The apparatus for driving the LED includes a first driving control element, a first current detection unit, a first effective value detection unit, a first reference signal generation unit, and a first comparison unit. The first driving control element controls a current flowing through a first LED channel, in response to a first pulse-width modulated control signal. The first current detection unit detects the current flowing through the first LED channel. The first effective value detection unit detects an effective value of the current detected by the first current detection unit. The first reference signal generation unit generates a preset reference signal having a sawtooth waveform. The first comparison unit compares the reference signal from the first reference signal generation unit with the effective value from the first effective value detection unit.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for cooperatively controlling ambient level lighting in a controlled area, and task level lighting for task areas in the controlled area, wherein each task area is a separate sub-area of the controlled area.

Abstract: Apparatus, systems, and methods related to controlling multiple strings of light emitting diodes (LEDs) are disclosed. An apparatus may include internal current limiter circuits that are each coupled in series with an associated string of LEDs and are configured to at least partially regulate the current through the associated string of LEDs. The apparatus may also be configured to control external current limiter circuits that are each coupled in series with a corresponding internal current limiter circuit and the string of LEDs associated with the corresponding internal current limiter circuit.

Abstract: Disclosed herein is a circuit assembly comprising a light-emitting diode (LED) load in combination with a filament bulb simulation circuit, the filament bulb simulation circuit being configured to simulate a load that would be presented to a monitoring system by a filament bulb. In this manner, a filament bulb can be effectively replaced with one or more LEDs and thereby achieve power consumption savings. Also disclosed is a method for monitoring an LED circuit assembly with a monitoring system to determine whether the LED circuit assembly is deemed operational.

Abstract: A ballast circuit for a light emitting diode (LED) based lamp including power factor correction with protective isolation. The circuit includes a transformer with electrically isolated windings and a power factor correction circuit that receives no feedback from a secondary winding side of the transformer. An LED-based lamp assembly and a method of driving an LED-based light source are also provided.

Abstract: A light output device comprises a power supply and a plurality of light source device arrangements arranged in a line extending from a power connection, with adjacent light source device arrangements in the line connected together with an electrical connector arrangement. Each light source device arrangement is associated with a control circuit from the plurality of control circuits for providing independent control of the light source device arrangement output based on the control signal. The device can be reduced in length by disconnecting the connector arrangement between an adjacent pair of light source device arrangements and the remaining light source device arrangements extending from the power source are independently controlled by the control signal.

Abstract: There is provided a backlight unit driver capable of driving multi-channel lamps of a backlight unit, especially LED lamps, by supplying a driving power to the lamps using a single transformer and maintaining the current balance of the driving power supplied to each of the lamps.

Abstract: A driving circuit for an LED lamp including no more than 4 strings each having an input and an output terminals outputs a DC voltage of no more than 70V to the input terminals. The driving circuit includes constant current circuits each coupled between the output terminal of a corresponding string and ground. An on-off control signal controls whether the constant current circuits work to control whether the LED lamp works. A dimming control signal controls a duty cycle of working of to the constant current circuits to control a brightness of the LED lamp. The driving circuit further includes an overvoltage protection circuit and a switch. When a voltage at one input terminal is too high or a short circuit occurs in one string, the overvoltage protection circuit outputs an overvoltage control signal and accordingly the switch forces the on-off control signal to control the constant current circuits not to work.

Abstract: An LED driver with open loop dimming including a full wave rectifier circuit, a DC/DC converter, and an oscillator circuit. The rectifier is configured to receive an input voltage in the form of an AC conductive angle modulated voltage and to provide a rectified voltage. The DC/DC converter converts the rectified voltage to an output voltage and an output current, where the output current has a magnitude which varies proportionately with a square of a quadratic mean of the input voltage. The oscillator circuit controls switching of the DC/DC converter with constant frequency and constant duty cycle. The DC/DC converter may be a flyback converter and may include a transformer operated in DCM. The driver may include output voltage and/or output current limit. The output current may be limited when the input voltage is within normal operating range of an AC line voltage from which the input voltage is derived.

Abstract: An adaptive switch mode LED driver provides an intelligent approach to driving multiple strings of LEDs. The LED driver determines an optimal current level for each LED channel from a limited set of allowed currents. The LDO driver then determines a PWM duty cycle for driving the LEDs in each LED channel to provide precise brightness control over the LED channels. Beneficially, the LED driver minimizes the power dissipation in the LDO circuits driving each LED string, while also ensuring that the currents in each LED string are maintained within a limited range. A sample and hold LDO allows PWM control over extreme duty cycles with very fast dynamic response. Furthermore, fault protection circuitry ensures fault-free startup and operation of the LED driver.

Abstract: A lighting device includes a first lighting source, a second lighting source, and a controller. The first lighting source yields a first illumination pattern. The second lighting source yields a second illumination pattern. The patterns overlay to yield a third illumination pattern. The controller shifts available power between the first lighting source and the second lighting source.

Abstract: A ballast to power a lamp includes two switches, each to selectively connect the ballast to respective high voltage terminals, each having two states (ON and OFF). The ballast also includes a converter circuit that provides a voltage to energize the lamp, and a detector circuit. The detector circuit includes two inputs, each coupled to a respective switch; two resistors, each coupled to a respective input; two outputs, each connected to the converter circuit; a transistor network; and a capacitor. One output provides the converter circuit with power, and is connected to the input via the resistors. The other provides the converter circuit with a control signal, indicating a voltage level so as to power the lamp to a particular light level, depending on the switches' states. The transistor network detects a differential voltage between the inputs, generating the control signal as a result. The capacitor smoothes the control signal.

Abstract: The present disclosure relates to a driving device for a backlight with a plurality of LED units. The driving device can include a control module for controlling output voltage of the driving device; a light modulation module for adjusting overall current of the backlight; and a current regulating module for obtaining signals for adjusting individual current of each LED unit and adjusting the individual current of each LED unit according to the signals.

Abstract: A driver arrangement for LEDs may include a PWM controller to deliver a feed voltage between an output line and a ground output line, said controller having a pin, a current regulator to regulate the feed current, a switch to connect said pin to a scaled-down version of the voltage on the first output line, and a control line to receive a signal to produce dimming, said control line coupled to said regulator and said switch to couple said regulator to a reference voltage and control switching, whereby: in one of the levels of a PWM control signal, said regulator interrupts said feed current, the voltage on said ground output line is floating, and in the other levels, said regulator is coupled to said reference voltage, said switch disconnects said pin from said voltage on the output line and the voltage on said ground output line is regulated.

Abstract: A driver for driving a light emitting device includes an output stage and a driving stage. The output stage is for outputting a driving current to the light emitting device according to a driving signal, wherein the light emitting device is coupled between the output stage and a second reference voltage different from the first reference voltage. The driving stage is for generating the driving signal to the output stage, wherein one of the third reference voltage and the fourth reference voltage is within a range between the first reference voltage and the second reference voltage, and the other of the third reference voltage and the fourth reference voltage is outside the range between the first reference voltage and the second reference voltage.

Abstract: An arc protection circuit is provided for a current-fed, parallel-resonant inverter ballast. The circuit includes a lamp current rate of change sensing circuit coupled with one or more lamps to detect a total lamp current; a ballast shutdown circuit to disable the ballast in response to a disturbance in the detected signal; a startup delay circuit, at least a portion of which defines a first time delay from a predetermined condition during which the ballast can not be disabled by the shutdown circuit; and an automatic restart circuit to enable restarting of the ballast, at least a portion of which defines a second time delay during which the ballast remains disabled, after which the ballast is restarted.

Abstract: A driver circuit (10) for a light emitting diode comprises a first driver circuit (32, 32?, 32?) for generating a first current output for driving the light emitting diode, wherein the first driver circuit has a control switch for interrupting the supply of the first current output. A second driver circuit (50) is for generating a second current output for driving the light emitting diode, and the second driver circuit also has a control switch for interrupting the supply of the second current output. The overall output of the driver circuit comprises a pulse width modulated output current which alternates between a high current (Ihigh) generated by the first driver circuit and a low current (Ilow) generated by the second driver circuit. By providing separate driver circuits for two different current requirements, the circuits can be optimised for each function. For example the high current value can comprise an LED operation current, and the low current value can comprise a non-zero measurement current.

Abstract: A lighting apparatus includes a solid state lamp including one or more solid state lighting elements, and a power circuit including a current limiting device electrically connected to the lamp. The current limiting device configured to impose a maximum threshold on the current delivered to the lamp, wherein the current limiting device functions as essentially a constant current source. The lighting apparatus includes a housing for the power circuit and lamp, as a module unit.

Abstract: A high pressure discharge lamp lighting device in this invention comprises a converter, an inverter, an igniter, a controller, and a pulse voltage detection circuit. The converter outputs the direct current voltage. The inverter converts the direct current voltage into the lighting voltage which is alternating current voltage, and applies the lighting voltage to the high pressure discharge lamp through an output terminal. The igniter is configured to output the pulse voltage superimposed on the lighting voltage, whereby the starting voltage is applied to the high pressure discharge lamp. The controller is configured to control the igniter to allow the igniter to superimpose the pulse voltage on the lighting voltage. The pulse voltage detection circuit detects the starting voltage to output the detection signal. The starting voltage regulation circuit regulates the starting voltage to the desired voltage value of the voltage on the basis of the detection signal.

Abstract: A method for the closed-loop control of the operation of a light source which is supplied with power by a DC/DC voltage converter, a manipulated variable being regulated by a setpoint value for an operational parameter of the DC/DC voltage converter being input, wherein the method comprises the steps of: increasing the switching frequency of the DC/DC voltage converter by an increase value prior to rapid changes in the setpoint value; waiting for a retention time; setting the new setpoint value; waiting for the end of a total retention time; and lowering the switching frequency of the DC/DC voltage converter by the increase value.

Abstract: This invention relates to an ambience lighting system for use in conjunction with a display device including an image display region. A central control receives an incoming audio video stream (AVS) and to determines color information at the periphery of the image to be displayed. Light sources are disposed in a pre-fixed arrangement in relation to the periphery of the image display region, and local control units are coupled to open or more light sources selected from the multiple light sources for locally operating the at least one coupled light source. The central control unit is adapted to transmit the determined color information as a stream to each respective local control unit, which use a portion of the received color information to operate the at least one coupled light source, the portion being determined based on the position of the at least one coupled light source within the pre-fixed arrangement.

Abstract: A dimmable ballast and methods are presented in which the operating frequency of a self-oscillating inverter is controlled according to a sensed lamp current for dimming control or cathode heating, and an AC bus voltage of the inverter is controlled to be at or below a voltage threshold value to prevent over driving operating lamps when one or more lamps are being replaced.