Abstract: Various embodiments relate to a power factor controller based single-stage flyback driver and a light-emitting system. The driver includes a primary-side circuit, a secondary-side circuit, a power factor controller, a current feedback circuit, a voltage feedback circuit, and a feedback signal generation circuit, wherein, in the secondary-side circuit, the output voltage is divided using a first voltage division resistor and a second voltage division resistor so as to provide the sampling of the output voltage to the voltage feedback circuit, and the first voltage division resistor or the second voltage division resistor is connected in parallel with a compensation branch having a capacitive reactance.

Abstract: A power supply protected against open circuit conditions at its output terminals, and methods for so protecting, are disclosed. A front end circuit receives an input voltage and provides a regulated front end DC voltage to a voltage converter circuit, which in turn provides a DC output voltage to the output terminals to drive a light source. An open circuit protection circuit is coupled between the voltage converter circuit and the output terminals. It has a non-conducting state to couple the DC output voltage to the output terminals, and a conducting state to establish a short circuit across the output terminals in response to charging of a capacitor during an open circuit condition at the output terminals. A restart circuit intermittently discharges the capacitor during the open circuit condition to place the open circuit protection circuit in the non-conducting state when the open circuit condition is resolved.

Abstract: In various embodiments, a control system for an electronic circuit iteratively applies voltage to and senses current from a load to regulate operation of the load.

Abstract: A driver circuit for driving light emitting diodes (LEDs). The driver circuit includes a string of LEDs divided into n groups and the n groups of LEDs is electrically connected to each other in series, where a downstream end of group m?1 is electrically connected to the upstream end of group m. The driver circuit also includes a power source coupled to an upstream end of group 1 and provides an input voltage. The driver circuit further includes current regulating circuits, where each of the current regulating circuits is coupled to the downstream end of the corresponding group at one end and coupled to a ground at the other end. Each of the current regulating circuits includes a sensor amplifier and a cascode having first and second transistors. The driver circuit also includes detectors, where each of the detectors detects a source voltage of the first transistor.

Abstract: Provided is a step up/down converter, in which the inductor current can be easily detected by a simple configuration in any connecting mode of the switches.

Abstract: Apparatus and associated methods reduce harmonic distortion of a excitation current by diverting the excitation current substantially away from a number of LEDs arranged in a series circuit until the current or its associated periodic excitation voltage reaches a predetermined threshold level, and ceasing the current diversion while the excitation current or voltage is substantially above the predetermined threshold level. In an illustrative embodiment, a rectifier may receive an AC (e.g., sinusoidal) voltage and deliver unidirectional current to a string of series-connected LEDs. An effective turn-on threshold voltage of the diode string may be reduced by diverting current around at least one of the diodes in the string while the AC voltage is below a predetermined level. In various examples, selective current diversion within the LED string may extend the input current conduction angle and thereby substantially reduce harmonic distortion for AC LED lighting systems.

Abstract: Backlight panel circuit, backlight panel and light emitting diode driver are disclosed. The backlight panel circuit comprises: a LED driver including a plurality of voltage followers and a PWM signal transmitter; LED chains; and a plurality of switch circuit units corresponding to the plurality of voltage follows in a one-to-one relationship. Each of the switch circuit units comprises a first switch circuit with a current input terminal being connected to an output terminal of a corresponding voltage follow, a current output terminal being connected to a first LED chain, and a signal input terminal being connected to a signal output terminal of the PWM signal transmitter; and a second switch circuit with a current input terminal being connected to the output terminal of the voltage follow, a current output terminal being connected to a second LED chain, and a signal input terminal being connected to the signal output terminal of the PWM signal transmitter.

Abstract: A power supply apparatus of an embodiment includes a first filter, a second filter, and a switching power supply. The first filter and the second filter attenuate a common mode current to a level lower than a normal mode current. The switching power supply is connected between the first filter and the second filter, and supplies electric power to an illumination load via the second filter.

Abstract: An electronic ballast for a lighting unit may include a Power Factor Correction (PFC) circuit, an inverter, and a control circuit for controlling startup of the inverter, wherein the control circuit is coupled between the PFC circuit and the inverter and includes a switching device coupled in a startup loop for the inverter; a unidirectional conductive device coupled between a PFC power supply circuit for providing an operation current to a PFC controller of the PFC circuit and an input of the PFC controller for preventing a startup current flowing through the PFC circuit from triggering the switching device; and a triggering device coupled to the switching device and a connection point between the unidirectional conductive device and the PFC power supply circuit for controlling switch-on and switch-off of the switching device.

Abstract: An LED controller is disclosed herein. An embodiment of the controller includes a first input connectable to a power source and an output connectable to at least one light-emitting diode (LED). A power factor correction circuit is coupled between the first input and the output, wherein the power factor correction circuit operates in a first state when the power factor is corrected and wherein the power factor correction circuit operates in a second state when the power factor is not corrected. The power factor correction circuit is in the first state when no dimming of the LED is sensed, and the power factor correction circuit is in the second state when dimming of the LED is sensed.

Abstract: An apparatus for controlling the constant current for multi-channel LEDs includes: a plurality of LED channels each comprising an LED array, a transistor, and a variable emitter resistor; a feedback sensing circuit for sensing the collector or drain voltage of a transistor of each of the LED channels; and a controller for increasing the variable emitter resistance of an LED channel in which the collector voltage of the transistor is higher than those of the other LED channels, in response to a feedback sensing result input from the feedback sensing circuit.

Abstract: A multi-string LED drive system for multiple LED strings powered by a common line voltage. A plurality of current control circuits are connected in series with respective LED strings, each of which includes a transistor which causes a desired LED string current to be conducted when a sufficient voltage is applied to the transistor's gate. A “maximum” circuit receives each of the gate voltages at respective inputs and outputs a voltage which is proportional to the greatest of the received voltages. A line regulator circuit receives the output of the maximum circuit and a signal which represents a target gate voltage at respective inputs and generates the common line voltage such that the highest of the gate voltages is approximately equal to the target gate voltage, such that system power efficiency is optimized in cases of imbalance between LED string voltage drops and/or sink device characteristics.

Abstract: A switched-capacitor voltage converter which is particularly well-suited for receiving a line voltage from which to drive current through a series of light emitting diodes (LEDs). Input voltage is rectified in a multi-level rectifier network having switched capacitors in an ascending-bank configuration for passing voltages in uniform steps between zero volts up to full received voltage VDC. A regulator section, operating on VDC, comprises switched-capacitor stages of H-bridge switching and flying capacitors. A current controlled oscillator drives the states of the switched-capacitor stages and changes its frequency to maintain a constant current to the load. Embodiments are described for isolating the load from the mains, utilizing an LC tank circuit or a multi-primary-winding transformer.

Abstract: The present invention provides an LED backlight drive circuit, which includes a first power supply module, an electrical inductor, a rectifier diode, a MOS transistor, an electrolytic capacitor, an LED light string, a voltage division module, a voltage comparator, a second power supply module, and an LED constant-current drive chip. The LED backlight drive circuit is arranged to include a voltage comparator in an external circuit of the LED constant-current drive chip to detect output voltage of the drive circuit so that high voltage, the voltage comparator is caused to supply a low voltage level to forcibly pull down a PWM dimming signal or an ENA enabling signal of the LED constant-current drive chip to achieve an over-voltage protection function and also enable removal of over-voltage protection module from a conventional LED constant-current drive chip.

Abstract: A power supply apparatus and a display apparatus including the same are provided. The power supply apparatus according to an exemplary embodiment includes a power factor correction circuit unit which corrects a power factor of input power and outputs the corrected power factor and a controller which controls whether to operate the power factor correction circuit unit according to an input status of a first signal indicating a status of power supplied to the display apparatus and an input status of a second signal indicating an operation status of a display unit included in the display apparatus.

Abstract: A load driving device has a switch N1, a driver that performs on/off control of the switch in accordance with SWON, a comparator that compares Vdet1 with Vth, and based on a result of the comparison, generates IPEAKDET, an ADC that converts Vdet1 into ADCOUT, a DAC that converts IPEAKSET into Vth, and a logic portion that, upon receiving inputs of IPEAKDET and ADCOUT, outputs SWON and IPEAKSET. The logic portion includes a computation circuit that calculates Y1 by using a computation equation expressed by Y1=AVE×?+?×Ton/2 (where Y1: a signal value of IPEAKSET; AVE: an average current set value of an output current; ?: an adjustment coefficient for AVE; Ton: an on period; ?: a change rate of AVCOUT). The computation circuit determines ? in accordance with computation mode setting signals ISO and PFC.

Abstract: A driver circuit for driving light emitting diodes (LEDs). The driver circuit includes a string of LEDs divided into n groups and the n groups of LEDs is electrically connected to each other in series, where a downstream end of group m?1 is electrically connected to the upstream end of group m. The driver circuit also includes a power source coupled to an upstream end of group 1 and provides an input voltage. The driver circuit further includes current regulating circuits, where each of the current regulating circuits is coupled to the downstream end of the corresponding group at one end and coupled to a ground at the other end. Each of the current regulating circuits includes a sensor amplifier and a cascode having first and second transistors. The driver circuit also includes detectors, where each of the detectors detects a source voltage of the first transistor.

Abstract: A lighting device includes a first array of LEDs, a temperature sensor, memory, and a system controller. The memory may include a first duty cycle offset and first curve information that defines a relationship between temperature and a duty cycle for driving at least one LED of the first array of LEDs. The system controller will determine a temperature based on information from the temperature sensor. Based on the temperature, the system controller will determine a first pre-calibrated duty cycle that corresponds to the temperature from the first curve information and then adjust the first pre-calibrated duty cycle with the first duty cycle offset to generate a first calibrated duty cycle. The LED is then driven with a first pulse width modulated signal having the first calibrated duty cycle.

Abstract: Method and means for driving one or more LEDs. The method includes turning a power switch on to provide current through an inductor and the power switch, measuring voltseconds of the LEDs at a cycle time, comparing the measured voltseconds to a reference signal at an end of the cycle time, generating a signed discrete logical signal based on a difference between the measured voltseconds and the reference signal, and generating a control signal using the signed discrete logical signal to regulate a peak current through the power switch by keeping the cycle time voltseconds substantially constant. The reference signal may be proportional to a set average LED voltage.

Abstract: A protection circuit of a DC-DC converter is disclosed. An input terminal of the DC-DC converter receives an input voltage and an output terminal of the DC-DC converter provides an output voltage. The DC-DC converter includes an output stage between the input terminal and the output terminal. The protection circuit includes a current sensor, a comparator, a determining circuit, and a protection control circuit. The current sensor provides a sensing signal. The comparator compares a default over-voltage with the sensing signal to provide an over-current control signal. The determining circuit provides a determining control signal. The protection control circuit determines whether to enable a short protection according to the over-current control signal and the determining control signal.

Abstract: A filter device (10) for filtering high-frequency interferences, such as due to switching flanks of a DC converter, has a current path (4) between an input (2) and an output (3), and an inductor (L) in the current path (4), wherein the inductor (L) is disposed in the current path (4) as a first component and is connected to the input (2), and wherein a reverse polarity protective diode (D) is disposed in series with the inductor (L) downstream thereto.

Abstract: Systems and methods are provided for providing a substantially constant and equal current to a plurality of current driven loads. In one embodiment, a system is provided that comprises a plurality of current regulated outputs and a plurality of current driven loads. The plurality of current regulated outputs and the plurality of current driven loads are arranged in a single current loop configuration with a respective current regulated output providing an output voltage to a respective current driven load of the plurality of current driven loads.

Abstract: An LED driver is presented with a sensing circuit and attenuator circuits to provide three-way switched dimming as well as phase-cut dimming to control the output power driving an LED load allowing installation into conventional three-way switched lamp sockets or in sockets wired to a wall or table mounted phase-cutting dimmer control. When installed in a three way socket, the circuit senses the position of the three way switch and changes the lamp current accordingly. The lamp can also be dimmed by a table-top dimmer or a wall dimmer (in a three-way socket or in a conventional dual contact socket) by applying a phase-cut power input, with the driver circuit including circuitry to sense the average value of a phase-cut power line to adjust lamp current.

Abstract: A multi-stage power supply for a load control device is able to operate in a low-power mode in which the power supply has a decreased power consumption when an electrical load controlled by the load control device is off. The load control device comprises a load control circuit and a controller, which operate to control the amount of power delivered to the load. The power supply comprises a first efficient power supply (e.g., a switching power supply) operable to generate a first DC supply voltage. The power supply further comprises a second inefficient power supply (e.g., a linear power supply) operable to receive the first DC supply voltage and to generate a second DC supply voltage for powering the controller. The controller controls the multi-stage power supply to the low-power mode when the electrical load is off, such that the magnitude of the first DC supply voltage decreases to a decreased magnitude and the inefficient power supply continues to generate the second DC supply voltage.

Abstract: A discharge lamp system includes a discharge lamp, a power source, a converter, a lamp state signal detection module and a controller. The power source provides a DC power. The converter converts the DC power into a current required by the discharge lamp. The lamp state signal detection module receives a lamp state signal and outputs a lamp state detection signal. The controller processes the lamp state detection signal and a given synchronization signal to generate an average lamp current signal and a pulse current signal, and then processes the average lamp current signal and the pulse current signal to generate a control signal. The controller performs current control of the discharge lamp through the converter according to the control signal. Furthermore, a method for controlling a discharge lamp is also disclosed herein.

Abstract: A lighting device includes: a series circuit of an inductor and a switching element; a diode which regenerates and supplies an energy of the inductor; and a control circuit which controls on/off of the switching element. The control circuit includes a drive signal generator which outputs a high frequency pulse drive signal; and a drive control section which turns on and off the switching element based on the high frequency drive signal and a PWM signal. The drive signal generator changes an ON time of the high frequency drive signal such that, after the PWM signal is changed from OFF to ON, a peak value of the load current gradually drops along an envelope of a specific slope, and the specific slope of the envelope is changed based on a duty ratio of the PWM signal.

Abstract: The present invention relates to a high efficiency LED driver and driving method thereof. In one embodiment, a high efficiency LED driving method configured for a LED device can include: (i) receiving a DC bus voltage and generating a driving voltage for the LED device through a power switch; (ii) comparing the DC bus voltage against a sum of the driving voltage and a first reference voltage; (iii) where when the DC bus voltage is greater than the sum of the driving voltage and the first reference voltage, generating a first output current; (iv) where when the DC bus voltage is greater than the driving voltage and less than the sum of the driving voltage and the first reference voltage, generating a second output current; and (v) matching an average current of the first output current and the second output current with a corresponding driving current.

Abstract: This disclosure relates to illumination systems. In particular it relates to a method and system for avoiding flicker (in particular 100 Hz or 120 Hz flicker) in solid state lighting devices such as LED or OLED assemblies. A controller for a driver circuit of a solid state lighting device (SSL) is described. The driver circuit comprises a power converter to convert a varying input voltage into a drive voltage for the SSL device. The input voltage is derived from a rectified AC mains voltage and frequency. The power converter is used with a maximum voltage step-up conversion ratio. The controller synchronizes to the mains frequency and determines a plurality of pulse intervals repeated at a pulse frequency where the pulse frequency is greater than a perceptual frequency of light intensity variations perceivable by a human eye.

Abstract: The present invention discloses a high efficiency constant current LED driver, which comprises a rectification bridge, a PFC main circuit, an isolated DC/DC converter, a PFC controller and a PFC bus control circuit. Since the input voltage is an intermediate PFC bus voltage, which varies with the output voltage of the DC/DC converter. When the isolated DC/DC converter is an LLC resonant circuit, the operating frequency of the LLC circuit is close to the resonant frequency within a wide output voltage range. Thus, the gain range and the operating frequency is narrow, and can enable the constant current module to work with a high efficiency at a wide output voltage range. When the isolated DC/DC converter is a symmetric half bridge, or an asymmetric half bridge or a full bridge circuit, the duty cycle of DC/DC circuit is close to 50% within a wide output voltage range. Thus, the changing range of the duty cycle of the DC/DC converter will be narrow and can improve the efficiency dramatically.

Abstract: A dimmable light emitting lamp configured to interface with cat-ear dimmer switches. The lamp includes one or more light emitting devices. The lamp also includes circuitry configured to receive an input voltage and provide regulated current to the one or more light emitting devices. The input voltage has a first voltage pulse that does not represent a dimming level of a dimmer switch and a second voltage pulse that represents the dimming level of the dimmer switch. The circuitry determines a first duration corresponding to a length of the first voltage pulse and a second duration corresponding to a length of the second voltage pulse responsive to first duration. The circuitry adjusts the regulated current to the light emitting devices according to the second duration to adjust output light intensity of the light emitting devices.

Abstract: An improved LED module that is thermally self-stabilizing, and that is able to be retrofitted into an existing flashlight is provided. In one embodiment, the LED module includes a light emitting diode, an amplifying circuit and a microchip. The amplifying circuit includes a temperature sensing device to sense heat from the light emitting diode. The output of the amplifying circuit is input to the microchip which output to a switching device that regulates energy that is delivered to the light emitting diode. The switching device may be part of a boosting circuit, a bucking circuit or an inverting circuit.

Abstract: This invention relates to a power factor correction circuit of an electronic ballast. The electronic ballast includes a rectification circuit, a first capacitive element and an inverter. The power factor correction circuit comprises a unidirectional element, an inductive element and a second capacitive element. The unidirectional element is connected in series with the inductive element, and the second capacitive element is connected in parallel with the unidirectional element and the inductive element. A junction of the unidirectional element and the second capacitive element is coupled to a first output terminal of the rectification circuit, a junction of the inductive element and the second capacitive element is coupled to an input terminal of the inverter, and the first capacitive element is coupled between a second output terminal of the rectification circuit and a junction of the unidirectional element and the inductive element.

Abstract: An embodiment of the present invention is directed to a method and circuit to control light emitting diode (LED) output. The method includes receiving a line voltage signal which powers a lighting circuit comprising an LED and determining an adjustment of a threshold based on a variation of the line voltage signal and/or a controller delay or other practical controller limitation or imperfection. The method further includes dynamically adjusting a threshold or other reference of a controller which controls a switch of said lighting circuit for compensating for line variations to maintain a substantially uniform LED current.

Abstract: Provided are systems and methods for protecting display components from adverse operating conditions. A lighting panel system according to some embodiments includes a lighting panel including a plurality of strings of solid state lighting devices arranged across the panel and a protection system configured to determine an adverse operating condition and adjust a lighting panel luminance setting responsive to the adverse operating condition.

Abstract: An emergency lighting module for providing emergency power to a solid state luminaire is provided. The emergency lighting module includes a control circuit configured to detect a line voltage, a first input configured to receive an input voltage from the solid state luminaire, and a bidirectional booster/charger circuit coupled to the microcontroller and configured to charge a battery using the input voltage. The bidirectional booster/charger circuit is further configured to provide an output voltage. The emergency lighting module is configured to provide the output voltage to the solid state luminaire in response to a reduction of the line voltage.

Abstract: Disclosed are circuits that allow LED bulbs to be replaced regardless of color or construction of the LED element. When used for an LED light string, replacing an LED bulb does not affect the operation of the entire string. When used for other illumination purpose, for example, room light, the bulbs are interchangeable because they have the same operating voltage and current. A standardized input impedance is selected for all of the LED bulbs regardless of construction and color. A resistor circuit is used to create the standardized input impedance while optimizing the operating parameters of the LED element. The resistor circuit includes a bypass element so that if a LED element burns open, a series wired LED string will not go dark. This eliminates the necessity for parallel connected LED bulbs and allows enjoyment of other advantages and economies of series wired LED strings.

Abstract: Thermal management and control techniques for light emitting diode and other incandescent replacement light technologies using a current controller are disclosed.

Abstract: A light emitting diode (LED) light source, LED driver circuitry and methods for controlling the brightness of an LED light source are presented. In some embodiments, an LED driver control circuit receives a dimming command signal to dim the LED light source, modulates a continuous direct current (DC) level to dim the LED light source, and determines that a predetermined threshold level has been reached. At this time, the process includes initiating a fixed pulse width generator (PWG) control signal having a fixed duty cycle, automatically adjusting the LED current amplitude to its nominal current level, and decreasing the current amplitude while the fixed PWG control signal is active to achieve commanded lower dimming of the LED light source.

Abstract: An automotive lamp device is provided. The automotive lamp device includes a lamp housing into which a first lamp or a second lamp is inserted and which includes a plurality of lines, and a lamp driver module which is connected to a first line among the plurality of lines, supplies a first level of voltage and/or current to the first lamp if the first lamp is inserted into the lamp housing, and supplies a second level of voltage and/or current to the second lamp if the second lamp is inserted into the lamp housing.

Abstract: An LED package containing integrated circuitry for matching a power source voltage to the LED operating voltage, LEDs containing such integrated circuitry, systems containing such packages, and methods for matching the source and operating voltages are described. The integrated circuitry typically contains a power converter and a constant current circuit. The LED package may also contain other active or passive components such as pin-outs for integrated or external components, a transformer and rectifier, or a rectifier circuit. External components can include control systems for regulating the LED current level or the properties of light emitted by the LED. Integrating the power supply and current control components into the LED can provide for fabrication of relatively small LEDs using fewer and less device-specific components.

Abstract: A lighting device such as an electronic ballast or LED driver includes circuitry to detect power converter activity and act accordingly. A power factor correction (PFC) circuit includes an inductor, a power converter switch, and a PFC controller effective to provide driving signals the power converter switch to turn on and off. A power converter activity detection circuit includes a first capacitor coupled between the PFC controller and the power converter switch, a zener diode, and a second capacitor coupled between the first capacitor and ground. An output voltage for the power converter activity detection circuit as referenced from a node between the first capacitor and the second capacitor is representative of activity by the power converter switch, and is provided to a lighting device controller which may accordingly maintain operation of the lighting device where a mains power interruption is only temporary but would otherwise disable the device.

Abstract: An illumination light communication device includes a power supply unit controlling a load current in a light source unit to be maintained constant based on a dimming signal; an impedance unit series connected to the light source unit; a switch element parallel connected to the impedance unit to connect/disconnect the impedance unit with the light source unit; and a control unit controlling on/off of the switch element to modulate a light intensity of the light source unit such that a binary communication signal is superimposed on illumination light therefrom. The control unit controls the impedance of the impedance unit such that a difference between magnitudes of the load currents respectively when the pulse of the communication signal is superimposed and is not superimposed is maintained constant regardless of a dimming rate of the dimming signal in a range of a dimming rate equal to or greater than a predetermined level.

Abstract: A light source control device controlling a light source that emits light corresponding to supplied current and a color wheel having a plurality of color segments that converts the light emitted from the light source, the light source control device includes: a current generation circuit, which supplies current to the light source, based on a control signal for controlling an amount of the light of the light source; and a control circuit unit, which stores a plurality of modulation factors corresponding to the plurality of color segments and has a plurality of calculation units corresponding to the plurality of color segments, and which operates the calculation unit corresponding to the segment in synchronization with each segment to thus calculate control information of the control signal.

Abstract: To a constant-current power supply whose output current can be variably set, light emitting modules can be connected in parallel. A control unit recognizes connection information outputted from an information output unit provided in each of the light emitting modules and varies the output current of the constant-current power supply. Drive can be controlled in response to a state of the connected light emitting modules such as the connecting number of light emitting modules.

Abstract: To a constant-current power supply whose output current can be variably set, light emitting modules can be connected in parallel. A control unit recognizes connection information outputted from an information output unit provided in each of the light emitting modules and varies the output current of the constant-current power supply. Drive can be controlled in response to a state of the connected light emitting modules such as the connecting number of light emitting modules.

Abstract: Apparatus and associated methods reduce harmonic distortion of a excitation current by diverting the excitation current substantially away from a number of LEDs arranged in a series circuit until the current or its associated periodic excitation voltage reaches a predetermined threshold level, and ceasing the current diversion while the excitation current or voltage is substantially above the predetermined threshold level. In an illustrative embodiment, a rectifier may receive an AC (e.g., sinusoidal) voltage and deliver unidirectional current to a string of series-connected LEDs. An effective turn-on threshold voltage of the diode string may be reduced by diverting current around at least one of the diodes in the string while the AC voltage is below a predetermined level. In various examples, selective current diversion within the LED string may extend the input current conduction angle and thereby substantially reduce harmonic distortion for AC LED lighting systems.

Abstract: A multi-string LED driving method and system requires generating pulse-width-modulated (PWM'd) driving signals to respective LED strings to control their brightness levels, and staggering the timing of the driving signals such that the number of LED strings driven on simultaneously varies over time by no more than one LED string. The PWM'd driving signals are generated to, for example, achieve local dimming for a display device which employs a multi-string LED backlight system; the present method enables local dimming to be achieved while maintaining a relatively constant load on the drive circuit. The staggering of the timing of the PWM'd driving signals is preferably implemented by arranging the ON times of the driving signals such that they occur serially, such that the loading imposed by the LED strings is spread throughout each switching cycle.

Abstract: To a constant-current power supply whose output current can be variably set, light emitting modules can be connected in parallel. A control unit recognizes connection information outputted from an information output unit provided in each of the light emitting modules and varies the output current of the constant-current power supply. Drive can be controlled in response to a state of the connected light emitting modules such as the connecting number of light emitting modules.

Abstract: Reduction of luminance dispersion of a plurality of light-emitting panels combined into one light-emitting device is achieved by the use of a new light-emitting device which has a photosensor, a plurality of light-emitting panels, DC/DC converters connected to their respective light-emitting panels, and a control circuit configured to control output currents of the DC/DC converters in accordance with illuminance data acquired with the photosensor. The control circuit successively turns on the plurality of light-emitting panels, and controls the output currents of the DC/DC converters in accordance with differences of the illuminance data acquired with the photosensor when the light-emitting panels are turned on.

Abstract: The present invention relates to a double-output high-efficiency LED light-modulating circuit, comprising: a single-stage flyback power factor corrector, a DC/DC convertor, an LED module, and a light-modulating switch. In the present invention, it mainly utilizes the single-stage flyback power factor corrector for carrying out the purposes of reducing the components of an LED luminaire controlling circuit and increasing the circuit power conversion efficiency. Moreover, the double-output high-efficiency LED light-modulating circuit further includes a twin-bus light modulation framework, which can not only reduce the cross voltage of the power switch in back-end DC/DC convertor, but also process a high-frequency light modulation and a low-frequency light modulation to the LED luminaire. Therefore, because the cross voltage of the power switch has been reduced, a power switch with lower Rds can be used in the back-end DC/DC convertor for increasing switching speed and reducing switching losses.