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

Abstract: A method of driving a light source includes outputting a variable driving voltage to a light source part, sensing a first voltage based on the driving voltage and developed at a first end of the light source part, sensing a second voltage developed at a second end of the light source part due to current passing through the light source part and adjusting the driving voltage while using the first and second voltages so that power consumption by the light source part is substantially constant irrespective of temperature of the light source part and/or irrespective of a duty cycle ration being used to drive the light source part. Thus, a luminance of the light source part may be maintained at substantially uniform levels.

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

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

Abstract: A lighting system includes a lighting panel having a string of solid state lighting devices and a current supply circuit having a voltage input terminal, a control input terminal, and first and second output terminals coupled to the string of solid state lighting devices. The current supply circuit is configured to supply an on-state drive current to the string of solid state lighting devices in response to a control signal. The current supply circuit includes a charging inductor coupled to the voltage input terminal and an output capacitor coupled to the first output terminal. The current supply circuit is configured to operate in continuous conduction mode in which current continuously flows through the charging inductor while the on-state drive current is supplied to the string of solid state light emitting devices.

Abstract: A luminary dimming system having a three terminal dimming unit. The dimming unit includes a power controller and a receiver and is responsive to dimming directives received by the receiver. The power controller controls a buck switch and a freewheel switch in a manner that allows reduction of alternating current voltages. Such voltage reduction is accomplished in a manner that preserves the waveform of the source voltage and the power factor exhibited by the luminary.

Abstract: Disclosed are lighting fixtures and lighting systems for controlling lighting based on a combination of inputs. The lighting fixtures may comprise a light source, inputs electrically connectable to sensors for sensing daylight, occupancy and environmental conditions, inputs electrically connectable to a group lighting controller output, a memory, and a lighting controller for controlling the dimming state of light sources based on received inputs. The lighting systems may comprise lighting fixtures with dimmable light sources and controllers in electrical communication with the light sources. The controllers may determine dimming states of the light sources based on group inputs and local inputs indicative of light levels, occupancy statuses, and environmental conditions near the lighting fixtures.

Abstract: LED controllers, LED lighting systems and control methods capable of providing an average luminance intensity independent from the variation of an AC voltage. A string of LEDs are divided into LED groups electrically connected in series between a power source and a ground. A LED controller has path switches, each for coupling a corresponding LED group to the ground. A management center controls the path switches, for making an input current from the power source to the string substantially approach a target value. A line waveform sensor coupled to the power source holds a representative signal during a cycle time of the power source. The representative signal is in response to an attribute of the power source, and substantially determines the target value.

Abstract: Aspects of the disclosure provide a circuit that includes a first circuit, a second circuit and a bridge circuit. The first circuit is coupled to a magnetic component to receive electric energy transferred via the magnetic component and thus configured to store the electric energy and generate a supply voltage. The second circuit is also coupled to the magnetic component. The second circuit is switchable and is configured to deplete a portion of the electric energy when the second circuit is switched on. The bridge circuit is coupled between the first circuit and the second circuit to provide a charge flow path when the second circuit is switched off.

Abstract: A system for controlling a set of light sources may include a set of light sources, at least one optical conduit arranged relative to the set of light sources so as to collect excess light from the set of light sources, and at least one sensor coupled to the optical conduit and configured to sense light collected by the optical conduit. The system may also include a controller configured to control the emittance of the set of light sources based on the light sensed by the sensor. A method for controlling a set of light sources may comprise individually varying power supplied to at least some of the light sources in an imperceptible manner, sensing light emitted by a light source for which the power has been varied, and controlling the emittance of the set of light sources based on the sensed light.

Abstract: A lighting circuit include a connecting section connected to a light source module to thereby form at least a first path and a second path, a power supplying section connected to the connecting section and capable of supplying first direct-current power and second direct-current power to the light source module, a detecting section configured to detect the connection of the light source module, and a control section configured to determine, when the detecting section detects the connection of the light source module, whether the light source module is connected to the first path or the second path and, when determining that the light source module is connected to the first path, cause the power supplying section to supply the first direct-current power and, when determining that the light source module is connected to the second path, cause the power supplying section to supply the second direct-current power.

Abstract: According to systems and methods of this disclosure, a controller may be configured to: operate in a first compatibility mode of operation, determine from an input signal of the lamp assembly during operation in the first compatibility mode whether the first compatibility mode of operation provides compatibility between the lamp assembly and a power infrastructure to which it is coupled, select the first compatibility mode of operation from a plurality of modes of operation as a compatibility mode responsive to determining that the first compatibility mode of operation provides compatibility between the lamp assembly and a power infrastructure to which it is coupled, and select a second compatibility mode of operation from the plurality of modes of operation as the compatibility mode responsive to determining that the first compatibility mode of operation does not provide compatibility between the lamp assembly and the power infrastructure to which it is coupled.

Abstract: An electrical supply device may include a transformer with a secondary winding to feed a current to a load; control circuitry for the device; an auxiliary supply source for said control circuitry. The auxiliary supply source may include an output capacitor across which a supply voltage is provided for said control circuitry; at least one charge accumulation capacitor to be traversed by the current fed to said load; a comparator sensitive to the voltage on said at least one charge accumulation capacitor; and a switch interposed between said at least one charge accumulation capacitor and said output capacitor, said switch coupled to said comparator, whereby when the voltage on said at least one charge accumulation capacitor reaches a reference level, said switch couples said at least one charge accumulation capacitor to said output capacitor by transferring onto said output capacitor the charge on said at least one charge accumulation capacitor.

Abstract: A controller (306) executes a method (400) of controlling a solar power converter (20, 300) connected to receive output power from a solar power source (10). The method comprises: measuring (430) an open circuit voltage (VOC) of the solar power source; determining a short circuit current (ISC) output by the solar power source; using (440) the measured open circuit voltage (VOC) and the measured short circuit current (ISC) to determine an estimate of a voltage maximum power point (VMPP) for the solar power source corresponding to a maximum power point (MPP) for transferring the output power from the solar power source to a load; executing (450) a perturb-and-observe algorithm (500) beginning at the estimated VMPP to determine an actual VMPP for transferring the output power from the solar power source to the load; and operating (470) the solar power converter at or approximately at the actual VMPP.

Abstract: A driving circuit comprising a control unit, a current control unit, a pulse width modulation control unit and a current driving unit is described. The control unit provides a first control signal and a second control signal. The current control unit is connected to the control unit, and converts a reference current into a plurality of current setting signals based on a data signal and the first control signal. The pulse width modulation control unit is connected to the control unit and outputs a pulse signal based on the data signal and the second control signal. The current driving unit is connected to the pulse width modulation control unit and drives the light emitting diode based on a driving current, wherein the control unit generates a continuous conduction time in a predetermined operation period based on the pulse signal and the current setting signals.

Abstract: The invention relates to a method for generating light with a desired light color by using at least one light-emitting diode emitting red r-LED, at least one light-emitting diode emitting green g-LED, at least one light-emitting diode emitting blue b-LED and at least one light-emitting diode emitting white w-LED. In order to improve the CRI value, according to the invention it is proposed that weighting values ascertained according to the RGB algorithm and further weighting values ascertained according to the RGBW algorithm be combined together by using a correction factor.

Abstract: A system provides white light having a selectable spectral characteristic (e.g. a selectable color temperature, delta uv, and intensity) using a combination of sources (e.g. LEDs) emitting light of three, four, five, or six different characteristics, for example, one or more white LEDs, and one or more LEDs of each of three primary colors, plus cyan and royal blue. A controller maintains a desired spectral characteristic, e.g. for white light at a selected point on or within a desired range of the black body curve. In addition, the controller provides selectable adjustments for values of the spectral characteristics, while maintaining substantially constant overall output intensity for the light output of White LEDs, thereby achieving Maximum Utilization.

Abstract: A constant current LED driver circuit includes a unified controller operable to control start up peripheral circuits and control power output of the driver circuit. The unified controller initializes, starts driver circuit components in a predetermined order, and controls operation to prevent runaway operation, failure to start, and nuisance shut downs. Additionally, due to centralized operational condition monitoring, the controller can detect conditions that would cause unnecessary shut downs and prevent such nuisance shutdowns. The unified controller enables fast, finite control over switches of a DC-to-DC converter of the driver circuit to improve output current and voltage control, improving closed loop responsiveness and operation of the DC-to-DC converter.

Abstract: A light fixture includes a driver circuit that fully defines operational characteristics for operation outside of “Nominal Operation” of the driver circuit. The driver circuit increases a target current or set point when the current of the light source (i.e., output current of the driver circuit) or the voltage of the light source (i.e., output voltage of the driver circuit) is below a minimum operating current or minimum operating voltage of the driver circuit regardless of a command current level of the driver circuit. The driver circuit implements a soft start ramp up scheme having a default rate of increase for a set point or target current. After a shutdown, the driver circuit periodically attempts to restart operation by increasing the set point or target current from zero (i.e., shutdown) at a reduced rate as compared to the default rate.

Abstract: A semiconductor light source lighting circuit includes a switching regulator that produces a drive current ILED with a switching element, and a control circuit that controls turning on and off of the switching element so that the magnitude of the drive current ILED approaches a target value. The control circuit includes an error comparator that compares the drive current ILED and the target value, an up/down counter that performs a counting operation, in which the control digital value is incremented or decremented based on the result of the comparison, a D/A converter that converts the control digital value into an analog duty ratio setting signal S4, and a drive circuit that controls the turning on and off of the switching element based on the signal S4. The up/down counter stops the counting operation when the switching regulator is brought into the inactive state.

Abstract: An illumination system (10; 100) for generating light comprises: at least one a lamp assembly (14; 114) capable of generating light (17; 117) with a variable color; a controller (15; 115) for controlling the lamp assembly; a user input device (19) coupled to the controller. The controller (15; 115) is designed, on the basis of data received from the user input device (19), to generate color control signals for the lamp assembly. The controller (15) is designed, on the basis of data received from the user input device (19), to calculate a path (47) in a color space (31), to calculate the coordinates of a set of color points (E; CP(2), CP(3)) along the calculated path (47), and to generate its color control signals in accordance with the calculated color points. The illumination system may be for generating dynamic light sequences, or for generating a spatial color distribution.

Abstract: Disclosed herein is a remotely adjustable lighting system with security features. The lighting system includes a lamp (e.g., luminaire) which carries solid-state light sources and a sensor. The solid-state light sources emit visible light at an adjustable output intensity. The sensor is responsive to line-of-sight wireless signals, and the lamp increases and decreases the output intensity of the light sources in response to output signals of the sensor. The lamp provides security features by selectively accepting and rejecting instructions carried by the line-of-sight wireless signals to vary the output intensity of the light sources.

Abstract: A lighting apparatus includes an illuminance sensor, a dimming control device and a light source. The lighting apparatus calculates a light output characteristic of the light source based on an illuminance measurement value when the light source is turned off and an illuminance measurement value when the light source is lit with a predetermined output, and calculates an ambient illuminance based on the light output characteristic. The illuminance measurement by the illuminance sensor is performed every predetermined period, and dimming control is performed on the light source based on the calculated ambient illuminance.

Abstract: A lighting device includes a DC/DC power converter, a controller/processor electrically connected to the DC/DC power converter, a light emitting diode (LED) current control circuit communicably coupled to the controller/processor and electrically connected to the DC/DC power converter, and two or more LEDs comprising at least a first color LED and a second color LED electrically connected to the LED current control circuit. The LED current control circuit provides an on/off signal having a cycle time to each LED in response to one or more control signals received from the controller/processor such that the two or more LEDs produce a blended light having a specified color based on how long each LED is turned ON and/or OFF during the cycle time.

Abstract: A first driver switches on and off a driving current ILED according to a first pulse signal which is pulse-width modulated according to an externally supplied target luminance level of a light emitting element. An oscillator generates a cyclic signal SOSC having a predetermined frequency. A pulse modulator generates a second pulse signal which is switched to an on level that corresponds to the on state of a switching transistor in synchronization with the cyclic signal SOSC, and which is switched to an off level that corresponds to the off state according to a feedback voltage. A second driver switches on and off the switching transistor according to the second pulse signal. The oscillator is configured to be reset according to a first edge which is transition of the first pulse signal from a first level that corresponds to the off state to a second level that corresponds to the on state.

Abstract: Various embodiments of the invention allow for active AC ripple noise cancellation. In certain embodiments, noise cancellation is accomplished by modulating an LED driver output in a polarity opposite to the ripple, thereby, preventing interference with ripple-sensitive loads. Certain embodiments take advantage of a filter network to prevent the LED driver from modulating LED current in response to ripple that falls within a visible frequency range so as to prevent flicker in an LED backlight display. In addition to protecting ripple-sensitive loads from large ripple currents, efficiency is increased by reducing both I2·R losses and peak currents, thereby, extending the useful battery life time in mobile devices.

Abstract: There is provide a light emitting diode lighting apparatus capable of being generally used in various kinds of dimmer, the apparatus including: a dimmer varying waveforms of input power according to a dimming signal; a bleeder adjusting a bleeding current under control; a controller comparing a latching current of the dimmer with the bleeding current of the bleeder to control the amount of the bleeding current; and an LED driver receiving a current other than the bleeding current flowing through the bleeder from among the currents from the dimmer to driver a light emitting diode (LED).

Abstract: A method for driving light adjustments, a device therefor and a light adjustable lamp including the device are disclosed. The device includes a light source driving circuit, an MCU and a temporary power supplying circuit. The MCU includes a current detecting module, an analyzing and processing module and a storage module. The analyzing and processing module obtains a connecting signal or a disconnecting signal of the light source driving circuit and thereafter extracts a stored firmware program of gradually varying brightness of a light source or stored information about a constant brightness state of the light source from the storage module for analyzing and processing, so as to generate a controlling signal of adjusting the brightness of the light source and send the controlling signal into the light source driving circuit. Then the light source driving circuit adjusts the brightness of the light source according to the controlling signal.

Abstract: The driving circuit for a light emitting diode (LED) backlight includes at least two lightbars arranged in parallel connection. An output end of each of the LED lightbars is coupled with a converter module, and the converter module is configured with a digital potentiometer balancing a voltage difference between the LED lightbars and adjusting a resistance by an electric signal. In the present disclosure, the digital potentiometer adjusting the resistance by the electric signal is arranged in the converter module connected with the LED lightbar in series, and the resistance of the digital potentiometer is dynamically adjusted according to the resistance of different LED lightbars during use. Thus, the total voltage of each LED lightbar and the digital potentiometer connected with the LED lightbar in series is constant.

Abstract: Embodiments of LED driver circuits and the associated methods are disclosed herein. In one embodiment, the LED driver circuit comprises a switch-mode converter, a controller, a feedback circuit, and a gating circuit. The feedback circuit includes a current balance circuit. The gating circuit is responsive to both a current feedback signal and a voltage feedback signal and is configured to select one of them as the feedback signal.

Abstract: Strings of light-emitting elements are driven by providing a fixed voltage reference to a plurality of parallel-connected current sources, each of the current sources being connected in series with a string, supplying current from each current source to the string to which it is connected, whereby the fixed voltage reference is independent of the current supplied to each string, and taking up excess voltage not required by any one of the strings of light-emitting elements.

Abstract: A LED current control system for use with an LED drive system which includes LED strings connected in series with respective current sink circuits, each of which causes a current to be conducted by the LED string to which it is connected. The drive system includes 3 or more ‘dimming’ inputs with which the LED string currents can be adjusted. The LED current control system comprises at least one minimum circuit which receives two or more dimming inputs and produces an output which is proportional to the lesser of the inputs, a multiplier circuit which receives the outputs of the minimum circuits and at least one other dimming input and produces an output ILED which is proportional to the product of the received signals, and a sink control circuit which receives ILED and controls the current sink circuits such that the string currents vary with ILED.

Abstract: A driving device includes a switching power supply circuit to convert input power to output power; a first switching element which opens and closes a circuit of a load; an output capacitor connected in parallel to the load and the first switching element; a selection switch disposed between the inductor and the output capacitor, the selection switch switching between a first selection state where the load is electrically connected to the inductor and the second selection state where a reference potential portion is electrically connected to the inductor; a timing controller which operates the switching power supply circuit while the first switching element is closed; and a controller which puts the selection switch into the second selection state before the first switching element is closed.

Abstract: According to one embodiment, a detection circuit including first and second comparators and a determining unit is provided. The first comparator includes a first input terminal for inputting a first detection voltage, a second input terminal for inputting a first threshold voltage, and a first output terminal configured to output a first output signal. The second comparator includes a third input terminal for inputting a second detection voltage, a fourth input terminal for inputting a second threshold voltage higher than the first threshold voltage, and a second output terminal configured to output a second output signal. The determining unit is configured to determine the presence or absence of conduction angle control of an AC voltage and whether the conduction angle control is a phase control system or an opposite phase control system on the basis of a time difference between the first output signal and the second output signal.

Abstract: Disclosed is a multi-segment LED driving circuit used in an AC operating mode for outputting a drive current to drive a plurality of serially connected LED strings. The LED driving circuit includes at least one detection part, at least one comparison part and at least one adjusting part. The detection part detects an input voltage and an output voltage at both ends of each string and its next string to form a detected value provided for the comparison part to compare the detected value with a reference value to turn on or off the adjusting part so as to control the strings through which the drive current passes and then sequentially drives the strings to emit light. The LED driving circuit can adjust the load of the circuit immediately based on the change of voltage value of the AC power to ensure the stability of the drive current.

Abstract: The disclosure provides a LED light illuminating control system and a control method for illuminating LED ceiling lights, the system being applied in an electronic device. A detecting unit determines the entry of a person into the room, a capturing unit positioned on a ceiling of the room for captures image, and all the LED lights are illuminated, then all the LED lights other than those illuminating the location of the person are switched off. When the person moves to another part of the room, the LED light illuminating control system controls all the LED lights to illuminate, and after a set period switches off all the LED lights other than those illuminating the new location of the person, thus saving a lot of power.

Abstract: A light driving apparatus includes a first rectifying unit for receiving AC power and rectifying the AC power into DC, a switching element controlled to turn on or off by a control signal, a transforming unit having a transformer and an inductor connected to a primary side of the transformer in parallel, a second rectifying unit for rectifying a secondary side output of the transforming unit and supplying an output voltage thereof to a LED unit, and a control unit provided in the primary side to give a constant-current control function so that a secondary side output is maintained consistently. According to the present disclosure, it is possible to simplify the circuit structure of the secondary side and improve the efficiency by controlling the secondary side current at the primary side without secondary side feedback information.

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: An adaptive anti-glare light system including a sensor, a color selection engine, a controller, and a plurality of light sources each configured to emit a source light. The sensor transmits a source color signal designating a reflected light characterized by a detected color and a discomfort glare rating. The color selection engine determines a dominant wavelength of the detected color, and a combination of the light sources that the controller may operate to emit a combined wavelength that matches the dominant wavelength of the detected color. A method of adapting light as a countermeasure to glare comprises receiving the detected color, determining a subset of the plurality of light sources that may be combined to form an adapted light that matches the detected color, and operating the light sources with a white light to emit the adapted light at or above a threshold discomfort glare level.

Abstract: A field emission device and a method of driving the multi-electrode field emission device having a single driving power source are disclosed. The field emission device includes a cathode electrode, one or more gate electrodes, a voltage division unit, and a power source unit. The cathode electrode is figured such that at least one emitter is formed thereon. The gate electrodes are disposed between an anode electrode and the cathode electrode, and each have one or more openings through which electrons emitted from the emitter can pass. The voltage division unit has one or more divider resistors, and divides a voltage applied from the power source unit using the divider resistors and then applies partial voltages to the one or more gate electrodes. The power source unit includes a single power source, and applies the voltage to the voltage division unit.

Abstract: A device, system and method to drive light emitting diodes (LEDs) are disclosed. An exemplary system may include a string of LEDs coupled across a voltage source configured to provide an input voltage. The string of LEDs may include a plurality of separate groups of LEDs and a plurality of switch circuits. Each of the switch circuits may include a switch coupled in parallel with an associated one of the groups of LEDs to control current flow through the associated group of LEDs in response to a control signal from a controller circuit. A switch protection circuit may be associated with at least one of the switches. A steering circuit may also be coupled in series and associated with each of the groups of LEDs.

Abstract: A bleed circuit is applied to a transformer based on a bleed-on time and a bleed-off time determined by monitoring an output voltage waveform of the transformer.

Abstract: A method for operating a fluorescent lamp (5) having a nominal power (WLa) and stabilized with an EM ballast (B) comprises the steps of during normal operation, short-circuiting the lamp during a closing time interval (CTI) during each current period in order to operate the lamp at a reduced power. The method comprises the step of detecting whether the lamp is stabilized by means of an inductive ballast or by means of a capacitive ballast. If it is found that the ballast is capacitive, the timing of the closing time interval (CTI) is set such that the closing time interval (CTI) has a first closing time segment (CTS1) immediately before a zero-crossing of the current, having a first duration (?1) higher than zero, and a second closing time segment (CTS2) immediately after said zero-crossing of the current, having a second duration (?2) higher than zero.

Abstract: A lighting device for a semiconductor light emitting element includes a series circuit of two switching elements which are alternately turned on, the series circuit being connected to a direct current (DC) input power source and a reactance circuit connected between a connection node of the two switching elements and one end of the DC input power source through a capacitor, an output of the reactance circuit being supplied to the semiconductor light emitting element through a rectifier circuit. A dimming operation of the semiconductor light emitting element is performed by varying a ratio of ON periods of the two switching elements.

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 lighting apparatus includes a string of serially-connected light-emitting devices including at least a first segment and a second segment and a control circuit configured to control a relationship of light outputs of the first segment and the second segment by diverting current from a node of the string to at least one energy storage device and subsequently transferring energy from the at least one energy storage device to at least the first segment. The control circuit may be configured to divert the current responsive to a control input, such as a temperature and/or a dimming level. The at least one energy storage device may include at least one inductor. In some embodiments, the control circuit may control at least one color characteristic of light produced by the string.

Abstract: A two-terminal current controller controls a first current flowing through a parallel-coupled load. During a rising period of a rectified AC voltage, when a load voltage does not exceed a first voltage, the two-terminal current controller operates in a first mode. When the load voltage exceeds the first voltage but does not exceed a second voltage, the two-terminal current controller operates in a second mode. When the load voltage exceeds the second voltage, the two-terminal current controller operates in a third mode. When the load voltage drops to a third voltage smaller than the second voltage after exceeding the second voltage, the two-terminal current controller operates in the second mode when a difference between the second and third voltages exceeds a hysteresis band and operates in the third mode when a difference between the second and third voltages does not exceed the hysteresis band.

Abstract: The invention relates to a driver (100) for a light emitting device system (112), comprising power supply terminals (108) and a detector circuit (106), the power supply terminals being adapted for supplying electrical power from the driver (100) to the light emitting device system and the detector circuit being adapted for capturing sensed information of the light emitting device system via the supply terminals by sensing an electrical loading of the terminals caused by the light emitting device system and for determining an operating condition of the light emitting device system, using the sensed information, wherein the driver is further adapted to control the supplied power depending on the determined operating condition.

Abstract: To control multiple electronic circuits organized in a series configuration, this document introduces a single-wire power, control, and feedback system. Specifically, individually controlled electronic circuits are arranged in a series configuration that is driven by a control unit located at the head of the series. The head-end control unit provides both electrical power and control signals down a single wire to drive all of the electronic circuits in the series in a manner that allows each electronic circuit to periodically draw power from the single wire and receive control information. Each electronic circuit in the series may communicate back to the head-end control unit by drawing power or not during a specified time slot.

Abstract: A power factor correction converter in a buck-boost configuration may include a set-up circuit configured to supply an input voltage, a buck transistor connected to the set-up circuit, and configured to receive a current from the diode bridge, a first diode connected to the buck transistor, a boost transistor, a resistor connected to the boost transistor, a coil that connects the buck transistor and the boost transistor, a buck-boost PFC regulator connected to the set-up circuit, and configured to regulate a time pattern of the on/off status of the first transistor and the second transistor synchronously, a second diode connected to the coil and the boost transistor, and configured to output a first level voltage, a capacitor connected to the second diode and a load connected to the second diode.