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: Integrally formed LED light wires are provided, comprising a conductive base comprising a support substrate, wherein the support substrate comprises a first plurality of wires, threads, or a combination thereof, wherein the plurality of wires, threads, or a combination thereof comprises at least one weft element arranged in a first direction and at least two warp elements, each arranged in a second direction such that the at least one weft element and each of the at least two warp elements form plural intersections therebetween, a first bus element and a second bus element, each adapted to distribute power from a power source, a third bus element adapted to distribute a control signal, wherein the first, second, and third bus elements are woven, stitched, or knitted into the support substrate; and a plurality of light emitting diode (LED) modules, each LED module comprising a microcontroller and at least one LED.

Abstract: A line voltage signal at a first voltage and a first current supplied by a line voltage switching device responsive to a sensed or detected event can be provided to a first node of a regulator. A portion of the line voltage signal can be passed at the first voltage through a capacitive device in the regulator and provided at a second node for return to an electrical circuit containing a load device. The remaining portion of the line voltage signal can be passed to a voltage divider comprising at least a first resistive device and a second resistive device.

Abstract: The lighting apparatus in accordance with the present invention includes a dimming control unit configured to control, in accordance with a dimming ratio, a light source including a plurality of light emitting elements designed to emit light in response to DC power. The dimming control unit is configured to, when the dimming ratio falls within a first dimming range, vary supply power to the light source in accordance with the dimming ratio. The dimming control unit is configured to, when the dimming ratio falls within a second dimming range different from the first dimming range, vary, in accordance with the dimming ratio, a lighting number defined as the number of the light emitting elements to be lit.

Abstract: The present invention provides a structure of color mixing circuit of LED light. The LED light includes two input terminals and two output terminals. The two input terminals are respectively an input terminal of reverse parallel connection of any two light-emitting chips of three primary-color light-emitting chips of R, G, B and an anode input terminal of the remaining light-emitting chip and the two output terminals are respectively an output terminal of reverse parallel connection of any two light-emitting chips of the three primary-color light-emitting chips of R, G, B and a cathode output terminal of the remaining light-emitting chip. The structure is simple and the purposes of reducing the number of IC control chips and synchronous color change of light-emitting chips are achieved with modification only made on electrical connection among the three primary-color light-emitting chips in realizing operation of a group of LED lights connected in series.

Abstract: An LED apparatus includes an LED component and a current-limiting device. The LED component includes at least one LED having a corresponding current-limiting resistance value. The current-limiting device includes a plurality of PTC devices connected in series. The plurality of PTC devices are capable of effectively sensing the temperature of the LED and are electrically coupled to the LED component. The resistance value of the current-limiting device increases with the increment of sensed temperature. The current-limiting device has a resistance close to or equal to the current-limiting resistance value at a temperature at which the LED operates normally. When the temperature of the LED gradually increases to an abnormal temperature, current allowable to be flowed through the current-limiting device gradually decreases to be lower than LED operating current.

Abstract: Illuminated moldings with integrated control are provided. The illuminated moldings with integrated control use low voltages, are energy efficient and easy to install and use. The illuminated moldings with integrated control may be attached to various surfaces of different objects. The illuminated molding is insulated and does not carry electricity, and can be placed under water with never a risk of shock even if something damages or cuts the molding. Further, the illuminated moldings with an integrated control allow a user to control various illumination characteristics and effects such as the turn on or turn off time, the color, the brightness, the transition between various operation modes. The integrated control may be wired or wireless.

Abstract: Semiconductor light emitting devices include a first string of at least one blue-shifted-yellow LED, a second string of at least one blue-shifted-green LED, and a third string of at least one LED that emits light in the red color range. These devices include at least a first circuit that is configured to provide an operating current to at least one of the first LED or the second LED and a second circuit that is configured to provide an operating current to the third light source. The drive currents supplied by the first and second circuits may be independently controlled to set a color point of the light emitting device at a desired color point.

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: Lamp color matching and control systems and methods are described. One embodiment includes a lighting node and a controller. The lighting node can include a plurality of light emitting diodes configured for illumination and further configured for optical communication with the controller, a communicator configured for radio communication with the controller, a memory configured to store a node identifier, a control logic, and a temperature sensor. The controller can include an optical sensor configured to sense the correlated color temperature and brightness of the lighting node and further configured for optical communication with the lighting node, and a communicator configured for radio communication with the lighting node. The controller can calibrate the lighting node as well as perform light copy and paste, light following, and light harvesting operations with the lighting node.

Abstract: A data communication method is described for transmitting a data packet comprising data bytes in a daisy chained bus structure of a LED illumination system. The method comprises: the nodes of a group, except the last node of the group retransmitting the data packet without removing a first data byte from the incoming data packet; and the last node in the group removing the first byte from the data packet before retransmission. The invention further comprises a communication node, illumination assembly and bus structure implementing the method according to the invention.

Abstract: The present invention relates to a method and an arrangement for visual indication of an electrical quantity, being one or several of power, current and/or voltage through a conductor. The arrangement comprises a substantially wire shaped illuminator and a controller which controls at least one illumination characteristic of said illuminator with respect to said electrical feature.

Abstract: A light emitting diode (LED) driver circuit controls switching of an output transistor. The LED driver circuit monitors inductor current flowing through an output inductor that is coupled to one or more LEDs. In response to detecting that the inductor current has reached a peak value, the LED driver circuit switches OFF the output transistor. The LED driver circuit switches ON the output transistor in response to detecting zero crossing of the inductor current. The LED driver circuit may detect zero crossing of the inductor current from a gate voltage of the output transistor by detecting for a negative spike.

Abstract: A flexible, integrally formed single piece light emitting diode (LED) light wire that provides a smooth, uniform lighting effect from all directions of the LED light wire. The integrally formed single piece LED light wire contains a conductive base comprising first and second bus elements formed from a conductive material. The bus elements distribute power from a power source to LEDs that are mounted on the first and second bus elements so that it draws power from and adds mechanical stability to the first and second bus elements. The flexible, integrally formed single piece LED light wire is assembled so that the first and second bus elements are connected to each other prior to the LED being mounted and such integrally formed single piece LED light wire is formed without a substrate.

Abstract: A software touchscreen displayed on start up for a LAN for an automated light. The software touchscreen is displayed by the software on initial startup, and later, after the initial startup, the same touchscreen is used for controlling the light.

Abstract: A lighting apparatus for retrofitting an existing luminaire includes a plurality of light emitting diodes (LED) of similar or differing wavelengths arranged and configured in at least one light bar array, a heat sink module thermally coupled to the at least one light bar array, an electronic power module electrically coupled to the at least one light bar array, and a plate coupled to the at least one light bar array, electronic power module and the heat sink module, the plate arranged and configured for coupling to the luminaire to provide quick and easy installation and replacement of the at least one light bar array, heat sink module and electronic power module into and from the luminaire.

Abstract: An outdoor overhead lamp assembly uses light emitting diodes to provide illumination for an area to be illuminated. The lamp assembly includes a unitary housing, which may be formed from a single casting. The housing includes mechanical mounting structure for mounting the housing to a mast arm. The housing includes an electrical compartment for housing electrical components and connections. Heat sink fins are formed on the integral housing that provide for thermal control of the electronic components and LED modules within the lamp assembly. The LED modules are mounted to aiming platforms within an optical compartment for the assembly. An external lens provides environmental protection for the LEDs and their individual lenses. The housing may also include structures for mounting decorative coverings or “skins” to accommodate different aesthetic requirements.

Abstract: The invention concerns a lighting device for creating dynamic atmospheres, the lighting device comprising: a light source adapted to operate in a plurality of color states, the light source emitting differing colors for each color state; a controller for controlling the color state of the light source; the controller comprising a random generator to provide a transition between a previous and a subsequent state, wherein the controller is adapted to provide the transition based on probabilistic output provided by the random generator implementing a stochastic model, the probabilistic output depending on the previous color state. In addition, a method is provided for generating the stochastic model; and a method for creating dynamic atmospheres based on probabilistic output provided by the stochastic model.

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: A high CRI white light emitting device comprises: a blue solid state light emitter (LED) operable to generate blue light; a phosphor material operable to absorb a portion of the blue light and to emit green/yellow light and a red solid state light emitter (LED) operable to generate red light. The emission product of the device comprises the combined light generated by the blue and red LEDs and green/yellow light generated by the phosphor material and appears white in color. The device further comprises a drive circuit operable to compensate for variation in the ratio (relative contribution) of red to blue light in the emission product such as to ensure that said variation is less than 20% over an operating temperature range of at least 25° C. The drive circuit can reduce variation in the CRI and CCT of the device's emission product over the operating temperature range.

Abstract: An illumination module includes a plurality of Light Emitting Diodes (LEDs) located in different zones to preferentially illuminate different color converting surfaces. The flux emitted from LEDs located in different zones may be independently controlled by selectively routing current from a single current source to different strings of LEDs in the different zones. In this manner, changes in the CCT of light emitted from LED based illumination module may be achieved.

Abstract: An LED lighting arrangement on a flexible substrate. The flexible substrate has an adhesive on a first surface. Straps are attached to the first surface of the flexible substrate by the adhesive. Each strap has a first surface, a second surface, and first and second terminals exposed on the first surface. The attachment of each strap to the substrate is with the second surface of the strap adhered to the substrate. LEDs are attached to the straps and coupled to the terminals on the straps. An arrangement of one or more wires is attached to the first surface of the flexible substrate by the adhesive. The wires are connected to the first and second terminals on the first surfaces of the plurality of straps to provide power to the LEDs.

Abstract: A method of configuring an LED driver is disclosed. The LED driver being arranged to provide a supply current to an LED fixture comprising a plurality of LEDs. The method comprises: identifying the LED fixture (LF), sending via a communication network (NTW) a configuration request to a configuration database (DB), receiving configuration data from the configuration database; and configuring the LED driver (LPS) according to the configuration data.

Abstract: A music flasher controller comprises a central control module, a plurality of execution modules, a plurality of light-emitting units, a power supply module, a music encoding module, a player, a signal collecting module, and a signal analysis module, thereby allowing rhythmed on/off change of the control lamp with music, exhibiting a music-light-show effect and having a flexible form, with the player not necessary to be wire-connected with the signal collecting module, thus having the advantages of easy construction, simple installation, and effective cost reduction. A music flasher control system equipped with the music flasher controller enables flexible addition or reduction of the lamp group, thus having the advantage of high scalability. A control method of the music flasher controller is also provided such that the lamp can be on/off with the music rhythm.

Abstract: According to the present invention, anode-side ends of LED arrays (1011) and (1012) are connected to an identical point. A constant current circuit (1003) drives the LED array (1011) by a constant current, whereas, a constant current control circuit (3) drives the LED array (1012) by a constant current and by pulses.

Abstract: A ballast (4) for providing power to a high intensity discharge lamp (8) includes a first sensor (32) and a control subsystem (16). The first sensor (32) generates a first signal indicative of a current level in the ballast (4). The control subsystem (16) computes a real time power level of the ballast (4) based at least upon the first signal, compares the computed real time power level to a specified power level, and modifies a frequency of operation of the ballast (4) in response to the comparison. The first sensor (32) can measure the current level at an output of the ballast (4). The ballast (4) can also include a second sensor (32) that generates a second signal indicative of a voltage output of the ballast (4). The control subsystem (16) can compute the real time power level of the ballast (4) based upon the second signal.

Abstract: A driving circuit includes a first PWM driving module and a second PWM driving module. The first PWM driving module generates a first square-wave signal to drive a first illumination unit according to a first data signal of a data stream, wherein the first square-wave signal, having a rising edge located at the beginning of the display cycle, represents an illumination period of the first illumination unit in a display cycle. The second PWM driving module generates a second square-wave signal to drive a second illumination unit according to a second data signal of the data stream, wherein the second square-wave signal, having a falling edge located at the end of the display cycle and having a rising edge being behind the rising edge of the first square-wave signal, represents an illumination period of the second illumination unit in the display cycle.

Abstract: A system and method are provided for a pixel module to determine its location in a large scale LED display. The system and method determine the pixel module's location based upon the data received by the module and the identity of the module's port via which the data was received.

Abstract: A remotely controllable track lighting system includes a track with lamps supported on the track that are individually controlled by a wireless remote. Each lamp may be set to different intensity levels (e.g., high, mid, low, off) or to the same intensity level. All lamps may be set, upon initially turning on the lamps or at another time, to previously set intensity levels. The track system may also be powered via a wall switch where initially turning on the lamps via the wall switch causes all of the lamps to return to their previously set intensity levels or the user can move the wall switch off then on within a short period of time (e.g., 3 seconds) to cause all of the lamps to be set high.

Abstract: A serial-type LED device includes p light source units and a dimming circuit. Each light source unit includes first and second terminals, m light strings and m current balance units. Each light string includes LEDs coupled in series to have a first terminal coupled to the first terminal of a corresponding light source unit and a second terminal coupled to the second terminal of the corresponding light source unit through a corresponding current balance unit. The first terminal of the first light source unit is coupled to a second DC voltage, and the second terminal of the i-th light source unit is coupled to the first terminal of the (i+1)-th light source unit, where m and p are integers greater than or equal to 2 and i is any integer from 1 to (p?1). The dimming circuit coupled to the second terminal of the p-th light source unit controls the second DC voltage according to a current outputted from the p-th light source unit.

Abstract: An LED lighting device is provided with output impedance control to stabilize an optical output across a wide current range. A switching power supply generates the output current, with switching control circuitry to determine switching frequency and an ON period for an associated switch, and to turn on/off the switch according to the determined frequency and ON period. An impedance element is coupled across output terminals for the lighting device, with an impedance value set so that a load current is larger than a current flowing to the impedance element at maximum on-duty of the switch and a current flowing to the impedance element is larger than the load current at minimum on-duty. The impedance element may be a variable impedance element, wherein an impedance control circuit adjusts the variable impedance such that an impedance value for minimum on-duty of the switch is smaller than that for a maximum on-duty.

Abstract: Aspects of the disclosure provide a lighting system. The lighting system includes a transformer having a primary winding on a receiving path and a secondary winding on a delivering path. The receiving path receives electric energy regulated based on a dimming angle. The delivering path delivers the received electric energy. According to an aspect of the disclosure, the lighting system includes a secondary switch, and a dimming controller. The secondary switch is switched on to couple a light source, such as an LED array, and the like, with the delivering path to emit light in response to the delivered electric energy and is switched off to decouple the light source from the delivering path. The dimming controller is configured to detect the dimming angle based on an electrical property of the delivering path. Then, the dimming controller switches on and switches off the secondary switch based on the dimming angle.

Abstract: Electronic devices require correct power in order to operate correctly. Receiving an incorrect power signal could potentially result in immediate and/or long term harm to the electronic device and/or catastrophic conditions. Certain devices, such as programmable logic controller (“PLC”) modules, may provide variable power to electronic devices, such as field devices comprising sensors and/or actuators. The present inventors have recognized that deciphering between AC and DC input signals before coupling electronic devices to such power sources may advantageously avoid harmful and/or catastrophic conditions. Aspects of the present invention provide an electronic circuit for deciphering between an AC and a DC input signal. Systems and methods are also described.

Abstract: A method of reducing electricity usage during peak demand periods includes the steps of establishing predetermined load reduction criteria representative of a desire by a power provider to reduce loading on an electricity supply grid, and coordinating with a facility having lighting equipment to permit the power provider to turn-off one or more of the lighting equipment by sending instructions to a master controller at the facility in response to the predetermined load reduction criteria, and establishing a list of lighting equipment to be turned-off in response to the instructions, and configuring the master controller to send an override control signal to the lighting equipment to implement the instructions, and configuring the lighting equipment to send a response signal to the master controller providing a status of the lighting equipment.

Abstract: A pulse width modulation (PWM) dimming circuit comprises a switch unit, a current generation unit, a mirror current source, a multi-path output unit, a plurality of current balance units and a plurality of LED lamp strings. The switch unit receives a PWM signal which controls the switch on or off. The current generation unit is connected with the switch unit and generates a current of a predetermined magnitude when the switch unit is on. The mirror current source is connected with the current generation unit and receives the current to generate a mirror current. The multi-path output unit is connected with the mirror current source and receives and output the mirror current in multiple paths. The current balance units are connected between the multi-path output unit and the LED lamp strings respectively. The PWM dimming circuit decreases both the difficulty and the manufacturing cost and is easy to operate.

Abstract: A method of automatically programming a new load control device that replaces an old load control device takes advantage of a remote identification tag (e.g., an RFID tag) located in the vicinity of the old device. The remote identification tag stores an identifier that is representative of a location in which the old device is installed. The method includes the steps of: (1) storing a setting of an old device in a memory of a controller; (2) associating the setting with the identifier of the old device in the memory of the controller; (3) the new device retrieving the identifier from the remote identification tag after the new device is installed in the location of the old device; (4) the new device transmitting the identifier to the controller; and (5) the controller transmitting the setting of the old device to the new device in response to receiving the identifier.

Abstract: A file system for a stage lighting system that maintains the different files associated with the stage lighting system. Each of the files that can represent an effect are maintained within the system within a configuration file. The configuration file can be updated on each start of the system so that the system can maintain information indicative of current configuration files. A test mode can also be entered in which a pre-formed show can be tested against the current state of the configuration files.

Abstract: A solid-state lighting system comprises a plurality of light-emitting devices (e.g., light-emitting diodes) and an alternating current to direct current (AC-DC) converter that converts AC power to DC power for powering the plurality of light-emitting devices. The AC-DC converter is configured to perform AC-DC conversion directly, without the need for or use of a bridge rectifier or step-down transformer. According to one aspect of the invention, the light-emitting devices of the solid-state lighting system are autonomous and individually powered by a plurality of DC power supplies generated from the DC power produced by the AC-DC converter. According to another aspect, a plurality of phase-offset dimmer control signals are generated based on waveform distortions in a dimming signal produced by a conventional dimmer switch. The phase-offset dimmer control signals are used to individually control the dimming of the light-emitting devices.

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 plant illumination apparatus includes a light source module including a first light source and a second light source generating lights having different wavelengths, an environment-detecting module detecting an external environment to obtain a real-time environment parameter, and a control module connected to the light source module and the environment-detecting module. The control module includes a processor unit and a storage unit storing a database of plant growing environment parameters. The processor unit loads at least one preset growing environment parameter corresponding to a plant growth timing from the database of plant growing environment parameters, and compares the preset growing environment parameter with the real-time environment parameter to output at least one comparison result. The processor unit adjusts the first light source and the second light source according to the comparison result, so that an adjusted environment parameter matches the preset growing environment parameter.

Abstract: Techniques are disclosed for providing a decentralized intelligent nodal lighting system. The intelligent nodal lighting system may be controlled using a wireless protocol, such as Wi-Fi, and each lighting node in the system may have its own independent Wi-Fi address and may receive, store, and interpret commands from a wirelessly connected controller. Each intelligent light node may contain a CPU and memory for storing and interpreting commands from the controller to achieve a desired light color, intensity, or quality. In some embodiments, individual lighting nodes may be dynamically added or removed from the lighting system without interrupting the system's operation.

Abstract: Control of lighting fixtures in a lighting network may be distributed among the lighting fixtures. The lighting fixtures may be broken into groups that are associated with different lighting zones. At least some of the lighting fixtures will have or be associated with one or more sensors. Within the overall lighting network or the various lighting zones, the lighting fixtures may share sensor data from their sensors. Each lighting fixture may process sensor data provided by its own sensor, a remote standalone sensor, or lighting fixture, and process the sensor data according to the lighting fixture's own internal logic to control operation of the lighting fixture. The lighting fixtures may also receive control input from other lighting fixtures, control nodes, light switches, and commissioning tools. The control input may be processed along with the sensor data according to the internal logic to further enhance control of the lighting fixture.

Abstract: A semiconductor apparatus includes an input terminal to which an input voltage is applied; an output terminal at which an output voltage is obtained; a power supply circuit unit configured to generate the output voltage from the input voltage, the output voltage having a value corresponding to a duty cycle of a voltage setting signal that is externally applied to the semiconductor apparatus; and a determination circuit unit determining whether the voltage setting signal has a predetermined signal level for the duration of a first predetermined time or longer. The determination circuit unit activates the power supply circuit unit when the voltage setting signal does not have the predetermined signal level for the duration of the first predetermined time or longer. The power supply circuit unit is deactivated when the voltage setting signal has the predetermined signal level for the duration of the first predetermined time or longer.

Abstract: A lighting system includes a plurality of LED lights having at least two different color LED lights. A controller is coupled to the LED lights for independently controlling the intensity of sets of different color LED lights. A program stored on a storage device is operable on the controller to control the intensity of each of the different sets of different color LED lights to produce light representative of color and intensity changes of outdoor daylight conditions.

Abstract: In embodiments of the present invention, a method and system is provided for designing improved intelligent, LED-based lighting systems. The LED based lighting systems may include fixtures with one or more of rotatable LED light bars, integrated sensors, onboard intelligence to receive signals from the LED light bars and control the LED light bars, and a mesh network connectivity to other fixtures.

Abstract: An LED driver includes an LED driver circuit adapted to receive a 110 volt AC current and to rectify the AC current into a low voltage DC output current; a PWM generator including control means to generate a PWM signal with an adjustable duty cycle; means operatively connecting the PWM generator to the LED driver circuit to provide the driver circuit with the PWM signal, the LED driver circuit generating a fixed frequency pulse in which the pulse width is modulated proportional to the PWM signal duty cycle to control LED brightness, wherein the driver circuit, the PWM generator and the connecting means are sized to fit within a standard 110 volt AC outlet box.

Abstract: A control system (10) comprises: a controlled device (15) controlled by a controller (30) having receiving means (34) for receiving command signals (40), and having a first, second and third storage locations (31, 32, 33) for storing a personal ID or address (PID), network ID (NID), and the ID (RCID) of a remote control device, respectively; at least one user-operable remote control device (17), designed for transmitting command signals. A command signal comprises a target address code, a network ID code, a sender address code, and a command code. Normally, the controller only responds to control signals if target address code, network ID code, and sender address code match with the information in memory. The controller is capable of operating in a NO NETWORK mode (200), in which the controller responds to a reset command irrespective of target address code, the network ID code, and the sender address code.

Abstract: A linear light-emitting diode (LED)-based solid-state lamp using a novel voltage sensing and control mechanism operates normally in both single-ended and double-ended luminaire fixtures. The voltage sensing and control mechanisms automatically detect supply source configuration in the fixture and make proper management so that the linear LED lamp works in any fixtures without operational uncertainty or risk of fire. When used with shock protection switches on the two lamp bases at two opposite ends, the universal lamp fully protects a person from possible electric shock during initial installation and re-lamping.

Abstract: A system and method for driving one or more LEDs by regulating their brightness by controlling the LEDs' average current or voltage. The system includes a switching power converter and an integrated digital regulator with at least one of electrical, thermal, and optical feedbacks. The regulator is constructed as a PI or PID controller for continuous mode of operation of the power converter. Current is provided through an inductor and a power switch during an on time of the power switch. The ampseconds of the inductor are measured at an off time and compared with a periodic ramp signal. A set reference signal is also compared with the periodic ramp signal. Based on the comparisons between the ramp signal, the measured ampseconds, and the reference signal, a control signal is generated to regulate the peak current through the power switch.

Abstract: A driver circuit for one or more LEDs includes a power circuit having an output terminal, a capacitor coupled to the output terminal and a switch, and a control circuit coupled to the power circuit for controlling the power circuit. The control circuit is configured to operate the switch for coupling a resistance in series with the capacitor in response to detecting an open circuit condition at the output terminal. Additionally, or alternatively, the driver circuit may include a switched mode power supply, and the control circuit may be configured to switch operation of the switched mode power supply from a current control mode to a voltage control mode, and reduce a current setting for the current control mode, in response to detecting an open circuit condition at the output terminal.