Abstract: A microcontroller-based multifunctional electronic switch uses a detection circuit design to convert external motion signals into message carrying sensing signals readable to the microcontroller. Based on the time length of sensing signals and the format of the sensing signals received in a preset instant period of time the microcontroller through the operation of its software program codes written in the OTPROM is able to recognize the working modes chosen by the external signal generating user and thereby selecting the appropriate loops of subroutine for execution. The system and method of the present invention may simultaneously be applicable to detection circuit design using infrared ray sensor, electrostatic induction sensor, conduction based touch sensor or push button sensor for performing multifunction such as controlling the on/off switch, the illumination power and the color temperature within the capacity of a single lighting device or an electrical appliance.

Abstract: The present invention discloses a driving circuit including a rectifying circuit and a first current-controlling circuit. Input terminals of the rectifying circuit are connected to output terminals of an AC power source. The first current-controlling circuit and a plurality of light-emitting elements be driven are connected in series, and then are connected between two output terminals of the rectifying circuit. The driving circuit further includes a plurality of switches and a switch-controlling circuit; the switches are connected in parallel with two terminals of one or some light-emitting elements connected in series to form many light-emitting element subunits. Control-signal output terminals of the switch-controlling circuit are connected to control terminals of the switches respectively, to control the switches in an ON-OFF state according to an instantaneous value of a DC voltage outputted from the rectifying circuit, for controlling an amount of light-emitting elements which should be lighten.

Abstract: In one novel aspect, driving a string of light emitting elements, such as LEDs, includes applying a drive signal to circuitry that regulates a voltage appearing at a source of a transistor whose drain is coupled to one end of the string of light emitting elements and whose source is coupled to ground through a resistive element. Sequencing of the drive signal and a voltage supply signal for the light emitting elements is controlled such that the voltage supply signal is not increased above a predetermined allowable voltage for the transistor until the transistor is turned on, and such that the supply voltage is not decreased below the allowable voltage for the transistor until the transistor is turned off.

Abstract: When a pulsating current is applied to an LED string included in an LED lighting device, and the number of LEDs caused to light up is changed, the LED lighting device is in efficient, since there are LEDs lighting up for a long period of time and LEDs lighting up only for a short period of time. The LED string includes LED string 407 that lights up for a long period of time and LED string 408 that lights up only for a short period of time within a period of the pulsating current. The element size of the LED 102 included in LED string 407 is different from the element size of LED 203 string 408. Thus, the amount of light emission per unit area LED string 407 may be equal to the amount of light emission per unit area LED string 408.

Abstract: A LED driver is disclosed herein. In one embodiment, the LED driver comprises a rectifier circuit, a driving current generating circuit, a bus voltage detection circuit, a LED configuration control circuit, and a LED array. The LED driver according to the present disclosure reconfigures the prior LED array, balances usage of each LED by switching operation of each LED, which results in long lifetime of the LED driver while reducing power dissipation or increasing a PF value.

Abstract: The lighting circuit comprises an AC input connectable to receive an AC input voltage, a switched LED array comprising a plurality of LEDs reconfigurable into a plurality of configurations and having an input for receiving a LED driving voltage, a switched capacitor array having an input for receiving a charging voltage and an output selectively connectable to the input of the switched LED array and comprising a plurality of capacitors and switches connected to selectively couple the capacitors across the input or output, a first switched rectifier connected between the AC input and the switched LED array, a second switched rectifier connected between the AC input and the switched capacitor array, and, a control system configured to monitor the AC input voltage and control the switched LED array, the switched capacitor array and the first and second switched rectifiers based on the AC input voltage and a desired light output.

Abstract: An LED lamp according to one aspect of the present invention includes: a first LED array that is annularly arranged on a mounting board and includes first LED elements connected in series; a second LED array that is arranged within an inner circumference of the first LED array on the mounting board, includes second LED elements connected in series, and emits light having an emission color different from an emission color of the first LED array; a FET switch arranged in series on a path through which current flows to the second LED array; and a constant power output circuit, wherein the number of the first LED elements is greater than the number of the second LED elements, and a total forward voltage of the first LED array is greater than a total forward voltage of the second LED array.

Abstract: A straight tube LED lamp according to one aspect of the present invention includes: a first LED array including first LED elements connected in series; a second LED array that includes second LED elements connected in series, and emits light having a different emission color from an emission color of the first LED array; a FET switch provided in a path through which current flows to the second LED array; and a constant power output circuit that outputs power without changing a total value of the power, wherein the number of the first LED elements connected in series is greater than the number of the second LED elements connected in series, a total forward voltage of the first LED array is greater than a total forward voltage of the second LED array, and the first LED elements are in alignment with the second LED elements.

Abstract: An LED lamp according to one aspect of the present invention including: a first LED array including first LED elements connected in series; a second LED array that includes second LED elements connected in series and emits light having an emission color different from an emission color of the first LED array; a FET switch that is provided between the two LED arrays and switches between a first current path to the first LED array and a second current path to the second LED array; a constant power output circuit that outputs the same power value to a current path through which current flows before the switching and a current path through which current flows after the switching, wherein a total forward voltage of the first LED array is different from a total forward voltage of the second LED array.

Abstract: A lighting device includes a plurality of light emitting diodes (LEDs) configured to emit a light. The lighting device further includes a color controller configured to repeatedly assert and deactivate a control signal to control whether one or more LEDs of the plurality of LEDs are turned on or turned off. The color controller asserts the control signal for a first time period and deactivates the control signal for a second time period, where a color of the light emitted by the plurality of LEDs depends on the first time period and the second time period. The color controller changes the color of the light emitted by the plurality of LEDs by changing one or both of the first time period and the second time period.

Abstract: A microcomputer is configured to perform a first control and a second control. The first control is of: starting operation of a power converter, when a first power supply voltage exceeds a starting voltage; and stopping the operation of the power converter, when the first power supply voltage is below a maintaining voltage. The second control is of: switching off a second switching element, when a second power supply voltage exceeds a first threshold voltage; maintaining an off-state of the second switching element until the second power supply voltage is below a second threshold voltage; and switching on the second switching element, when the second power supply voltage is below the second threshold voltage.

Abstract: A lighting device includes a power converter, a second switching element and a microcomputer. The power converter is configured to convert DC power that is received from a power supply, and supply an output obtained by the conversion to a load. The second switching element is configured to short-circuit at least one LED of a plurality of LEDs, as part of the load. The microcomputer is configured to control the power converter, and control switching on/off of the second switching element. The microcomputer is configured to reduce an output current of the power converter, in a case where a power supply voltage of the battery is a reference voltage or less. A reduction amount of the output current in an on-state of the second switching element is lower than the reduction amount of the output current in an off-state of the second switching element.

Abstract: A circuit is disclosed for driving a plurality of LED strings from an AC supply and arranged to, in use, drive current through a series arrangement of a plurality N of the LED strings when the AC voltage is sufficient to drive the plurality N of the LED strings: the circuit comprising a first current source configured to be switchably connected to a one end of said series arrangement of N LED strings; a series combination of a second current source and a heat dissipater, wherein the series combination of the second current source and the heat dissipater is arranged in parallel with the first current source; and a current balancer for balancing the current through the first current source and the second current source. A driver for such a circuit is also disclosed.

Abstract: To provide a direction indicating apparatus that is less susceptible to a change of a power supply voltage and can reduce the difference in brightness of a direction indicating lamp using an LED element between a direction indicating operation and a hazard operation. A direction indicating apparatus includes a pulse signal generating part, a first switching element, a variable resistor circuit, a direction indicating switch, a hazard switch, first and second direction indicating lamps, a voltage detecting part and a lighting status detecting part.

Abstract: A light emitting element driving device, which flashing-drive a plurality of light emitting element arrays connected in parallel by switching elements connected in series with each of the plurality of light emitting element arrays, the light emitting element driving device including: a current detection unit configured to detect respective currents flowing through each of the plurality of light emitting element arrays as currents of the light emitting element arrays; a selection unit configured to select the smallest current of the light emitting element arrays of the detected currents obtained by the current detection unit; and an output voltage control unit configured to control output voltage supplied to the plurality of light emitting element arrays so that the current of the light emitting element arrays selected by the selection unit becomes a preset reference current value.

Abstract: A lighting system includes a first light string configured to receive a first voltage and output continuous illumination, a second light string, a module electrically connected to the second light string, and a controller electrically connected to the module. The controller receives a user input and outputs a control signal based on the user input. The module receives the control signal and selectively controls a second voltage to the second light string according to the control signal.

Abstract: LED drivers and lighting systems having a dynamically reconfigurable switching network is disclosed. The lighting system comprises a switching network which provides interconnections between LEDs or LED lamps that can dynamically reconfigure between largely parallel circuits and largely serial circuits as the instantaneous voltage of a power supply varies. When the instantaneous voltage of the power source is low, the switching network interconnects the LED lamps in a largely parallel configuration. As the instantaneous voltage increases, the switching network reconfigures and interconnects the LED lamps with increasing serial configurations. As the instantaneous voltage begins to decrease, the switching network reconfigures and interconnects the LED lamps back to a largely parallel configuration.

Abstract: A control circuit performs ON/OFF control for a switching element so that LED current flowing in an LED unit is within a rated current range. In the case where the LED unit is lit, a voltage applied between both ends of series connection of a reactor and the LED unit becomes a first bus voltage, when the switching element is ON, and becomes a voltage lower than the first bus voltage, that is determined based on the first bus voltage and a second bus voltage, when a switching element is OFF.

Abstract: Described herein is a circuit and method for independent control of series connected light emitting diodes (LEDs). The circuit includes a first light emitting diode (LED) connected in series with a second LED. A current source is connected in series with the first LED and the second LED and a shunt circuit is connected in parallel with the first LED and the second LED. The shunt circuit includes a pair of serially connected resistors. The shunt circuit prevents inadvertent excitement of the LEDs due to leakage currents but minimally affect illumination characteristics of the LEDs. A pair of transistors is connected to the first LED and the second LED, respectively, and is biased using a set of bias resistors. A tri-state control signal switches on and off the pair of transistors and enables excitation of the first LED, the second LED or both via the current source.

Abstract: An electronic device is provided. The electronic device includes a plurality of load units, a plurality of serial-parallel switch units and a control module. The control module switches the serial-parallel switch units to a first state or a second state according to a level variation of an input voltage. Connection relations of the load units are correspondingly changed according to the level variation of the input voltage. In this way, the electronic device can be driven by an alternating-current voltage.

Abstract: A lamp including a first set of light emitting diodes configured to generate first light, a second set of light emitting diodes configured to generate second light, and a third set of light emitting diodes configured to generate third light. The first light, the second light, and the third light combine to produce white light. A first switch is located at a base portion of the lamp. The state of the first switch corresponds to a color temperature of the white light. A color temperature adjustment module is configured to vary outputs of the first, second, and third sets of light emitting diodes in accordance with the color temperature of the white light selected by a user using the first switch.

Abstract: A LED backlight driving circuit is disclosed. The driving circuit includes a boost circuit for converting an input voltage to a needed output voltage and for providing the output voltage to at least one LED strings, a follower circuit connecting to a negative end of the LED string, and a reference voltage module connecting to a reference voltage and the follower circuit. The follower circuit is for detecting a negative end voltage of the LED string and for generating a follower voltage according to the negative end voltage. The follower voltage couples with a reference voltage module. The reference voltage module adjusts the output voltage according to the follower voltage generated by the follower circuit. The output voltage is adjusted in accordance with the voltage drop of the LED string. In addition, a liquid crystal device including the LED backlight driving circuit is also disclosed.

Abstract: An enhanced control mechanism for an LED light string system is provided for switching between one of two DC output phases or polarities so as to actuate one or the other of two LEDs within the bulbs on the light string. The control mechanism is further configured to allow switching so as to pass through the input power provided by a high-to-low voltage converter that is plugged into its electrical power feeding end. The control mechanism may then provide rectified AC voltage, or DC voltage, of various switched values to the LED string according to the particular needs of the LED bulbs.

Abstract: Provided is a lighting apparatus using LEDs (light-emitting diodes having improved flicker performance. In general, in a direct-drive LED lighting apparatuses of the related art which use no switching-mode power supply (SMPS), percent flicker (hereinafter referred to as “% F”) is 100%. In contrast, the % F of the LED lighting apparatus having improved flicker performance according to the present invention is 40% or less that is equivalent to the % F of fluorescent lamps using a magnetic ballast.

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: Circuits and methods prevent ringing of white LED drivers by adding a high voltage coil switch (CS) circuit, a high voltage edge detector circuit, and a boot strap circuit. The coil switch (CS) circuit to short the coil of a boost converter, when the current in it reaches zero during DCM, comprises a series of 2 identical HV enhancement NMOS with bulk switch system. An Edge Detector circuit senses the fast falling edge of an LX node. A Boost Strap circuit lifts the gate of coil switch circuit above the battery voltage level and turns on the coil switch. A Boost Strap (BS) system lifts the gate of CS above the VBAT level and turns on CS, wherein minimum current is required to minimize impact on efficiency.

Abstract: A protection circuit of a backlight driver circuit includes a backlight driver circuit. The backlight driver circuit includes a backlight driver integrated circuit (IC), and the backlight driver IC includes a protection pin that controls the backlight driver IC to enter a protection mode. The backlight driver circuit further includes a protection circuit, and the protection circuit includes a monitoring unit that monitors a temperature of the backlight driver circuit. When the temperature of the backlight driver circuit exceeds a preset temperature, the monitoring unit sends the protection signal to the protection pin to control the backlight driver IC to enter the protection mode.

Abstract: An LED controller and a method for controlling an LED device is disclosed. A current sense signal is representative of a load current flowing through the LED device. The current sense signal is compared with an upper threshold value and a lower threshold value. Current is provided to the LED device via an inductor coupled in series with the LED device when the current sense signal exceeds the upper threshold. A load current loop is closed over a free-wheeling diode when no current is provided to the LED device while the current sense signal is below the lower threshold. The upper threshold and the lower threshold are adjusted dependent on the current sense signal such that peak values of the current sense signal match corresponding desired peak values.

Abstract: In one embodiment, a driver circuit for light-emitting diodes has a first DC/DC converter (DCDC1) with an input (IN) for feeding a supply voltage (VBAT) and with a first output (OUT), a second DC/DC converter (DCDC2), which is coupled on the output side to the first output (OUT) and is designed for operation with energy supplied in advance, a current source (IFlash) that is connected to the first output (OUT), and a main output (LED OUT), which is coupled to the current source (IFlash) and is designed to be connected to the light-emitting diodes. The first DC/DC converter (DCDC1) is designed for operation in a current-limiting mode. The second DC/DC converter (DCDC2) is designed for regulation to a nominal voltage (Vds) of the current source (IFlash).

Abstract: A luminaire according to one embodiment includes a DC power supply circuit, a switching power supply, and a lighting load. The DC power supply circuit converts an AC voltage controlled in phase to a DC voltage. The switching power supply is connected to the DC power supply circuit, and is controlled so that an input current becomes a constant current. The lighting load is connected as a load circuit of the switching power supply.

Abstract: A lighting apparatus is disclosed. The lighting apparatus is capable of achieving improved aesthetics by irradiating mood lighting into a storage container and also, of functioning to display a variety of status information about the storage container to the outside and to sterilize the interior of the storage container.

Abstract: Semiconductor light emitting devices are provided that include a first string of light emitting diodes (“LED”) that emit unsaturated light having a color point that is within at least eight MacAdam ellipses of one or more points within a first blue-shifted-yellow region on the 1931 CIE Chromaticity Diagram, a second string of LEDs that emit unsaturated light having color point that is within at least eight MacAdam ellipses from one or more points within a second blue-shifted-green region on the 1931 CIE Chromaticity Diagram, and a third light source that emits radiation having a dominant wavelength between 600 and 720 nm. A drive circuit is provided that is configured to supply a first drive current to the first string of LEDs, a second drive current to the second string of LEDs and a third drive current to the third string of LEDs, wherein at least two of the first, second and third drive currents are independently controllable.

Abstract: An illumination apparatus capable of controlling current amounts of LEDs and enabling various electrical connections is provided. An applied driving voltage is divided, and a divided voltage is compared with a reference voltage to generate sampling signals. A logic operation is performed on the sampling signals to generate a switch control signal and a current control signal. The switch control signal controls electrical connection of LEDs to which the driving voltage is applied. Also, the current control signal may select LEDs that are to perform light emitting operations. A target voltage is set by processing the sampling signals and used to determine driving currents of the LEDs that are to perform the light emitting operations.

Abstract: Disclosed herein is a light emitting diode (LED) driving apparatus including: at least one energy storages connected in series with each other; a plurality of LEDs each connected in parallel with each of the energy storages; and a switching control unit selectively connecting the at least one energy storages according to a level of applied voltage to charge/discharge voltage in/from the selected energy storages and control driving of the LEDs by the charging/discharging operation. Therefore, it is possible to easily drive the LEDs without a converter.

Abstract: An electrical circuit is described that comprises a first string and second LED string coupled in parallel, a first and second transistor, at least one bypass transistor, and a controller. The first transistor is coupled to the first LED string at a first terminal of the first transistor. The second LED string includes multiple LED color strings coupled in series. The second transistor is coupled to the second LED string at a first terminal of the second transistor. The bypass transistor is coupled to one of the color strings. A first terminal of the bypass transistor is coupled to a first terminal of the color string. The second terminal of the bypass transistor is coupled to a second terminal of the color string. The controller controls a gate voltage of the first and second transistors and the bypass transistor to operate all transistors in linear modes.

Abstract: A driving circuit includes a plurality of light-emitting units, a plurality of switches, and a voltage generating module. The light-emitting units are coupled with each other in series and are driven with an input voltage varying according to a frequency. Each switch has a preset voltage and an activation voltage and includes a light-emitting end, a control end, and a setting end. The light-emitting ends are coupled with the light-emitting units, and the setting ends of the switches are coupled with each other. The voltage generating module includes a plurality of control units and provides a plurality of control voltages to the switches, and each switch is driven to be activated or to be deactivated according to a relation of the preset voltage and a difference between the control voltage and the activation voltage when the input voltage drives the light-emitting units, the switches, and the control units.

Abstract: A lighting system includes methods and systems to mix colors of light emitted from at least two LED emitters. In at least one embodiment, the lighting system includes a controller that responds to phase-cut angles of the dimming signal and correlates the phase-cut angles with a predetermined black body radiation function to dynamically adjust a color spectra of the mixed light in response to changes in phase cut angles of the phase-cut dimming level signal. In at least one embodiment, the controller utilizes the predetermined black body radiation function to dynamically adjust the color spectra of the mixed, emitted light in response to changes in phase cut angles of a phase-cut dimming level signal. In at least one embodiment, the predetermined black body radiation function specifies correlated color temperatures (CCTs) that model the CCTs of an actual non-LED based lamp, such as an incandescent lamp.

Abstract: The invention relates to an LED converter for operating a load comprising at least one LED series that includes at least one LED, preferably multiple LEDs. On the primary side, the LED converter comprises a resonant converter supplied with a direct current voltage. The resonant converter has a half-bridge that is constructed of two reciprocally clocked switches and that provides a supply voltage for the LED series through a serial/parallel resonance circuit connected to the midpoint of said half-bridge. To regulate the power transferred by the LED converter to the LED series as a feedback factor in each switch-on cycle, a control unit is designed to directly or indirectly determine a peak value of the feedback factor through the lower-potential switch of the half-bridge and to adjust the clocking of the half-bridge, i.e. the frequency and/or the duty factor, as a control factor.

Abstract: Solid state lighting systems are disclosed for providing uniform brightness of LEDs serially connected in a string. In some embodiments, the LEDs can be powered directly from the mains such that no switch-mode power supply or the output storage elements associated therewith are needed. In some such cases, a linear regulator and switches can be used to control the current through the LEDs to provide uniform brightness. Other embodiments can be used with a switch-mode based driver topology and/or storage elements coupled in parallel with clusters of the LEDs. In any such cases, control logic (e.g., microcontroller or other suitable controller) can be used to control the switches accordingly to provide uniform brightness, and in some cases, to mitigate the implications of having no SMPS output storage element. In some embodiments, the switching pattern provided by the control logic is random, although other switching patterns can be used.

Abstract: A lighting device for an AC power supply comprising at least two lighting groups, wherein each lighting group has a group input and a group output and at least one LED, wherein the at least one LED is arranged between the group input and the group output, wherein the lighting groups are connected to one another in series.

Abstract: A method for providing a kickstart pulse to a dimmer circuit for a light source that is slow starting. The method includes receiving an initial power signal for a light source electrically coupled to a dimmer circuit, and generating, using the initial power signal, a pulse signal. The method also includes sending, for a period of time, the pulse signal to a load control circuit for the light source. In such a case, the light source is illuminated by the pulse signal for the period of time, and the magnitude of the pulse signal is greater than the magnitude of a steady-state signal generated by the dimmer circuit for the light source. The method can be performed using discrete components, integrated circuits, software, some other electrical device, or any combination thereof. A kickstart circuit and a dimmer circuit, using substantially the method described above, is also disclosed herein.

Abstract: An LED lighting device includes a slave driving stage and a master driving stage. The slave driving stage includes a first luminescent device and a first current controller for providing a constant current setting in an ON phase. The master driving stage includes a second luminescent device and a current control unit having a second current controller and a current envelope controller. The second current controller provides a current envelope in the ON phase. The current envelope controller sets a level of the current envelope according to a rectified AC voltage. The driving current is regulated by the first current controller according to the constant current setting when the constant current setting is smaller than the level of the current envelope, or by the second current controller according to the current envelope when the level of the current envelope is smaller than the constant current setting.

Abstract: An LED driving device includes: a rectifying circuit for outputting a DC voltage to a string of M LED units; (M?1) first switching circuits each coupled between a corresponding one of first to (M?1)th LED units and ground; and a second switching circuit coupled between an Mth LED unit and ground. When the DC voltage is sufficient to turn on first to kth LED units, where 1?k?M, the kth LED unit is coupled to ground through first and second conductive paths provided by a resistor unit, and a corresponding first switching circuit or the second switching circuit, and each of the first to (k?1)th LED units is coupled to ground through a third conductive path provided by a corresponding first switching circuit and the resistor unit.

Abstract: An LED bulb is described, comprising LEDs within a shell and a driver circuit to operate the LEDs at a plurality of brightness levels. The driver circuit comprises first and second inputs to receive AC, a neutral input, a converter circuit, first and second rectifier circuits, a detector circuit, and a processing circuit. The first rectifier circuit is connected to the first and neutral inputs and rectifies the AC received. The second rectifier circuit is connected to the second and neutral inputs and rectifies the AC received. The detector circuit is connected to the first and second rectifier circuits. The processing circuit has a first and a second processor input, and is connected to the detector circuit. The processing circuit produces a chop signal with a duty cycle based on whether the first or second input is hot. The converter circuit powers the LEDs based on the chop signal.

Abstract: LED controllers, LED lighting systems and control methods capable of providing an average luminance intensity independent from the variation of an AC voltage. LEDs are divided into LED groups electrically connected in series between a power source and a ground. A disclosed LED controller has path switches, a management center and a line waveform sensor. Each path switch is for coupling a corresponding LED group to the ground. The management center controls the path switches. When turning off an upstream path switch, the management center controls a downstream path switch for a downstream LED group to make the driving current passing the upstream LED group substantially approach a target value. The line waveform sensor is coupled to the power source, sensing the waveform of the input voltage of the power source. The line waveform sensor is configured to decrease the target value when the input voltage increases.

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: An LED lighting system powered by an AC power source comprising a rectifier module configured to provide a rectified output to a first group of LED devices and a second group of LED devices electrically coupled to the first group of LED devices. A current monitor module electrically coupled to the first group and to the second group of LED devices is configured to determine a first current level using a drawn current level signal associated with the first group of LED devices and a second current level using a reference current level signal associated with the second group of LED devices. The current monitor module is electrically coupled to a temperature sensing module that is configured to generate at least one compensation factor based at least in part on a temperature. The compensation factor is used to control (directly or indirectly) current through the LED devices.

Abstract: A Light Emitting Diode (LED) driver circuit for driving an LED string has a switch-mode power supply coupled to the LED string. A control circuit is provided and has a first terminal coupled to a pulse width modulated input and a second terminal coupled to the switch mode power supply. A disconnect switch is coupled to a third terminal of the control circuit and the LED string.

Abstract: A light emitting diode (LED) driving apparatus and an LED backlight system using the same are provided. The backlight control circuit suitable for driving an LED string includes a complex function pin, a driving circuit and a backlight control circuit. The backlight control circuit includes a control current generating unit, a first current comparing unit and a second current comparing unit. The control current generating unit receives a dimming control signal and an enable control signal from the complex function pin to generate a control current accordingly. The first and the second current comparing units are respectively configured to compare the control current with first and second predetermined currents to respectively generate a first and a second control signals. The driving circuit determines to be turned on or off according to the second control signal, and further adjusts a luminance of the LED string according to the first control signal.

Abstract: A lighting module includes a power line for receiving a power supply current and a ground line, a segmentation point for cutting the lighting module into two parts, a first set of light sources upstream of the segmentation point, a second set of light sources downstream of the segmentation point, wherein the first and second sets of light sources are connected in series, and a resistive element connected to the intermediate point between the first and the second set of light sources, and the ground line, which is configured in such a way that: when the lighting module has not been cut, the resistive element has a resistance which is greater than the resistance of the portion of the lighting module downstream of the segmentation point, and when the lighting module has been cut, the resistive element has a resistance which is less than the resistance thereof.