Abstract: An LED fluorescent lamp includes: an LED array having a plurality of LEDs connected in series; a first connection pin and a third connection pin connected to one side of the LED array; a second connection pin and a fourth connection pin connected to the other side of the LED array; at least one pair of capacitors connected to the LED array; and a short-circuit means for connecting at least one of the first connection pin and the third connection pin, and the second connection pin and the fourth connection pin, wherein the capacitors include: a first capacitor having one end connected to the first connection pin and the other end connected to one side of the LED array; a third capacitor having one end connected to the third connection pin and the other end connected to the one side of the LED array; a second capacitor having one end connected to the second connection pin and the other end connected to the other side of the LED array; and a fourth capacitor having one end connected to the fourth connection pin

Abstract: A light unit includes a bulb having a light source with lead wires and a separator, a switch member that includes a support member and a pair of spring terminals, and a socket having two or more conductive terminals and adapted to receive the bulb and the switch member. The switch member is adapted to cause the pair of spring terminals to contact one another to form an electrical short circuit across the pair of conductive terminals and the light source when the bulb is completely or partially removed from the socket. The lead wires form an electrical connection across the conductive terminals and the separator breaks contact between the pair of spring terminals when the bulb is seated in the socket.

Abstract: Integrated circuits, control methods, and related lighting systems are provided. One integrated circuit controls the currents flowing through light-emitting-diode chains, each having several light emitting diodes forward-connected between a main cathode and a main anode while all the main anodes are connected to a power node. The integrated circuit has a short detection node, a constant current source, a voltage clamping circuit, and a short-circuit comparator. The short detection node detects the highest cathode voltage of the main cathodes. The constant current source provides a constant current to the short detection node. While the light-emitting-diode chains are unlit, the voltage clamping circuit clamps the short detection node at a predetermined voltage. When the voltage of the short detection node exceeds a threshold voltage, the short-circuit comparator asserts a fault signal, indicating a short circuit of a light emitting diode.

Abstract: A backlight unit includes a power converter which generates a light driving voltage in response to a voltage control signal with a first level, a plurality of light emitting strings, wherein each of the light emitting strings receives the light driving voltage through a first end thereof, and a controller which generates the voltage control signal. The controller is connected to a second end of at least one of the light emitting strings and detects a level of a signal at the connected second end to detect an operation state of the light emitting strings. The controller generates the voltage control signal with a second level to stop the power converter from generating the light driving voltage when the operation state of the light emitting strings is in an abnormal state.

Abstract: In accordance with certain embodiments, an illumination system comprising a plurality of power strings features elements facilitating compensation for failure of one or more light-emitting elements connected along each power string.

Abstract: A LED driving device adapted to driving N LED strings connected in series is provided. N is a positive integer greater than 1. The LED driving device includes (N?1) switch units, a current source, a detection unit and a control unit. The ith switch unit electrically connects to the (i+1) LED string in parallel or to the ith LED string in parallel, and 0<i?(N?1). The current source supplies a driving current to drive the N LED strings. The detection unit outputs a detection signal according to a voltage of the current source, a first reference voltage and a second reference voltage. The control unit outputs a plurality of first control signals according to the detection signal to dynamically control an amount of the (N?1) switch units turned on.

Abstract: A plurality of switching units interleaves with a plurality of LED-based lighting units to configure the interconnection of the LED-based lighting units for providing multiple lighting modes. Each switching unit disposed between a leading lighting unit and a trailing lighting unit is separately controlled by a controller. The switching unit can be configured to connect the two LED-based lighting units in parallel or in series, or to bypass the leading LED-based lighting unit. All the LED-based lighting units are connected in series when an input voltage supply is at a maximum voltage level, and connected in parallel when the input voltage supply is at a minimum voltage level. As the input voltage level decreases, the number of LED-based lighting units connected in parallel increases, and vice versa.

Abstract: An electronic device including series-connected open failure-susceptible components and re-routing assemblies for directing current through an ancillary current path to maintain operability of the series array despite an open-failed component therein. The re-routing assembly can be constituted as an ancillary circuit containing a bypass control element arranged to maintain the ancillary circuit in a non-current flow condition when none of the open failure-susceptible components has experienced open failure, and to re-route current from a main circuit around an open-failed component therein and through the ancillary circuit and back to the main circuit, to bypass the open-failed component so that all non-failed series components of the main circuit remain operative when electrically energized.

Abstract: A Pulse Width Modulation (PWM) controlling circuit and a Light Emitting Diode (LED) driver circuit having the same are provided. An LED driver circuit includes a voltage detector connected to a plurality of LED arrays, the voltage detector being configured to determine a connection status of each of the LED arrays according to a corresponding level of the feedback voltage, and detect a minimum feedback voltage from feedback voltages of the LED arrays that are determined to be connected, a controller configured to output a control signal to one of abort and control boosting of the LED arrays according to the detected minimum feedback voltage, and a Pulse Width Modulation (PWM) signal generator configured to output a PWM signal corresponding to the outputted control signal according to an on/off state of a dimming signal that drives the LED arrays that are determined to be connected.

Abstract: A driver circuit of lighting sources for powering a plurality of lighting sources, comprising switching means (20) which can be operated to modify the path of the overall power supply electric current crossing said lighting sources. Said switching means can be operated to switch the path of the overall power supply electric current between at least one first path, corresponding to a first circuit configuration of the interconnections between the lighting sources, and at least one second path, corresponding to a second circuit configuration of the interconnections between the lighting sources.

Abstract: In some embodiments, a solid state lighting circuit may include one or more of the following features: (a) a plurality of emitters operably connected to a power supply (b) the power supply operably coupled in series with a current limiting device, where one or more of the emitters is bypassed with a switched circuit, and (c) at least one MOSFET switch operably coupled to the voltage divider circuit.

Abstract: A lighting fixture and power supply are provided that allows a power factor correction (PFC) single ended primary inductance controller (SEPIC) that provides a controlled voltage output to provide a constant current to an LED load. The power supply provides an efficient and stable power supply for LEDs. Multiple power supplies can be provided on the same printed circuit board to control multiple LED channels.

Abstract: Provided is a circuit, a device and a method of direct-driving an LED. According to an embodiment, the LED direct-driving circuit includes an LED unit having a plurality of LED groups serially connected to each other, a switching unit including a plurality of switches respectively connected to the plurality of LED groups, each switch configured to emit light from at least one LED group serially connected to the switch according to an ON operation, and a switching control unit configured to compare a signal according to a line voltage sensed from an input voltage of the LED unit with an output voltage of the LED unit to calculate a comparison value, generate a PWM carrier signal having a frequency varied according to the line voltage, and output a control signal for controlling the switching unit by comparing the comparison value with the frequency-varied PWM carrier signal.

Abstract: An LED illumination system includes: a load including an LED lamp; and a power supply device, the LED lamp configured to be physically mounted on and demounted from the power supply device, the power supply device comprising: a current feedback control unit; a first voltage comparison unit configured to determine whether the load is in a mounted state; a voltage feedback control unit configured to decrease the voltage of the power supply device to a safe voltage when demounting, and to increase the voltage of the power supply device to perform the constant current control when mounting; and a semiconductor switch element connected in series between the load and the detection resistor, wherein the mounted and demounted states of the load is detected by a voltage of a main electrode of a high potential side of the semiconductor switch element.

Abstract: An LED module for use in sign letter channel lights comprises a substrate, a reflector mounted on the substrate, an LED mounted within the reflector on the substrate and a Zener diode shunt element connected in parallel across the LED, a printed circuit board on the substrate, wherein the LED is mounted on the printed circuit board, and an insulating cover. The module may be entirely encapsulated. An LED driving protection circuit provides ground fault protection for a plurality of series connected LED modules.

Abstract: The disclosed implementations utilize the voltage drop inherent in the device string to power a device control IC. In some implementations, current is drawn from the bottom of the device string and applied to a voltage supply pin of the device control IC. In some implementations, current is drawn from some other location in the device string (e.g., near the bottom or midpoint of the device string) using a switch. In some implementations, current is drawn from near the bottom and the bottom of the device string at different times, such that less current is drawn from the bottom of the device string as the duty cycle of the device string increases and more current is drawn from near the bottom of the device string as the duty cycle of the device string increases.

Abstract: The present disclosure provides a light emitting diode driving circuit, comprising: a power conversion module having an input end, a control end and an output end, wherein the input end receives a voltage, the control end controls the regulation of the duty cycle signal therein according to a received control signal, and the output end outputs a DC voltage having a constant current and a variable voltage value; an overcurrent protection circuit having a switch module and a first resistor connected in series, wherein the overcurrent protection circuit and a LED load connected in series with each other are connected to the power conversion module, so as to turn off the electrical channel between the LED load and the power conversion module when overcurrent occurs; and an overvoltage protection circuit for outputting the control signal when overvoltage occurs and thereby protecting the LED load.

Abstract: A multicolored LED luminaire module is provided that can be controlled using a single driver and only two wires. The LED luminaire module comprises a plurality of LEDs and a sequencer. The sequencer connects each LED to the circuit in a predetermined order. Synchronously with the sequencer, the driver transmits a control signal comprising a time division multiplexed (TDM) signal that combines the driving currents for each LED into one TDM signal. The sequencer and TDM rate are sufficiently fast such that the light emitted by the LED luminaire appears to be the combined light from all the LEDs.

Abstract: A light system (FIG. 2) is disclosed. The light system includes a plurality of series connected light emitting diodes (240-246). Each of a plurality of switching devices (230-236) has a control terminal and each has a current path coupled in parallel with a respective LED. A plurality of fault detector circuits (220-226) are each coupled in parallel with a respective light emitting diode. Each fault detector circuit has a first comparator (FIG. 7, 704) arranged to compare a voltage across the respective light emitting diode to a respective first reference voltage (708). When a fault is defected, a control signal is applied to the control terminal to turn on a respective switching device of the plurality of switching devices.

Abstract: An apparatus includes at least one LED, at least one charge storage device and a switching circuit configured to route current through the least one LED to the at least one charge storage device for a first state of an applied voltage and to discharge the at least one charge storage device via the at least one LED for a second state of the applied voltage. The apparatus may further include a current control circuit coupled in series with the at least one LED.

Abstract: The present application discloses an open circuit protecting circuit, an open circuit protecting method and an illuminating apparatus. The open circuit protecting circuit is configured in an apparatus with a LED load being supplied with power by a current source, and comprises: a switch circuit, a timer circuit and a detecting circuit. When the LED load malfunctions, the open circuit protecting circuit carries out the following operations: the detecting circuit sends an enabling signal to the timer circuit, the timer circuit sends a driving signal with a set time to the switch circuit and the switch circuit is in the on-state during the set time, so as to make the LED load be short circuited to protect the circuit from being damaged. The open circuit protecting circuit can also resume to normal work automatically after the open circuited malfunction is cleared, and thus a hot-plugging function can be realized.

Abstract: An active clamp current sink is used to voltage protect a low voltage rated, high power current sink that drives illumination current through a string of serially connected LEDs. When the LEDs are turned off as part of a PWM configuration, the forward voltage on the LEDs falls, and the voltage presented to the low voltage rated, high power current sink rises. The active clamp current sink monitors the voltage across the high power current sink and ensures that an adequate current flows through the LEDs. This minimally adequate current maintains a sufficiently large forward voltage through the LEDs, and therefore a sufficiently small voltage is presented to the high power current sink.

Abstract: An apparatus, method and system for controlling one or multiple lighting sources such as those powered by driver circuits or voltage splitting methods, to provide an alternative current path around a failed lighting source when one or more individual lighting sources fail.

Abstract: A system topology and circuit design for efficiently and stably driving currents through strings of solid state light emitting elements by providing current sources that are controlled by a stable voltage reference.

Abstract: A lighting system comprising a constant current power source one or more sets of light emitting elements, and associated circuitry. The light emitting elements may be light emitting diodes (LEDs) that have been selected to emit light having specific wavelengths corresponding to specific colors. The lighting system may selectively control the intensity of each set of LED by utilizing pulse-width modulation. The sets of LEDs may be serially connected and selectively operated independently of each other set of LEDs.

Abstract: The present invention relates to an LED driver IC, a driving method of the LED driver IC, and an LED light emission device using the LED driver IC. The LED light emission device includes an LED string, a power switch supplying power to the LED string, a dimming switch controlling light emission duty of the LED string, and an LED driver IC controlling switching operation of the power switch and the dimming switch. The LED driver IC senses a difference between a control electrode voltage of the dimming switch and a sense voltage generated according to a current flowing to the dimming switch, and triggers the OCP operation according to a result of comparison between the sensed voltage and a predetermined OCP reference voltage.

Abstract: A method for controlling a light emitting diode (LED) is provided. Initially, the LED, which had been active, is deactivated, and a voltage for a current that corresponds to the persistence of the LED is generated. The voltage is then integrated so as to generate an integrated voltage, and the integrated voltage is compared to a threshold. When the integrated voltage is less than the threshold, the LED is then activated.

Abstract: An apparatus, method and system are disclosed for providing AC line power to lighting devices such as light emitting diodes (“LEDs”). A representative apparatus comprises: a plurality of LEDs coupled in series to form a plurality of segments of LEDs; first and second current regulators; a current sensor; and a controller to monitor a current level through a series LED current path, and to provide for first or second segments of LEDs to be in or out of the series LED current path at different current levels. A voltage regulator is also utilized to provide a voltage during a zero-crossing interval of the AC voltage. In a representative embodiment, first and second segments of LEDs are both in the series LED current path regulated at a lower current level compared to when only the first segment of LEDs is in the series LED current path.

Abstract: A dimming controller can operate in a first mode or a second mode to control dimming of a light source. A voltage control terminal provides a driving signal to control a control switch. When the dimming controller operates in the first mode, the driving signal controls the control switch in a first state and a second state alternately to adjust a first current flowing through the first light element to a target level. When the dimming controller operates in the second mode, the driving signal controls the control switch in the second state to cut off the first current. A high voltage terminal conducts a current flowing through the control circuit and the second light element when the dimming controller operates in the second mode. The control circuit conducts a second current flowing through the second light element during the second mode.

Abstract: A driving circuit includes a plurality of light-emitting units, a plurality of switches, and a bias current module, wherein 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 reference voltage and a critical activation voltage and includes a light-emitting end and a bias end opposite to the light-emitting end, wherein the light-emitting end is coupled with the light-emitting units, and the bias ends of the switches are coupled with each other. The bias current module is coupled with the bias ends of the switches and has an operating bias voltage varying according to the frequency, wherein each switch is driven to be activated or to be deactivated according to a relation of the critical activation voltage and a difference between the reference voltage and the operating bias voltage.

Abstract: A light-emitting diode (LED) driving circuit for driving a plurality of first lightbars and a plurality of second lightbars is provided. The LED driving circuit includes a first current mirror, a second current mirror and a control circuit. The first current mirror, if enabled, balances currents of the first lightbars. The second current mirror, if enabled, balances currents of the second lightbars. During a first period, the control circuit disables the second current mirror and adjusts the duration of enabling the first current mirror according to a dimming signal. During a second period, the control circuit disables the first current mirror and adjusts the duration of enabling the second current mirror according to the dimming signal. Therefore, only the first lightbars or the second lightbars are driven in each period.

Abstract: The driving circuit includes a power module, a plurality of LED modules, and a constant current component. Each LED module includes a bypass circuit and at least one light emitting diode. The light emitting diode is serially connected between a first end and a second end of the bypass circuit. The first end of each bypass circuit is coupled to the power module or a third end of an adjacent upstream bypass circuit for serially connecting the constant current component electrically, thereby achieving the illumination of different total numbers of LED units in accordance with various voltage changes, and cascade light emitting diodes having increased power efficiency.

Abstract: A method of driving current from an AC power supply through a series arrangement of a varying number of strings of LEDs is disclosed, the method comprising, adding LED strings to the series arrangement in a first order during an increasing voltage part of a cycle of the AC power supply cycle and subsequently removing LED strings from the series arrangement in a second order s during a decreasing voltage part of the cycle, wherein the second order is not the reverse of the first order. A driver for operating such a method is also disclosed, as is an IC embodying such a driver.

Abstract: A LED lamp that includes a LED lamp controller with delayed startup after a fault condition is detected. The type of the fault condition is used in determining a length of the startup delay, such as a number of power cycles during which the LED lamp controller is prevented from completing its configuration. Examples of different types of fault conditions include faults in a supply voltage or faults in a feedback voltage to the LED lamp controller. Fault type information can also be stored in circuitry that retains data and is not reset across the power cycles.

Abstract: According to one embodiment, a marker lamp is supplied with electric power from an alternating constant-current power supply device via a saturable device. The marker lamp includes a solid-state light-emitting circuit functioning as a light source and a lighting circuit configured to subject the solid-state light-emitting circuit to lighting control. The marker lamp further includes an abnormality monitoring device configured to monitor a state of the solid-state light-emitting circuit and open, if detecting an abnormal state, an output side of the saturable device corresponding to the marker lamp.

Abstract: Disclosed are an LED emitting device and driving method thereof. The LED emitting device controls an LED drive switch connected to a first end of an LED string to control an output current supplied to the LED string. The LED emitting device generates feedback information on the output voltage or the output current supplied to the LED string, and uses the output current to sense an open lamp state of the LED string. The LED emitting device uses a voltage at a first end of the LED drive switch to sense a change of the LED string to a normal state from the open lamp state.

Abstract: A light-emitting diode (LED) fluorescent lamp which can replace a typical fluorescent lamp is provided. The LED fluorescent lamp includes an LED array including a plurality of LEDs connected in series; first through fourth connection pins; first through fourth capacitors connected to the first through fourth connection pins, respectively; a first diode having an commonly connected to second ends of the first and third capacitors and a cathode connected to a first end of the LED array; a second diode having an anode connected to a second end of the LED array and a cathode commonly connected to second ends of the second and fourth capacitors. The LED fluorescent lamp can replace a typical fluorescent lamp without a requirement of the installation of additional equipment or the change of wiring.

Abstract: A driving apparatus of an LED device is provided. The LED device includes a plurality of LED channels, and each LED channel includes a plurality of LEDs connected in series. A power converter has an output terminal connected to a first terminal of each LED channel, and converts an input voltage into an output voltage to output the output voltage to the output terminal. A plurality of current controllers correspond to the plurality of LED channels, respectively. Each current controller is connected to a second terminal of a corresponding LED channel, and controls a current of the corresponding LED channel. The voltage sensor outputs a sensed voltage corresponding to the output voltage of the output terminal. The fault controller determines whether to stop operation of the power converter by comparing the sensed voltage with a reference voltage.

Abstract: An apparatus, method and system for controlling one or multiple lighting sources such as those powered by driver circuits or voltage splitting methods, to provide an alternative current path around a failed lighting source when one or more individual lighting sources fail.

Abstract: A light-emitting device, electrically connected to an external variable voltage source, includes a plurality of light-emitting modules sequentially electrically connected in series and electrically connected to the external variable voltage source. Each light-emitting module has at least one light-emitting unit, a first connection terminal and a second connection terminal. At least one of the light-emitting modules has a control unit and a bypass unit electrically connected to the light-emitting unit. The second connection terminal of the light-emitting module having the bypass unit and the control unit is electrically connected to the first connection terminal of the other light-emitting module and serves as a detection terminal. The control unit detects a voltage of the detection terminal and accordingly controls the bypass unit to adjust a current flowing through the light-emitting unit.

Abstract: An apparatus includes first and fourth bypasses, a current detector, and a current controller. The first bypass is connected serially to a first LED, and controls the current amount in the first LED. The fourth bypass is connected serially to a second LED, and controls the current amount in the first and second LEDs. The detector detects current detection signal based on the current amount on an output line along which the first and second LEDs are connected serially to each other. The controller provides control signal for controlling the first and fourth bypasses based on the detection signal. The controller includes one output for providing the control signal. The first and fourth bypasses are connected in parallel to the one output.

Abstract: Disclosed are various embodiments of bypass circuits that can be used with series connected LED strings for backlighting circuits in LCD displays. The bypass circuits can also be used for other implementations of series wired LED strings. The bypass circuit may comprise a latch, such as a silicon controlled rectifier that is connected to the output of a comparator circuit that compares the voltage at the cathode of an LED in the LED string to a reference voltage. In this manner, a circuit is created around each LED that is burned out.

Abstract: Circuits for controlling a plurality of LEDs connected in series are disclosed herein. The circuit includes a plurality of switches, wherein each switch is connectable between the anode and cathode of one of the plurality of LEDs. Each of the switches has a first state wherein current does not pass through the switch and a second state wherein current passes through the switch. The circuit also includes an input for receiving data to program the switches and a data line for transferring data between a circuit controlling second LEDs that are connected in parallel with the first LEDs and the circuit. In addition, the circuit includes a data output for transferring data to other circuits controlling third LEDs that are connected in series with the first LEDs.

Abstract: The present inventions relate to a control circuit for controlling a plurality of serially connected groups of LEDs. A control unit is connected in parallel to each group of a plurality of serially connected groups of LEDs. Each LED group is connected to the adjacent group of LEDs. The control unit is connected to a group of LEDs. The control unit performs the functions of voltage regulating/current regulating/bypass for the associated group of LEDs. The control unit can act as a by-pass unit permitting current to flow through the control unit rather than through the associated group of LEDs.

Abstract: An LED lighting circuit capable of preventing thermal breakdown, including: an LED module, having a top end coupled to a line voltage; and a controller, coupled to the line voltage and a bottom end of the LED module, the controller including: an amplifier, having a positive input end coupled to an adjustable reference voltage; a transistor, having a gate terminal coupled to an output end of the amplifier, a first channel terminal coupled to the bottom end of the LED module, and a second channel terminal coupled to a negative input end of the amplifier; a current sensing resistor, coupled between the second channel terminal and a ground; and a reference voltage generator, used for generating the adjustable reference voltage according to the line voltage.

Abstract: Consistent with an example embodiment there is a method for regulating a LED current (ILED) flowing through a LED circuit arrangement at a mean LED current level. The method includes establishing an oscillating converter current (IL), establishing a first and a second current control indicator representative of a flow of a converter current (IL); regulating a peak and valley current level of the converter current in dependence on the first current control indicator; controlling a converter current period (T) of an oscillation of the converter current in dependence on the second current control indicator to be within a period control range (Tref) and feeding at least part of the converter current to the LED circuit arrangement.

Abstract: A light-emitting diode (LED) driver circuit and a light apparatus including the LED driver circuit are provided. The light apparatus includes an LED array, an input unit, a rectifier, and a control circuit. The LED array includes LED devices connected to one another in series. The input unit receives an alternating current (AC) power source. The rectifier circuit full-wave rectifies the received AC power source signal and supplies the full-wave rectified AC power source signal to the LED array. The control circuit selectively lights the LED devices according to a voltage level of the full-wave rectified AC power source signal. The control circuit includes switching elements and comparators. The switching elements selectively force nodes between the LED devices to be grounded. The comparators turn-on one of the switching elements according to the voltage level of the full-wave rectified AC power source signal.

Abstract: A lighting apparatus includes a plurality of light emitting diode (LED) sets coupled in series. The apparatus further includes a bypass circuit coupled in parallel with one of the LED sets and configured to sense and control a bypass current when the one of the LED sets is in a first bias state and to attenuate the bypass current responsive to a transition of the one of the LED sets to a second bias state. The first bias state may be substantially non-conducting and the second bias state may be conducting. The apparatus may include a plurality of such bypass circuits, respective ones of which are coupled in parallel with respective ones of the LED sets such that the bypass circuits are coupled in series.

Abstract: Ladder network circuits for controlling operation of a string of light emitting diodes (LEDS). The circuits include a number of sections connected in series. Each section includes one or more LED junctions, a variable resistive element coupled to the LED section, and a switch coupled to the variable resistive element and the LED section for controlling activation of the LED. The sections can include a transistor coupled between the switch and variable resistive element. The series of sections are connected to an AC power source, rectifier, and dimmer circuit. When receiving power from the power source, the sections activate the LEDs in sequence throughout the series of the sections. The dimmer circuit controls activation of a selection of one or more of the sections in order to activate in sequence the LEDs in only the selected sections, providing for both dimming and color control of the LEDs.

Abstract: Provided is an LED driving apparatus. The LED driving apparatus includes a plurality of LED groups each comprising one or more diodes, a switch group comprising a plurality of switch units connected respectively to the LED groups to drive the connected LED group when a control signal is activated, and a switch controlling unit configured to compare an input voltage of the LED groups with an output voltage of the LED groups, calculate a comparison value, and generate the control signal according to the comparison value. Accordingly, the LED driving apparatus drives the LED groups selectively according to the difference between the input voltage of the LED group and the output voltage of the LED group, thereby overcoming the problem of heat generation by forward voltage distribution.