Abstract: A gas sensor module (100) includes an infrared light emitting diode (10) configured to emit infrared light in accordance with a drive current, a quantum infrared sensor (20) configured to detect infrared light that passes through a detection target gas, a drive circuit (30) configured to output the drive current to the infrared light emitting diode (10), a charging circuit (50) to be connected to a power source and configured to output a charge current having a smaller current amount than the drive current, and a capacitor (40) configured to charge by the charge current being supplied from the charging circuit (50) and discharge by supplying the drive current to the drive circuit (30).

Abstract: A light-emitting diode (LED) strip is disclosed. The LED strip includes: an input terminal for receiving a first reference signal, a first LED coupled to an end of a power bus and driven by a first current signal, the first current signal being supplied to the first LED via the power bus; a current-copying circuit arranged to control a flow rate of the first current signal based on the first reference signal; and a first switching element arranged to re-couple the first LED to the power bus when the first LED is disconnected from the end of the power bus as a result of the LED strip being cut at a first location.

Abstract: Light-emitting diode (LED) driver systems that are scalable and can be used for N-color LED systems are provided. An LED system having N LED strings of different color can be efficiently driven with independently controllable constant current sources for each string from a single power source. The driver system can include a power converter having an inductor.

Abstract: A sound lamp includes an illuminating device including a circuit board, a single-piece controller, and sixteen light emitting members. The single-piece controller has sixteen legs. Each of the light emitting members has a first end and a second end. The first ends of the light emitting members are connected in parallel. The second end of each of the light emitting members is electrically connected with one of the legs of the single-piece controller. The single-piece controller controls lighting sequences of the light emitting members. Thus, the single-piece controller controls the light emitting members, such that the light emitting members are brightened gradually and dimmed gradually at different cycles, so as to simulate a real flame of an oil kettle.

Abstract: The present application discloses an LED light string control system, which comprises a direct-current power supply, a polarity change control unit and a forward-reverse connection LED light string circuit, wherein the direct-current power supply is electrically connected with the polarity change control unit, and the polarity change control unit is electrically connected with the forward-reverse connection LED light string circuit. The present application further discloses an LED light string control method, which comprises: a polarity change control unit outputs a changed-polarity voltage with a specific frequency according to a timing sequence; and LED lamps with the corresponding polarity in a forward-reverse connection LED light string circuit are lighted according to the polarity-changed voltage.

Abstract: A light-emitting diode (LED) strip is disclosed. The LED strip includes: an input terminal for receiving a first reference signal, a first LED coupled to an end of a power bus and driven by a first current signal, the first current signal being supplied to the first LED via the power bus; a current-copying circuit arranged to control a flow rate of the first current signal based on the first reference signal; and a first switching element arranged to re-couple the first LED to the power bus when the first LED is disconnected from the end of the power bus as a result of the LED strip being cut at a first location.

Abstract: Various embodiments provide a light emitting diode (LED) flasher bulb that provides a flashing function for LED string lights. The LED flasher bulb is inserted into any one of a plurality of connectors of the LED string lights, and is compatible with an alternating current power source. The LED flasher bulb alternates the LED string lights between an on state in which LEDs of the LED string lights are lit up, and an off state in which the LEDs are not lit up. The LED flasher bulb is able to continuously alternate the LED string lights between the on state and the off state according to a determined pattern independent of the AC signal generated by the AC power source being positive or negative.

Abstract: The invention provides a lighting module for use in a reflector which comprises at least one first light source emitting first light having a first light distribution with a first main direction and at least one second light source emitting second light having a second light distribution with a second main direction opposite to the first main direction. A base connects the lighting module to a luminaire socket. The base has a longitudinal axis extending from the base. The first light source is positioned on the longitudinal axis and the second light source is positioned at a non-zero distance to the longitudinal axis. The first main direction and the second main direction are substantially perpendicular with respect to the longitudinal axis.

Abstract: The present disclosure provides a display panel and a display device including the display panel. The display panel includes a display area and a peripheral area outside the display area. The display area is provided with OLEDs, first and second power lines. The peripheral area is provided with at least one driving chip. OLEDs are distributed in a matrix. First power lines extend in a first direction, second power lines extend in a second direction, and first power lines are intersected and connected with second power lines to form a grid structure electrically connected with anodes of OLEDs. The driving chip is electrically connected with the grid structure. The grid structure includes grids defined by first power lines being intersected with second power lines, and has a larger grid density at one position than that at another position closer to the driving chip.

Abstract: Disclosed is a control circuit for a lighting apparatus using an LED as a light source. The control circuit controls a driving current of a driving circuit, using a monitoring result for a rectified voltage and a monitoring result for an output voltage of a specific LED group among a plurality of LED groups.

Abstract: An LED module for a luminaire has a downwardly directed heat sink comprising cooling fins that extend rearward from the module's front end and downward from its top wall, which has a top face that abuts the underside of a luminaire carrier plate. A circuit board carrying at least one LED is mounted on the front face, and a prism is mounted to the heat sink over the LED(s). The front (light-emitting) face of the catadioptric prism has several prominent side-by-side sections which emit beam patterns that diverge laterally and overlap in a central region. A prominent full-width upper section on the front face emits a primarily downwardly directed beam pattern to help fill in dark spots.

Abstract: An LED tube lamp includes a lamp tube, a first external connection terminal and a second external connection terminal coupled to the lamp tube and for receiving an external driving signal; an LED lighting module coupled to the first external connection terminal and configured to receive a signal for emitting light, the signal derived from the first external driving signal; and a ballast interface circuit coupled between the first external connection terminal and the LED lighting module.

Abstract: An LED lamp A1 includes a plurality of LED modules 1 and a substrate 2 on which the LED modules 1 are mounted in a row. A light guide 3 covering the LED modules 1 is provided on the substrate 2. The light guide 3 is held in close contact with each of the LED modules. With this arrangement, a proper amount of light is obtained with the use of a smaller number of LED modules 1 or with less power consumption.

Abstract: The present invention relates to a lighting device (11) comprising a light emitting portion with at least two solid state light sources, SSL (18). The light emitting portion includes a first cover member (12a) with a first light source carrier (13a) and a first light transmitting portion (14), a second cover member (12b) with a second light source carrier (13b) and a second light transmitting portion (14). The first and second cover member are arranged such that a first light transmitting portion is aligned with the second SSL to allow transmission of light emitted from the second SSL through the first cover member, and a second light transmitting portion is aligned with the first SSL to allow transmission of light emitted from the first SSL through the second cover member. According to this design, light emitted from an SSL on one cover member will be transmitted through the other cover member. Dissipation of heat from each SSL may be provided in the other direction, i.e.

Abstract: The invention describes a low-power load arrangement (1) comprising a low-power load (3); a driver (2) for the low-power load (3); connectors (300) for connecting to an electronic transformer (2) realized for converting a mains power supply (4) to a power supply for a normal-power load (5); and a reverse current generating means (LP, SB) realized to provide a reverse current (Irev_LP, Irev_SB) to sustain self-oscillation during operation of the electronic transformer (2), wherein the direction of current flow of the reverse current (Irev_LP, Irev_SB) is opposite in direction to the output current of the electronic transformer (2).

Abstract: A linear light-emitting diode (LED) tube lamp using a six-diode combination and a ballast compatible and AC mains operable (BA) LED driving circuit operate normally with AC mains in a single end and with an electronic ballast in double ends. The BA LED driving circuit configured to operate in a wide range of input voltages and frequencies, especially for various high voltages and high frequencies associated with various electronic ballasts to provide a regulated power and a current from either electronic ballast or AC mains. With a cycle-by-cycle current control and power switching at a constant on-time and varied off-time, an over-rated surge current is limited, preventing occasional fire hazards occurred in the ballast. An additional frequency sensitive device is used to prevent a possible electric shock from occurring for both configurations during initial installation and re-lamping, thus no shock protection switches needed.

Abstract: An LED lamp includes a rectifier, an integrated circuit and a string of series-connected LEDs. The lamp receives an incoming AC signal such that a rectified version of the signal is present across the LED string. The integrated circuit includes a plurality of power switches. Each power switch is coupled so that it can separately and selectably short out a corresponding one of several groups of LEDs in the string. As the voltage across the string increases the integrated circuit controls the power switches such that the number of LEDs through which current flows increases, whereas as the voltage across the string decreases the integrated circuit controls the power switches such that the number of LEDs through which current flows decreases. LED string current flow is controlled and regulated to provide superior efficiency, reliability, anti-flicker, regulation against line voltage variations, power factor correction, and lamp over-voltage, over-current, and over-temperature protection.

Abstract: The LED flash module includes: a module substrate (111); an energy device (18) arranged on the module substrate; an LED module (320) arranged on the module substrate, the LED module in which a plurality of LED block units (320a-320f) are arranged horizontally, the LED block units in which a plurality of LED elements emitting light using a power source supplied from the energy device are arranged vertically; an EDLC charger circuit (311) arranged on the module substrate, and configured to charge the energy device; and an LED driver control circuit (313) arranged on the module substrate, and configured to control light emission from the LED element, wherein a wire length from a plus terminal (321) of the power supply unit to the LED element and a wire length from the LED element to a minus terminal (322) of the power are substantially equivalent with respect to each LED element.

Abstract: A light engine has a pillar with first and second ends; a circuit board on the first end of the pillar, a light source mounted on the circuit board encircling the pillar and facing towards the second end of the pillar, and a surface extending from the second end of the pillar, that surface and the exterior of the pillar between that surface and the circuit board being coated with a reflective remote phosphor that is excited by light from the light source. The light engine may be used in a light bulb, with a frosted globe enclosing the circuit board and mounted round the outer edge of the phosphor-coated surface, and an Edison screw or other standard base connected to the second end of the pillar.

Abstract: A LED bulb includes a circuit board, a lighting module, a conductive connector, and a lamp shade. The circuit board includes a slot. The lighting module is arranged on the circuit board and includes a transmissive substrate. The lighting module includes a circuit layer attached to the transmissive substrate, an electrode component arranged on one end of the transmissive substrate and inserted into the slot and electrically connected to the circuit layer, and a plurality of LED dies placed on the transmissive substrate and electrically connected to the circuit layer. The conductive connector is arranged on the other side of the circuit board and electrically connected to the circuit. The lamp shade is assembled with the conductive connector such that the circuit board and the lighting module are arranged between the conductive connector and the lamp shade.

Abstract: A retrofit lamp includes at least one series circuit having a multiplicity of LEDs having a circuit arrangement. The at least one series circuit including is coupled between a first rectifier output connection and a second rectifier output connection. A breakdown apparatus is coupled between a third connection terminal and a fourth connection terminal. The breakdown apparatus may have the following properties: up to a first threshold value of the voltage drop across said breakdown apparatus during operation, the breakdown apparatus is nonconducting. If the first threshold value is exceeded, the breakdown apparatus becomes conducting. The breakdown apparatus remains conducting as long as current is supplied to it which is above a second threshold value. As soon as the current falls below the second threshold value, the breakdown apparatus becomes nonconducting again. In the conducting state, the breakdown apparatus has a forward voltage which is below a third threshold value.

Abstract: A light emitting diode (LED) fluorescent lamp includes an external connection pin including a first connection pin and a second connection pin, an LED array including a plurality of light emitting diodes (LEDs) connected in series, a current stabilizing capacitor connected in parallel to the LED array, and a capacitive element unit connected between the LED array and the external connection pin and configured to vary an impedance of a fluorescent lamp ballast connected to the capacitive element unit through the external connection pin.

Abstract: An LED flash module includes: a module substrate; an energy device disposed on the module substrate; an LED module arranged on the module substrate includes a plurality of LED blocks arranged in a first direction, each LED block including a plurality of LED elements which is arranged in a second direction perpendicular to the first direction and emits light with power supplied from the energy device; a charger circuit arranged on the module substrate to charge the energy device; and a control circuit arranged on the module substrate to control emission of LED elements. A wiring length from one of the LED elements to a plus terminal of a power supply portion supplying power to each of the LED elements and a wiring length from the one of the LED elements to a minus terminal of the power supply portion is substantially the same for all of the LED elements.

Abstract: The LED lighting tube compatible with an electronic ballast has two snubber circuits, a waveform conversion circuit, and at least one LED light string. The snubber circuits are connected to terminals of the LED lighting tube, and input terminals of each snubber circuit are connected to electrode pins of a corresponding terminal. Each snubber circuit has at least one resistor connected in series between the electrode pins of the corresponding terminal. The waveform conversion circuit has multiple rectifier diodes, and input terminals of the waveform conversion circuit are respectively connected to output terminals of the snubber circuits, with a recovery time of each rectifier diode being under 2.5 us. Two ends of the at least one LED light string are respectively connected to output terminals of the waveform conversion circuit, and each one of the at least one LED light string includes multiple LED units connected in series.

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 lossless LED forward voltage matching network connected between an AC source and a driver of an LED array, where the LED array is series connected and sequentially activates as the output voltage of the LED driver exceeds the respective forward voltages of the LED arrays. The matching network reduces the voltage from the AC source to approximate the total of the forward voltages of the series connected LED arrays to increase the efficiency of the device.

Abstract: A driving device for an illuminating device may include a plurality of sub illuminating units. The driving device may include a plurality of sub driving modules in series connected to an input voltage source to distributively store energy from the input voltage source. Each of the sub driving modules is allocated with and electrically connected with one sub illuminating unit so as to release the stored energy to the sub illuminating unit allocated thereto.

Abstract: A feedback control circuit, adapted to control a converting circuit to transform an input power into an output voltage for driving an LED module. The feedback control circuit comprises a detection circuit, a PWM circuit, a PWM logic control circuit and a PWM control circuit. The detection circuit is coupled to at least one LED string of the LED module and generates at least one detection signal. The PWM circuit comprises a capacitance, a charging circuit and a discharging circuit, and determines a capacitance voltage of the capacitance to increase, decrease, or maintain. The PWM logic control circuit compares a level of the least one detection signal with a high reference level and a low reference level to control the PWM circuit to adjust the capacitance voltage. The PWM control circuit controls the converting circuit to execute the power transformation in response to the capacitance voltage of the capacitance.

Abstract: A light string includes a number of lights. The lights are electrically connected in series and powered by an AC power supply. At least one capacitor is connected in parallel to one of the lights. Each light or a part of lights of the light string of the present invention is electrically connected in parallel to a capacitor. When the light string is powered on, the capacitor is charged and absorbs a surge current which may occur. Thus, the voltage dropped on each light rises slowly and the lights are safe. The capacitor also performs power compensation and electrical connection. When the filament of the light bulb fails and the bulb remains in the light string, or when the bulb is removed from its socket for replacement, the closed path for flow of electrical current is still closed.

Abstract: A device for improving power efficiency for power factor correction is disclosed, which comprises a primary load, a power module, a power factor correction module, a current source module, and a secondary load. The power module rectifies an alternating current (AC) voltage to a pulsating direct current (DC) voltage. The power factor correction module filters the pulsating direct current (DC) voltage to a driving voltage. The current source module is connected to the power module, the primary load and a side of the power factor correction module that drives the primary load with the driving voltage. The secondary load is connected to another side of the power factor correction module, and is driven by the power factor correction module.

Abstract: The present disclosure involves a device. The device includes a rectifier coupled to receive energy from an alternating current (AC) voltage source. A capacitor is coupled to the rectifier. A plurality of LEDs and a current limiter are coupled in series. The current limiter is configured to limit a current through the LEDs. The plurality of LEDs and the current limiter are collectively coupled to the capacitor in parallel. A current controller is coupled to both the capacitor and the current limiter in series. The current controller is configured to control at least a charging current of the capacitor. The device has a first current path during a first period of operation and a second current path during a second period of operation. The capacitor charges during the first period of operation and discharges during the second period of operation.

Abstract: A light emitting diode (LED) fluorescent lamp includes an external connection pin including a first connection pin and a second connection pin, an LED array including a plurality of light emitting diodes (LEDs) connected in series, a current stabilizing capacitor connected in parallel to the LED array, and a capacitive element unit connected between the LED array and the external connection pin and configured to vary an impedance of a fluorescent lamp ballast connected to the capacitive element unit through the external connection pin.

Abstract: The present invention is a lighting module, in particular, a lighting module that emits warmer color light as it dims. The lighting module preferably has a dimmable power source and a printed circuit board having at least two series of LEDs. The first LED series has a resistor and three LEDs that operate at full brightness at a first voltage, e.g. 12v. The second LED series has a voltage regulator, two capacitors and three LEDs that operate at full brightness at a second voltage, e.g. 6v, less than the first voltage. The first series has a different color light output from the second series. The module produces a linear color shift for a range of voltages, e.g. from seven volts to twelve volts.

Abstract: A light-emitting diode (LED) tube is applied to a lamp holder with a ballast, and has a lighting module, a first control module and a second control module connected to two ends of the lighting module, and a harmonic elimination module connected to the first and second control modules and parallelly connected to the lighting module. Each of the first control module and the second control module has a simulation circuit unit and a rectification unit. Each of the simulation circuit units and the harmonic elimination module has a switching element. The first and second control modules adjust electrical signals from the ballast, and the harmonic elimination module eliminates harmonic waves generated by the ballast so that the lighting module is compatible with the ballast and is lit. Accordingly, the LED tube can be directly mounted on a fluorescent lamp holder with the lamp holder intact.

Abstract: A method and apparatus for a boost converter topology for low battery voltage support. In the method, an input voltage is boosted by closing first through third switches and then opening a fourth switch to charge a capacitor. The first and second switches are then opened. The voltage is then doubled by closing the third and fourth switches to discharge the first capacitor into a second capacitor and charging a third capacitor. A further embodiment provides an additional method for selectively boosting an input voltage to an electronic device. The method first characterizes the efficiency of a circuit, and then determines a crossover point for a ratio of output voltage to input voltage, and then enabling or disabling a voltage boost converter based on the crossover point.

Abstract: An LED lighting device includes a power converter for outputting a variable output voltage, two LED lamps being connected in series between output terminals of the power converter; a current detector for detecting an output current from the power converter; a first detector for detecting the output voltage of the power converter and generating a first detection voltage corresponding to the output voltage; a second detector for detecting an applied voltage to one of the two LED lamps and generating a second detection voltage corresponding to the applied voltage; and a controller for controlling the power converter to adjust the output voltage to thereby make the output current coincide with a target value. The controller controls the power converter to decrease the output voltage if at least one of the second detection voltage and the deference between the first and the second detection voltage does not fall within a range.

Abstract: The LED lighting tube that is compatible with an electronic ballast has two snubber circuits, a waveform conversion circuit, and at least one LED light string. The snubber circuits are connected to terminals of the LED lighting tube, and input terminals of each snubber circuit are connected to electrode pins of a corresponding terminal, and each snubber circuit has at least one resistor connected in series between the electrode pins of the corresponding terminal. The waveform conversion circuit has multiple rectifier diodes, wherein input terminals of the waveform conversion circuit are respectively connected to output terminals of the snubber circuits, wherein a recovery time of each rectifier diode is under 2.5 us. Two ends of the at least one LED light string are respectively connected to output terminals of the waveform conversion circuit, wherein each one of the at least one LED light string comprises multiple LED units connected in series.

Abstract: A series spark gap includes at least three partial spark gaps. In a continuous operation mode, a supply voltage acting over the partial spark gaps is divided by a first voltage dividing mechanism. During triggering, more than half of the partial spark gaps are bypassed by using a bypass mechanism such that more than half of the supply voltage acts over the partial spark gaps that are not bypassed, whereby the partial spark gap or the partial spark gaps that are not bypassed ignite. The voltage acting over the bypassed partial spark gaps is divided asymmetrically using the bypass mechanism, whereby the bypassed partial spark gaps ignite sequentially in the order determined by the asymmetric voltage division.

Abstract: The LED lighting apparatus includes: a rectification block; an LED block including a first light emitting group and a second light emitting group; a charging/discharging block configured to charge electric charges in a charging period, and discharge electric charges in a discharging period; a driving control unit configured to determine a voltage level of a rectified voltage, controls a path selection switch to connect the rectification block to the LED block and controls the charging/discharging block to charge electric charges in the charging period, and controls the path selection switch to connect the rectification block to a ground and controls the charging/discharging block to discharge electric charges from the charging/discharging block to the LED block in the discharging period; and a path selection switch configured to connect the rectification block to the LED block in the charging period, and connect the rectification block to the ground in the discharging period.

Abstract: The LED light tube compatible with a light fixture having an ballast has a translucent tube and an LED light bar mounted in the translucent tube. and having at least one waveform conversion circuit having multiple rectifier diodes and at least one LED light string connected to the at least one waveform conversion circuit, wherein a recovery time of each rectifier diode is under 1 ?s; the ballast determines the at least one waveform conversion circuit and the at least one LED light string as low impedance loads, thus, the ballast does not output a high voltage AC power and burn the LED light tube; a recovery time of each rectifier diode is also short such that the LED light tube can endure a high frequency AC power outputted by the ballast. As such, the LED light tube is compatible with the light fixture.

Abstract: A LED driving apparatus and an operating method thereof are disclosed. The LED driving apparatus includes a power, at least one LED string, a LED control unit, and an input voltage detection circuit. At least one LED string is coupled to the power and includes LEDs connected in series. The input voltage detection circuit is coupled to two ends of at least one LED of the LEDs respectively and used to judge whether an input voltage is lower than a LED conducting voltage. The input voltage detection circuit includes a charging capacitance to be charged when the at least one LED string is conducted. If the judged result of the input voltage detection circuit is yes, the input voltage detection circuit will control the charging capacitance having a charging voltage to discharge to the at least one LED string.

Abstract: Disclosed are methods and lighting system with LEDs. An exemplified system comprises series-coupled light-emitting diodes, an integrated circuit, and an energy storage apparatus. The series-coupled light-emitting diodes are divided into several LED groups coupled in series. The integrated circuit comprises nodes respectively coupled to the LED groups, for providing a driving current to selectively flow through at least one of the LED groups. The energy storage apparatus has two ends coupled to a predetermined LED in a predetermined LED group. When the driving current flows through the predetermined LED group the energy storage apparatus energizes; and when the driving current does not flow through the predetermined LED group the energy storage apparatus de-energizes to illuminate the predetermined LED.

Abstract: Emergency lighting devices and methods are disclosed. An emergency lighting device includes a passive resonant converter circuit configured to be coupled to an emergency lighting module and to an input end of a group of solid state emitters, at which the group of solid state emitters receives a normal operation current from an LED driver. The passive resonant converter circuit is configured to receive an emergency operation current from the emergency lighting module and to provide a converted emergency operation current to the group of solid state emitters at an emergency input of the group of solid state emitters in response to the emergency operation current. The emergency lighting module may be a fluorescent emergency lighting module.

Abstract: A system includes: a first converter for receiving a pre-stage input DC voltage from a power source, and providing a pre-stage output DC voltage including a first DC voltage or a second DC voltage; a modulator the modulator controlling the first converter; a second converter, coupled to the first converter; and a controller, the controller controlling an operation mode of the second converter and notifying the modulator about the operation mode of the second converter. The modulator and the controller receive an external voltage indication signal indicating whether the pre-stage output DC voltage is the first DC voltage or the second DC voltage. The modulator controls the first converter to output the pre-stage output DC voltage based on the voltage indication signal. The modulator notifies the controller about whether the pre-stage output DC voltage reaches a target level.

Abstract: The invention describes an adaptive circuit (1, 1?) for driving a lower-voltage DC load (2) from a rectified higher-voltage AC supply (3), which adaptive circuit (1, 1?) comprises a charge-storage circuit (21, 21?), which charge storage circuit (21, 21?) comprises a first capacitor (C1) and a second capacitor (C2) connected essentially in series, wherein the second capacitor (C2) is connected at least in parallel with the load (2); and an active switch (22, 22?) realized as a controlled current source (22, 22?) for controlling a load current (Iload) through the load (2) such that, in a closed switch state, load current (Iload) is drawn essentially from the first capacitor (C1) of the charge-storage circuit (21, 21?), and, during an open switch state, load current (Iload) is drawn essentially from the second capacitor (C2).

Abstract: The present disclosure provides a decorative light string system comprising a light string comprising a plurality of lighting bulbs arranged electrically in series, wherein each light bulb comprises at least two LED chips, wherein half of said LED chips are connected in parallel and wherein half of said LED chips are connected in reverse parallel; and an adapter comprising a rectifier, wherein when the plug of the light string is plugged into the outlet adapter in a first orientation, the rectifier allows passage of a half-rectified wave lighting the LEDs connected in parallel, and wherein when the plug of the light string is plugged into the outlet adapter in a second orientation, the rectifier allows passage of a half-rectified wave lighting the LEDs connected in reverse parallel. Also included are methods of using said adapter and said decorative light string system.

Abstract: A light-emitting device includes a power module, a first light-emitting module, a second light-emitting module, a third light-emitting module, and a control module. The power module is configured to rectify an AC voltage for providing a periodic driving voltage. The first, second, third light-emitting modules are connected in series. The control module is configured to make the first, second, third light-emitting modules being driven by the driving voltage in response to different driving stages in a cycle period of a driving voltage. An average-diode-junction-area of the first light-emitting module is different from an average-diode-junction-area of the second light-emitting module or an average-diode-junction-area of the third light-emitting module.

Abstract: An LED constant-current drive circuit includes a BUCK circuit consisting of a transformer T1, a diode D9, a capacitor C5 and a field effect transistor Q1; a voltage limiting circuit consisting of a resistor R1, a diode D8, a capacitor C1, a resistor R3, a triode Q2, a zener diode DZ1 and a diode D10; and a current limiting circuit consisting of a resistor R4, a triode Q3, a triode Q4 and a resistor R2. When the transistor Q1 is turned on, a current flows through a primary side of the transformer T1 and an LED load, and then flows through the transistor Q1 and the resistor R2, and then flows back to a negative electrode of a power supply. When the transistor Q1 is turned off, the current flows through the primary side of the transformer T1, the LED load and the diode D9, thus forming a loop.

Abstract: Configurations for an LED driver are disclosed. The proposed LED driver receives an input voltage, drives an LED and includes a compensation capacitor set including a first and a second capacitors connected to each other in series, wherein the first capacitor is electrically connected to the LED, the second capacitor is grounded, the compensation capacitor set provides a compensation voltage to the LED such that the LED is conductible when an instantaneous voltage value of the input voltage is lower than an LED conduction voltage.

Abstract: LED light source comprising a string of LED loads (LED1-LED4) supplied by a rectified mains voltage. The number of LED loads carrying current is increased as the momentary amplitude of the rectified mains voltage increases, and is decreased as the momentary amplitude of the rectified mains voltage decreases. The order in which the LED loads start carrying a current and the order in which the LED loads stop carrying a current is reversed for each half period of the mains.