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 circuit for a light emitting diode lighting apparatus includes a driving data memory device in which central portion driving data for driving the light emitting diodes are separated into many sections within one cycle of the driving power; a drive controller for reading the central driving data, charging driving data, and outer driving data stored in the driving data memory device; a first D/A converter for converting digital central driving data and outer driving data output from the drive controller to analog signals, and a second D/A converter for converting charging driving data to an analog signal; a static current driving device having static current driving devices respectively connected to tabs of light emitting diodes according to an output signal of the first D/A converter; and a charging static current driving device for charging the charging capacitor according to the output signal from the second D/A converter.

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 lighting driver includes a shunt switch circuit configured to detect when an input of the lighting driver is connected to mains power without a ballast, and in response thereto to disable the lighting driver, and further configured to detect a type of ballast connected to the input of the lighting driver when the input of the lighting driver is connected to the ballast, and to regulate a bus voltage of the shunt switch circuit according to the detected type of ballast; and a switching mode power supply configured to receive the bus voltage of the shunt switch circuit and in response thereto to supply a lamp current to drive one or more light emitting diodes.

Abstract: What is described is a lighting unit 10 with a plurality of lighting segments 30a, 30b. The lighting segments 30a, 30b are arranged on a strip 40 in spaced relation from each other. Each lighting segment 30a, 30b is connected to an electrical supply terminal 20. In order to obtain a lighting unit with a flexible electrical configuration, each lighting segment 30a, 30b comprises at least one LED element and at least one driver circuit 36 including a controllable, current limiting element for controlling a current through the LED element.

Abstract: An image display apparatus according to an implementation of the present invention includes: pixel circuits disposed in rows and columns; first power lines and control lines disposed in respective rows; a third power line; second switching transistors disposed at least one for each of the rows and each having a gate terminal connected to the control line disposed in the corresponding row, one of a source terminal and a drain terminal connected to the first power line disposed in the corresponding row, and the other of the source terminal and the drain terminal connected to the third power line; and a power supply unit which supplies the same voltage to the first power lines and the third power line when the second switching transistors are turned ON.

Abstract: An LED device for use with an AC voltage power source configured such that at least one LED emits light during a positive phase of power provided from an AC power supply and at least one LED emits light during the negative phase of power provided from an AC power supply. The LED device includes a first power connection lead and a second power connection lead, both leads capable of being connected to and receiving power from an AC power supply.

Abstract: This disclosure provides a circuit and a method for driving an LED display. The driving circuit comprises a selection circuit for selecting a first light emitter from the plurality of light emitters, a pre-charging circuit for charging an equivalent capacitor of the display panel with respect to the selected first light emitter, and a power circuit for supplying power to the first light emitter after the first light emitter is selected, wherein the power circuit is configured to supply a driving current to the first light emitter in one or more stages. The driving circuit and method of this disclosure can be used to significantly increase the refresh rate and resolution of the LED display.

Abstract: The present invention provides an illumination device, an illumination system, and a lamp. The illumination system includes the illumination device and a light modulation module. The illumination device includes a light emitting diode (LED) array, an alternating current (AC) current source, and an output power control module. The AC current source is electrically coupled to the LED array. The output power control module is electrically coupled to the LED array and the AC current source. The LED array, the AC current source, and the output power control module together form a closed-loop control loop. The light modulation module is electrically coupled to the closed-loop control loop for modulating illumination brightness of the LED.

Abstract: A method of controlling a solid state lighting apparatus can be provided by receiving a solid state lighting characteristic selection signal at a solid state lighting apparatus and selecting, responsive to the solid state lighting characteristic selection signal, a solid state lighting model that defines a relationship between different lighting parameters used to vary light output from the solid state lighting apparatus responsive to a user input provided to the solid state lighting apparatus.

Abstract: This disclosure provides a circuit and a method for driving an LED display. The driving circuit comprises a selection circuit for selecting a first light emitter from the plurality of light emitters, a pre-charging circuit for charging an equivalent capacitor of the display panel with respect to the selected first light emitter, and a power circuit for supplying power to the first light emitter after the first light emitter is selected, wherein the power circuit is configured to supply a driving current to the first light emitter in one or more stages. The driving circuit and method of this disclosure can be used to significantly increase the refresh rate and resolution of the LED display.

Abstract: A system to allow a fluorescent lamp to be dimmed or otherwise improve color performance of the lamp while maintaining a constant spectral distribution. In one embodiment, the lamp will dim in light output and not shift in color temperature. An LED array is positioned under a fluorescent lamp such that its light injects back into the lamp that part of the color spectrum that diminishes as a fluorescent lamp dims. The LED array is positioned centrally along the underside of the lamp. The light from the LED is never directly visible but shines through the lamp; the lamp acting as a diffuser. The brightness level of the LEDs can be determined as a preset level relative to a predetermined dim setting or can be regulated through an electronic monitoring sensor. The monitoring could evaluate the shift in color spectrum and or intensity and render the appropriate injection of light spectrum to maintain a constant unwavering color temperature.

Abstract: An LED drive circuit is disclosed, which comprises a square wave generator configured to generate a square-wave signal for driving an LED unit, an LLC resonance circuit configured to transform the square-wave signal outputted by the square wave generator into a sinuous wave of a reduced voltage level, and the LED unit comprising at least one LED sub-unit. The LED sub-unit comprises at least a first LED lamp set and a second LED lamp set connected in parallel, and LEDs of the first LED lamp set are disposed in a direction opposite to those of the second LED lamp set. The square wave generator, the LLC resonance circuit and the LED unit are connected in sequence. The LED drive circuit of the present disclosure can drive an LED and has a reduced cost.

Abstract: An LED backlight source drive circuit, an LED backlight source and a liquid crystal display device are provided. LED backlight source drive circuit includes a voltage input terminal, a coupling module, and a rectifier module. The coupling module is connected to the voltage input terminal for receiving a current complying with a total working voltage of two power consumption modules from the voltage input terminal, and converting the current into a current complying with a working voltage of one power consumption module. The rectifier module is connected to the coupling module for inputting the current complying with the working voltage of one power consumption module into two serially-connected power consumption modules, thereby supplying power to the power consumption modules. The LED backlight source and the liquid crystal display device include two power consumption modules and the above LED backlight source drive circuit.

Abstract: The present invention provides a passive LC ballast and an associated method of manufacturing a passive LC ballast for use with any one of a plurality of high voltage discharge lamps. The passive LC ballast has an inductance and a capacitance selected in accordance with one of a set of one or more inductance-capacitance pairs. Each inductance-capacitance pair defines a respective inductance and a respective capacitance such that, when the inductance and the capacitance of the passive LC ballast is selected in accordance with any one of the inductance-capacitance pairs and the passive LC ballast is used with any one of the lamps, the lamp operates between respective minimum and maximum lamp powers of the lamp.

Abstract: A load driving circuit comprises a converting circuit, a converting controller, a load driving modulator, and a charge spike protection circuit. The converting circuit is adapted to be coupled to an output power source and supplies a driving power source to drive a load. The converting circuit has an output capacitance coupled to an output end thereof. The converting controller controls an amount of the driving power source responsive to a current or a voltage of the load. The load driving modulator and the load, connected in series, are coupled to the output end and so the load driving modulator adjusts an electronic state of the load. The charge spike protection circuit is coupled to the output capacitance and at least one connecting node of the load and the load driving modulator to provide a unidirectional charge release path to the output capacitance.

Abstract: There is provided an LED driving circuit including: at least one ladder network circuit including: (n+1) number of first branches connected in parallel with one another by n number of first middle junction points between a first junction point and a second junction point, where n denotes an integer satisfying n?2, (n+1) number of second branches connected in parallel with one another by n number of second middle junction points between the first junction point and the second junction point, the (n+1) number of second branches connected in parallel with the first branches; and n number of middle branches connecting the first and second middle junction points of an identical m sequence to each other, respectively, wherein each of the first and second, and middle branches comprises at least one LED device.

Abstract: An LED driving apparatus is provided. The apparatus includes an LED Portion 10, a charging/discharging capacitor 111, a capacitor charging and discharging paths, and a capacitor charging constant current portion 110. The LED driving portion 3 controls a current in the LED portion 10. The capacitor 111 is connected in parallel to the LED portion 10. The charging and discharging paths are connected to the capacitor whereby charging and discharging the capacitor, respectively. The constant current portion 110 is connected on the charging path and controls a charging current so that the capacitor is charged at a constant current. When rectified voltage applied to the LED portion becomes high, the capacitor is charged with the charging current through the charging path. When the voltage becomes low, the capacitor is discharged at a discharging current through the discharging path so that the discharging current is applied to the LED portion.

Abstract: Light Emitting Diodes (LEDs) are increasingly used in illumination applications. To control multiple Light Emitting Diodes (LEDs), or any other controllable light source, this document introduces a single-wire multiple-LED power and control system. Specifically, individually controlled LED units are arranged in a series configuration that is driven by a control unit located at the head of the series. Each of the individually controlled LED units may comprise more than one LED that is also individually controllable. The head-end control unit provides both electrical power and control signals down a single wire to drive all of the LED units in the series in a manner that allows each LED unit to be controlled individually or in assigned groups.

Abstract: The invention provides a current balancing circuit, which includes a plurality of light-emitting diode assemblies; an AC power generator for providing currents required by the light-emitting diode assemblies; and a plurality of current-equaling elements connected to the AC power generator, each of which is connected to a common mode connecting two light-emitting diode assemblies for balancing currents of the light-emitting diode assemblies.

Abstract: The present invention is directed to providing an LED driving circuit that can be reduced in size and produced at low cost, and that can effectively prevent a shoot-through current that may flow between a plurality of LED arrays. The LED driving circuit includes a rectifier, a first LED array containing a plurality of LEDs, a second LED array containing a plurality of LEDs; a connection unit for connecting the first and second LED arrays in series relative to the rectifier or for connecting the first and second LED arrays in parallel relative to the rectifier, a control unit for switching the connection of the first and second LED arrays relative to the rectifier from parallel to series by controlling the connection unit, and a reverse current preventing diode disposed between the first LED array and the second LED array.

Abstract: The present invention relates to a start auxiliary device for driving a gas discharge lamp cluster, the gas discharge lamp cluster comprising n gas discharge lamps connected in series, the start auxiliary device comprises: a primary start circuit including a primary start capacitor (C1) and a primary start inductor (L1); and a step-up unit (T1) including a first terminal (101), a second terminal (102), and a third terminal (103). When the step-up unit (T1) is excited by the primary start capacitor (C1) and the primary start inductor (L1) of the primary start circuit, the step-up unit (T1) outputs a high auxiliary start voltage at the third terminal (103) to start the respective gas discharge lamps in the gas discharge lamp cluster. In addition, the present invention also relates to a ballast having the start auxiliary device and an illumination device having the ballast.

Abstract: The present invention relates to a light emitting device including a light emitting element having a plurality of light emitting cells arranged on a substrate, a first electrode arranged on each light emitting cell of the plurality of light emitting cells, a second electrode arranged between the substrate and each light emitting cell of the plurality of light emitting cells, the second electrode being disposed to face the first electrode. The light emitting device also includes a conductive material electrically connecting the second electrode arranged under a first light emitting cell of the plurality of light emitting cells to the first electrode arranged on an adjacent second light emitting cell of the plurality of light emitting cells, and a control unit configured to control waveforms of a voltage and a current applied to the light emitting element.

Abstract: There is provided an LED driving circuit. The LED driving circuit according to an aspect of the invention may include: at least one ladder circuit including: (n?1) number (here, n is a positive integer satisfying n?2) of first branches provided between first and second junction points, and connected in-line with each other by n number of first middle junction points, (n?1) number of second branches arranged in parallel with the first branches, and connected in-line with each other by n number of second middle junction points between the first and second junction points, and n number of middle branches connecting m-th first and second middle junction points to each other, wherein at least one LED device is disposed on each of the first, second, and middle branches. Here, the number of LED devices included in each of the first and second branches is greater than the number of LED devices included in each of the middle branches.

Abstract: A capacitive current-sharing control circuit for LED lamp strings includes a signal generating unit, a control unit, a current-sharing unit, and a light-emitting unit. The control unit is used to control a driving voltage, which is generated from the signal generating unit, to drive the light-emitting unit, thus effectively providing a stable current source to the light-emitting unit to maintain illuminating brightness of the LED lamp strings.

Abstract: An LED driver is comprising: at least two LED strings; a rectifier rectifying an alternating current (AC) voltage for supply to the LED strings; at least two balancing capacitors positioned at a current path of each LED string for carrying out a current balancing of the LED strings; at least two path control elements for controlling the current path of each LED string; and a controller controlling the path control elements.

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: An exemplary current regulating circuit of LED string includes a capacitor, an inductor, a diode, a switch and a detection circuit. First and second terminals of the capacitor respectively are connected to a low voltage and a preset voltage. A first terminal of the inductor is connected to the low voltage. Positive and negative terminals of the diode are respectively connected to a second terminal of the inductor and a high voltage. First and second terminals of the switch are respectively connected to the second terminal of the inductor and the preset voltage. The detection circuit detects the low voltage to thereby switch ON-OFF states of the switch in demand. Moreover, a LED illumination device using the current regulating circuit also is provided.

Abstract: A Buck converter may include an input for connecting a DC voltage source; an output for connecting an LED; and a diode, an inductor and a main switch; wherein the diode and the main switch are coupled in series, wherein the inductor is coupled between the connecting point for the diode and the main switch, and a first output connection, wherein the converter further includes: a first auxiliary switch supplied with a first voltage; and a second auxiliary switch supplied with a second voltage, wherein the first auxiliary switch and the second auxiliary switch are coupled to the main switch such that the first voltage stipulates the switch-off time for the main switch and the second voltage stipulates the switch-on time for the main switch.

Abstract: Electronic circuit for LEDs usage without the necessity of using converters or rectifiers takes advantage of the waves in both polarities from the source of alternating current, saving space and minimizing the number of components in the circuits. This circuit is formed by two LEDs series connected in parallel but with an inverse polarity, with or without Zener protection diodes. To this type of circuit, capacitive arrangements can be added to limit the total electric current of the circuit. This way when it operates in a sufficiently high frequency, the LEDs give the optical perception that they are turn on simultaneously. In the implementation of this circuit, the illumination and signaling systems obtains low cost devices, low energetic consumption and excellent illumination levels.

Abstract: A LED string is divided into segments that each have a bypass-switch and a driver for the bypass-switch. The driver is powered by a supply voltage locally generated from the forward-voltages of the LEDs of the segment.

Abstract: Provided are an LED driving circuit capable of preventing distortion of LED currents and having a high operating speed, and a display device including the LED driving circuit. The LED driving circuit includes a current driving circuit, a dynamic headroom controller and a power supply circuit. The current driving circuit controls current signals flowing through LED strings in response to a first control signal that includes information of an LED current and a current-driving-circuit enabling signal. The dynamic headroom controller generates a dynamic headroom control signal having a voltage level that changes according to a logic state of the current-driving-circuit enabling signal. The power supply circuit generates an LED driving voltage that changes according to the dynamic headroom control signal.

Abstract: Provided is an LED driving apparatus capable of improving a power factor through a non-insulation type simplified circuit structure, including: a light emitting unit having at least one LED; a rectifier rectifying an alternate current (AC) voltage applied from external power; a power supply unit supplying driving power to the light emitting unit, and having an inductor connected to an output terminal of the light emitting unit; and a switch controller.

Abstract: Disclosed is a lighting device including a circuit including at least two parallel-connected light-emitting diodes of opposite pole in a first parallel branch and comprising at least two parallel-connected light-emitting diodes of opposite pole in a second parallel branch, and also including a capacitor and a coil. At least one of the diodes emits red light, blue light, and/or white light.

Abstract: A light string includes a plurality of remote units and a control unit. Each of the plurality of remote units includes a microcontroller and is connected to a plurality of lights. Each microcontroller stores one or more programs for controlling the lights in the plurality of lights. The control unit is connected to the plurality of remote units by a power supply line. The control unit sends information via the power supply line to the plurality of remote units. The information indicates a program of the one or more programs to be executed by the microcontroller of each of the remote units to individually control the plurality of lights.

Abstract: An AC LED package and circuits are disclosed along with an AC LED driver. The AC LED circuit may include as few as one LED or an array of anti-parallel LEDs driven with AC power sources and AC LED drivers at various voltages and frequencies. The AC LEDs are pre-packaged in various forms and materials and designed for mains or high frequency coupling in various forms to AC power sources, inverter type drivers or packages. The AC LED driver is a fixed frequency driver that provides a relatively constant voltage output to different size loads within the wattage limitation of the driver and in some cases is a direct mains power source.

Abstract: An image display apparatus according to an implementation of the present invention includes: pixel circuits disposed in rows and columns; first power lines and control lines disposed in respective rows; a third power line; second switching transistors disposed at least one for each of the rows and each having a gate terminal connected to the control line disposed in the corresponding row, one of a source terminal and a drain terminal connected to the first power line disposed in the corresponding row, and the other of the source terminal and the drain terminal connected to the third power line; and a power supply unit which supplies the same voltage to the first power lines and the third power line when the second switching transistors are turned ON.

Abstract: The present invention discloses a decorative light string device, which comprises: a power plug receiving AC power, a tail socket coupled to the power plug, and a LED string with one end thereof coupled to the power plug and the other end thereof coupled to the tail socket, wherein each of the power plug and tail socket has a diode and a capacitor coupled to the diode, whereby a DC voltage, which is twice the peak voltage of the AC power, is output to the LED string.

Abstract: The present invention relates to a transformer-free LED lighting device using the AC power from city electricity directly, which comprises a coupling capacitor, a bridge rectifier circuit and a current limiting resistor, wherein, there is a current limiting resistor cascading between the first input end of the bridge rectifier circuit and the first leading-in end of the electrical source of the AC power from city electricity, there is a coupling capacitor cascading between the second input end of the bridge rectifier circuit and the second leading-in end of the electrical source of the AC power from city electricity, there is a LED tube connecting between two output ends of the bridge rectifier circuit. The transformer-free LED lighting device using the AC power from city electricity directly. This invention shall simplify the circuit structure and reduce production cost for LED lighting devices. It is catered for the mass-production.

Abstract: A single magnetic storage element is used to provide power to multiple lighting devices, which may be strings of light-emitting diodes (LEDs) of different color. A switching circuit controls alternating application of energy among the multiple lighting devices and another switching circuit may charge the primary winding to different energy levels to control the intensity of the multiple lighting devices. In particular, the multiple lighting devices may be controlled to provide a desired color profile while dimming the lighting devices, while requiring only a single magnetic storage element for supplying energy to the lighting devices.

Abstract: A solid state lighting arrangement constituted of: a power source providing a current which is discontinuous in at least one direction; a plurality of light emitting diode (LED) strings arranged to receive the provided current from the power source; and a plurality of reactance elements, each of the plurality of reactance elements arranged in series with a particular one of the plurality of LED strings, such that current flowing from the power source through each of the LED strings creates a voltage drop across the series arranged reactance element, wherein the voltage drop across each of the series arranged reactance elements responsive to the discontinuous current is at least 10 times greater than the maximum difference between the voltage drops among the plurality of LED strings.

Abstract: A multi-channel circuit having respective channels powered through transformers having primary windings connected in series allows substantially equal constant currents to be provided through all channels by cross-regulation while only a single channel need be monitored and controlled. The variation in current between channels is generally small and largely insensitive to imbalances between voltages on loads due, for example, to different numbers of LEDs in series connected strings in illumination devices and can be further reduced by inverse coupling between inductors in respective channels. Efficiency is improved through reduction in the number of stages of the constant current source since the respective channels provided both DC-to-DC conversion and constant current regulation.

Abstract: There is provided an LED driving circuit including: at least one ladder network circuit including: (n+1) number of first branches connected in parallel with one another by n number of first middle junction points between a first junction point and a second junction point, where n denotes an integer satisfying n?2, (n+1) number of second branches connected in parallel with one another by n number of second middle junction points between the first junction point and the second junction point, the (n+1) number of second branches connected in parallel with the first branches; and n number of middle branches connecting the first and second middle junction points of an identical m sequence to each other, respectively, wherein each of the first and second, and middle branches comprises at least one LED device.

Abstract: A light-emitting diode (LED) string is provided. The LED string includes a power plug configured for connecting with a power source to power the LED string; one or more LED sockets configured for electrically connecting with the power plug; one or more LEDs configured for being installed on and electrically connecting with the LED sockets; and a control module configured for being electrically connected with anyone of the LED sockets. The control module includes a control circuit, an input terminal and an output terminal, the control circuit electrically connects with one of the LED sockets via the input terminal and the output terminal and controls a current flowing through the LED string to change from a first value to a second value, thereby controlling the LED string to light.

Abstract: A light string includes a load comprising a trigger LED assembly and a lighting assembly connected in series with the trigger LED assembly, the lighting assembly comprising a plurality of series connected lamps comprising an LED; and a rectifier for converting a source of AC into DC which is supplied to the load. The trigger LED assembly is adapted to flash and cause the lamps to flash. In one embodiment the trigger LED assembly includes a trigger LED and a capacitor connected in parallel with the trigger LED. The trigger LED includes a first LED and a second LED. The cathode of the first LED is connected to the cathode of the second LED, the anode of the first LED is connected to the positive terminal of the capacitor, and the anode of the second LED is connected to the negative terminal of the capacitor respectively.

Abstract: An electrical circuit for use as a string of lights in one embodiment includes a rectifier for converting AC into DC; and a plurality of lamps connected in series, each lamp having an LED, and wherein at least one of the lamps each has a Zener diode connected in series with the LED, a positive terminal of the lamp proximate the rectifier is connected to a positive terminal of an output of the rectifier, and a negative terminal of the lamp distal the rectifier is connected to a negative terminal of the output of the rectifier. In another embodiment, the Zener diode is replaced with a resistor. Hence, no resistors are provided externally of the lamp.

Abstract: A light-emitting diode (LED) string is provided. The LED string includes a power plug configured for connecting with a power source to power the LED string; one or more LED sockets configured for electrically connecting with the power plug; one or more LEDs configured for being installed on and electrically connecting with the LED sockets; and a control module configured for being electrically connected with anyone of the LED sockets. The control module includes a control circuit, an input terminal and an output terminal, the control circuit electrically connects with one of the LED sockets via the input terminal and the output terminal and controls a current flowing through the LED string to change from a first value to a second value, thereby controlling the LED string to light.

Abstract: An AC LED package and circuits are disclosed along with an AC LED driver. The AC LED circuit may include as few as one LED or an array of anti-parallel LEDs driven with AC power sources and AC LED drivers at various voltages and frequencies. The AC LEDs are pre-packaged in various forms and materials and designed for mains or high frequency coupling in various forms to AC power sources, inverter type drivers or packages. The AC LED driver is a fixed frequency driver that provides a relatively constant voltage output to different size loads within the wattage limitation of the driver and in some cases is a direct mains power source.

Abstract: A light emitting diode (LED) lamp assembly comprises an LED string and a plug. The LED string comprises multiple LEDs connected together in series. The plug is connected to the LED string and an external AC power source and has a circuit board. The circuit board is mounted in the plug, turns the LED string on or off, converts AC power to DC power and comprises an AC/DC circuit, a control circuit and a switch circuit. The AC/DC circuit is connected to the external AC power source and the LED string and converts AC power to DC power to provide operating power for the LEDs. The control circuit is connected to the AC/DC circuit to regulate illumination of the LEDs. The switch circuit is connected between the LED string and the AC/DC circuit and is controlled by the control circuit to turn the LEDs on or off.

Abstract: Disclosed is a low cost LED string circuit design that uses an inexpensive half-wave rectification and low-pass filter circuit that is designed to produce minimal flicker in the LED string that is connected to the circuit. The components of the half-wave rectification and low-pass filter circuit are selected in accordance with design principles that prevent glittering and flickering of the LED string. The circuit components of the half-wave rectification and low-pass filter circuit can be embedded in an outlet plug or as a separate independent unit between an AC power plug and the LED string.