Abstract: The invention relates to an isolated converter (100) for providing a current supply to an LED load, comprising: a galvanic isolation stage (101); a sensing circuit (103) on a primary side of the isolation stage (101), which is magnetically coupled to a secondary side of the isolation stage (101); wherein the sensing circuit (103) is configured to receive a feedback signal that is proportional to a secondary side current; and a control unit (105) configured to determine an output current of the converter (100) based on the feedback signal; wherein at least one electrical characteristic of the sensing circuit (103) and/or the control unit (105) is adjustable to convert the feedback signal from a first ratio to a second ratio to the secondary side current.

Abstract: The present disclosure discloses a lamp controller, comprising a DC power supply, a control unit and a switch unit that is controlled to be turned on or turned off by the control unit, an output end of the DC power supply is electrically connected to the control unit and the switch unit in respective, wherein the switch unit comprises three sets of switch circuits, each set of switch circuit comprises a load connecting part as well as a first switch tube and a second switch tube that are independently controlled by the control unit, a first pin of the first switch tube is connected to an output end of the control unit, a second pin of the first switch tube is connected to the DC power supply.

Abstract: A lighting system for plant cultivation comprises a light source, a light source driving unit that drives the light source, and a control unit that transmits a pulse signal to the light source driving unit. The control unit comprises a first pulse generating unit that generates a first pulse signal (S1) of a predetermined frequency, a second pulse generating unit that generates a second pulse signal (S2) of a frequency different from the predetermined frequency, and a pulse signal selecting unit that selects any one of the first pulse signal (S1) and the second pulse signal (S2) to transmit the selected one to the light source driving unit.

Abstract: A lighting system includes an LED controller, and an LED array which includes first and second LED sub-arrays, wherein the LED array is operatively coupled to the LED controller. The lighting system includes an antenna in communication with the LED controller. First and second wavelength spectrums are provided by the first and second LED sub-arrays, respectively, and are adjustable in response to adjusting an input signal provided to the antenna.

Abstract: An LED control circuit controls a switching operation of a switch by hysteretic control. The LED control circuit includes a controller integrated circuit (IC) that senses a current sense voltage from a current sense resistor that is on a low-side of the switch. The LED control circuit senses the current sense voltage during on-time of the switch to determine when to turn off the switch. During off-time of the switch, the controller IC determines when to turn on the switch by comparing a sawtooth voltage to a turn-on threshold that is generated from the on-time of the switch.

Abstract: A light emitting diode (LED) driving device includes a rectifier, a voltage converter, a variable impedance unit, and a controller. The rectifier rectifies an alternating current (AC) voltage to generate a first voltage. The voltage converter generates a second voltage for driving a plurality of LEDs from the first voltage. The variable impedance unit is connected to an input terminal of the rectifier. The controller adjusts impedance of the variable impedance unit based on at least one of the first and second voltages.

Abstract: In various embodiments, a method for powering light sources from a input power supply through a converter circuit is provided including a primary side and a secondary side separated by a galvanic barrier, wherein the primary side includes a power factor control block with an output capacitor. The method may include providing save circuitry on said secondary side for saving operational data of the converter upon failure of said input power supply; and powering said save circuitry during saving said operational data with energy derived from said output capacitor of said power factor control block.

Abstract: The present application discloses a light-emitting diode (LED) lighting system, including: a toroidal transformer comprising a pair of input terminals and a pair of output terminals; and an illuminant comprising an LED circuit; wherein the illuminant is electrically connected to the pair of output terminals of the toroidal transformer. The present application uses a toroidal transformer to simplify a circuit and reduce the number of electronic parts used. On one hand, a service life of a product can be prolonged, and on the other hand, costs can be reduced and a recycling rate is high, which is beneficial to environmental protection.

Abstract: An illumination system includes a master power supply providing power to several illumination modules. The master power supply is constructed and arranged to generate high-frequency and low-voltage electrical power provided to a primary wire forming a current loop. Each illumination module includes an electromagnetic coupling element and several light sources.

Abstract: A backlight module detecting abnormal lamp tubes and an LCD employing such a backlight module are proposed. The LCD includes a voltage calculator for detecting voltage applied on ends of a lamp tube to monitor the lamp tube. Once the lamp tube becomes abnormal, the voltage varies accordingly. The voltage calculator calculates a voltage signal from a plurality of lamp tubes and produces a voltage value. A protection circuit regards the voltage value as a feedback signal to decide if there are any abnormalities. Once any of the lamp tubes is abnormal, the protection circuit transmits the voltage signal to a pulse-width modulated integrated circuit (PWM IC) to activate a protective function. The protection circuit of the present invention obtains the protection signal by sampling the voltage signal of the ends of the lamp tube and then gets the control signal by means of the calculation of the voltage calculator.

Abstract: A light-emitting diode arrangement has a frame-shaped piezo transformer having at least one output-side connection, and having a light-emitting diode module that generates electromagnetic radiation, which module is disposed within the frame-shaped piezo transformer and electrically connects to the output-side connection of the piezo transformer by at least one output-side electrical conductor, wherein radiation emitted by the light-emitting diode module in the direction of the piezo transformer is reflected at the latter.

Abstract: A method of driving one or more than one light-emitting diodes with a pulsed current comprising: switching a first current flowing from a direct current (DC) voltage to an inductance apparatus comprising an inductor or a flyback transformer for charging the inductance apparatus; switching the pulsed current flowing from the light-emitting diodes to the inductance apparatus for transferring energy stored in the inductance apparatus to the light-emitting diodes; switching a second current flowing from the inductance apparatus to the direct current (DC) voltage for transferring energy stored in the inductance apparatus to the direct current (DC) voltage; wherein switching the first current, switching the pulsed current, and switching the second current are controlled to regulate the pulsed current supplied to the light-emitting diodes.

Abstract: A method of switching a plurality of switches for supplying a pulsed current to one or more than one light-emitting diodes involves: switching a current from a direct current (DC) voltage to an inductance component, for example an inductor or a flyback transformer, for charging the inductance component; switching a current from the inductance component to the light-emitting diodes for transferring energy from the inductance component to the light-emitting diodes; switching a current from the inductance component to the direct current (DC) voltage for transferring energy from the inductance means back to the direct current (DC) voltage; controlling the switchings to regulate the current in the inductance component for supplying the pulsed current to the light-emitting diodes is disclosed.

Abstract: Aspects of the disclosure provide a circuit that includes a detection circuit and a controller. The detection circuit is configured to detect a starting of a conduction in a power supply provided via an electronic transformer. The controller is configured to control a current regulating circuit to pull a current from the electronic transformer at a pre-determined level during a time duration following the starting of the conduction, and pull the current at a reduced level according to a pre-determined profile after the time duration.

Abstract: The present invention relates to a multi-output self-balancing power circuit. In one embodiment, a multi-output self-balancing power circuit can include: a transformer formed by a primary winding and n (e.g., greater than 2) series connected secondary windings; n output circuits corresponding to the n secondary windings, where each of the n output circuits can include a rectifier diode and a filter capacitor, and a load can be parallel coupled with the filter capacitor; n output circuits series coupled between a first output terminal of a first secondary winding and a second output terminal of an nth secondary winding; and (n?1) current balancing capacitors coupled between a common junction of n secondary windings and a common junction of n output circuits.

Abstract: An electric lighting driver circuit for driving an illuminating unit to emit light includes a flyback converting unit for converting a DC input voltage to a low ripple DC voltage, and a half-bridge converting unit electrically connected to the flyback converting unit, for converting the low ripple DC voltage to a low frequency, rectangular wave output voltage to drive the illuminating unit to emit light. The flyback converting unit includes a dual-output winding transformer connected to the half-bridge converting unit. The dual-output winding transformer includes a first winding at a primary side of the dual-output winding transformer and a second winding and a third winding at a secondary side of the dual-output winding transformer. The third winding converts leakage inductance attributed to the first winding and the second winding to electrical energy that is provided to the half-bridge converting unit.

Abstract: A switching power supply circuit includes a full-wave rectification circuit that performs full-wave rectification of an AC input voltage so as to generate a primary voltage, a transformer that transforms the primary voltage into a secondary voltage utilizing electromagnetic induction between first and second isolated windings, a rectifying and smoothing circuit that generates a DC output voltage from the secondary voltage so as to supply the DC output voltage to a load, a primary current control circuit that performs on/off control of primary current based on a result of comparison between a primary current detection voltage corresponding to the primary current flowing in the first winding and a first reference voltage, and a reference voltage correction circuit for monitoring an on-duty ratio of secondary current flowing in the second winding so as to correct the first reference voltage.

Abstract: A power supply apparatus for LED is provided. The power supply apparatus for LED includes a transformer, a first output unit, and a second output unit. The transformer includes a primary winding, a secondary winding receiving a power induced from the primary winding, and a tertiary winding receiving the power induced from the primary winding. The first output unit is connected to the secondary winding of the transformer, and outputs a first power current to an LED in a first operating condition. The second output unit is connected to the tertiary winding of the transformer, and outputs a second power current to the LED in a second operating condition. When the LED is connected to the power supply apparatus for LED, the power supply apparatus allows a current equal to or less than a predetermined current to flow in the LED, thereby protecting the LED from an overcurrent.

Abstract: Power consumed by an LED driver may be reduced by drawing, from an electronic transformer or dimmer, an input current that is constant over a plurality of input voltages. Power derived from the constant input current is provided to the LED driver.

Abstract: A converter for an LED driver for an LED light source. The converter has a flyback transformer. The primary receives a rectified AC voltage. A switching transistor is coupled in series with the primary. A controller controls the switching transistor on and off to generate a bus voltage across the secondary and a center tap voltage at a center tap of the secondary. The controller is powered by a first low-voltage DC voltage. A first power supply receives the center tap voltage and generates a second low-voltage DC voltage when the center tap voltage is above a cutover voltage. A second power supply has an output coupled to the first power supply output. The second power supply receives the bus voltage and generates the second DC voltage when the center tap voltage is below the cutover voltage.

Abstract: A control circuit selects a first control mode in which a switching element is turned on/off so as to flow current in an inductor in a continuous mode by which the current flows in the inductor without a sleep period, thereby fully lighting a light source load. The control circuit selects one of a second control mode in which a turn-on time of the switching element is changed and a third control mode in which an oscillating frequency is changed according to an interval, to which the designated dimming ratio corresponds, to light the light source load. An output capacitor connected between output terminals of a step-down chopper circuit smoothes a pulsation component of an output current supplied to the light source load and has capacity set so that a ripple ratio of the output current is less than 0.5 at the full lighting of the light source load.

Abstract: A light emitting diode (LED) driver circuit that generates current for driving an LED load includes a voltage converter circuit configured to supply a drive current to the LED load in response to a control signal, a control circuit that generates the control signal, and a bias voltage generating circuit that generates the bias voltage for the control circuit. The bias voltage generating circuit is galvanically isolated from a power supply voltage and from the LED load. The voltage converter circuit regulates a level of the drive current supplied to the LED load in response to the control signal.

Abstract: A power control system includes a transformer and a controller regulates a current on a secondary-side of the transformer based on a primary-side signal value. In at least one embodiment, the secondary-side current is a current out of a filter coupled to a rectifier and the secondary-side of the transformer and into a load. In at least one embodiment, the primary-side signal value is a sample of a current in the primary-side windings of the transformer. In at least one embodiment, the primary-side signal value represents a sample value of a primary-side transformer current. Proper timing of sampling the primary-side signal value substantially eliminates contributions of a transformer magnetizing current from the primary-side transformer current sample. Sampling the primary-side signal value when contributions of the transformer magnetizing current are substantially eliminated allows at least an average of the secondary-side current to be determined from the primary-side signal value.

Abstract: A power supply system includes a transformer having a primary winding on its primary side for coupling to a power source and one or more secondary windings on its secondary side. A first control circuit is disposed on the primary side of the transformer for controlling a current flow in the primary winding. A second control circuit disposed on the secondary side of the transformer, and the second control circuit is configured to provide a regulated output voltage. In the power supply system, the first control circuit is configured to generate a control signal for controlling the current flow in the primary winding without using a feedback control signal from the secondary side of the transformer.

Abstract: In at least one embodiment, a system and method provide current compensation in a lighting system by controlling a lamp current to prevent a current through a triac-based dimmer from undershooting a holding current value. In at least one embodiment, at least one of the lamps includes a controller that controls circuitry in the lamp to draw more lamp current for a period of time than needed to illuminate a brightness of the lamp at a level corresponding to particular phase-cut angle of the supply voltage. By drawing more current than needed, the controller increases the dimmer current during the period of time to prevent the dimmer current from falling below the holding current value. In at least one embodiment, the period of time corresponds to a compensating pulse of the lamp current at a time when the dimmer current would otherwise fall below the holding current value.

Abstract: A lighting system for wirelessly providing power to a lighting assembly across a wall. The lighting system may be used, for example, for powering the lighting assembly positioned on an outside portion of the wall, such as on the outside of a boat hull. An example of the lighting system includes a power transmitter with a multi-frequency generator connected to a power source and a controller. The multi-frequency generator is configured to generate an oscillating signal at a predetermined frequency according to a control signal received from the controller. The power transmitter includes a transmitting coil connected to receive the oscillating signal. A receiving coil is positioned to form an inductive coupling with the transmitting coil. A plurality of conditioning units are connected to the receiving coil to receive the oscillating signal. The plurality of conditioning units are connected to provide power to a corresponding light or set of lights.

Abstract: A light-emitting diode arrangement includes a piezoelectric transformer having at least one output connection position, and a high-voltage light-emitting diode including a high-voltage light-emitting diode chip including at least two active regions connected in series with one another, wherein the high-voltage light-emitting diode is electrically connected to the output connection position of the piezo transformer.

Abstract: A multi-lamp driving system includes a filter circuit, a switch circuit, a pulse width modulation (PWM) controller, a protection circuit, transformers, and an abnormity detection circuit. Primary windings of the transformers are connected to the switch circuit in parallel, and high voltage terminals of secondary windings of the transformers are connected to lamps respectively. The abnormity detection circuit converts current signals flowing through the lamps into voltage signals, and retrieves highest and lowest voltage signals corresponding to highest and lowest current signal respectively. Then the abnormity detection circuit determines if a difference between the highest voltage signal and the lowest voltage signal exceeds a predetermined value, and generates a trigger signal if the difference between the highest and lowest voltage signals exceeds the predetermined value.

Abstract: A lamp driver circuit to selectively energize one or more lamps is provided. The inverter circuit has a transformer with primary and secondary windings to provide voltage to the lamps. A filter is connected to the primary winding to receive a primary winding signal representative of the voltage across the primary winding. The primary winding signal has a frequency spectrum and the filter detects a particular characteristic of the frequency spectrum that is indicative of an end of life (EOL) condition of the one or more lamps. A control circuit is connected to the inverter circuit and to the filter. The control circuit is configured to discontinue energizing of the one or more lamps by the inverter circuit when the particular characteristic of the frequency spectrum of the primary winding signal is detected by the filter.

Abstract: The present invention discloses a light emitting device driver circuit and a method for driving a light emitting device. In the present invention, the secondary windings of a transformer provide positive and negative secondary voltages, so as to generate positive and negative output voltages. A light emitting device circuit is coupled between the positive and negative output voltages. As such, the specification to withstand high voltage for a device in the circuit is reduced.

Abstract: The transmission branch of an interface circuit has a transformer. On the input side there are applied to the transformer, for example from a controller, high-frequency impulses. The output side of the transformer controls a switch, such as for example a power transistor, which modulates the desired digital signals onto a connected bus line.

Abstract: An electronic ballast for parallel lamp operation with program start including an electronic ballast for fluorescent lamps operably connected in parallel, each of the fluorescent lamps having lamp filaments. The electronic ballast includes a current fed self oscillating inverter (110) and preheat windings (127) operably connected to the current fed self oscillating inverter (110) to provide filament power (134) to the lamp filaments during the preheat time. The current fed self oscillating inverter (110) includes an output transformer (112) having a primary output transformer winding (114) and a secondary output transformer winding (116), the secondary output transformer winding (116) being operably connected to provide lamp power (132) to the fluorescent lamps; and a switch circuit (118) operably connected in series with the primary output transformer winding (114), the switch circuit (118) having a switch (120) operably connected in parallel with an inductor (124).

Abstract: A backlight unit, with a parallel configuration of plural lamps, having improved reliability is disclosed. The backlight unit driver includes: first and second lamps connected parallel to each other; a DC/AC inversion portion inverting a DC voltage into an AC voltage to apply the AC voltage to the lamps; a transformer transforming the AC voltage from the DC/AC inversion portion; a positive polarity AC signal compensator compensating an electric current difference between the first and second lamps using positive polarity AC signals from the first and second lamps; and a negative polarity AC signal compensator compensating the electric current difference between the first and second lamps using negative polarity AC signals from the first and second lamps.

Abstract: There is provided a transformer having a minimized leakage inductance. The transformer includes: a winding part including a pipe shaped body part having a plurality of coils wound therearound and flange parts extended from both ends of the body part in an outer diameter direction thereof; and a core coupled to the winding part, wherein a flange part formed at one end of the body part includes at least one lead groove, and the coils are led to the outside of the winding part through the at least one lead groove.

Abstract: A multi-lamp driving system includes a power supply and at least one balance transformer. Each balance transformer includes two cores, two primary windings, two secondary windings and two protection windings. Each primary winding is wrapped around a core and serially connected to a lamp to form a first circuit branch in parallel connection with each other. The first circuit branches are powered by the power supply. The Each secondary winding is wrapped around a core and connected to a primary winding. The two secondary windings are connected in series to form a short circuit loop. Each of the protection windings is wrapped around a core and connected to a primary winding. The protection windings are wrapped in opposite directions and connected in series to form a second circuit branch. The second circuit branch outputs voltage signals to the power supply when induced voltages crossing the protection windings are unequal.

Abstract: A light-emitting diode driver circuit includes: a first-rectifier circuit to output a first-rectified voltage; a transformer including primary and secondary coils and an auxiliary coil inductively coupled to the primary or secondary coils, the primary coil being applied with the first-rectified voltage; a transistor connected in series to the primary coil; a second-rectifier circuit to output a second-rectified voltage obtained by rectifying a voltage generated in the auxiliary coil; a capacitor to be charged with the second-rectified voltage; and a control circuit to control on and off of the transistor based on a charging voltage of the capacitor so that the charging voltage becomes equal to a predetermined voltage, the secondary coil outputting a voltage that varies with a frequency corresponding to a frequency of the first-rectified voltage and that corresponds to a turns ratio between the primary and secondary coils, as a voltage for driving a light-emitting diode.

Abstract: A lighting controller includes a housing and a power transformer mounted in the housing for stepping down an inputted AC power signal at a first higher voltage to at least one output AC power signal at a second lower voltage for powering a plurality of light fixtures. The controller further includes a switching device that can be closed and opened to connect and disconnect a primary winding of the power transformer to a source of AC power that can provide the inputted AC power signal. At least one wire connection terminal is connected to a secondary winding of the power transformer. A face pack is removably mounted in the housing and is operatively connected to the source of AC power and the switching device. The face pack includes a display, at least one manually actuable input device, a processor, a memory operatively connected to the processor, and an operational program stored in the memory.

Abstract: An LED package containing integrated circuitry for matching a power source voltage to the LED operating voltage, LEDs containing such integrated circuitry, systems containing such packages, and methods for matching the source and operating voltages are described. The integrated circuitry typically contains a power converter and a constant current circuit. The LED package may also contain other active or passive components such as pin-outs for integrated or external components, a transformer and rectifier, or a rectifier circuit. External components can include control systems for regulating the LED current level or the properties of light emitted by the LED. Integrating the power supply and current control components into the LED can provide for fabrication of relatively small LEDs using fewer and less device-specific components.

Abstract: A power control system includes a transformer and a controller regulates a current on a secondary-side of the transformer based on a primary-side signal value. In at least one embodiment, the secondary-side current is a current out of a filter coupled to a rectifier and the secondary-side of the transformer and into a load. In at least one embodiment, the primary-side signal value is a sample of a current in the primary-side windings of the transformer. In at least one embodiment, the primary-side signal value represents a sample value of a primary-side transformer current. Proper timing of sampling the primary-side signal value substantially eliminates contributions of a transformer magnetizing current from the primary-side transformer current sample. Sampling the primary-side signal value when contributions of the transformer magnetizing current are substantially eliminated allows at least an average of the secondary-side current to be determined from the primary-side signal value.

Abstract: The present invention provides a power supply apparatus for an LED lamp, which mainly uses an isolation transformer to convert a high voltage AC input signal into a low voltage AC signal and thus generate a driving voltage for driving an LED lamp, comprising: a waveform and frequency modulation module disposed on the primary side of the isolation transformer for modulating an input waveform and a frequency f; and a secondary rectifier filter module disposed on the secondary side of the isolation transformer for converting the low voltage AC signal after passing through the isolation transformer into the driving voltage. In this way, the power supply apparatus for an LED lamp utilizes the principle of persistence of vision of human eyes to modulate the waveforms and frequencies of voltages for driving LEDs and can still maintain the normal operation.

Abstract: A transformer is disclosed. The transformer includes a first pin, a second pin, a first side winding, a second side winding, and a jump pin. The second side winding is coupled to the first pin and the second pin. The first pin is between the jump pin and the second pin. The jump pin is coupled to the second pin inside the transformer.

Abstract: An output voltage monitoring circuit monitors an output voltage of a capacitor charging circuit. A first sample-and-hold circuit samples and holds a voltage of a connection point of a primary coil of a transformer and a switching transistor. A first monitoring comparator compares output of the first sample-and-hold circuit with a predetermined first reference voltage. When the output of the first sample-and-hold circuit exceeds the first reference voltage, a signal processor executes predetermined signal processing. The first sample-and-hold circuit starts a sampling period after a predetermined first time has elapsed after the switching transistor is turned OFF. When a voltage drop across a detection resistor reaches a third reference voltage, the first sample-and-hold circuit ends the sampling period.

Abstract: A synchronous operating system for operating a plurality of discharge tube lighting apparatuses at the same frequency and same phase includes (1) an oscillator of a triangular wave signal whose inclination for charging a capacitor C2 and inclination for discharging the same are the same, (2) a signal generation part to generate, in a period shorter than a half period of the triangular wave signal, a first drive signal having a pulse width corresponding to a load current, and (3) a signal generation part of a second drive signal having a pulse width substantially equal to that of the first drive signal and a phase difference of about 180 degrees with respect to the same.

Abstract: A LED driving circuit includes a transformer, a rectifying filtering circuit, a PWM IC, a constant current circuit, and a feedback circuit. The transformer has a primary side and a secondary side. The rectifying filtering circuit is coupled to the secondary side and has a first output terminal. The PWM IC is coupled to the primary side. The constant current circuit has a second output terminal. A LED load is adapted to couple between the first output terminal and the second output terminal. The feedback circuit has a first input terminal coupled to the first output terminal to receive a first voltage and a second input terminal coupled to the constant current circuit to receive a second voltage. The second voltage varies with a conduction status of the LED load. The feedback circuit is adapted to control the PWM IC according to the received first and second voltages.

Abstract: An illumination apparatus comprises a plurality of LEDs and a control system connected to receive dimmer-modulated AC line voltage and control the LEDs. The control system is configured to operate in a plurality of different modes wherein changes in dimmer-modulated AC line voltage adjust various characteristic of the LEDs.

Abstract: A switch mode power supply (SMPS) system includes a rectifying circuit for coupling to an AC input voltage and a transformer having a primary winding for coupling to the rectifying circuit and a secondary winding coupled to the primary winding. The system also has a power switch coupled to the primary winding and a control circuit coupled to the power switch. The control circuit is configured to control current flow in the primary winding such that an envelop waveform formed by peak points of current pulses are in phase with the magnitude of the AC input voltage. Moreover, the SMPS system is configured to provide a constant average output current.

Abstract: A discharge tube driving device which drives a plurality of discharge tubes includes a switching circuit which generates a driving pulse, and a driving transformer which has a primary winding for receiving the driving pulse and a secondary winding for generating a high-frequency driving signal. The plurality of discharge tubes comprises a first discharge tube group and a second discharge tube group. One-side terminals of discharge tubes in the first discharge tube group are connected to the positive high-voltage terminal of the secondary winding of the driving transformer. One-side terminals of discharge tubes in the second discharge tube group are connected to the negative high-voltage terminal of the secondary winding of the driving transformer. Another-side terminals of the discharge tubes in the first discharge tube group are respectively connected to another-side terminals of the discharge tubes in the second discharge tube group.

Abstract: A driving circuit of multi-lamps including a power supply module, a transformer module, a first detection module, and a control module is provided. Whether the power supply module is turned off is controlled by a control signal. The transformer module respectively provides a driving signal and an inverted driving signal to a first terminal and a second terminal of each lamp according to the AC signal. The first detection module detects a first indication signal combined by signals of the first terminal of one lamp and the second terminal of another lamp. The control module generates the control signal according to the first indication signal. Therefore, whether the lamps have a problem of a short circuit or an open circuit, or are in abnormal states can be known from the variations of the first indication signal, and a protection function for the driving circuit can be activated.

Abstract: An illumination system includes a power supply having a boost converter operating in the discontinuous conduction mode, a flyback converter operating in the critical conduction mode, and a switch coupled to the flyback converter. Several light emitting diodes receive power from the power supply. The boost converter may include a boost inductor (LB) and a boost diode (DB), constructed to perform the boost power factor correction (PFC) function. The flyback converter may includes a flyback inductor (LFB) and a flyback diode (DFB) and the power supply may be constructed to turn on the switch around the point where the current flowing in the flyback inductor reaches zero value.

Abstract: The present invention provides a multiple lamp driving capable of being applied to a multiple lamp system such as an LCD, wherein the multiple lamp driving device includes: a power supply unit for supplying a driving voltage to a lamp unit provided with first to 4nth lamps; and a balancing circuit unit including first to nth balance transformers for receiving the driving voltage from the power supply unit and balancing currents flowing through the first to 4nth lamps, wherein each of the first to nth balance transformers includes a primary side connected to the power supply unit in series and first and second secondary sides electrically connected to the primary side, each one end of the first and second secondary sides is connected to one end of one of the first to 4nth lamps, each of the other ends of the first and second secondary sides is connected to one end of another among the first to 4nth lamps, and the other ends of all of the first to 4nth lamps are connected to a ground.