Abstract: A light emitting element drive device includes an electric conduction switch that is provided along a power input line, a voltage detection unit that detects a power source voltage containing a noise component when the electric power is supplied to the power input line, a conversion processing unit that converts the detected power source voltage containing the noise component to a digital value, a data generation unit that generates data of a predetermined number of bits, and a control unit that turns on the electric conduction switch. The control unit determines a delay time based on the predetermined number of bits. The delay time corresponds to a time between supplying the electric power to the power input line and turning on the electric conduction switch. The control unit turns on the electric conduction switch after the delay time passes. Thus, an excessive rush current is prevented.

Abstract: A driver circuit for a dimmable solid state light source, and devices such as lamps and fixtures incorporating the same, and methods of driving such sources, are provided. A supply voltage circuit provides a supply voltage to a power factor controller circuit, such that the supply voltage is maintained within the high end of a nominal supply voltage operating range of the power factor controller circuit. The driver may also include an open circuit protection circuit for disabling the power factor controller circuit when an open circuit occurs in the load, and/or protection against electromagnetic interference (EMI).

Abstract: A circuit for dimming a light emitting diode is provided. The circuit includes an alternating current input voltage that is delivered to a light emitting diode. The circuit also includes a correction circuit configured to monitor the input voltage, which also delivers a current to the light emitting diode, wherein the current delivered to the light emitting diode is commensurate with the input voltage. The circuit also includes a simulation circuit electrically coupled to the correction circuit and configured to deliver an additional voltage to the correction circuit to modify a setpoint voltage when the input voltage falls below a predetermined value.

Abstract: A light-emitting diode includes at least one light-emitting diode chip, at least one control device, wherein each of the light-emitting diode chips is electrically connected to one of the at least one control devices, each of the at least one control devices including a data storage device in which brightness data for each light-emitting diode chip which is connected to the control device is stored, and the control device drives the connected light-emitting diode chip with a current which is selected according to stored brightness data for the light emitting-diode chip.

Abstract: A method and a device for controlling a discharge Lamp, and a discharge lamp system are disclosed herein. The method includes the operations of: when the lamp current changes, determining a percentage of change of the lamp current according to a synchronous signal and obtaining a second lamp current after a discharge lamp current changes according to the percentage of change of the lamp current and a first lamp current; obtaining a modulating signal according to a current difference between the first lamp current and the second lamp current; and generating a pulse voltage signal according to the modulating signal. The pulse voltage signal transits from a first voltage to a second voltage during the time period when the lamp current is transited from a first lamp current to a second lamp current during a transition time.

Abstract: A ballast (4) for providing power to a high intensity discharge lamp (8) includes a first sensor (32) and a control subsystem (16). The first sensor (32) generates a first signal indicative of a current level in the ballast (4). The control subsystem (16) computes a real time power level of the ballast (4) based at least upon the first signal, compares the computed real time power level to a specified power level, and modifies a frequency of operation of the ballast (4) in response to the comparison. The first sensor (32) can measure the current level at an output of the ballast (4). The ballast (4) can also include a second sensor (32) that generates a second signal indicative of a voltage output of the ballast (4). The control subsystem (16) can compute the real time power level of the ballast (4) based upon the second signal.

Abstract: An electronic ballast includes a converter, an inverter circuit, a controlling unit, and a current crest factor improvement circuit. The controlling unit issues a first control signal to control the converter and issues a second control signal and a third control signal with opposite enabling/disabling states to control on/off states of corresponding switch elements of the inverter circuit. During a dead time between the enabling state of second control signal and the enabling state of the third control signal, these switch elements are simultaneously in the off state. During the dead time, the current crest factor improvement circuit is triggered to generate a restraining signal. According to the restraining signal, an output power of the converter is decreased to a predetermined value in real time or the converter is suspended.

Abstract: A lighting device includes: a power conversion unit which converts a direct current (DC) power into a power required by a load; an output current detection unit which detects an output current of the power conversion unit; and a source voltage detection unit which detects a source voltage. Further, the lighting device includes an operation unit which calculates an output current command value so as not to exceed an upper limit of the output current command value set according to a resistance value of an externally connected resistor; and a control unit which controls the power conversion unit such that the output current thereof the power conversion unit becomes the output current command value.

Abstract: Aspects of the disclosure provide a lighting system. The lighting system includes a transformer having a primary winding on a receiving path and a secondary winding on a delivering path. The receiving path receives electric energy regulated based on a dimming angle. The delivering path delivers the received electric energy. According to an aspect of the disclosure, the lighting system includes a secondary switch, and a dimming controller. The secondary switch is switched on to couple a light source, such as an LED array, and the like, with the delivering path to emit light in response to the delivered electric energy and is switched off to decouple the light source from the delivering path. The dimming controller is configured to detect the dimming angle based on an electrical property of the delivering path. Then, the dimming controller switches on and switches off the secondary switch based on the dimming angle.

Abstract: A serial-type LED device includes p light source units and a dimming circuit. Each light source unit includes first and second terminals, m light strings and m current balance units. Each light string includes LEDs coupled in series to have a first terminal coupled to the first terminal of a corresponding light source unit and a second terminal coupled to the second terminal of the corresponding light source unit through a corresponding current balance unit. The first terminal of the first light source unit is coupled to a second DC voltage, and the second terminal of the i-th light source unit is coupled to the first terminal of the (i+1)-th light source unit, where m and p are integers greater than or equal to 2 and i is any integer from 1 to (p?1). The dimming circuit coupled to the second terminal of the p-th light source unit controls the second DC voltage according to a current outputted from the p-th light source unit.

Abstract: An LED lighting device is provided with output impedance control to stabilize an optical output across a wide current range. A switching power supply generates the output current, with switching control circuitry to determine switching frequency and an ON period for an associated switch, and to turn on/off the switch according to the determined frequency and ON period. An impedance element is coupled across output terminals for the lighting device, with an impedance value set so that a load current is larger than a current flowing to the impedance element at maximum on-duty of the switch and a current flowing to the impedance element is larger than the load current at minimum on-duty. The impedance element may be a variable impedance element, wherein an impedance control circuit adjusts the variable impedance such that an impedance value for minimum on-duty of the switch is smaller than that for a maximum on-duty.

Abstract: In various embodiments, a control system for an electronic circuit iteratively applies voltage to and senses current from a load to regulate operation of the load.

Abstract: The present invention relates to a lighting and/or indicating device, such as a vehicle headlamp, equipped with at least one halogen bulb, wherein it comprises a switch-mode power supply device for supplying power to the halogen bulb, said switch-mode power supply device comprising means for regulating the luminous flux provided by the halogen bulb and being installed close to the halogen bulb so as to minimize electromagnetic interference and dispersion of the supply voltage at the terminals of the halogen bulb.

Abstract: Features of the invention are related to drive circuits that provide both power factor correction and voltage conversion in a single circuit and in some implementations drive an LED array. This single stage converter uses a buck-boost topology and can operate LED arrays that have DC voltages above or below the AC line voltage. An output side filter and bulk energy storage device is placed at the output of the circuit. Bulk energy storage can be provided by an inductor, a capacitor, or a combination of an inductor and a capacitor. The output side filtering can be provided by a capacitor or a capacitor and an inductor. The circuit also includes a switch and a switch control device for controlling the switch to provide power factor correction.

Abstract: A high-efficiency Alternating Current (AC)-driven Light-Emitting Diode (LED) module includes a full-wave rectification unit, an LED unit, at least one instantaneous current control unit, and at least one input power compensation unit. The full-wave rectification unit rectifies commercial supply voltage. The LED unit is configured such that LEDS connected in series are arranged separately or in groups. The instantaneous current control unit sequentially controls the sections of the LEDs connected in series. The input power compensation unit actively controls variations in input current and power attributable to variations in input voltage. The full-wave rectification unit, the LED unit, the instantaneous current control unit, and the input power compensation unit are formed of a one-board module (ASIC) or an Integrated Circuit (IC).

Abstract: A ballast which controls the open-circuit voltage of the ballast. The ballast includes a power factor corrector (PFC) for receiving an AC input voltage and converting the AC input voltage into a power factor corrected DC voltage; a DC/DC converter connected to the PFC and having a switch placed at a low-voltage side of the DC/DC converter for converting the DC voltage of the PFC into a DC output voltage according to the switching operation of the switch; a controller connected to a control terminal of the switch of the DC/DC converter for sending a switching control signal to control the switch; and an open-circuit voltage controller for detecting a voltage associated with the open-circuit voltage of the ballast and regulating the duty ratio or pulse density or switching frequency of the switching control signal in response to the results of the detection, thereby controlling the open-circuit voltage.

Abstract: A driving apparatus for a fluorescent tube and a method thereof and an illumination apparatus using the same are provided. The driving apparatus stops providing power, when a fluorescent tube has broken, to both ends of the broken fluorescent tube regardless of whether a power switch related to the fluorescent tube is in ON or OFF state, and thus making sure that a person is under a safety condition without getting an electric shock during replacing the broken fluorescent tube; moreover, the driving apparatus automatically detects the newly installed fluorescent tube and automatically light up the newly installed fluorescent tube after the broken fluorescent tube is replaced and it is unnecessary to switch the power switch related to the fluorescent tube anymore, and thus avoiding a potentially hazard for the person who climbs up and down a ladder repeatedly.

Abstract: A high efficiency light emitting diode power supply for roadway lighting fixtures is provided. The power supply enables conditioning and monitoring of input power and monitors LEDs current to ensures consistent performance of the LED by changing a power correction factor. The LED output can also be adjusted based upon age or external input parameters and by modifying the power correction factor value. In addition, the LED output can be dimmed, turned down in output to a lower level at any time of night for a prescribed duration in order to further save energy. This dimming function uses a programming scheme that keeps track of the “seasons” (summer, fall, winter and spring) so that time of night is tracked accurately all year long.

Abstract: There are provided a light driving apparatus capable of being commonly used in various types of dimmers, and a driving method therefor. The light driving apparatus includes: a driving unit supplying driving power to a light emitting device according to controlling to drive the light emitting device; and a general-purpose dimming controlling unit controlling dimming of the light emitting device by converting a range of a brightness control signal of an external dimmer into a first voltage range according to a preset ratio to control the supply of power from the driving unit.

Abstract: A power supply topology is used in which a transistor is provided on the side of an output node of a rectifying circuit. An inductor is provided on the side of a reference node, a resistor is inserted between the transistor and the inductor, and one end of the resistor is coupled to a ground power supply voltage of a PFC circuit. The PFC circuit includes a square circuit which squares a result of multiplication of an input voltage detection signal and feedback information (output voltage of an error amplifier circuit). The PFC circuit drives on the transistor when a detection voltage developed at the resistor reaches zero, and drives off the transistor when the detection signal reaches an output signal of the square circuit.

Abstract: A lighting device includes: a lighting unit for supplying a lighting power to a light source unit; and a controller, for controlling the lighting unit. The lighting unit has an inductor and a switching element, and a diode for flowing a flyback current of the inductor to the light source unit during an OFF period of the switching element, and the controller has a unit for intermittently driving an ON/OFF operation of the switching element by a PWM signal and a unit for driving the switching element by a frequency higher than that of the PWM signal during an ON period of the PWM signal, and when the PWM signal falls, the controller reduces a peak value of a load current flowing through the light source unit during a certain period.

Abstract: Representative embodiments of the disclosure provide a system, apparatus, and method of controlling an intensity and spectrum of light emitted from a solid state lighting system. The solid state lighting system has a first emitted spectrum at full intensity and at a selected temperature, with a first electrical biasing for the solid state lighting system producing a first wavelength shift, and a second electrical biasing for the solid state lighting system producing a second, opposing wavelength shift. Representative embodiments provide for receiving information designating a selected intensity level or a selected temperature and providing a combined first electrical biasing and second electrical biasing to the solid state lighting system to generate emitted light having the selected intensity level and having a second emitted spectrum within a predetermined variance of the first emitted spectrum over a predetermined range of temperatures.

Abstract: A light source driving device configured to drive a light-emitting unit is provided. The light source driving device includes a direct voltage source, a first capacitance unit, and a switching current adjustment circuit. The direct voltage source is coupled with the light-emitting unit and supplies a direct voltage. The first capacitance unit and the light-emitting unit are connected in parallel. The switching current adjustment circuit and the light-emitting unit are connected in series. The switching current adjustment circuit is configured to bear a part of a voltage stress of the direct voltage source and is configured to switch the direct voltage.

Abstract: An illuminating apparatus is disclosed. The illuminating apparatus includes a detecting unit, an illuminating unit, and a control unit. The illuminating unit includes multiple illuminating sets and a switching unit for adjusting a connection relationship among the illuminating sets. The detecting unit is for detecting an inputted power supply received by the illuminating unit while the control unit is coupled to the detecting unit and the switching unit. The control unit based on a detected inputted power supply controls the switching unit according to a predetermined setting parameter, so as to ensure a conducting voltage of the illuminating unit to vary according to a variation in the inputted power supply.

Abstract: A system and method for driving one or more LEDs by regulating their brightness by controlling the LEDs' average current or voltage. The system includes a switching power converter and an integrated digital regulator with at least one of electrical, thermal, and optical feedbacks. The regulator is constructed as a PI or PID controller for continuous mode of operation of the power converter. Current is provided through an inductor and a power switch during an on time of the power switch. The ampseconds of the inductor are measured at an off time and compared with a periodic ramp signal. A set reference signal is also compared with the periodic ramp signal. Based on the comparisons between the ramp signal, the measured ampseconds, and the reference signal, a control signal is generated to regulate the peak current through the power switch.

Abstract: Features of the invention are related to drive circuits that provide both power factor correction and voltage conversion in a single circuit and in some instances drive an LED array. This single stage converter uses a SEPIC or Cuk topology and can operate LED arrays that have DC voltages above or below the AC line voltage. An output side filter and bulk energy storage device is placed at the output of the circuit. Bulk energy storage can be provided by an inductor, a capacitor, or a combination of an inductor and a capacitor. The output side filtering can be provided by a capacitor or a capacitor and an inductor. The circuit also includes a switch and a switch control device for controlling the switch to provide power factor correction.

Abstract: A LED drive circuit according to the present invention comprises a controller and a programmable signal. The controller generates a switching signal coupled to switch a magnetic device for generating an output current to drive a plurality of LEDs. The programmable signal is coupled to regulate a current-control signal of the controller. The switching signal is modulated in response to the current-control signal for regulating the output current, and the level of the output current is correlated to the current-control signal.

Abstract: A system including a power transistor configured to receive an alternating current (AC) line voltage and a control circuit. During a rising portion of a half cycle of the AC line voltage, the control circuit is configured to turn on the power transistor when the AC line voltage reaches a first value and turn off the power transistor when the AC line voltage reaches a second value. The second value is greater than the first value. During a falling portion of the half cycle, the control circuit is configured to turn on the power transistor when the AC line voltage reaches the second value and turn off the power transistor when the AC line voltage reaches the first value.

Abstract: A discharge lamp system includes a discharge lamp; a power supply device for providing DC input voltage and current; a converter connected to the discharge lamp and the power supply device for providing power for the discharge lamp; a DC input voltage detecting unit connected to the power supply device for detecting the DC input voltage; a DC input current detecting unit connected to the power supply device for detecting the DC input current; a lamp state detecting unit for detecting a signal responsive to the lamp state; a controller connected to the converter, the DC input voltage detecting unit, the DC input current detecting unit and the lamp state detecting unit for controlling the discharge lamp according to the signal responsive to the lamp state, the DC input voltage and the DC input current. A controlling method for the discharge lamp system is also disclosed herein.

Abstract: Methods and apparatus are described that can provide improved power factor correction and total harmonic distortion, efficiency and/or direct feedback of load current variations to a power source inverter. In one example, a power supply, for example, a ballast, can have an input circuit, an output circuit and an inverter circuit coupled between the input circuit and the output circuit. A current feedback circuit is coupled between the output circuit and the inverter circuit and configured to feed current back to the inverter circuit through a transformer stage separate from the inverter as a function of a current level in the output circuit.

Abstract: An apparatus for driving an LED device having a plurality of LED channels is disclosed. Each LED channel has a plurality of LEDs connected in series. A power converter converts an input voltage into an output voltage and outputs the output voltage to an output terminal that is connected to first terminals of the plurality of LED channels. A plurality of current controllers are connected to second terminals of the plurality of LED channels, respectively. Each current controller controls a current of a corresponding LED channel. A detection controller determines a detection time based on voltages of the second terminals of the plurality of LED channels. A state detector detects the open-circuited states of the plurality of LED channels based on voltages of the second terminals of the plurality of LED channels at the detection time.

Abstract: A primary side PFC driver circuit is disclosed that includes a switch control circuit for commanding a switch to allow an inductor coupled to an output load (e.g., LEDs) to transfer energy provided by an input voltage source. The switch control circuit provides two signals for commanding the switch. A first signal having a first frequency, with a duty cycle in proportion to the input voltage amplitude, commands the switch to allow the average input current to be proportional to the input voltage amplitude. A second signal having a second frequency higher than the first frequency pulses the output load with substantially constant current pulses based on a value of the first signal (e.g., while the first signal is high). The current pulses produce a substantially constant current in the output load.

Abstract: The invention discloses a driving circuit structure for driving light-emitting loads. The driving circuit structure may include a power supplying device, a signal processing device and an impedance balancing device and a dimming control unit. The power supplying device is used for supplying an alternating current power supply. The signal processing device is used for converting the alternating current power supply into a direct current power supply, so as to drive the light-emitting loads. The impedance balancing device is used for balancing an alternating current magnitude of the alternating current power supply, so as to stabilize a direct current magnitude of the direct current power supply for driving the light-emitting loads. The dimming control unit is capable of controlling output luminance of the light-emitting loads.

Abstract: Implemented are a switching power supply device and a light-emitting diode lighting device in which a variation in load current can be suppressed against a wide range of variation in AC voltage. The configuration of the switching power supply device and the light-emitting diode lighting device includes: a rectifier unit which rectifies AC input voltage and outputs pulsating-current voltage; a power converting unit which receives the pulsating-current voltage and supplies a predetermined load current to a load; a current detecting unit which detects the load current; a drive control unit which controls the power converting unit to regulate the load current to a constant level; and an input voltage detecting unit which detects a variation in the AC input voltage. The drive control unit controls the power converting unit depending on the variation in the AC input voltage detected by the input voltage detecting unit.

Abstract: A lighting device includes a lighting part, a switching part and a luminance fine-tuning part. The lighting part at least includes a first light emitting diode unit for outputting light with a first color temperature and a second light emitting diode unit for outputting light with a second color temperature. The switching part is coupled with a power source. By changing the number of times the switching part is turned on, the light with desired color temperature and luminance is produced by the lighting part according to the user's requirements. By operating the luminance fine-tuning part, the selected luminance is slightly increased or decreased.

Abstract: Power control systems generate electromagnetic interference (EMI). In at least one embodiment, a power control system includes a switching power converter and a controller that utilizes a spread spectrum strategy to reduce peak EMI values of the power control system. The controller generates a power regulation, switch control signal to control an input voltage to output voltage conversion by the switching power converter. The controller modulates the period of the control signal in accordance with the spread spectrum strategy. The spread spectrum strategy is an intentional plan to spread the spectrum of the control signal to reduce peak EMI values, and, thus, reduce the potential for degradation in performance, a malfunction, or failure of an electronic circuit caused by the EMI. The controller also modulates a pulse width of the switch control signal in response to modulation of the period of the control signal to provide power factor correction.

Abstract: A power-factor-corrected power supply adapted to supply power to one or more light emitting diodes (LEDs), comprises: a triac dimmer electrically connected between an alternating current source and a bridge rectifier; a damping circuit electrically connected between the alternating current source and the bridge rectifier; a bleeder circuit configured to conduct current between a supply terminal of the bridge rectifier and ground only when a triac in the triac dimmer is not conducting current; a fast startup circuit configured to conduct current between the supply terminal of the bridge rectifier and a voltage supply terminal of a power-factor-corrected controller when the triac dimmer is initially turned on until a supply voltage capacitor coupled to the voltage supply terminal of the power-factor-corrected controller has charged; a dimming slope control circuit configured to reduce a first voltage sensed at a current sensing terminal of the power-factor-corrected controller, such that a reduced amount of cur

Abstract: Apparatus and associated methods reduce harmonic distortion of a excitation current by diverting the excitation current substantially away from a number of LEDs arranged in a series circuit until the current or its associated periodic excitation voltage reaches a predetermined threshold level, and ceasing the current diversion while the excitation current or voltage is substantially above the predetermined threshold level. In an illustrative embodiment, a rectifier may receive an AC (e.g., sinusoidal) voltage and deliver unidirectional current to a string of series-connected LEDs. An effective turn-on threshold voltage of the diode string may be reduced by diverting current around at least one of the diodes in the string while the AC voltage is below a predetermined level. In various examples, selective current diversion within the LED string may extend the input current conduction angle and thereby substantially reduce harmonic distortion for AC LED lighting systems.

Abstract: A power supply circuit drives circuits having different numbers of series-connected LEDs without changing a circuit constant or a component. An LED series circuit is connected to a power converter circuit of a power supply circuit. The power converter circuit is controlled by a control arithmetic circuit, and supplies a constant current to the LED series circuit. A voltage detection circuit detects a voltage applied to the LED series circuit. The control arithmetic circuit checks whether the LED series circuit has 40 LEDs or 20 LEDs, based on the voltage detected by the voltage detection circuit. The control arithmetic circuit holds a constant-current value table for 40 LEDs and a constant-current value table for 20 LEDs. In accordance with the detected voltage, the control arithmetic circuit selects one constant-current value table, and controls the power converter circuit based on the constant-current value table selected.

Abstract: Representative embodiments of the invention provide a system, apparatus, and method of controlling an intensity and spectrum of light emitted from a solid state lighting system. The solid state lighting system has a first emitted spectrum at a full intensity level and at a selected temperature, with a first electrical biasing for the solid state lighting system producing a first wavelength shift, and a second electrical biasing for the solid state lighting system producing a second, opposing wavelength shift. Representative embodiments provide for receiving information designating a selected intensity level or a selected temperature; and providing a combined first electrical biasing and second electrical biasing to the solid state lighting system to generate emitted light having the selected intensity level and having a second emitted spectrum within a predetermined variance of the first emitted spectrum over a predetermined range of temperatures.

Abstract: Systems and methods for a digital-to-charge converter (“DQC”) are disclosed. A DQC may include a converting circuit configured to receive a first digital signal indicative of a voltage across a capacitor coupled to an output pin of the digital-to-charge converter and to determine a present charge of the capacitor based at least in part on the first digital signal. The DQC may also include an error determining circuit coupled to the converting circuit, wherein the error determining circuit is configured to receive a second digital signal indicative of a target charge via an input pin of the digital-to-charge converter and to determine a difference between the target charge and the present charge. The DQC may further include a correction circuit coupled to the error determining circuit and configured to control a programmable current source to produce an analog signal at the output pin in response to the determined difference.

Abstract: A ballast includes a power supply subsystem, a power factor correction circuit, a control subsystem and a half bridge. In one embodiment, the power supply subsystem receives an input line voltage that is within a range of approximately 310-530 volts AC or other suitable ranges. Further, in one embodiment, the power supply subsystem provides a rectified DC output. The power factor correction circuit receives the rectified DC output. In one embodiment, the power factor correction circuit includes a boost converter and a buck converter that produce a selected stable bus voltage that is less than approximately 700 volts DC. The control subsystem outputs control signals based on a digital input. The half bridge receives the bus voltage and the output control signals. Additionally, the half bridge outputs a high frequency signal to a lamp. In one embodiment, the control subsystem includes a microcontroller and a ballast controller.

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: A boost circuit for an LED (Light Emitting Diode) backlight driver circuit is disclosed; said boost circuit includes a PWM (Pulse Width Modulation) chip, a second capacitor, and a signal processing circuit. A VCC pin of the PWM chip is coupled to the input node, and the PWM chip is utilized to generate a PWM signal. One end of the second capacitor is coupled to an output pin of the PWM chip, and the second capacitor is utilized to filter out a direct current component of the PWM signal. One terminal of the signal processing circuit is coupled to the second capacitor, and another terminal thereof is coupled to a gate of the switch. The signal processing circuit is used to adjust the filtered PWM signal for generating corresponding high levels and low levels. A regulator is omitted in the present invention, therefore reducing costs.

Abstract: A simple, cost-effective and efficient short circuit protection with simple routing of the ground on the PCB is achieved in an asynchronous DC-DC boost converter wherein a voltage sensing controller selectively isolates an input power supply to a load in the event of a short circuit. The controller alleviates need for additional components by utilizing the circuit for under voltage lockout protection and the circuit for overvoltage protection to generate signals for detecting short circuit. A predetermined offset voltage is added to a sensed output voltage to generate a reference voltage that is compared to a sensed input voltage and an output signal having a high state is generated in the event that the reference voltage is less than the sensed input voltage for selectively disabling the source of input power when the output signal is in the high state.

Abstract: The present application relates to a lighting applications. In particular, the present application describes examples of lighting fixtures and light bulbs containing a light transmissive optic. The orientation of the solid state emitters together with the contoured output surface of the light transmissive optic produce a tailored light output distribution over a designated planar surface. The light generated by the solid state light emitters is of a sufficient intensity to illuminate the designated planar surface.

Abstract: A ballast that selectively operates multiple lamps is provided. The ballast includes a switching network, capable of operating in a number of switching configurations. The ballast also includes a control circuit, and two lamp control switches. The control circuit is connected to the switching network, and provides respective control signals via respective output terminals as a function of the switching configuration of the switching network. Each lamp control switch is in parallel with its lamp and is connected to a respective output terminal. The first lamp control switch is connected to a ballast power supply, and either provides power to the first lamp or does not, depending on the first control signal. The second lamp control switch is connected to the first lamp control switch and to ground, and either provides power to the second lamp or does not, depending on the second control signal.

Abstract: A lighting device such as an electronic ballast or LED driver includes a power factor correction (PFC) controller responsive to input power supply signals to generate control signals, a PFC boost converter responsive to said control signals to generate a boosted output voltage, and a fast start circuit with a power supply source and an energy storage device, a magnitude of the input power supply signal corresponding to energy stored in the energy storage device. During a first mode, the fast start circuit responds to a rectified mains input to enable the power supply source and charge the energy storage device. During a second mode, the fast start circuit responds to a magnitude of the power supply signal to disable the power supply source and discharge the energy storage device. The boost converter during the second operating mode maintains controller operation while the power supply source is disabled.

Abstract: An apparatus and a method for common use of a power supply and a display apparatus using the same are provided. The display apparatus includes a display panel, a backlight unit which provides backlight to the display panel, and a power supply unit for common use which comprises an adjusting circuit unit comprising a plurality of resistances, and provides a current of a magnitude corresponding to a combination state of the plurality of resistances to the backlight unit. Accordingly, the power supply apparatus for common use adjusts an output current easily and is commonly used for diverse display apparatuses, and thus a manufacturing process is efficiently improved.

Abstract: In a power supply device 1, power factor improving circuits 15 and 16 are connected to an external power supply and configured to supply electric power to a driving circuit 19, improve a power factor of an input current to the driving circuit 19, and perform an interleave operation. The driving circuit 19 subjects an LED 111 to lighting control.