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 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: 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: 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: 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: 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: 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 driver circuit for one or more LEDs includes a power circuit having an output terminal, a capacitor coupled to the output terminal and a switch, and a control circuit coupled to the power circuit for controlling the power circuit. The control circuit is configured to operate the switch for coupling a resistance in series with the capacitor in response to detecting an open circuit condition at the output terminal. Additionally, or alternatively, the driver circuit may include a switched mode power supply, and the control circuit may be configured to switch operation of the switched mode power supply from a current control mode to a voltage control mode, and reduce a current setting for the current control mode, in response to detecting an open circuit condition at the output terminal.

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: 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 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: A DC-DC converter and an organic light emitting display comprising: a voltage generator receiving an input voltage through an input terminal to selectively generate a first voltage and a second voltage, outputting the first voltage and the second voltage through first and second output terminals, a capacitor coupled to the output terminal; and a switch unit discharging voltage stored in the capacitor according to the control signal.

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 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: 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: 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: 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: The present invention relates to a multi-output current-balancing circuit, which in one embodiment can include: (i) a transformer having a primary winding and a plurality of secondary windings, where the primary winding receives an AC input current; (ii) a plurality of first and second rectifier circuits and a plurality of first current balancing components, where each of the first and second rectifier circuits and the first current balancing components is coupled to a corresponding secondary winding, where each the first current balancing component is configured for current balancing between each of the first and second rectifier circuits of the corresponding secondary winding; and (iii) at least one second current balancing component, where each second current balancing component is coupled to a pair of the second rectifier circuits that correspond to different secondary windings, where the second current balancing components are configured for current balancing between different the secondary windings.

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.