Abstract: Methods, systems, and devices are described for sensing a phase-cut dimming signal and outputting a control signal compatible with a switching power circuit. Embodiments of the invention generate at least one of a low-frequency pulse-wave-modulated control signal, an analog output control signal, or a digital (e.g., higher-frequency pulse-wave-modulated) output control signal. Some embodiments further provide preloading and/or startup control functionality to allow proper functioning of the circuitry under small-conduction-angle (i.e., highly dimmed) conditions.

Abstract: A phase cut angle converter with range detection for a phase cut dimmer constituted of: a phase cut angle detector arranged to detect the phase cut angle presented by the phase cut dimmer blocking a portion of an alternating current mains power sine wave from reaching a power converter, and output a signal whose value is responsive to the detected phase cut angle; a storage functionality constituted of a memory in communication with the phase cut angle detector, the storage functionality arranged to detect each of a minimum value and a maximum value for the detected phase cut angle of the phase cut angle detector and store the minimum value and the maximum value on the memory; and a signal adjustment functionality arranged to convert the detected phase cut angle to a dimming signal responsive to the stored minimum value and the maximum value for the detected phase cut angle.

Abstract: An LED drive circuit is provided that is connectable to a phase-control light controller and drives an LED load by use of a voltage obtained by rectifying a phase-controlled alternating current voltage inputted from the phase-control light controller. The LED drive circuit includes: a first phase angle detection portion that detects a phase angle in a present cycle; a second phase angle detection portion that detects a phase angle in a cycle preceding the present cycle by at least one cycle; a bias portion that generates a detection signal by adding a predetermined delay time to a phase angle obtained by averaging the phase angle detected by the first phase angle detection portion and the phase angle detected by the second phase angle detection portion; and a drive portion that starts current supply to the LED load at timing based on the detection signal generated by the bias portion.

Abstract: Exemplary apparatus and associated methods involve a bypass module for modulating conductivity of one or more current paths to provide a first set of LEDs that are conducting near minimum output illumination and having a larger conduction angle than that of a second set of LEDs that conduct at a maximum output illumination. In an illustrative example, the conductivity of a bypass path in parallel with a portion of the second set of LEDs may be reduced while the AC input excitation is above a predetermined threshold voltage or current. The bypass path may be operated to provide a reduced effective turn-on voltage while the input excitation is below the predetermined threshold. For a given maximum output illumination at a maximum input excitation, the bypass module may control current through selected LEDs to construct an input current waveform with substantially improved power factor and reduced harmonic distortion.

Abstract: An apparatus and method of retrofitting a light fixture are disclosed. One method includes interfacing a retrofit controller with a dimming ballast of the light fixture, connecting the retrofit controller to at least one sensor, and connecting the retrofit controller to a power supply and a network. Another embodiment includes a light fixture retrofit controller and a separate sensor unit. The combination of the retrofit controller and a separate sensor unit are operative to provide power and dimming control of a dimming ballast of an existing light fixture. The dimming control is base on at least one of a signal sensed by the separate sensor unit and control information received from a network.

Abstract: In various embodiments, a power supply device for light sources may include a feed line from mains via a phase-cut dimmer, selectively switchable between a conductive state and a non-conductive state, to permit or interrupt feeding of the device from mains. The device may include a power stage to feed at least one light source from said feed line from mains; a drive stage for said power stage; and a supply stage for said drive stage, said supply stage connected to said feed line from mains. The device may further include a sensor to detect when said dimmer is non-conductive and when said dimmer is conductive. The drive stage may be coupled to the sensor to disable driving of said power stage when the sensor indicates that the dimmer is non-conductive, and enable driving of the power stage when the sensor indicates that the dimmer is conductive.

Abstract: A lighting source that can be deployed in a hazardous environment is disclosed. For example, the lighting source comprises at least one light emitting diode and a power supply for providing power to the at least one light emitting diode. The lighting source also comprises an enclosure for housing the at least one light emitting diode and the power supply, where said lighting source is for deployment in a hazardous environment.

Abstract: Devices (1) have branches (20,30) for receiving AC voltages. First branches (20) comprise first light-emitting diode circuits (21) and first arrangements for phase-shifting first currents flowing through the first light-emitting diode circuits (21) with respect to the AC voltages. Second branches (30) comprise second light-emitting diode circuits (31) and do not comprise second arrangements for phase-shifting second currents flowing through the second light-emitting diode circuits (31) with respect to the AC voltages. As a result, an overall flicker index of the device (1) will be smaller than individual flicker indices of the light-emitting diode circuits (21,31). The first arrangements may comprise capacitors (22) coupled serially to the first light-emitting diode circuits (21). The branches (20,30) may further comprise resistors (23,33) coupled serially to or forming part of the light-emitting diode circuits (21,31).

Abstract: An LED drive circuit in which an alternating voltage from a phase control dimmer is input and an LED is driven. The LED drive circuit comprises a phase angle detector for detecting the phase angle at which a phase control element inside the phase control dimmer switches from off to on; a switching power supply for feeding a current to the LED; a switching element connected in series to the LED; and a controller for controlling the switching power supply and the switching element in accordance with the output of the phase angle detector; wherein the controller places the switching element in an always-on state in a case in which the phase angle detected by the phase angle detector is equal to or less than a predetermined value, and the controller pulse-drives the switching element in a case in which the phase angle detected by the phase angle detector is greater than the predetermined value.

Abstract: An electronic ballast is provided, including first a second input connections for connecting an alternating supply voltage; an EMC filter; a rectifier; a capacitor for providing the DC operating voltage for the output stage; and a power factor correction device, which comprises a number n of partial devices for power factor correction, as well as a control device for controlling the number n of partial devices, the power to be provided at the output of the power factor correction device being a total power currently to be provided, the power to be provided by the partial device i being a currently to be provided partial power of the partial device i. The control device is configured to control at least first and second partial devices as a function of the currently to be provided total power in such that their currently to be provided partial powers differ from one another.

Abstract: A microprocessor operated controller device and associated method for modifying an AC input power to provide a reduced power AC output power to a load when coupled to the controller device. The AC output power has a series of cut-out pulses in each half cycle of the AC output power waveform. The device includes a switching system having a plurality of switching elements for positioning the series of cut-out pulses in each half cycle of a waveform of the AC input power to result in said reduced power AC output power and a switch control system for coordinating opening and closing of the plurality of switching elements during positioning of the series of cut-out pulses. The switch control system includes a synchronization system for synchronizing the switching system with timing of each half cycle of the AC input power waveform.

Abstract: A universal dimmer has a switching element, a load current measurement element, a current evaluator for evaluating the current passing through the load, and a firing angle adjuster such as a regulator or transforming element. The current passing through the load is measured and evaluated so as to direct the firing angle adjuster to adapt firing angles of the switching element so that a load RMS current is proportional to a dimmer input signal, regardless of the type of load being controlled. The universal dimmer is capable of dimming the output from linear and non-linear loads using AC power line phase angle control to vary output power of linear and non-linear loads, ranging from regular linear loads such as incandescent lamps, to non-linear loads, such as LED lamps, compact fluorescent lights (CFLs'), etc. as well as linear loads with large phase shift, that is, inductive and capacitive loads.

Abstract: A two-wired LED light adjusting system, for controlling the luminance adjustment for a LED lamp module. The light adjusting circuit includes a phase modulating circuit, a LED driving circuit and a controller. The phase modulating circuit generates a phase modulating voltage. The controller detects the phase modulating voltage of various waveforms. When the controller detects the phase modulating voltage of different waveforms, the controller controls the LED driving circuit to enable the LED lamp module to emit light of different luminance according to waveforms of the phase modulating voltage.

Abstract: Embodiments of the present invention provide for the rapid reignition of a high intensity discharge lamp. In one embodiment of the invention, an apparatus for a fast reigntion of a high intensity discharge lamp is disclosed. The apparatus is comprised of a ballast operatively coupled to the lamp that is configured to receive power from a power supply. The apparatus is also comprised of a timer circuit that enters a timing phase and produces a quantum of timing information when the lamp ceases receiving power from the power supply. This timer circuit does not require external power during the timing phase. The apparatus is additionally comprised of a control circuit that receives the timing information and permits the ballast to reignite the lamp based on the information.

Abstract: The semiconductor device is included in the LED driving circuit (current regulator) of driving the LED array (with series-connected number m×parallel-connected number n), and is formed of a plurality (n pieces) of LED driving devices of controlling a current (constant-current driving) flowing in each string. A vertical semiconductor device, for example, a vertical MOSFET is used as the LED driving device. Both of a main device functioning as a constant-current driving device and a subsidiary device functioning as a circuit-breaking switch during dimming are formed inside a chip of the device, which are formed of the vertical semiconductor devices. In a first surface of the device, each source region of the main device and the subsidiary device is formed so as to be insulated from each other through an isolation region.

Abstract: A dimmable LED driver provides accurate full range dimming for LED lighting. The driver utilizes the timing of an AC signal rather than its power output or other characteristics to accurately determine the level of light a user desires. In this manner, the driver provides accurate full range dimming without the need for calibration to specific AC power levels. The driver may detect the period of an AC signal allowing the driver to be used with various frequencies without the need for calibration. In one or more embodiments, the driver compares the pulse widths of a dimmed AC signal to the period of the AC signal to determine the desired light level. The driver may comprise a signal processor and controller in one or more embodiments.

Abstract: The present invention relates to a method for driving and to an associated command and control device for discharge lamps (2), for example high pressure sodium lamps (2), supplied by an alternating current electrical supply network. Both the method and the device provide the use of an electronic microprocessor (7) receiving on the input side data relating to the current drawn by the lamp (7) and connected on the output side to a power switch (6) for high frequency switching of the alternating current supply to the lamp.

Abstract: The present invention relates to providing an improved phase controlled dimming LED driver circuitry, system and a method thereof, which is configured to enable dimming intensity of light generated by a light source, said phase controlled dimming driver circuitry being connected to a phase control dimmer that provides to it a regulated alternating current (AC) signal, wherein said phase controlled dimming driver circuitry does not include a microprocessor and pulse width modulates its output current, provided to said light source, at a frequency unrelated to the AC signal frequency. Further, the phase controlled dimming driver circuitry applies amplitude modulation (AM) and pulse width modulation (PWM) substantially simultaneously to the output current provided to the light source.

Abstract: A system (100) for current and/or temperature control of light fixtures includes a sensor (110) structured to be in communication with a light fixture (150), sense a current flow or a temperature of the light fixture (150), and communicate an input signal relative to the current flow or the temperature; a variable switch (120) structured to be in communication with the light fixture (150) and regulate the current flow of the light fixture (150) in response to a control signal; and a controller (130) in communication with the sensor (110) and the variable switch (120) and structured to monitor the input signal communicated by the sensor (110), compare the input signal to a condition, and communicate the control signal to the variable switch (120) to control its operation. A method for current and/or temperature control of light fixtures includes providing the system (100), monitoring the current flow or the temperature of the light fixture (150); and regulating the current flow of the light fixture (150).

Abstract: A system and method modify phase delays of a periodic, phase modulated mains voltage to generate at least two independent items of information during each cycle of the periodic input signal. The independent items of information can be generated by, for example, independently modifying leading edge and trailing edge phase delays of each half cycle phase modulated mains voltage. Modifying phase delays for the leading and trailing edges of each half cycle of the phase modulated mains voltage can generate up to four independent items of data. The items of data can be converted into independent control signals to, for example, control drive currents to respective output devices such as light sources to provide multiple items of information per cycle.

Abstract: An electronic ballast device includes a stabilizer and a sweep frequency circuit for preheating. The stabilizer includes a first input terminal, a second input terminal and an output terminal connected to a fluorescent lamp. The sweep frequency circuit includes a boost element, an impedance element, a switch and a frequency selective circuit. The boost element includes a first end and a second end separately electrically connected to the first input terminal and the impedance element. The switch includes an input terminal electrically connected to the common contact point of the boost element and the impedance element, an output terminal and a reference voltage input terminal electrically connected to the common contact point of the boost element and the stabilizer. Furthermore, the frequency selective circuit is electrically connected to the output terminal of the switch, the first input terminal of the stabilizer and the second input terminal of the stabilizer.

Abstract: A light source (10) is disclosed, emitting multi-colored light with light of at least two different colors, emitted from a number of primary light sources (1) wherein the primary light sources (1) are divided into groups and the brightness values of the primary light sources (1) within a group are determined and controlled separately according to color, such that the color location of the multi-colored light lies in a given region of the CIE standard color diagram. The invention further relates to a method for controlling such a light source (10) and an illumination device with such a light source (10), for example, for backlighting a display.

Abstract: Methods, systems, and devices are described for sensing a phase-cut dimming signal and outputting a control signal compatible with a switching power circuit. Embodiments of the invention generate at least one of a low-frequency pulse-wave-modulated control signal, an analog output control signal, or a digital (e.g., higher-frequency pulse-wave-modulated) output control signal. Some embodiments further provide preloading and/or startup control functionality to allow proper functioning of the circuitry under small-conduction-angle (i.e., highly dimmed) conditions.

Abstract: In one example embodiment, a drive probe is coupled to the lamp body to provide the primary power for ignition and steady state operation of the lamp. Feedback may be used to adjust frequency in response to changing conditions of the lamp during startup. A phase shifter may be used to adjust the phase of the power between ignition and steady state operation. A sensor may detect a lamp operating condition that automatically triggers a shift in phase after the fill in the bulb is vaporized. In another example embodiment, a method for sequentially optimizing the drive power and phase shift applied to the lamp is disclosed that may reliably regulate the lamp current consumption to desired startup and operational levels despite variations in lamp environmental conditions.

Abstract: An AC conversion circuit includes a main transformer having a primary winding and a secondary winding to electrically insulate the AC power source side and the discharge tube side from each other, an IC1 arranged on the AC power source side, a plurality of switching elements arranged on the AC power source side and driven by the IC1, to pass a current through the primary winding of the main transformer based on the DC power, an IC2 arranged on the discharge tube side, to generate a pair of rectangular-wave signals for conducting PWM control on a current passing through the discharge tube and having the same pulse width with a duty ratio of less than 50% and a phase difference of about 180 degrees, and one or more signal transfer insulated elements to send the pair of rectangular-wave signals from the IC2 to the IC1.

Abstract: Waveform management systems and methods for ballasts are provided. The system includes a lamp, a ballast, a first interface, a storage unit, and a processing unit. The processing unit obtains at least one first waveform from the storage unit, and writes the first waveform to the ballast via the first interface. The processing unit transmits an illumination signal to the ballast via the first interface, such that the ballast controls the illumination of the lamp according to the first waveform.

Abstract: A system and method modify phase delays of a periodic, phase modulated mains voltage to generate at least two independent items of information during each cycle of the periodic input signal. The independent items of information can be generated by, for example, independently modifying leading edge and trailing edge phase delays of each half cycle phase modulated mains voltage. Modifying phase delays for the leading and trailing edges of each half cycle of the phase modulated mains voltage can generate up to four independent items of data. The items of data can be converted into independent control signals to, for example, control drive currents to respective output devices such as light sources to provide multiple items of information per cycle.

Abstract: A dimmable LED driver provides accurate full range dimming for LED lighting. The driver utilizes the timing of an AC signal rather than its power output or other characteristics to accurately determine the level of light a user desires. In this manner, the driver provides accurate full range dimming without the need for calibration to specific AC power levels. The driver may detect the period of an AC signal allowing the driver to be used with various frequencies without the need for calibration. In one or more embodiments, the driver compares the pulse widths of a dimmed AC signal to the period of the AC signal to determine the desired light level. The driver may comprise a signal processor and controller in one or more embodiments.

Abstract: Solid state light sources are compatible with AC phase-cut dimmers. The light sources may have switching mode power supplies having primary and secondary sides that are in first and second circuit parts that are electrically isolated from one another. Information regarding a waveform of input electrical power is extracted in the first circuit part and passed to a controller in the second circuit part by way of a galvanic isolator. Additional isolated paths may be provided to provide bi-directional exchange of information between the first and second circuit parts and/or to provide for the exchange of additional information relevant to control. The signal path from the first side to the second side may have a low latency.

Abstract: This system is a no touch single pole single throw (spst) two wire electronic light switch that uses an Infrared Proximity Detector to create a working system designed to replace existing mechanical switches common in households. The use of a Micro Controller enables the system to adapt to different loads and load types while requiring a minimum number of parts to perform the necessary tasks.

Abstract: A driver circuit or controller flexibly drives either a half-bridge or a full-bridge switching network in a backlight inverter without modification, redundant circuitry or additional components. The driver circuit includes four outputs to provide four respective driving signals that establish a periodic timing sequence using a zero-voltage switching technique for semiconductor switches in the switching network.

Abstract: A discharge lamp lighting apparatus includes a discharge container, a pair of electrodes and a power supply apparatus. An alternating current of a frequency, which is lower than stationary frequency, is inserted periodically into the alternating current of stationary frequency. When a lighting current value of the discharge lamp is smaller than a predetermined lower limit, the frequency is set as predetermined minimum frequency. When the lighting current value of a discharge lamp is larger than a predetermined maximum value, the frequency is set as predetermined maximum frequency. When a lighting current value of the discharge lamp is between the lower limit and the maximum value, the frequency is set as a selected frequency corresponding to the lighting current value. The selected frequency increases according to an increase of frequency change as a lighting current value increases.

Abstract: A modified Costas control loop (80) using switched analog low pass filters (R2, C1, C2) (R3, C3, C4) and rectangular to polar conversion (341) computes an angular phase reference error that is processed by a digital loop filter (342) to control a counter (441) and a state machine (442) that are used to control the gating of a controllably conductive circuit (84) interposed between an AC source (81) and a phase-controlled load (83) such as a dimmable lamp.

Abstract: A power supply with a capacitor providing an output voltage. A switch is connected between a voltage source and the capacitor. A control terminal of the switch has a switching threshold. The switch conducts a charging current from the voltage source into the capacitor. A control circuit controls the switch on when the voltage source is below a predetermined level and off when the voltage source is above the level. A control voltage supply circuit provides a control supply voltage. A control terminal voltage for the switch derived from the control supply voltage with a magnitude in excess of the switching threshold drives the switch on in a saturated region of operation.

Abstract: An LED lamp utilizes AC power and bi-directional LED chips to provide dimming capabilities. The dimming capabilities of the lamp reduce the junction temperature of the LEDs on the bi-directional LED chips and thus prolong the life expectancy of the LED lamp.

Abstract: TRIAC or SCR based dimmer circuits with temperature compensation features to enable them to also function properly with outdoor line or low voltage AC light fixtures. The TRIAC's or the SCR's operate as static switches that are ideal for driving directly resistive loads, such as incandescent lamps, in line or low voltage AC dimmer circuits. The performance of this type of a circuit is very temperature dependent but it can be compensated for temperature related changes in the output or load RMS voltage by means of preventing variations in the trigger angle the circuit is running at. Temperature compensation is achieved by means of zener diodes being incorporated in the trigger circuit section of a TRIAC or an SCR based dimmer circuit.

Abstract: Provided are a pulse width modulation (PWM) apparatus and a light source-driving apparatus including the PWM apparatus. The PWM apparatus includes a voltage division part, a capacitor part, a first operational amplifier, a first noise reduction part, and a second operational amplifier. The voltage division part divides and outputs an input voltage. The capacitor part charged by an input current or discharged for provides a charge voltage. The first operational amplifier operates according to a result of comparing a divided voltage output from the voltage division part with the charge voltage output from the capacitor part. The first noise reduction part removes a high frequency noise of the divided voltage. The second operational amplifier converts a signal generated from the capacitor part into a pulse width modulation signal by a dimming control signal.

Abstract: Disclosed is a circuit arrangement for supplying a lamp wattage to a high-pressure discharge lamp (Lp) in the form of an alternating current having an operating frequency. The alternating current is generated by a full bridge that is composed of two half-bridge branches. The lamp wattage can be adjusted via the phase which the two half-bridge branches have relative to each other. The lamp wattage is modulated by means of the transmission function of an interface if the operating frequency is frequency-modulated. Said modulation of the lamp wattage can be compensated by adequately correcting the phase.

Abstract: A driving system with a changeable output phase includes a PWM unit to generate a duty cycle signal, a first driving unit, a second driving unit, a first transformer and a second transformer. The first driving unit and the second driving unit receive an input power and the duty cycle signal to drive respectively the first transformer and the second transformer to transform the input power to a first driving power and a second driving power. At least one of the first driving unit and the second driving unit is connected to a power phase control unit which generates a phase switching signal to modulate the driving phase of the connecting driving unit so that the first driving power and the second driving power output from the first and second transformers have a same or different phase to drive loads at the rear end.

Abstract: A dimming system and method of operating the same are provided. The dimming system includes a first terminal configured to operatively connect to a first conductive line, a second terminal configured to operatively connect to a second conductive line, and a third terminal configured to operatively connect to a third conductive line. The first conductive line is configured to connect to a load, the second conductive line is configured to supply an alternating current, and the third conductive line is configured to connect to a current path. The dimming system further includes a controller operatively connected to at least one of the first, second and third terminals for controlling operation of the dimming system. The first and second terminals are configured for electrically connecting to a primary power supply and the first and third terminals are configured for electrically connecting to a secondary power supply.

Abstract: A dimming system and method of operating the same are provided. The dimming system includes a first terminal configured to operatively connect to a first conductive line, a second terminal configured to operatively connect to a second conductive line, and a third terminal configured to operatively connect to a third conductive line. The first conductive line is configured to connect to a load, the second conductive line is configured to supply an alternating current, and the third conductive line is configured to connect to a current path. The dimming system further includes a controller operatively connected to at least one of the first, second and third terminals for controlling operation of the dimming system. The first and second terminals are configured for electrically connecting to a primary power supply and the first and third terminals are configured for electrically connecting to a secondary power supply.

Abstract: A description is given of a method and a circuit arrangement for operating a high-pressure gas discharge lamp with a lamp current superposed with first current pulses, in particular in a system for the time-sequential production of (primary) colors and possibly white segments, from which an image to be displayed is synthesized, in which, in order to change or correct color and/or brightness properties of the image, the first current pulses are adjusted with regard to their amplitude and/or temporal length and/or temporal position relative to the production of the colors and/or white segments. A description is also given of a projection system comprising such a circuit arrangement.

Abstract: Even in a high pressure discharge lamp causing temperature difference between electrodes when an AC current is supplied, the temperature difference is eliminated to suppress the arc movement, thereby suppressing flickering caused thereby during stable lighting. The lamp current is formed into a current waveform including a standard period current supplied at a predetermined standard period and a short period current of a period shorter than the same and, on every one-half period of the standard period current, formed into a current waveform by supplying the short period current inverting the polarity from the identical polarity to the opposite polarity in the next one-half period for 1 period, in which the duty ratio before and after the polarity inversion of the short period current and the duty ratio before and after the polarity inversion side can be decided automatically by the duty ratio.

Abstract: A lighting source that can be deployed in a hazardous environment is disclosed. For example, the lighting source comprises at least one light emitting diode and a power supply for providing power to the at least one light emitting diode. The lighting source also comprises an enclosure for housing the at least one light emitting diode and the power supply, where said lighting source is for deployment in a hazardous environment.

Abstract: A detector circuit monitors the phase relationship between the lamp voltage and the excitation voltage, and if one or more conditions are met, triggers the open lamp protection process in a discharge lamp system. The detection circuit can be incorporated into a lamp voltage feedback circuit and implemented on the integrated circuit level with less cost and circuit complexity.

Abstract: An incandescent lamp includes a lamp voltage conversion circuit within the lamp and connected to a lamp terminal, where the voltage conversion circuit converts a first line voltage at the lamp terminal to a second RMS load voltage usable by a light emitting element of the lamp. The voltage conversion circuit includes a triac phase-controlled dimming circuit, which in turn includes a voltage controlled resistor that varies a resistance in the phase-controlled dimming circuit as the first voltage varies so as to maintain the second voltage substantially constant. The voltage conversion circuit may be an integrated circuit that is in the lamp base and connected between the lamp terminal and the light emitting element.

Abstract: A power supply unit capable of varying power supplied to a light source at timings determined by synchronization signals is provided. The power supply unit comprises an interface that receives a plurality of types of synchronization signals with different pulse widths and a control unit that changes a setting of output power supplied by the power supply unit in accordance with the pulse widths of the plurality of types of synchronization signals. The control unit includes obtaining a standard time interval from a cycle of a standard type of synchronization signal that has a longest pulse width, parsing for determining type of each synchronization signal, redefining supply power values corresponding to respective types of synchronization signals, and changing the setting of output power of the power supply unit to a supply power value corresponding to a type of the synchronization signal.

Abstract: A system (100) for current and/or temperature control of light fixtures includes a sensor (110) structured to be in communication with a light fixture (150), sense a current flow or a temperature of the light fixture (150), and communicate an input signal relative to the current flow or the temperature; a variable switch (120) structured to be in communication with the light fixture (150) and regulate the current flow of the light fixture (150) in response to a control signal; and a controller (130) in communication with the sensor (110) and the variable switch (120) and structured to monitor the input signal communicated by the sensor (110), compare the input signal to a condition, and communicate the control signal to the variable switch (120) to control its operation. A method for current and/or temperature control of light fixtures includes providing the system (100), monitoring the current flow or the temperature of the light fixture (150); and regulating the current flow of the light fixture (150).

Abstract: In one embodiment of the present invention, an output control device is disclosed capable of reducing a chip size and realizing a low cost. An output control device includes a switching transistor controlling an output voltage by having an on/off time ratio controlled and a control IC controlling the on/off time ratio of the switching transistor on the basis of the output voltage controlled by the switching transistor. The switching transistor is made of a lateral power MOSFET.

Abstract: A method of driving a lamp that uses a DC to AC inverter that is connected to a primary winding of a transformer is disclosed. The inverter frequency is variable, and in one embodiment, may be controlled by a voltage controlled oscillator. Circuitry is included that monitors the phase relationship between a voltage across a secondary of the transformer and a current through the primary of the transformer. The circuitry monitors the phase relationship and adjusts the inverter frequency, such as by adjusting voltage controlled oscillator, so that the phase relationship is maintained at a predetermined relationship.