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

Abstract: A light source driving circuit includes a transformer, a switching circuit, a control circuit, a brightness adjusting circuit and an isolator circuit. The brightness adjusting circuit is connected to a secondary winding assembly of the transformer and the light-emitting element for detecting an output voltage and/or an output current and generating a control signal according to the brightness adjusting signal. The isolator circuit is used for isolating the primary winding assembly of the transformer from the brightness adjusting circuit. The isolator circuit generates a feedback current according to the control signal. According to the feedback current, the switching circuit is controlled by the control circuit. As a status of the brightness adjusting signal is changed, a status of the control signal is changed and a time period of changing the status of the control signal is longer than a time period of changing the status of the brightness adjusting signal.

Abstract: A power supply unit provides a voltage, and a driving current to a series of light emitting diodes. A dimming unit adjusts a duty cycle of an original dimming signal to generate a dimming signal according to the driving current and an ideal current. A current sink coupled to the series of light emitting diodes adjusts a duty cycle of the driving current according to the dimming signal.

Abstract: A driving method for a discharge lamp that lights by performing discharge between two electrodes while alternately switching a polarity of a voltage applied between the two electrodes includes: modulating an anode duty ratio, which is a ratio of an anode time for which one of the electrodes operates as an anode in one period of the polarity switching, within a predetermined range; and changing the predetermined range to make a maximum value of the modulated anode duty ratio higher than a maximum value of an initial anode duty ratio of the discharge lamp when a predetermined condition is satisfied.

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: A light-emitting element drive device capable of expanding a dimming range of a light-emitting element, enabling a constant minimum dimmed luminance to be obtained irrespective of individual differences between devices. A burst signal generating circuit 12 generates a burst signal Vburst which is a PWM dimming signal generated based on a dimming analogue voltage Vbr indicating a dimming level.

Abstract: The present invention provides a remote control and adjustment apparatus disposed in an energy saving lighting apparatus and a control system of the same. The remote control and adjustment apparatus of the invention includes a RF wireless transceiver, a processing module and a power module. The wireless transceiver can receive a first signal from a remote controller. The processing module can receive the first signal from the wireless transceiver, and generate a second signal or generate and send a third signal according to the first signal. Particularly, the second signal includes at least a control parameter, and the processing module can control the energy saving lighting apparatus operating based on the control parameter. Additionally, the power module can provide electric power for the operation of the remote control and adjustment apparatus.

Abstract: An appliance includes a cabinet, a solid state lighting device assembly integrated in the cabinet, and a power controller coupled to the solid state lighting device assembly for supplying electrical power to the solid state lighting device lighting assembly. The power controller is configured to provide a pulse modulated power signal to the solid state lighting device assembly that has a duty cycle. Each solid state lighting device in the solid state lighting device assembly cycles on and off in accordance with duty cycle.

Abstract: A discharge lamp lighting apparatus of the present invention comprises: a power supply section for supplying a discharge lamp voltage prescribed in accordance with the characteristic of the discharge lamp; an inverter for inversely converting the discharge lamp voltage supplied by the power supply section into an AC voltage to be applied to the discharge lamp; and a control section for controlling the discharge lamp voltage in the power supply section and a drive frequency in the inverter, based on the AC voltage applied to the discharge lamp and an AC current flowing in the discharge lamp.

Abstract: A device for supplying diodes LED includes an electric bridge (ABHG) with input terminals (A, B) and output terminals (H, G), including diodes (DS1, DS2) interposed between branches (AH, BH), with cathodes turned toward the terminal (H); Two MOSFET elements (M1, M2) are interposed between the branches (AG, BG). A capacitor (C) is derived between the terminals (H) and (G). A switch (KR) and LED diodes arranged in series, with their anodes oriented toward the terminal (H), and a first current sensor (S1) are arranged along a derived branch (R), between the terminals (H) and (G). An electric control unit (CE) receives in input feedback control signals coming from the first sensor (S1) and operates opening/closing of the switches (M1) and (M2), as well as of the branch switch (KR) in suitable relation with the trend of the alternating current (iz), to obtain a predetermined trend of the branch current (ir.) for power supplying the LED diodes.

Abstract: An LED lamp includes a bi-direction constant current device coupled between a power supply and a LED load to provide stable positive and negative currents to the LED load. The bi-direction constant current device includes a pair of current sources face-to-face or back-to-back connected in series between the power supply and the LED load, and two protective elements shunt to the pair of current sources, respectively.

Abstract: A fluorescent-lamp-driving device contains a driving control circuit that receives direct current power voltage and a lamp control signal for performing drive control on fluorescent lamps and converts the direct current power voltage to alternating current power voltage, and a transformer containing a winding at its primary side and windings for driving a heater and for maintaining discharge at its secondary side. The alternating current power voltage is supplied to heaters of the fluorescent lamps at their high electric potential side. The driving control circuit increases the frequency of the alternating current power supply to a frequency thereof in which voltage of the fluorescent lamps is equal to a discharge start voltage of the fluorescent lamps or less based on the lamp control signal at a period of starting-up time of the fluorescent lamps.

Abstract: A dimmer circuit applicable for LED device and control method thereof is disclosed in the embodiments of the present invention. The dimmer circuit is applicable for controlling at least a LED device. The dimmer circuit includes a rectifier, a bleeder, a phase angle detect circuit, a constant current circuit and a programmable micro controller. The phase angle detect circuit couples to the programmable micro controller. The constant current circuit couples to the LED device The programmable micro controller generates a PWM signal according to the output signal of the phase angle detect circuit to adjust current of the constant current circuit.

Abstract: A Light Emitting Diode safety illumination device with thermal control and dimming compatibility for use with incandescent light dimmers and light fixtures. Circuit method and structure combine to provide thermal curve management of temperature control parameters overriding and taking priority over power and dimming of the intensity of illumination.

Abstract: Control apparatus for controlling an aspect of an apparatus are disclosed. In certain embodiments, the control apparatus comprises a dimmer that includes a variable impedance. In certain embodiments of the invention, the dimmer may be a TRIAC dimmer having a voltage at a gate electrode of the TRIAC that is always below a trigger voltage for the TRIAC such that the TRIAC never turns on and the remaining components within the TRIAC dimmer can be used as discreet components in a larger circuit. In the control apparatus, the dimmer may be coupled to a signal generation circuit that may generate an output signal whose frequency (period) is dictated at least in part by an impedance of the variable impedance. The output signal may be used to control an aspect of an apparatus such as the intensity, color or color temperature for a lighting apparatus.

Abstract: The present invention discloses an LED driving method and an LED driving system, the method comprising: generating a PWM control signal with a PWM dimming signal; and controlling a PWM DC/DC converter with the PWM control signal, so as to generate a driving voltage of the LED.

Abstract: A method of striking a gas discharge lamp involves the steps of generating a high-frequency square-wave voltage having an operating frequency, generating a sinusoidal voltage from the high-frequency square-wave voltage, controlling the operating frequency to a low-end frequency, and increasing the amplitude of the sinusoidal voltage during successive pulse times and then decreasing the amplitude of the sinusoidal voltage towards the low-end amplitude at the end of each of the successive pulse times until the lamp has struck, where the length of each of the successive pulse times being greater than the length of the previous pulse time. A maximum amplitude of the sinusoidal voltage during each pulse time may be greater than a maximum amplitude of the sinusoidal voltage during the previous pulse time.

Abstract: System(s) and method(s) are provided for power management in an electronic display via compensation of a power source of a light-emitting-diode (LED) backlighting system. A compensation feedback loop includes a load-aware controller that receives the load condition from a dimming controller and supplies a control signal to the power source. An efficiency regulator functionally connected the backlight circuitry closes the compensation feedback loop and provides an input signal to the load-aware controller. The dimming controller implements phase-shifted pulse-modulation dimming, which based on duty cycle can establish a dimming equilibrium with two load conditions. The load aware controller includes a set of compensation blocks arranged in parallel, with a single compensation block connected to the input signal and that provides the control signal.

Abstract: In various embodiments, a method for obtaining a conduction angle of a trailing edge dimmer is provided. The method may include determining a time point t0 when the trailing edge dimmer starts to be conductive; determining an earliest time point t1 when a deviation from an ideal waveform appears; and determining the conduction angle t1-t0 of the trailing edge dimmer based on the earliest time point t1 when the deviation from the ideal waveform appears and the time point t0 when the trailing edge dimmer starts to be conductive.

Abstract: A light emitting diode driving device and light system are provided. The light emitting diode driving device drives a light source by a received alternating current voltage. The light emitting diode driving device includes a rectifier, a feedback unit, a protection unit, a switch unit, a timing unit, and a control unit. The rectifier is electrically coupled to an alternating current voltage source and the light source for providing the alternating current voltage to the light source. The feedback unit is used to detect a loading state and generate a feedback signal according the loading state for outputting the feedback signal. The protection unit is used to receive the feedback signal and compare the feedback signal with a reference voltage built in the protection unit for outputting a switch signal. The switch unit is used to receive the switch signal and connect or disconnect the alternating current voltage source and the light source.

Abstract: A light emitting control device for a light emitting diode print head includes a control unit, a pulse-mask unit, a strobe unit and a data output unit. The pulse-mask unit outputs n clock signals in sequence to a light emitting diode print head. The strobe unit outputs a strobe signal to the light emitting diode print head, so as to switch on the light emitting diode print head. The data output unit outputs a print data signal to the light emitting diode print head. When the pulse-mask unit outputs a k-th clock signal of the n clock signals, the pulse-mask unit delays the k-th clock signal for a predetermined time, and the data output unit pauses outputting the print data signal. After the predetermined time, the pulse-mask unit and the data output unit continue to output the rest of the clock signals and the print data signal.

Abstract: There is provided a discharge-lamp lighting device that, upon start-up of a high-intensity discharge lamp, alternately outputs a period A during which a starting circuit applies a high voltage to the high-intensity discharge lamp by resonance operation when a DC/AC inverter outputs a high-frequency voltage, and a period B during which the DC/AC inverter applies a low-frequency-square-wave voltage or a DC voltage to the high-intensity discharge lamp via the starting circuit. The period A for applying the high voltage by the resonance operation is set to about a time enough for a high-intensity discharge lamp in an initial aging stage to cause a dielectric breakdown, and a period C for alternately outputting the high-voltage generating period A and the period B for outputting the low-frequency-square-wave voltage or the DC voltage is set to about a time enough for a high-intensity discharge lamp in a life's last stage to cause a dielectric breakdown.

Abstract: An apparatus for generating a drive signal for a lamp device comprises a pulse generator for generating a first pulse train in response to a first brightness request for a first brightness and for generating a second pulse train in response to a second brightness request for a second brightness. The first pulse train has a first frequency and the second pulse train has a different second frequency. The second pulse train comprises two neighboring pulses of the first pulse train and comprises a further pulse between the two neighboring pulses, the further pulse not being comprised in the first pulse train.

Abstract: An electronic ballast circuit for driving a gas discharge lamp is operable to control the lamp to avoid flicking and flashing of the intensity of the lamp during low temperature conditions. The ballast circuit includes an inverter circuit for receiving a DC bus voltage and for generating a high-frequency output voltage, a resonant tank circuit for receiving the high-frequency output voltage and generating a sinusoidal voltage for driving said lamp, and a control circuit operatively coupled to the inverter circuit for adjusting an intensity of the lamp between a minimum intensity and a maximum intensity. The control circuit receives a control signal representative of a lamp temperature of the lamp, and increases the minimum intensity of the lamp if the lamp temperature of the lamp drops below a cold temperature threshold. In addition, the ballast circuit may also include a temperature sensing circuit operable to generate the control signal representative of the lamp temperature of the lamp.

Abstract: An LED drive circuit in which an alternating voltage is input and an LED is driven, and which can be connected to a phase control dimmer The LED drive circuit is provided with an edge detector for detecting an edge of the output voltage of the phase control dimmer; and a current extractor for extracting a current from a current feed line for feeding an LED drive current to the LED; wherein the value of the current extracted from the current feed line by the current extractor is varied in accordance with the detection results of the edge detector.

Abstract: An LED lamp includes two LED modules and a control module. The LED modules emit lights with different color temperatures. The lights are mixed in the LED lamp and form an output light with another color temperature. The control module controls the brightness levels of the lights emitted from the two LED modules to thereby control the color temperature of the output light.

Abstract: A controller for controlling dimming of a light-emitting diode (LED) light source provides a pulse signal by comparing a sensing signal indicative of a current flowing through the LED light source to a reference signal. The controller controls the current through the LED light source according to the pulse signal during a first state of a pulse-width modulation signal and cutting off the current through the LED light source during a second state of the pulse-width modulation signal. The controller receives a dimming request signal indicative of an operation of a power switch coupled between an AC power source and a bridge rectifier and adjusts both a level of the reference signal and a duty cycle of the pulse-width modulation signal based on the dimming request signal.

Abstract: A portable lighting device, such as a flashlight, with a mechanical power switch and multiple operating modes is provided. The mechanical power switch is disposed in series with the controller for the lighting device and acts as the user interface to the controller to change modes of operation. Because the mechanical power switch is in series with the controller, the portable lighting device does not consume battery power when the mechanical switch is open. A state machine coupled to the controller is polled by the controller each time it is powered up to determine the operational mode of the lighting device. A regulating circuit is used to power a controller and light source. The regulating circuit converts between current regulation and voltage regulation.

Abstract: The present invention provides an ultraviolet light irradiation device having a planer UV light source in which the irradiation intensity of UV light can be adjusted finely in a wider range. The ultraviolet light irradiation device of the present invention comprises an UV light source and a housing that holds the planer UV light source. In the UV light source, a plurality of thin plasma tubes, each of which has an UV phosphor layer formed therein, are arranged in parallel with each other on an electrode support sheet, and drive circuits apply a pulse voltage to electrode pairs provided between the electrode support sheet and an array of the thin plasma tubes. A control circuit controls a factor of the pulse voltage to be applied to the electrode pairs so as to adjust the irradiation intensity of the UV light.

Abstract: A power supply, such as for powering and supplying communication data to devices connected with a low voltage line, is disclosed. For example, a converter device is coupled with an alternating current voltage source. The converter device down-converts an alternating current voltage to a direct current voltage. A switching device is in communication with the converter device. A processor is in communication with the switching device. The processor outputs a signal to the switching device. The switching device generates a square wave signal as a function of the signal from the processor and the direct current voltage. A remote device is controlled by data encoded in the square wave signal.

Abstract: Provided are a crystallization apparatus and method, which prevent cracks from being generated, a method of manufacturing a thin film transistor (TFT), and a method of manufacturing an organic light emitting display apparatus. The crystallization apparatus includes a chamber for receiving a substrate, a first flash lamp and a second flash lamp, which are disposed facing each other within the chamber, wherein amorphous silicon layers are disposed on a first surface of the substrate facing the first flash lamp and a second surface of the substrate facing the second flash lamp, respectively.

Abstract: A driving device, a light emitting diode (LED) driving device and a method thereof are provided. The driving device includes a driving unit and a plurality of selection units. The driving unit produces a driving signal to drive a light emitting diode. The selection units are coupled to the driving unit and respectively correspond to a current value. The driving unit selects one of the selection units according a first pulse width modulation (PWM) signal. The current value corresponding to the selected selection unit is taken as the current value of the driving signal. The driving unit generates a duty cycle of a second PWM signal according to the duty cycle of the first PWM signal to serve as a duty cycle of the driving signal. In this way, power consumption of the LED is reduced.

Abstract: In one embodiment, a dimmer circuit is coupled to an electronic load and receives an alternating current (AC) signal. A phase control circuit turns the dimmer circuit on for a first portion of the AC signal to turn on the electronic load. The dimmer circuit turns off during a second portion of the AC signal to turn off the electronic load. A switch is coupled to the phase control circuit. The switch is controlled to couple the phase control circuit to ground when the dimmer circuit is off where the switch is part of a power supply supplying power to the electronic load.

Abstract: A light bar system for a vehicle compartment includes a circuit board having a plurality of capacitive-type, user-activated switches, an electrical power source coupled to the circuit board, a light emitting diode (LED) coupled to the circuit board, and a light bar affixed to the circuit board. The user-activated switches are coupled to a vehicle accessory to control the level of operation of the vehicle accessory. The most recently actuated one of the user-actuated switches is detected by the circuit board and the circuit board provides a pulse width modulated (PWM) signal to the LED with a duty cycle of the PWM signal based on the most recently actuated switch. A higher duty cycle PWM signal corresponds to a higher setting of the accessory.

Abstract: The invention discloses a novel control system for a Poly-Chromatic light-emitting diode (LED) lighting system, and applies feed forward and feedback control techniques to regulate the color and luminous outputs. Also, the control system is proposed for achieving luminous and color consistency for Poly-Chromatic LED lighting.

Abstract: A universal input voltage device is presented which may receive a wide range of regulated and unregulated input voltages, both DC and a wide range of variable frequency AC, and output a desired regulated current at a desired voltage independent of the fluctuation of input voltage and frequency. The circuit includes a preconditioning input circuit, a Buck converter circuit with over voltage protection, flyback and boost circuits, and a shutdown circuit configured to drive a predetermined electrical or electronic device.

Abstract: A light source system capable of dissipating heat includes a AC power supply for outputting a first power, a switch device for adjusting an output ratio of the first power according to a light setting, a light emitting device for generating a light source, and a control device for generating an active signal sequence, an heat-dissipation signal sequence and a burst signal according to lighting features of the light emitting device, and combining the active signal sequence and the heat-dissipation signal sequence, to generate a driving signal sequence, for timely outputting the driving signal sequence according to the burst signal, so as to generate the control signal.

Abstract: A backlight unit and a display apparatus are provided. The display apparatus includes a driving unit which applies a driving current using a duty cycle controlling to the light emitting unit; and a controller which controls a first driving current to be applied to the light emitting unit in a section of a plurality of frame sections, and a second driving current to be applied to the light emitting unit in another section of the plurality of frame sections. Therefore, luminance representation of backlight in a low grayscale region can be improved.

Abstract: A handheld device includes a row of lighting elements configured at the side of its top body that faces a keypad of its bottom body for illuminating the keypad when the two bodies slide away for use. The lighting elements projects light in a direction nearly parallel with the keypad and toward the surface of the keypad, and illumination of the keypad is therefore accomplishable in various environmental conditions. The lighting elements may also be used for illuminating the keypad or displayed with different strength or bright and dark periods based on the ambient brightness, and based on the charging rate of the handheld device's rechargeable battery when the handheld device is being charged.

Abstract: A power supply for a lighting luminary for fixing maximum and minimum illumination is applied to a TRIAC dimmer and at least one lighting luminary. The power supply includes a dimming circuit for fixing maximum and minimum illumination, an input voltage detector, a feedback circuit, a DC-to-DC converter, and a rectifier. The dimming circuit for fixing maximum and minimum illumination outputs a reference voltage. More particularly, the feedback circuit controls the lighting luminary be operated at maximum illumination when a conduction angle of the TRIAC dimmer is excessive according to the reference voltage. Similarly, the feedback circuit controls the lighting luminary to be operated at minimum illumination when a conduction angle of the TRIAC dimmer is excessively small.

Abstract: A power supply for a lighting luminary for improving dimming performance is disclosed. The power supply is applied to an AC source, a TRIAC dimmer, and at least one lighting luminary. The power supply includes a half-wave rectifier, an input voltage detector, a dimming signal generator, a feedback circuit, and a DC-to-DC converter. The input voltage detector is electrically connected to the half-wave rectifier. The dimming signal generator is electrically connected to the input voltage detector. The feedback circuit is electrically connected to the dimming signal generator. Besides, the DC-to-DC converter is electrically connected to the half-wave rectifier. More particularly, the half-wave rectifier provides a single-direction current path to avoid turning off the TRIAC dimmer during the dimming process because of the alternating positive and negative half cycles of the AC source.

Abstract: An electronic device, and a corresponding light emission control method for the electronic device, emit light by utilizing recombination of electrons and holes the device and method input a pulse-shaped driving signal having a duty ratio higher than or equal to 0.7 and lower than 1.0 and thereby causing light to be emitted intermittently. When an electron density is denoted by n, a hole density by p, a thermal velocity of electrons by Vth:n, a thermal velocity of holes by Vth:p, an electron capture cross section of a defect level by ?n, a hole capture cross section of a defect level by ?p, and a pulse width of the driving signal by W, the input driving signal has a pulse width W that satisfies W<1/{n·vth:n·?n·p·vth:p·?p/(n·vth:n·?n+p·vth:p·?p)}.

Abstract: A luminance adjusting device for an illuminator utilizes a circuitry to control the brightness of the illuminator, wherein power is stored in a power storage through a step-down circuit. The illuminator has a preset brightness. The preset brightness is done by the calculating processor to run according to an analyzed data received from a sampling frequency circuit to control a pulse modulator for driving the illuminator to emit light. The power switch is turned off and on again shortly, which triggers the calculating processor to control the pulse modular to drive the illuminator to change the preset brightness, so that the brightness of the illuminator is controlled by the time differentials of the power switch's on and off.

Abstract: In a lighting ballast there are typically several discrete components that combine to take an external AC signal and convert it to a DC signal, and back to an AC signal for powering a lamp. Several of these components can be housed on an application specific integrated circuit. By placing switching transistors (20, 22) their companion diodes (34, 36), and a rectifying circuit (52) on a monolithic integrated circuit (60), the ballast circuit as a whole is made more reliable and robust and can be manufactured at a lower cost than if discrete components had been used.

Abstract: A light source device includes a plurality of semiconductor light source elements, and a drive control section configured to cyclically supply a power signal with a sawtooth pulse waveform in which a crest value at the rise time is larger than a crest value at the fall time to each of the plurality of semiconductor light source elements by time division to thereby light-emission-drive the semiconductor light source elements.

Abstract: The present technology is generally related to Triac dimmer compatible driving circuits and methods thereof. The present technology also provides an electronic transformer that is integrated in the Traic dimmer compatible driving circuit. In one embodiment, the electronic transformer detects the conduction angles of an output AC voltage from the Triac dimmer and converts said output AC voltage into a PWM DC voltage having a duty cycle regulated by said conduction angles. Said PWM DC voltage is then applied to a WLED driver for driving a WLED.

Abstract: A first waveform (a rectangular waveform, for example) is applied as the waveform of the alternating current supplied to a high-pressure discharge lamp for a predetermined time from the beginning of lighting of the lamp and a second waveform (a staircase waveform, for example) is applied as the waveform of the alternating current after the elapse of a predetermined time (100 [s], for example). The alternating current with the first waveform has a lower absolute instantaneous value in a final section of each half-cycle period thereof than in the other sections and the alternating current with the second waveform has a higher absolute instantaneous value in a final section of each half-cycle period thereof than in the other sections.

Abstract: Various embodiments of a universal dimmer are disclosed. In one embodiment of a universal dimmer, a power limiting switch is connected to an input voltage. An output driver in the universal dimmer includes a power input and a load path, with the power input being connected to the input voltage. A variable pulse generator includes a control input and a pulse output, with the control input connected to a control input of the power limiting switch. The pulse output is connected to a control input of the power limiting switch. The variable pulse generator is adapted to effectively vary a duty cycle at the pulse output. The universal dimmer also includes a load current detector having an input and an output. The load current detector input is connected to the output driver load path. The load current detector output is connected to the variable pulse generator control input.

Abstract: A circuit for driving a light emitting diode (LED) comprises: an alternating voltage power supply, comprising a triac dimmer having a firing angle and output terminals that provide power to the LED; a zero crossing detector that detects a polarity change of the alternating voltage provided by the alternating voltage power supply and provides a zero crossing output signal indicative of the zero crossing; a timer triggered by the zero crossing output signal that generates a timer output signal during a time period of the timer; and LED power circuitry that reduces current to the light emitting diode based upon timing characteristics of the timer output signal.

Abstract: A two-wire dimmer for control of a lighting load from an alternating-current (AC) power source includes a semiconductor switch, a power supply, and a control circuit. The power supply includes an energy storage input capacitor that is able to charge only when the semiconductor switch is non-conductive. The control circuit continuously monitors the voltage on the input capacitor and automatically decreases the maximum allowable conduction time of the semiconductor switch when the voltage falls to a level that will not guarantee proper operation of the power supply. The dimmer of the present invention is able to provide the maximum possible conduction time of the semiconductor switch at high end (i.e., maximum light intensity) while simultaneously ensuring sufficient charging time for proper operation of the power supply, and hence, the dimmer.