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: A high intensity discharge (HID) ballast circuit comprises a trigger circuit, a power half-bridge self-excited oscillation circuit, which is arranged to enable self-excited oscillation by energizing an angle capacitor Cgs with a Miller capacitor Cdg of a power MOSFET when an original single pulse output by the trigger circuit is excited, and then output self-excited oscillation signals; and a filter loop which is arranged to match impedance for the self-excited oscillation signals, thereby converting a low-impedance voltage source to a high-impedance constant current source. The inherent phase relationship of the power MOSFET is utilized, and oscillation signals are generated by a power half-bridge self-excited oscillation circuit, and then impedance matching for the oscillation signals is performed by the filter loop, and finally an HID lamp is triggered. As a result, damages to human eyes caused by stroboscopic effect can be avoided and electro magnetic compatibility test can be passed.

Abstract: A current regulating LED strobe drive circuit is disclosed for efficiently producing a LED strobe that is consistent in both intensity and color. The circuit may include an inrush control for limiting an amount of current that is allowed to flow through the drive circuit upon activation, an energy storage component for storing and supplying power for flashing a LED, a current regulator electrically coupled to the energy storage component for sensing and regulating a current supplied by the energy storage element, a LED electrically coupled to the current regulator, and a flash control element electrically coupled to the current regulator for communicating a flash pulse signal that provides a pulsed pattern with which current is allowed to flow from the current regulator to the LED. The circuit may further include an output control having an operator interface for allowing an operator to define a desired light output level.

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 dimmable driver comprising a dimming control signal.

Abstract: The present invention relates to a light emitting diode driver that integrates a light emitting diode control function and a power switching control function at a secondary side insulated from a primary side in a power supply circuit, without using a photo coupler to control power switching at the primary side.

Abstract: A control circuit of a light-emitting element comprises a rectifying unit (30) which full-wave rectifies an alternating current power supply, a switching element (38), a reference voltage generating unit (40) which generates a reference voltage (Vref), and a comparator (42) which receives a voltage (Srec) rectified by the rectifying unit (30), compares a comparative voltage (Vcmp) corresponding to a current flowing to an LED (102) and the reference voltage (Vref), and controls switching of the switching element (38) according to a comparison result, wherein the reference voltage generating unit (40) comprises a voltage dividing circuit having a transistor (Q1) in which a resistance value between a source and a drain is changed according to the voltage rectified by the rectifying unit (30), and outputs, using the voltage dividing circuit, the reference voltage (Vref) according to the voltage (Srec) rectified by the rectifying unit (30).

Abstract: The present application relates to an illumination device having a light source module, a power supply module, a driving module, a control module and a start module. The driving module outputs a driving current to the light source module based on a power supply from the power supply module. The control module controls the magnitude of the driving current based on a first voltage signal generated by the power source module. After receiving the first voltage signal, the control module controls the driving module to steadily increase the driving current in a first stage output. After receiving the first voltage signal again, the control module controls the driving module to output a constant driving current equal to the driving current at the end of the first stage.

Abstract: A discharge lamp lighting device includes a power converter configured to receive a power from a power source, convert it into a voltage required by a discharge lamp and supply the voltage to the discharge lamp; and a controller which controls the power converter to drive the discharge lamp. The controller controls the power supplied to the discharge lamp according to a predetermined power curve. The controller controls the power curve to change based on at least one of a source voltage of the power source, an ambient temperature, a device temperature, a discharge lamp temperature and a discharge lamp voltage, and sets a sustained period of a max power value to a predetermined time period when the lighting of the discharge lamp is performed in a state where the discharge lamp temperature is equal to or less than a reference temperature.

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 power system for a dielectric barrier discharge system, such as used for generating ozone, can include a full bridge inverter stage and parallel resonant tank outputting a signal for powering a dielectric barrier discharge cell stack. The inverter stage is controlled using a combination of pulse width modulation (PWM) and frequency modulation (FM) to enable soft switching through all load conditions—from full load to light load. A current control loop error amplifier compensator can provide a duty cycle adjustment signal to a phase shift PWM controller chip that generates the switching signals for the inverter stage. A feedback signal is also used to adjust a clock frequency time constant of the PWM controller chip to provide the FM. In one embodiment, the feedback signal is an output of an inverting amplifier connected at an output of the current control loop error amplifier compensator.

Abstract: A lighting device includes a light emitting diode (LED) lamp, a power generating panel that is disposed at a position where the power generating panel is capable of receiving sunlight and light irradiated by the LED lamp and that is configured to generate electric power by receiving the sunlight and the light irradiated by the LED lamp, a storage battery that is configured to store the electric power generated by the power generating panel and to supply the electric power to the LED lamp, a lamp drive portion that is configured to drive the LED lamp using pulse signals, a remaining amount detection portion, and a control portion that is configured to control, in accordance with the remaining amount detected by the remaining amount detection portion, a pulse width and a period that are used when the lamp drive portion drives the LED lamp,

Abstract: Exemplary systems, methods and apparatuses for a distributed solid-state lighting system are disclosed which are also compatible with legacy AC luminaires. An exemplary adapter apparatus includes a first coupling interface to receive a first DC input voltage having a first DC input voltage level; a converter circuit to generate a second DC voltage having a second DC voltage level; a regulator circuit to generate a pulse width modulated DC or AC voltage; and a second coupling interface to provide the pulse width modulated DC or AC voltage to such an AC luminaire, lamp, or bulb. In exemplary embodiments, the pulse width modulated DC or AC voltage has a duty cycle substantially linearly proportional to the first DC input voltage level, which corresponds to a user-selected light output brightness or dimming level.

Abstract: A discharge lamp lighting device includes a resonant circuit section connected to a discharge lamp, a power conversion section adapted to convert direct-current power into alternating-current power, and then supply the discharge lamp with the alternating-current power via the resonant circuit section, and a control section adapted to change a frequency of the alternating-current power in a stepwise manner with a frequency, which is different from a frequency causing a resonance of the resonant circuit section, intervening between frequency values of the frequency changed in a lighting start period until the discharge lamp reaches a stationary lighting state.

Abstract: A power supply for illumination includes a detection circuit and a control circuit. The detection circuit compares an AC voltage whose phase is controlled with a first threshold voltage so as to detect a variation in a conduction state of phase control in the AC voltage, and compares the AC voltage with a second threshold voltage lower than the first threshold voltage so as to detect a zero-cross point of the AC voltage, thereby detecting a conduction period of the phase control. The control circuit outputs an output current according to the duration of the conduction period.

Abstract: A lighting apparatus for a high-pressure discharge lamp that has an electric discharge container made of quartz glass, and containing a pair of counter electrodes and a power supply unit that supplies AC current to the high-pressure discharge lamp. The power supply unit has a stationary power lighting mode and a modulated power lighting mode that supplies current having power less than power in the stationary power lighting mode. The modulated power lighting mode supplies a rectangular AC current having a first term and a second term. A mean high-frequency current value supplied to a first electrode is greater than a mean current value supplied to a second electrode in the first term. A current is supplied to the second electrode for a term longer than the half-cycle period in the second term, the current being lower than the mean high-frequency current value supplied to the first electrode.

Abstract: This disclosure relates to illumination systems. In particular it relates to a method and system for avoiding flicker (in particular 100 Hz or 120 Hz flicker) in solid state lighting devices such as LED or OLED assemblies. A controller for a driver circuit of a solid state lighting device (SSL) is described. The driver circuit comprises a power converter to convert a varying input voltage into a drive voltage for the SSL device. The input voltage is derived from a rectified AC mains voltage and frequency. The power converter is used with a maximum voltage step-up conversion ratio. The controller synchronizes to the mains frequency and determines a plurality of pulse intervals repeated at a pulse frequency where the pulse frequency is greater than a perceptual frequency of light intensity variations perceivable by a human eye.

Abstract: A technique of improving the life of a spark plug which generates spark discharge and AC plasma. A plasma ignition device includes a power control section which reduces AC power P after generation of AC plasma in an AC power supply period Sa during which the AC power P is continuously supplied to a spark plug within a maintainable power range Rp within which the AC plasma can be maintained.

Abstract: A high-pressure discharge lamp lighting device that suppresses deterioration and the expansion of inter-electrode distance in a pair of electrodes within a high-pressure discharge lamp, more effectively than conventional technology. The frequency of the AC current supplied to a high-pressure discharge lamp alternates between a first frequency and a second, higher frequency, while the magnitude of the AC current alternates between a first value and a second, higher value. The suppressing effect is realized by repeatedly alternating the frequency and repeatedly alternating between a first period at the first frequency and a second period at the second frequency, with the second, higher-magnitude current being used in the latter and the first current being used in the former.

Abstract: A light source device includes a discharge lamp having a light emitting case and a pair of electrodes, a drive device, a voltage detector, and a time measurement device, the drive device alternately repeats a first alternating current supply interval and a second alternating current supply interval, measures a period of the first and the second alternating current supply interval with the time measurement device, performs a change from the first alternating current supply interval to the second alternating current supply interval when the period of the first alternating current supply interval reaches a predetermined period A, and performs a change from the second alternating current supply interval to the first alternating current supply interval when the period of the second alternating current supply interval reaches a predetermined period B, or when an absolute value of an inter-electrode voltage of the pair of electrodes reaches a threshold value.

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: Various embodiments of a dimmable power supply are disclosed herein. For example, some embodiments provide a dimmable power supply including an output driver, a variable pulse generator and a load current detector. The output driver has a power input, a control input and a load path. The variable pulse generator includes a control input and a pulse output, with the pulse output connected to the output driver control input. The variable pulse generator is adapted to vary a pulse width at the pulse output based on a signal at the control input. The load current detector has an input connected to the output driver load path and an output connected to the variable pulse generator control input. The load current detector has a time constant adapted to substantially filter out a change in a load current at a frequency of pulses at the variable pulse generator pulse output.

Abstract: According to one embodiment, a control section receives supply of control power from a control power supply section through a capacitive element and divides, a period of each half cycle of an alternating-current voltage into a first section, a second section, and a third section. In the first section, the control section subjects a switch section to conduction control to supply electric power to a load and stops a converting action of the control power supply section. In the second section, the control section subjects the switch section to non-conduction control to interrupt the power supply to the load and stops the converting action of the control power supply section. In the third section, the control section subjects the switch section to the non-conduction control to interrupt the power supply to the load and causes the converting action of the control power supply to operate.

Abstract: A multiple location load control system comprises a main device and remote devices, which do not require neutral connections, but allow for visual and audible feedback at the main device and the remote devices. The main device and the remote devices are adapted to be coupled in series electrical connection between an AC power source and an electrical load, and to be further coupled together via an accessory wiring. The remote devices can be wired on the line side and the load side of the load control system, such that the main device is wired “in the middle” of the load control system. The main device is operable to enable a charging path to allow the remote devices to charge power supplies through the accessory wiring during a first time period of a half-cycle of the AC power source. The main device and the remote devices are operable to communicate with each other via the accessory wiring during a second time period of the half-cycle.

Abstract: Timer-based switching circuit synchronization in an electrical dimmer is provided. The energizing of a switching circuit in a dimmer is synchronized with an AC wave to facilitate providing by the dimmer electrical power to a load. The synchronizing includes starting a timer having a predetermined timeout, responsive to receipt of a zero-crossing signal. Responsive to receipt of a subsequent zero-crossing signal prior to reaching the timeout, the timer is restarted, and responsive to expiration of the timeout, a switching circuit is energized at a predetermined firing angle with respect to the zero-crossing signal to supply electrical power to the load.

Abstract: Threshold-based zero-crossing detection is provided. A power phase threshold detector detects when absolute value of a voltage level of the electrical power rises above a non-zero voltage threshold and outputs a zero-crossing signal to a controller to indicate occurrence of the zero-crossing. Delaying the zero-crossing signal to the point when the absolute value of the voltage level of the electrical power rises above the non-zero voltage threshold ensures completion of the zero-crossing of the power phase prior to signaling the controller. The controller provides signals to a switching circuit for controlling switching of electrical power to a load based on the zero-crossing indications.

Abstract: A system and method are disclosed for dimming light emitting diode (LED) lamps. A control unit is coupled to a dimmer and LED lamp. The dimmer receives power from an AC source and determines a phase angle of the AC power. The dimmer provides DC power to the lamp based on the phase angle. The control unit sends a control signal to the dimmer during a first portion of each half sine-wave of the received AC power. The control signal causes the dimmer to modify at least one function of the lamp. A plurality of LED lamps may be associated with a single dimmer, and the dimmer may individually instruct the lamps to modify their operational characteristics. The dimmer may send an operational signal back to the control unit. The operational signal may represent end of life information for the associated LED lamp. Other embodiments are described and claimed.

Abstract: A light source device includes a first light source configured to emit light within a first wavelength band, a second light source configured to emit light within a second wavelength band, and a light source control section configured to control drive timing of the first light source with a first drive pattern, and to control drive timing of the second light source with a second drive pattern which is an inverted pattern of the first drive pattern of the first light source, such that a light emission period for light-source light using light emitted by the second light source is positioned between light emission periods for the light-source light emitted by the first light source, and such that a frequency of the light-source light using light emitted by the second light source is higher than a frequency of light emitted by the first light source.

Abstract: A high pressure discharge lamp ballast performs driving with a synthesized current waveform comprising a combination of first and second sets of current waveforms. The ballast controls content rates of each of the sets per unit time; detects a rotation synchronization signal for a color wheel; applies a synthesized current waveform in accordance with the synchronization signal and the content rates to a high pressure discharge lamp; and detects a lamp voltage. A period of each of the first and second sets equals to one rotation of the color wheel. The number of inversions of the second set is larger than that of the first set. The content rate of the second set is set to RL% when the lamp voltage exceeds a value V, and the content rate of the second set is set to RH% when lamp voltage falls below a value V?.

Abstract: An LED driver circuit and an isolated DC-DC converter therefor are presented, in which a primary side state estimator circuit is provided for inferred output current sensing for closed loop control of pulse width modulated flyback or buck converters. Specifically, the estimator circuit includes a capacitance having a first terminal coupled to a comparator input of a pulse width modulation controller, and a second terminal coupled to an error input of an error amplifier, and a switching device having a first power terminal coupled to the second terminal of the capacitance, a second power terminal coupled to the circuit ground, and a control input terminal coupled to a drive output of the pulse width modulation controller.

Abstract: In an electronic device including a discharge lamp, and a lamp power supply section that supplies power to the discharge lamp, a control section makes the lamp power supply section execute a lamp refresh process of supplying power necessary for generation of a halogen cycle to the discharge lamp at predetermined time intervals during low power operation in which the discharge lamp is lighted with power less than the rated power. Further, the control section records, in a recording section (non-volatile memory), a control instruction which is issued to the lamp power supply section during low power operation.

Abstract: In at least one embodiment of the disclosure, a driving device for a discharge lamp includes an alternating current supply section and a frequency modulation section. The alternating current supply section supplies two electrodes of the discharge lamp with an alternating current. The alternating current comprises a plurality of modulation periods. The frequency modulation section modulates a frequency of the alternating current so as to provide a plurality of retentive periods within each of the modulation periods. Each retentive period has a constant frequency that is different from a frequency of its temporally adjacent retentive periods. The frequency modulation section lengthens a length of at least one of the retentive periods in the modulation period in response to a predetermined condition occurring. The frequency of at least one of the retentive periods is equal to or higher than a predetermined reference frequency.

Abstract: A light-emitting-element lighting circuit for dimming a light emitting element by a PWM dimming signal of a duty ratio corresponding to an input dimming signal is provided. The lighting circuit includes a PWM dimming signal generating unit which generates the PWM dimming signal by performing a summation of AC wave signals including a fundamental wave and harmonics of different frequencies that are integer multiples of a fundamental frequency of the fundamental wave. The fundamental frequency is equal to or higher than a frequency, at which a sound pressure level is at maximum, in an audible frequency range in a correlation spectrum between the sound pressure level generated from the light emitting element and a frequency of an AC wave signal inputted to the light emitting element.

Abstract: A discharge lamp lighting apparatus for lighting a discharge lamp in which an electric discharge medium, which contains xenon, is enclosed in an electric discharge container, and a pair of cathode electrode and anode electrode for main discharge is arranged to face each other, comprises a starter for generating dielectric breakdown in the electric discharge container of a discharge lamp, and a power supply circuit for supplying discharge current to the discharge lamp, wherein the power supply circuit has an output current modulation circuit for modulating the magnitude of current passed through the discharge lamp in at least a lighting steady state, according to a modulation signal, and wherein the output current modulation circuit controls speed of change so as to be 2.6 A or less per millisecond in case the magnitude of the lamp current per square millimeter in a cross section of the cathode electrode decreases.

Abstract: A lighting device with a drive device for dimming light-emitting diodes. The drive device comprises a dimming component that operates a switch in response to both a change in an input power signal and a system temperature. In one example, the dimming device can include a waveform generator that generates a signal with a waveform having levels that change in response to changes in temperature. The waveform defines the time during which the switch is open and closed, thereby determining the period of time the LEDs are energized. By operating the LEDs in this manner, the drive device effectively dims the LEDs to reduce the operating temperature and cool the LEDs.

Abstract: A low-voltage DC distribution board for indoor LED lighting with multiple LED lamps, comprises: a power converting module (2), arranged within a box casing (7) and connected with a power input port (1), the power converting module (2) including a set of output ports (3) with different output voltages; a set of selection switches (4) connected between the set of output ports of the power converting module (2) and a plurality of current regulators (5) which are connected to load connectors (6).

Abstract: The invention proposes a ballast control circuit and ballast control method for gas discharge lamp. The ballast control circuit and control method of the invention is advantageous by allowing the OFF time of the main switch of the ballast circuit to be fixed in order to prevent the transformer of the ballast circuit from being saturated when the gas discharge lamp is ignited and has a very low impedance, and allowing the OFF time of the main switch to be flexibly adapted when the gas discharge lamp is warmed up and its impedance has risen up to a certain value. The inventive ballast control circuit is configured to proceed with the switching of the main switch according to a lamp status signal indicative of the status of the lamp.

Abstract: The present invention provides a solid state illuminating system having a centralized controlling module, coupled with a monitoring module and a power supplying module, for converting electricity from a second format to a third format so as to embed a PWM signal therein in accordance with a status signal obtained by an user via a monitoring module. Accordingly, the present invention is capable of supporting various kinds of potential dimming control method and has the advantage of low manufacturing cost without substantially adjustment to the present illumining system.

Abstract: A constant current output sink or source eliminates a current limiting series resistor for a light emitting diode (LED) and maintains a constant light intensity from the LED for all operating and manufacturing variables of a digital device since the current through the LED is maintained at a constant value. The constant current output sink or source may be programmable for selection of a constant current value from a plurality of constant current values available.

Abstract: The present invention discloses a light source device, image pick-up system and pick-up method for time-delayed detection of fluorescence, essentially applying a pulsed-excitation light source installed inside a light source device in conjunction with a shutter to pick up a photoluminescence image of an object located at a predetermined detection site, the light source device comprising: a pulsed-excitation light source for emitting light towards the predetermined detection site; and a controller for instructing the pulsed-excitation light source to emit light, the controller being connected in feedback signals to the shutter, thereby closing the shutter when the pulsed-excitation light source emits light and opening the shutter as soon as the light pulse terminates in order to effectively shield reflection light and diffusive reflection light to purely capture the photoluminescence data.

Abstract: An electronic ballast for driving at least one light source may include an input for connecting a supply voltage; an output configured to connect the at least one light source; an oscillator, which is designed to provide an oscillator output signal with a first frequency at its output, the oscillator having a calibration input in order to alter the first frequency; and a microcontroller configured to provide a drive signal with at least one spectral component at a second frequency for the at least one light source, the microcontroller being coupled to the oscillator output and being designed to generate the second frequency as a function of the first frequency; wherein the electronic ballast furthermore includes a drive circuit, which is coupled to the calibration input, the drive circuit being designed to vary the first frequency during running operation of the electronic ballast via the calibration input.

Abstract: An illuminating device comprising semiconductor light-emitting devices employing a semiconductor light-emitting element, wherein outputted light is stably combined, separation of light is inhibited, and color tone is variable. Control for operating the light-emitting devices is as simple as possible.

Abstract: A switching power supply includes a switching element, a constant current element, a rectifying element, a first inductor, a second inductor, and a control circuit. If the switching element is on, the switching element supplies a power supply voltage to the first inductor and feeds an electric current. The constant current element turns off the switching element if the electric current of the switching element exceeds a predetermined upper limit. The rectifying element feeds the electric current of the first inductor if the switching element is turned off. The second inductor supplies the induced potential to a control terminal of the switching element. The control circuit supplies a pulse-like potential to a control terminal of the constant current element and outputs if an average of the potential is lower than a lower limit.

Abstract: Disclosed are circuits and methods for driving discharge devices wherein during illumination, a first electrode is driven with pulses that maintain ON state wall charges, while a reference electrode is held at a constant voltage. With these circuits and methods, one or more reference electrodes are held to a reference voltage, such as ground, while one or more electrodes initiate two discharges necessary to maintain a wall charge. Additionally, the invention discloses driving methods that reduce electrode inductance while maintaining the separation of a driving side and a reference side. Embodiments divide the plurality of driving electrodes into two or more groups of electrodes and utilize a resonant driver to transfer charge between the groups of electrodes. The electrode inductance is dramatically reduced because adjacent electrodes, rows of electrodes or groups of rows, have substantially equal but opposite current flows.

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: In various embodiments, a method for operating a high-pressure discharge lamp is provided. The method may include: during a first time slice, a voltage is applied to the high-pressure discharge lamp at a first frequency and said voltage is modulated with a second frequency and a first modulation level, during a second time slice, a voltage is applied to the high-pressure discharge lamp at a third frequency and said voltage is modulated with a fourth frequency and a second modulation level, and during a third time slice, a voltage is applied to the high-pressure discharge lamp at a fifth frequency.

Abstract: A light source device includes a discharge lamp that has a first electrode and a second electrode opposed to each other in a hollow portion in which a discharge medium is enclosed and a driving device that supplies a driving voltage to the first electrode and the second electrode. The driving voltage is applied to the discharge medium through the first electrode and the second electrode such that the discharge medium emits light.

Abstract: A light source device includes a discharge lamp, and a discharge lamp driving device that supplies a driving current to a pair of electrodes. The discharge lamp driving device includes an alternating current supply unit that supplies an alternating current with a frequency equal to or higher than 1 kHz and equal to or lower than 10 GHz to the electrodes, and a direct current supply unit that supplies a direct current to the electrodes.

Abstract: A circuit includes a switching power converter and a load current management circuit. The switching power converter provides a first current that varies between a first current value and a second current value in response to a dimming control signal. The load current management circuit provides a second current that varies between the second current value and a third current value in response to the dimming control signal. The second current varies in accordance with the first current. For example, the second current increases as the first current decreases and the second current decreases as the first current increases. In one example, the second current value corresponds to a required minimum load current for the power converter to regulate an output voltage.

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.