Abstract: A ballast circuit for a Light Emitting Diode (LED) has a regulator element coupled to the LED and to an input voltage source. A control circuit is coupled to the LED and to an input voltage source. A first switching device is coupled in series with the regulator element. A second switching device is coupled to the input voltage and the control circuit.

Abstract: A current control circuit and associated method are disclosed hereby. The current control circuit has a fly-wheel circuit, comprising an inductor, a rectifier and a load; a current sense circuit, detecting a load current, configured to generate a first current signal; a compensating circuit, generating a compensating signal; a control circuit, generating a control signal according to the first current signal and the compensating signal; a first switch, coupled to the fly-wheel circuit, turned ON and OFF according to the control signal. By the effect of the compensating signal, the drift error of the average load current is prohibited.

Abstract: A circuit for altering a level of impedance presented to a power supply including a power supply line includes an energy dissipating circuit, a detection circuit configured to generate a control signal indicative of a power consumption level in a load circuit coupled to the power supply line, and an activation circuit configured to controllably couple the energy dissipating circuit to the power supply line in response to the control signal. Methods of operating a solid state lighting apparatus including a power supply and a solid state lighting device coupled to the power supply include detecting a level of power consumption by the solid state lighting device, and coupling an energy dissipating circuit to the power supply in response to the level of power consumption by the solid state lighting device falling below a threshold level.

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

Abstract: A ballast lead wire configuration includes a ballast having a pair of power inputs and a pair of power outputs. A primary lamp is electrically connected to the ballast. A first primary lamp ballast terminal is formed on the primary lamp and electrically connected to the ballast. A second primary lamp ballast terminal is formed on the primary lamp and electrically connected to the ballast. A second lamp electrically connected to the ballast, and the second lamp is electrically connected to the first lamp in series. A first secondary lamp ballast terminal is formed on the secondary lamp and electrically connected to the ballast. A second secondary lamp ballast terminal is formed on the secondary lamp and electrically connected to the ballast. The first lamp and the second lamp are florescent lamps over 36 inches long.

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

Abstract: A lighting control device can include a control module and a processing module. The control module can provide a driving signal. The driving signal can modify a control voltage on a control interface. The control voltage can control a controllable ballast or driver. The processing module can determine a duty cycle of the driving signal. The control module and the processing module can receive power via the control interface and a power supply on the control device.

Abstract: A light control system and a light control method thereof are disclosed. The light control system is used for controlling a light-emitting device. The light control system includes an ambient status sensing module, a storage module, a controlling module, and a driver module. The ambient status sensing module is used for sensing an ambient state to generate an ambient state value. The storage module has a database for storing a plurality of parameter values, wherein the plurality of parameter values are corresponded to a plurality of ambient state values. The controlling module is used for searching the plurality of parameter values stored within the database according to the ambient state value, so as to generating a controlling signal. The driver module is used for driving the light-emitting device according to the control signal.

Abstract: A primary side regulation (PSR) type light emitting diode (LED) driving apparatus may be capable of precisely controlling output power. The LED driving apparatus may include: a power supplying unit converting an input power input to a primary side of the apparatus and supplying a driving power to the LED positioned on a secondary side of the apparatus; a secondary side feedback unit positioned on the secondary side and providing an output control signal based on a current flowing in the LED and a dimming signal; a dimmer positioned on the secondary side and providing the dimming signal; and a primary side feedback unit positioned on the primary side and transferring a feedback signal to the power supplying unit based on a detection signal obtained by indirectly detecting power induced in the secondary side and the output control signal.

Abstract: This disclosure provides an output stage for a LED driver circuit. The output stage has an input module, a regulator module for maintaining a constant internal voltage, and an output module for generating output signals.

Abstract: The power conversion apparatus converts power among a plurality of ports, and includes: a first voltage conversion unit that converts a voltage of a first port and outputs power having the converted voltage to a second port; and a second voltage conversion unit that performs a first operation of converting a voltage of one port of the second port and a third port and outputting power having the converted voltage to the other port, or a second operation of converting a voltage of the other port and outputting power having the converted voltage to the one port, and when performing the first operation the second voltage conversion unit switches from the first operation to the second operation when a vehicle condition where power of the one port is insufficient is detected.

Abstract: A multi-scene, multi-zone lighting device includes a support structure supporting multiple lighting zones, an ensemble of the zones defining a lighting scene. A master dimming control built into the support structure has a power input line and multiple dimmers. The zones are coupled to the dimmer output lines to receive a controlled setting from the corresponding dimmer. A remote control device communicates with the master dimming control, and has a memory for storing settings for the multiple zones and a user interface for a user to select a stored setting for each zone or a scene composed of multiple zones. Settings can be prestored or programmed by the user. The master dimming control includes a controller responsive to receiving the set of settings to set the controlled setting of the corresponding dimmer for each zone in the selected scene to conform the zones to the settings in the selected scene.

Abstract: A display circuit includes a first pulse width modulated (PWM) signal line coupled to a first switch, a second PWM signal line coupled to a second switch and the signal line, a transistor coupled to the second signal line between the first signal line and the second switch, a third switch coupled to a third PWM signal line, a fourth switch coupled to a fourth PWM signal line, a fifth switch coupled to a fifth PWM signal line, a light emitting diode (LED) including a red element coupled between the first and third switches, a green element coupled between the first and fourth switches, and a blue element coupled between the first and fifth switches, and an LED including a red element coupled between the second and third switches, a green element coupled between the second and fourth switches, and a blue element coupled between the second and fifth switches.

Abstract: A power supply device containing a first board, a second board, an enclosure into which the first board and the second board are installed, a power supply unit which supplies power to an external load, a control circuit unit for controlling output current and/or output voltage from the power supply unit to the external load, the control circuit unit being embedded on the first board, a memory which stores control information, the memory being utilized in the control circuit unit for controlling the output current and/or the output voltage from the power supply unit, and an interface unit which is capable of receiving the control information from an external device and transmitting the control information to the memory, the interface unit being embedded on the second board which is physically separated from the first board.

Abstract: The present invention provides an LED (Light-Emitting Diode) driving control circuit for controlling a converting circuit to transform an input power source into an output voltage for driving an LED module. The LED module has a plurality of LED strings. The LED driving control circuit includes a voltage detecting circuit and a feedback control circuit. The voltage detecting circuit has a plurality of detection circuits, and each detection circuit is coupled to a terminal of the corresponding LED string to determine whether a voltage of the terminal is higher or lower than a preset value. The voltage detecting circuit generates a feedback signal according to the determination results. The feedback control circuit controls the converting circuit to modulate the output voltage according to the feedback signal.

Abstract: Light emitting diode (LED) dimming and driver systems and associated methods of control are disclosed herein. In one embodiment, a system comprises a PFC stage and an LED driver stage. The LED driver stage comprises an isolated converter and a controller responsive to a dimming signal to dim LED strings for backlight. The controller also regulates an output current of the isolated converter.

Abstract: A system for configuring at least one output parameter of a lighting load power supply, the lighting load power supply having a programmable controller for regulating the output parameter to a target value and having a memory for storing a variable for setting the target value of the output parameter, the power supply having a communication port for receiving data for setting the target value, the system comprising a computer executing software allowing a user to select a target value of an output parameter of the lighting load power supply and having a first port providing data related to the selected output parameter; and a programming device having a second port in communication with the first port of said computer and for providing data relating to said selected output parameter in a form usable by said lighting load power supply to said communication port of said lighting load power supply for programming said programmable controller to set the output parameter to the selected target value.

Abstract: A ballast circuit adapted for converting an input alternating current (AC) mains power received at input terminals to an output alternating current (AC) to supply a load, e.g. a gas discharge lamp. The output terminals of the ballast connect to the load in parallel with another ballast circuit. The ballast circuit is configured to supply the output AC current to the load in parallel with an AC current output of the other ballast circuit. A synchronization module attached at the output is adapted for synchronizing the output alternating current (AC) of the ballast circuit with the AC current output of the other ballast circuit. The synchronization module is configured to synchronize phase of the output alternating current with phase of the AC current output of the other ballast circuit.

Abstract: An organic light emitting display includes a power supply source and a power voltage compensation unit. The power supply source supplies at least a first power voltage to a first power voltage line of the display. The power voltage compensation unit to generate a first compensation power voltage based on the first power voltage and a feedback power voltage from the first power voltage line. The first power voltage compensation unit outputs the first compensation power voltage to the first power voltage line.

Abstract: A backlight unit includes a dimming signal generator configured to generate first and second pulse width modulation signals, first and second driving blocks configured to receive a driving voltage to emit a light, a controller configured to receive the first and second pulse width modulation signals and an output signal from one of the first and second driving blocks to generate a voltage control signal, and a voltage converter configured to control a level of an input voltage in response to the voltage control signal to generate the driving voltage.

Abstract: A load control device for controlling the amount of power delivered to an electrical load is able to operate in a burst mode to adjust the amount of power delivered to the electrical load to low levels. The load control device comprises a control circuit that operates in a normal mode to regulate an average magnitude of a load current conducted through the load to a target load current that ranges from a maximum rated current to a minimum rated current. The control circuit operates in the burst mode to regulate the average magnitude of the load current below the minimum rated current. During the burst mode, the control circuit regulates a peak magnitude of the load current to the minimum rated current during a first time period, and stops regulating the load current during a second time period, such that the average magnitude of the load current is below the minimum rated current.

Abstract: A lighting system and method are provided for controlling a PWM duty cycle. The lighting system is provided with at least one device that is configured to emit light in response to receiving electrical power. The lighting system includes a power circuit and a feedback circuit. The power circuit is configured to selectively supply power to the device at a duty cycle corresponding to a first mode and a second mode, wherein the duty cycle of the first mode is less than 10% of the duty cycle of the second mode. The feedback circuit is configured to provide a feedback signal that is indicative of the energy provided to the device. The power circuit is further configured to disable power to the device during the first mode in response to the energy being greater than a threshold energy value, thereby adjusting the duty cycle.

Abstract: A backlight unit includes a DC-DC converter; a voltage control unit which controls output voltage of the DC-DC converter; a plurality of unit light emitting diode arrays; and current deviation compensating unit in connection with input terminals of the plurality of unit light emitting diode arrays. The current deviation compensating unit receives the controlled voltage of the voltage control unit and transfers a feedback signal to the voltage control unit based on the received voltage, and actively compensates a current deviation generated by electrical characteristics of the plurality of unit light emitting diode arrays and transfers the compensated current deviation to the input terminals of the plurality of unit light emitting diode arrays.

Abstract: A circuit for driving multiple light emitting diodes (LEDs) includes at least two sets of LEDs, each set comprised of one or more LEDs in series. The circuit further includes a single inductor connected in series with the two sets of LEDs. At least one set of LEDs is connected to a shunting transistor connected in parallel with the set of LEDs. The duty cycle of the shunting transistor is controlled by a single controller connected to the shunting transistor and the inductor.

Abstract: A preferred embodiment relates to controlling the amount of backlight power in an electronic display to account for the temperature in the backlight cavity. Another embodiment relates to a system for controlling the amount of backlight based on both the temperature of the backlight and the amount of ambient light.

Abstract: A driving circuit for controlling power of a light-emitting diode (LED) light source includes a transformer, a switch controller, and a dimming controller. The transformer has a primary winding that receives input power from an AC/DC converter and a secondary winding that provides output power to the LED light source. The switch controller coupled between an optical coupler and the primary winding receives a feedback signal indicative of a target level of a current flowing through the LED light source from the optical coupler, and controls input power to the primary winding according to the feedback signal. The dimming controller coupled to the secondary winding receives a switch monitoring signal indicative of an operation of a power switch coupled between an AC power source and the AC/DC converter, and regulates the output power by adjusting the feedback signal according to the switch monitoring signal.

Abstract: An insulated power supply device includes: an electric power conversion unit, a rectifier, a filter, a detection unit, a control circuit, and a signal transmission unit. The control circuit generates and outputs a control signal for a switching element that controls a current to be flown through a primary side of the electric power conversion unit. The signal transmission unit transmits, to the control circuit, a detection signal by the detection unit for detecting an output current or an output voltage. An output control pulse signal having control information in a duty ratio can be supplied as an outputted control signal individually to both of the control circuit and a secondary side of the electric power conversion unit. The output current or the output voltage can be thereby controlled.

Abstract: An LED drive circuit applied between an LED load and an AC power supply is provided. The circuit includes a rectifier, a power conversion module, a voltage regulator, a photo coupler and a controller. The rectifier rectifies and converts an AC voltage outputted from the AC power supply into a DC voltage. The power conversion module converts the DC voltage into a first drive voltage and a second drive voltage. The first drive voltage drives the LED load. The voltage regulator receives and processes the second drive voltage with a voltage regulating process to generate a third drive voltage not exceeding a maximum voltage rating of the controller. The photo coupler generates a feedback signal according to a signal outputted from the LED load. The controller receives the third drive voltage and generates a control signal to control the power conversion module according to the feedback signal.

Abstract: An LED actuating device comprises an LED actuating module, the LED actuating module comprises a micro-programmed control unit (MCU), a VF-value detection module, an actuator and an LED lamp unit; the MCU receives the VF value detected by the VF-value detection module; when the VF value is greater than or equal to a first boundary value, the LED lamp unit is actuated to operate in the constant current area at the first constant actuating current by the actuator; when the VF value is less than the first boundary value, the LED lamp unit is actuated to operate in the regulation area at the continuous step-down actuating current by the actuator until the VF is equal to the second boundary value, and the second boundary value is less than the first boundary value.

Abstract: A system according to various embodiments of the disclosure includes a bus and a plurality of devices coupled to the bus, the devices configured to communicate with each other via the bus. The system further includes a power supply coupled to the bus, the power supply for supplying power to the plurality of devices via the bus. The power supply is configured to detect an event, and in response to the event, alternately supply power to the plurality of devices via the bus at a first current level or at a second current level, the second current level less than the first current level. Among other things, embodiments in this disclosure help allow additional devices to be used on a bus, even where the total power consumption of the devices would normally exceed a maximum defined by a bus architecture.

Abstract: An actuating device comprises an LED actuating module. Said LED actuating module comprises a micro-programmed control unit (MCU), an actuator, a VF-value detection module, a PN-junction temperature acquisition module and an LED lamp unit. The MCU determines the current value matched with the LED lamp unit based on the VF value detected by the VF-value detection module and the temperature value detected by the PN-junction temperature acquisition module, and then determines the width of the PWM pulse output to the actuator according to the current value, and the actuator actuates an LED to operate at the matched current value.

Abstract: An illumination light source includes: a light-emitting unit; a disturbance detecting unit which detects a specific disturbance; a timer circuit that times a first period and a second period, the first period starting from when the disturbance detecting unit detects the specific disturbance, a second period immediately following after the first period; and a driving circuit that turns ON the light-emitting unit at a start of the first period, causes the light-emitting unit to emit light during the first period, causes the light-emitting unit to emit light that is different from the light emitted during the second period, and turns OFF the light-emitting unit at an end of the second period.

Abstract: An image display device includes a light source; a power supply section that supplies power to light source; a cooling fan that cools the light source; an input section; a drive section that supplies a voltage to cooling fan; a control section that controls drive section and power supply section. The control section sets a first power value for the output of the power supply section and also a first voltage value for the output of the drive section. The control section measures a time at which the light source has been lighted. If the measured value exceeds a threshold, the control section gradually increases the output of the power supply section up to a second power value that is greater than the first voltage value over a predetermined time.

Abstract: The present document relates to a method and system for dimming low power illumination devices, such as LED (Light Emitting Diode) assemblies. A controller for a driver circuit of a light source is described. The driver circuit controls a plurality of illumination states of the light source using a power converter, which converts power from an input voltage waveform of a mains power supply into a drive signal for the light source. The controller comprises an event detection unit; a state register to store an indication of a current state of the illumination states; a state processor to determine a target state of the illumination states, based on the detected event and based on the current state; and an output control unit controls the power converter of the driver circuit to provide a drive signal for the target state.

Abstract: In one embodiment, an LED driving circuit can include: (i) a sense circuit configured to sense an inductor voltage, and to generate a sense voltage signal; (ii) a protection control circuit configured to activate a first protection control signal in response to a comparison of the sense voltage signal against a first reference voltage to indicate an LED device is in a first load state; (iii) the protection control circuit being configured to activate a second protection control signal in response to a comparison of the sense voltage signal against a second reference voltage to indicate the LED device is in a second load state; and (iv) a PWM control circuit configured to control a power switch according to the first protection control signal or the second protection control signal, based on the load state of the LED device.

Abstract: An LED lamp comprising a housing, a drive circuit, LED dies driven by the drive circuit, and an output-select controller to program the drive circuit to drive the LED dies in one of a pre-sleep configuration and a general lighting configuration. The LED dies comprise LED dies of a first spectral output having a peak wavelength between 500 nm and 600 nm and of a second spectral output having a peak wavelength greater than 600 nm, first blue LED dies having a peak wavelength between 420 nm and 480 nm, and second blue LED dies having a peak wavelength below 420 nm. The drive circuit operates each of the LED dies of the first and second spectral outputs and the second blue LED dies in the pre-sleep configuration, and the LED dies of the first and second spectral outputs and the first blue LED dies in the general lighting configuration.

Abstract: A PFC LED driver capable of reducing flicker, including: a bridge rectifier, used to generate a full-wave-rectified line input voltage according to an AC power a single stage PFC constant average current converter, coupled with the bridge rectifier and used for forcing an input current to track the full-wave-rectified line input voltage and regulating an average value of an output current at a first preset value; and a peak current regulator, in series with an LED module to form a load for the output current to flow through, wherein the peak current regulator is used to regulate a peak of the output current at a second preset value, and the second preset value is higher than the first preset value.

Abstract: The present invention provides an overvoltage protection method for backlight drive circuit of 2D/3D mode and a backlight drive circuit using the method. The method includes: providing a liquid crystal display, the liquid crystal display having a 2D mode and a 3D mode, the liquid crystal display including a backlight drive circuit; the backlight drive circuit using the first overvoltage protection voltage level as an overvoltage protection voltage level when the liquid crystal display is set in the 2D mode; and the backlight drive circuit using the second the overvoltage protection voltage level as an overvoltage protection voltage level when the liquid crystal display is set in the 3D mode, the second the overvoltage protection voltage level being greater than the first overvoltage protection voltage level. Different overvoltage protection voltage levels are provided for the 2D and 3D modes so as to alleviate impact on components by over voltage.

Abstract: A discharge lamp lighting device according to the invention can reliably light a discharge lamp, and at the same time, prevent output of unnecessary high-voltage pulses with a simple circuit configuration. The discharge lamp lighting device includes a capacitor charged with a current from a direct-current power supply, a transformer adapted to output a starting pulse between electrodes of the discharge lamp in accordance with a discharge current flowing from the capacitor, a discharge control circuit adapted to switch ON/OFF the discharge current from the capacitor to the transformer, and a timing generation section adapted to switch the discharge control circuit to ON after a voltage between both ends of the capacitor has reached a reference voltage. The timing generation section can operate in accordance with a plurality of reference voltages.

Abstract: A power distribution system includes controller of a switching power converter to control the switching power converter and determine one or more switching power converter control parameters. In at least one embodiment, the switching power converter utilizes a transformer to transfer energy from a primary-side of the transformer to a secondary-side of the transformer. In at least one embodiment, the switching power converter control parameters includes a secondary-side conduction time delay that represents a time delay between when the primary-side ceases conducting a primary-side current and the secondary-side begins to conduct a secondary-side current. In at least one embodiment, determining and accounting for this secondary-side conduction time delay increases the prediction accuracy of the secondary-side current value and accurate delivery of energy to a load when the controller does not directly sense the secondary-side current provided to the load.

Abstract: The present invention provides a light emitting diode (LED) driving device, which comprises: a direct current/direct current (DC/DC) controller, for controlling an output segment that is used to generate an output voltage from an input voltage and supply the output voltage to an LED; an output current driver, for generating an output current of the LED; and an output discharging circuit, for performing, based on a predetermined control signal, discharging of the output voltage when a generation action of the output voltage and the output current stops.

Abstract: Described herein is a luminaire controller for a luminaire in which dimming signals can be provided to control the operation of the luminaire. The controller also includes an energy measurement module connected to a mains supply, a sensor module, a power switch, a central processing module and a ZigBee transceiver module. The controller, in addition to providing dimming signals in accordance with ambient lighting conditions sensed by a photocell in the sensor module provides efficient energy metering. In one embodiment, the luminaire controller is directly mountable on a luminaire which is to for control thereof.

Abstract: The invention relates to an HF system that comprises an HF device (5), particularly an HF lamp, as well an HF spark-plug or similar HF plasma application, and an HF signal-incoupling device (3) for operating said HF device (5). The HF system comprises an oscillator (7) for generating an HF signal to operate said HF device (5), and said system is characterised in that it comprises means (15) for generating a voltage signal (Uprop) that is proportional to the degree of adaptation of the HF device, on the basis of the HF signal generated by the oscillator (7) and a signal reflected by said HF device. Moreover, the system is characterised in that it comprises a device (27), preferably without a microprocessor, for generating a control signal (UA) for adapting the oscillator (7) output-frequency on the basis of the voltage signal (Uprop) which is proportional to the degree of adaptation of the HF device (5).

Abstract: There is provided a light emitting diode driver capable of improving power efficiency by using a resistor having a low power consumption rating while controlling an LED channel so that it has constant brightness stably. The light emitting diode driver includes: a power supplying unit converting an input voltage into a predetermined driving voltage so as to supply the driving voltage to an LED channel; and a driving unit amplifying a detection voltage detected based on a current from the LED channel by a predetermined gain and controlling the current flowing through the LED channel so that the amplified detection voltage has a level equal to that of a predetermined reference voltage.

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

Abstract: A method and an apparatus for producing situational acousto-optic effect are provided. In the method, a sound signal is detected and a fast Fourier transform (FFT) and a normalization calculation are performed on the sound signal to produce a frequency domain signal. Then, a plurality of frequencies having variations between the frequency domain signals produced before and after a time point are determined whether to fit in with a frequency spectrum of a specific tone. Once the frequencies fit in with the frequency spectrum, a light source is controlled to produce light with a color corresponding to the specific tone.

Abstract: A safety flashing detector that suitably detects unintentional flashing of the LED light engine in a traffic lamp is provided. The LED light engine may flash unintentionally when there are failures (hardware or software) inside a traffic lamp. In certain embodiments, unintentional flashing may be detected using a current sensor. If unintentional flashing is detected, the flashing detector may activate and shut down the LED light engine to remove the hazardous failure and eventually triggers the fuse blowout circuit. Hardware circuitry is suitably employed for both reliability and safety purposes, but software may also be employed.

Abstract: An inductive light-source module including a casing, a substrate, light sources, a circuit board, an infrared sensing device, a bi-incident lens and a control unit is provided. The substrate disposed in the casing includes a carrying surface facing a transparent portion of the casing. The light sources connected to the substrate are disposed on the carrying surface. The infrared sensing device is connected to the circuit board. The bi-incident lens disposed on the transparent portion is located on a light path of each light for scattering visible lights to pass through the transparent portion and transmit to the outside, and converging the infrared from the outside to the infrared sensing device. The control unit is coupled to the light sources and the infrared sensing device to drive the light sources to emit the visible lights according to a sensing signal generated by the infrared sensing device when sensing the infrared.

Abstract: A light emitting diode (LED) lighting system includes a switching power converter having an input for coupling to an alternating current (AC) power source, an output, and a switch. The LED lighting system also includes an LED lighting subsystem coupled to receive power from the output of the switching power converter. The LED lighting subsystem includes a current source for one or more LEDs, and the current source has a control node and a sense node. The LED lighting system additionally includes a switch state controller coupled to the switching power converter and coupled to the LED lighting subsystem. The switch state controller controls switching of the switch and varies a control current provided to the control node of the current source based on at least a parameter sensed from the sense node.

Abstract: A light emitting diode (LED) backlight driving circuit of the present disclosure includes a constant current driver chip, a power module, an LED lightbar coupled to the power module, a dimming module coupled to the LED lightbar, and a low-pass filter. The constant current driver chip comprises a multiplier, and the constant current driver chip generates a gate signal and a dimming signal that are sent to an input end of the multiplier. An output end of the multiplier is coupled to the power module, and is coupled to the dimming module through the low-pass filter.