Abstract: An addressable illuminator is disclosed consisting of multiple optical sources used in combination with an electrical circuit so that different combinations of the optical sources can be energized without exceeding eye-safety limits. Operation of multiple optical sources may be proximate, which is eye-safe, regardless of the number of or which ones of the optical sources are energized and regardless of the position of observers. An illuminator with multiple optical sources remains eye-safe when there are single-point electrical failures, such as short circuits, in the driving circuit. Monitoring or a feedback loop for the output power is not required or necessary to control the distance of an observer in order to be eye-safe.

Abstract: A light emitting module device includes: a power line through which power is supplied to light emitting modules; and a signal generation circuit which generates a control signal. The power line is shared by a plurality of the light emitting modules, and has switches and switches which turn on or off current conduction to the light emitting modules, through open/close operations. The signal generation circuit individually controls the switches and the switches. The open/close operations include a light-emission period in which the light emitting module emits light; and an extinction period in which the light emitting module is extinguished, and if there is a control signal to be transmitted to the light emitting module, the control signal is superimposed onto supply power. Since a control signal is superimposed onto supply power to each light emitting module, the light emitting modules can be individually controlled.

Abstract: A Light Emitting Diode (LED) light source control system for intelligentized layer breeding, comprises a plurality of LED lamps (30) equipped at a layer breeding place and a LED light source controller (10). Each of the LED lamps (30) comprises a red light LED and a green light LED. The LED light source controller (10) controls the LED lamps (30) to emit green light during the brooding period and the improved period of a layer; and the LED light source controller (10) controls the LED lamps (30) to emit red light during the egg producing period of a layer. The LED light source controller (10) controls the illumination intensity of the LED lamps (30) by regulating the duty ratio of an output Pulse-Width Modulation (PWM). The LED light source controller (10) controls the illumination time of the LED lamps (30) by utilizing a clock unit so as to implement different illumination time respectively during various stages of the brooding period, the improved period and the egg producing period of a layer.

Abstract: An apparatus to detect faulty connection of LED (open/short conditions) which may affect the function of LED display panel is presented. The apparatus basically controls the switches through control algorithm circuit to get the information of LED driver output pins voltage and compare them with two reference voltages to determine the open/short condition of individual LED.

Abstract: In at least one embedment, a circuit includes an input node, an energy node, a reference node, an output node, a first capacitive device, a first diode device, and a power converter. The first capacitive device is coupled between the energy node and the reference node. The first diode device has an anode coupled to the input node and a cathode coupled to the energy node. The power converter is coupled between the energy node and the output node.

Abstract: There is provided a light emitting diode driving apparatus satisfying regulations for current transferred to a light emitting diode. The light emitting diode driving apparatus includes: a power supplying unit receiving input power to convert the input power into a preset driving power and supplying the driving power to a light emitting diode unit including at least one light emitting diode; a detecting unit receiving the driving power supplied to the light emitting diode unit to detect voltage flowing in the light emitting diode unit; a controlling unit comparing detection voltage detected by the detecting unit with a preset reference voltage to control a power conversion operation of the power supplying unit; and a driving unit driving the power conversion operation according to controlling by the controlling unit.

Abstract: A backlight module used in a display device is provided. The backlight module comprises a first and a second view-angle LED groups, a first and a second switches, a LED drive circuit for generating a drive current and a mode-control unit. The first and the second switches enable or disable the first and the second view-angle LED groups according to a first and a second PWM signals respectively. The mode-control unit operates the backlight module in 2D or 3D display mode according to a mode-control signal. In the 2D display mode, the first and the second switches enable the first and the second view-angle LED groups synchronously to emit light according to the drive current. In the 3D display mode, the first and the second switches enable the first and the second view-angle LED groups with an interlaced manner to emit light according to the drive current.

Abstract: A system including a selection module to select one of a plurality of templates corresponding to a plurality of light emitting diodes, where the selected template includes one or more of temperature, current, and voltage characteristics of the plurality of light emitting diodes. A control module measures a voltage across one of the plurality of light emitting diodes; determines a temperature of the plurality of light emitting diodes based on the voltage measured across the one of the plurality of light emitting diodes and the selected template; and in order to maintain a luminosity of the plurality of light emitting diodes at a predetermined luminosity, adjusts current through the plurality of light emitting diodes based on the temperature, the selected template, and calibration data. The calibration data include current through the plurality of light emitting diodes and corresponding luminosities of the plurality of light emitting diodes.

Abstract: A lighting device includes a DC/DC power converter, a controller/processor electrically connected to the DC/DC power converter, a light emitting diode (LED) current control circuit communicably coupled to the controller/processor and electrically connected to the DC/DC power converter, and two or more LEDs comprising at least a first color LED and a second color LED electrically connected to the LED current control circuit. The LED current control circuit provides an on/off signal having a cycle time to each LED in response to one or more control signals received from the controller/processor such that the two or more LEDs produce a blended light having a specified color based on how long each LED is turned ON and/or OFF during the cycle time.

Abstract: Disclosed herein is a light emitting diode (LED) driving device for driving a multi-channel LED element or an LED array for each channel, the LED driving device including: a constant current driver driving currents flowing in each channel; a first switching unit selectively feeding-back voltage levels of each channel; and a switching controller controlling the turn on/off of the first switching unit, wherein matching characteristics of currents flowing in each channel is improved and a size of an integrated circuit (IC) chip is also reduced as compared to a case according to the related art, thereby making it possible to reduce a production cost and satisfy the trend of miniaturization of the chip, while solving a performance deterioration problem due to degradation of the matching of the currents between the channels.

Abstract: An LED lighting apparatus connected to a power source via two electric lines, includes first and second LEDs having different emission spectrum or chromaticity, a switching unit to monitor ON time length of power supplied from the two electric lines periodically to switch a control mode of the first and second LEDs between first and second modes as a condition that the ON time is not changed continues for more than a threshold value, a first control unit to determine, in the first mode, a total amount of average current to be supplied to the first LED and to the second LED depending on the ON time length of the electric power, and a second control unit to determine, in the second mode, a ratio of average currents to be supplied to the first LED and to the second LED depending on the ON time length.

Abstract: The embodiments disclosed herein describe a method of a power controller for monitoring for unsafe operating conditions of a drive transistor in a switching power converter of a LED lamp system by predicting the power dissipation of the drive transistor based on knowledge of the current through the drive transistor and a continuous observation of the voltage across the drive transistor. When the drive transistor approaches unsafe operating conditions, the power controller turns off the drive transistor.

Abstract: When a current which is conducted from a direct current power supply 8 to a choke coil L1 after a switching transistor 7 is turned on has a predetermined value, an LED lighting device. lights up an LED series circuit by conducting a pulse-shaped current which occurs by turning off the switching transistor 7 to the LED series circuit. A cycle period at which the pulse-shaped current is generated is determined according to the average value of the current flowing through the LED series circuit by using an oscillator (VCO) 4. The LED lighting device controls each of the pulse-shaped current value and the average current value arbitrarily.

Abstract: An LED device for use with an AC voltage power source configured such that at least one LED emits light during a positive phase of power provided from an AC power supply and at least one LED emits light during the negative phase of power provided from an AC power supply. The LED device includes a first power connection lead and a second power connection lead, both leads capable of being connected to and receiving power from an AC power supply.

Abstract: A lighting-dimming device has a dimming module with an encoding function and at least one light module with a decoding function and controlled by the dimming module. The dimming module is designated with a required brightness and address command by a user. A triode AC switch of the dimming module is controlled to chop a power based on the required brightness and address command. The chopped power is transmitted to the light module to control the brightness of the light module. In the chopped power, only a part of cycles of the power is chopped and most of the power waveforms are maintained. Therefore, a high power factor is maintained.

Abstract: A light-emitting diode (LED) emitter module includes a substrate having a plurality of base layers of an electrically insulating material, a plurality of electrical contacts disposed on a top one of the base layer, and a plurality of electrical paths coupled to the electrical contacts, wherein at least a portion of the plurality of electrical paths is disposed between the base layers. The emitter module also includes two or more groups of light-emitting diodes (LEDs), each group having one or more LEDs, and each of the LEDs is coupled to an electrical contact. The electrical paths are configured for feeding separate electrical currents to the groups of LEDs. The emitter module also includes a memory device containing information associating a plurality of output light colors with a corresponding plurality of combinations of electrical currents, each combination specifying an electric current for each of the two or more groups of LEDs.

Abstract: A backlight apparatus includes light emitting diode (LED) modules. Each LED module includes a first connection pin set, a second connection pin set, a driving circuit, a first LED string, and a second LED string. Each of the connection pin sets has a first and second power connection pins and a first and second ground connection pins. The first and second power connection pins are coupled to each other, and the first and second ground connection pins are coupled to each other. The first ground connection pin of the first connection pin set is coupled to the first power connection pin of the second connection pin set. The driving circuit is used to provide a driving signal. Each of the LED strings is serially connected between the second power connection pin and the second ground connection pin of each of the connection pin sets and receives the driving signal.

Abstract: An illuminating device comprising a plurality of semiconductor light-emitting devices differing in emission color and employing a semiconductor light-emitting element and a phosphor, wherein outputted light is stably combined, separation of light is inhibited, and color tone is variable, and which devices emit light outward on the basis of an emission from the semiconductor light-emitting element and from the phosphor which is excited by emission from the semiconductor light-emitting element to fluoresce or on the basis of emission from the phosphor which is so excited to fluoresce, the deviation duv of which from a blackbody radiation locus being within a range of ?0.02?duv?0.02, in the uv chromaticity diagram according to UCS (u,v) color system (CIE 1960), and outputted lights from the light-emitting part in which the plurality of kinds of the semiconductor light-emitting devices are integrated and arranged, are mixed together and emitted outward.

Abstract: A power supply device comprises: a DC power supply section that outputs a DC voltage; a voltage conversion section that supplies a DC power to a load by ON/OFF drive of a switching element; a resistor; a control section that performs the ON/OFF drive of the switching element; and an auxiliary winding. The control section comprises: a calculation section that calculates a drive period of the switching element; a count section compares a calculation result obtained in the calculation section with an upper limit value of the drive period; and a flip-flop. When the calculation result is shorter than the upper limit value, the flip-flop sets the drive period, using the calculation result. When the calculation result is longer than the upper limit value, the flip-flop sets the drive period, using the upper limit value.

Abstract: An alternating current-to-direct current (AC-to-DC) power supply has a first stage providing a first DC voltage and a second stage providing a second DC voltage. The AC-to-DC power supply has a first efficiency at the first stage and a second efficiency at the second stage that is less than the first efficiency. The second DC voltage is also less than the first DC voltage. A blower is electrically connected to the first stage of the AC-to-DC power supply to receive the first DC voltage from the AC-to-DC power supply to power the blower. Electrical connection of the blower to the first stage of the AC-to-DC power supply instead of to the second stage of the AC-to-DC power supply wastes less power and is more efficient.

Abstract: An LED lighting apparatus and a dimming method thereof are disclosed. The LED lighting apparatus is coupled to a power source through a power switch. The method includes providing a first lighting unit and a second lighting unit; detecting whether or not the power switch has been turned on; and gradually adjusting a light mixing ratio between the first lighting unit and the second lighting unit according to a turn-on duration of the power switch and storing a color temperature value, accordingly.

Abstract: A light emitting diode (LED) dimming module includes an energy storage circuit, a load interface circuit, and a switch circuit. The energy storage circuit provides a substantially continuous current in response to a converter current. The load interface circuit provides a modulated load current in response to the continuous current. The switch circuit, which is operatively coupled to the load interface circuit, switches in accordance with a duty cycle. The modulated load current is based on the duty cycle.

Abstract: Drivers and ballast circuits are presented having a boost converter with a triac compatibility circuit providing regulated current load to accommodate phase-cutting triac circuit holding current requirements, including auto switching driver circuit with overvoltage protection and an auto leveling circuit to regulate against thermal and load fluctuations.

Abstract: A load control system comprises a load control device for controlling an electrical load receiving power from an AC power source, and a controller adapted to be coupled in series between the source and the load control device. The load control system may be installed without requiring any additional wires to be run, and is easily configured without the need for a computer or an advanced commissioning procedure. The load control device receives both power and communication over two wires, and the controller generates a phase-control voltage that has at least one timing edge in each half-cycle, and transmits digital messages by modulating a timing edge of the phase-control voltage relative to a reference edge. The controller may be operable to receive inputs from a plurality of different input devices, and the load control device may be operable to control a plurality of different loads.

Abstract: It is provided an LED lighting device calibratable to 0 to 100% of wide range about a chromaticity and luminance of a illumination light by a simple configuration, and a driving method for the LED lighting device. The LED lighting device is provided with a first light-emitting unit and a second light-emitting unit differing a color temperature mutually, and a control circuit for executing a cyclic light/quench control of the first light-emitting unit and the second light-emitting unit, and for executing a light control of the first light-emitting unit and the second light-emitting unit by a PNM (Pulse Number Modulation) control in a fixed cycle so as to have a lighting period Ton for lighting/quenching the first light-emitting unit and the second light-emitting unit complementarily, and a quenching period Toff for quenching both the first light-emitting unit and the second light-emitting unit.

Abstract: A triac dimming control system processes the output of a triac based dimmer, generates a dimming control signal based on the output, and provides dimming at a load output based on the dimming control signal.

Abstract: Consistent with an example embodiment there is a method for regulating a LED current (ILED) flowing through a LED circuit arrangement at a mean LED current level. The method includes establishing an oscillating converter current (IL), establishing a first and a second current control indicator representative of a flow of a converter current (IL); regulating a peak and valley current level of the converter current in dependence on the first current control indicator; controlling a converter current period (T) of an oscillation of the converter current in dependence on the second current control indicator to be within a period control range (Tref) and feeding at least part of the converter current to the LED circuit arrangement.

Abstract: A circuit for operating at least one LED (“driver circuit”) includes input terminals to be connected to an input or operating voltage in the form of a direct current (DC) voltage or a rectified alternating current (AC) voltage, and output terminals to be connected to a load circuit containing the at least one LED. The circuit includes a clocked switch and an open-loop control circuit for clocking the switch. The open-loop control circuit is in the form of an integrated circuit (IC) and is provided with input and output pins. The open-loop control circuit generates a clock signal for the switch depending on at least two actual value signals, such that there is a control loop with the manipulated variable “clocking of the switch.

Abstract: A high gate voltage generator and a display module are provided. The high gate voltage generator includes a pulse width modulation (PWM) signal generating circuit, a boost circuit, and an amplifier circuit. The PWM signal generating circuit is used for outputting a PWM signal. The boost circuit is electrically connected to the PWM signal generating circuit and used for receiving an input voltage to boost the input voltage according to the PWM signal and then outputting a power voltage. The amplifier circuit is electrically connected to the boost circuit and used for receiving a reference voltage to amplify the power voltage and then outputting a high gate voltage. The reference voltage is greater than the high gate voltage and is provided by a backlight module electrically connected to the amplifier circuit.

Abstract: A light tube for illumination by a power supply circuit includes a bulb portion and at least one end cap disposed on the bulb portion. A plurality of light emitting diodes is disposed inside the bulb portion for illuminating in response to electrical current to be received from the power supply circuit. The light emitting diodes are arranged in spaced-apart groupings.

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 includes; first/second boost circuits that boost voltages applied to a first/second boost nodes in response to a first/second main signals, and respectively operated first/second transmission unit that control provision of boosted voltages to an output node. The power supply device also includes a bulk voltage controller connected between the boosted nodes and controlling a connection between the output node and a bulk node in response to a bulk control signal. Voltages respectively applied to the first and second transmission units are determined in response to an output node voltage, as well as the first/second main signals.

Abstract: The invention relates to an apparatus for controlling an illumination device, particularly in an aircraft, which comprises the following: a light source (6) which is suitable for emitting light with a wavelength in the visible range, and a pulse-width modulator (2) which delivers at least one output signal (5) that is connected to the light source (6) and is suitable for effecting brightness control of the light source (6), wherein the output signal (5) is composed from a first number of first subsignals (7) each having a first pulse width (8) and a second number of second subsignals (10) each having a second pulse width (11), which is shorter than the first pulse width (8), so that the brightness of the light source (6) can be adjusted by varying the first number and the second number for a brightness change and the output signal (5) is repeated after delivery of the first number and second number of subsignals (7, 10).

Abstract: A LED driving apparatus includes a rectifying circuit, first, second and third blocks, and first and second switching portions. The rectifying circuit is connected to AC power supply, and rectifies AC voltage of the AC power supply to provide pulsating current voltage. Each block includes a plurality of LEDs. The first, second and third blocks are serially connected to the output side of the rectifying circuit. The first switching portion switches ON/OFF of a first bypass path based on flowing current amount in the first block. The first bypass path bypasses the second block. The second switching portion switches ON/OFF of a second bypass path based on flowing current amount in the first and second blocks. The second bypass path bypasses the third block.

Abstract: The present invention relates to an electronic device for driving a light emitting diode, which includes a switch (Ts) being adapted to switch a switch-mode power converter, and controlling means (CNTL) being adapted for controlling the switch (Ts) in response to a sensing value (Vs) indicative of a current of the switch-mode power converter and for controlling by the switch (Ts) the output voltage of the switched power converter and a current (Tout) through the light emitting diode.

Abstract: In at least one embodiment, an electronic system adapts current control timing for half line cycle of a phase-cut input voltage and responsively controls a dimmer current in a power converter system. The adaptive current control time and responsive current control provides, for example, interfacing with a dimmer. The electronic system and method include a dimmer, a switching power converter, and a controller to control the switching power converter and controls a dimmer current. In at least one embodiment, the controller determines a predicted time period from a zero crossing until a leading edge of a phase-cut input voltage and then responsively controls the dimmer current to, for example, reduce current and voltage perturbations (referred to as “ringing”), improve efficiency, and reduce an average amount of power handled by various circuit components.

Abstract: The present invention relates to a backplane device for a light source matrix. A light source is preferably a LED or an OLED. A pixel circuitry of the backplane device is assigned to a light source of the light source matrix for controlling the light source. One light source and one pixel circuitry constitute a pixel. The pixels of the light source matrix are classified according to a pixel characteristic. The order of switching the light sources on and/or off depends on the pixel characteristic and not necessarily on the location of the pixel on the backplane device. A current being applied to the light sources is controlled by at least one driver. The at least one driver is electrically connectable to at least one pixel. The at least one driver is not belonging to the pixel circuitry of the pixel.

Abstract: A lighting device includes a voltage conversion circuit having at least a switching element connected to a positive potential side of the output terminals of the DC power source unit, and a drive unit which outputs a drive signal to the switching element. The drive unit has a first impedance element with a first impedance which is determined based on a power consumed by the drive unit before a predetermined time has elapsed after a control power source is supplied. A control capacitor for use in generating the drive signal is charged when the switching element is turned off during an on/off operation of the switching element. The lighting device further includes a second impedance element with a second impedance having a resistance component, which is arranged in a path in which the control capacitor can be charged in DC when the switching element does not perform the on/off operation.

Abstract: In at least one embodiment, an electronic system and method includes a controller to control a switching power converter in at least two different modes of operation depending on whether the controller detects a dimmer or not and/or whether a load requests more power than either of the two operational modes can provide. In at least one embodiment, the controller detects whether a dimmer is phase cutting an input voltage to a switching power converter. The controller operates the switching power converter in a first mode if the dimmer is detected, and the controller operates the switching power converter in a second mode if the dimmer is not detected. The controller also transitions between operating the switching power converter in the first mode and the second mode if a status of detection of the dimmer changes.

Abstract: A computing device is disclosed. The computing device includes a housing having an illuminable portion. The computing device also includes a light device disposed inside the housing. The light device is configured to illuminate the illuminable portion.

Abstract: A light emitting diode (LED) driver apparatus is provided. The LED driver apparatus includes an input unit, a PWM signal generation unit, a DC-DC converter, an LED driving unit, and a synchronization unit. The input unit is configured to receive a dimming signal. The PWM signal generation unit is configured to generate a PWM signal using an oscillator having a preset frequency. The DC-DC converter is configured to provide a driving voltage to an LED array using the generated PWM signal. The LED driving unit is configured to drive the LED array using the received dimming signal. The synchronization unit is configured to reset the oscillator based on a driving state of the LED array.

Abstract: A direction indication lamp control device includes: a pulse signal generation unit that generates a pulse signal; a current control element having one end to which power supply voltage is supplied, a control terminal to which the pulse signal is supplied, and the other end which outputs a drive current, the other end of the current control element being connected to one end of an external direction indication switch, and the other end of the direction indication switch being connected to a direction indication lamp; and a leak detection unit that causes the pulse signal generation unit to decrease the amplitude of the pulse signal in a case where the drive current corresponding to a pulse wave of the pulse signal is equal to or less than a leak detection current value during a leak detection period.

Abstract: System and method for regulating one or more currents. The system includes a system controller, an inductor, a first resistor, a switch and a first diode. The system controller includes a first controller terminal and a ground terminal, the system controller being configured to output a drive signal at the first controller terminal. The inductor includes a first inductor terminal and a second inductor terminal, the first inductor terminal being coupled to the ground terminal, the second inductor terminal being coupled to one or more light emitting diodes. The first resistor includes a first resistor terminal and a second resistor terminal, the first resistor terminal being coupled to the ground terminal. The switch is configured to receive the drive signal and coupled to the second resistor terminal. The first diode includes a first diode terminal and a second diode terminal and coupled to the first resistor.

Abstract: A solid state lighting device may include a power supply, a light emitting device, and a boost converter. The boost converter may have an input node electrically coupled to the power supply and an output node with the light emitting device electrically coupled between the output node and a reference node. The boost converter may include a switch electrically coupled in a current shunting path between the input node and the reference node, and a controller. The switch may be configured to shunt current from the power supply around the light emitting device. The controller may be configured to generate a pulse width modulation (PWM) signal to control a duty cycle of the switch to provide a pulse width modulated electrical current through the switch and a continuous electrical current through the light emitting device. Related methods are also discussed.

Abstract: A control system controls the operation of at least a first and a second independently controllable LED light member. The control system includes a frame member on which a plurality of electrical components can be mounted, and at least one input port for receiving at least one of a power source and a command signal source capable of sending a command signal to at least one of the first and second LED light members. A first driver member is provided for conducting power to deliver conditioned DC power to the first LED member. A first driver to frame connector removably couples the first driver member to the frame member. A second driver member conditions power to deliver conditioned DC power to the second LED member, and a second driver to frame connector removably couples the first driver member to the frame member. A first external output port is coupled to the first driver, and a second external output port coupled to the second driver.

Abstract: A modular area washlight illumination system and method for operating are provided that comprise an intelligent light module group that has: one or more light modules, each of which comprises a plurality of discrete illumination sources; a power supply; and an intelligent module group controller comprising: a) circuitry that controls the illumination levels of the illumination sources; and b) an interface for receiving and sending information. The system further comprises a system controller that comprises: a) an attendant control panel serving as a user interface; and b) a system controller interface that is connected to the module group controller interface.

Abstract: The present invention provides a driving circuit and a driving method for light-emitting diodes (LEDs), and a display apparatus using the same. The driving circuit comprises a power switch and a dimmer circuit. The method comprising: detecting a duty of a pulse width modulation (PWM) dimming signal; and when the duty of the PWM dimming signal is less than the predetermined duty, providing an analog dimming signal to the driving circuit. The present invention can be applicable to a display apparatus, and improve a noise problem when a duty of a conventional dimming is too low.

Abstract: Exemplary embodiments represent an operating device (100) for a light-emitting means (12) with an interface (15) for the bidirectional data interchange with a control device (20), wherein the operating device (10) has an energy or power measuring device (25) for determining an energy or power consumption of the light-emitting means. In this case, the operating device (10) is designed to send information relating to the energy or power consumption to the control device (20) or is designed such that the information relating to the energy or power consumption is accessible to the control device (20).

Abstract: The present invention relates to a parallel light emitting diode (“LED”) drive circuit and provides a drive circuit configured to drive a parallel array of LEDs. The drive circuit comprises: a switching control signal generator, a plurality of switches, a plurality of sampling resistors, and a plurality of chopper amplifiers. Each switch is coupled to a respective LED in the LED array. Each chopper operational amplifier configured to receive a reference voltage and a switching control signal generated by the switching control signal generator and generate an input offset voltage. Each chopper operational amplifier includes a differential amplifier including an input transistor pair and a current mirror transistor pair, of which the electrical positions can be reserved when the switching control signal is switched between a first state and a second state, wherein the offset voltage, which causes the lightness mismatching in a parallel LED circuit, can be cancelled.

Abstract: System and method for providing at least an output current to one or more light emitting diodes. The system includes a control component configured to receive at least a demagnetization signal, a sensed signal and a reference signal and to generate a control signal based on at least information associated with the demagnetization signal, the sensed signal and the reference signal, and a logic and driving component configured to receive at least the control signal and output a drive signal to a switch based on at least information associated with the control signal. The switch is connected to a first diode terminal of a diode and a first inductor terminal of an inductor. The diode further includes a second diode terminal, and the inductor further includes a second inductor terminal.