Abstract: A display device including: a display panel including first through N-th pixel rows; and a panel driver configured to sequentially receive first through N-th line data for the first through the N-th pixel rows in each frame period, and to drive the display panel based on the first through the N-th line data, the panel driver including: a current control circuit configured to determine a current control value for a (K+1)-th pixel row based on the first through K-th line data for the first through K-th pixel rows received in a current frame period and (K+1)-th through the N-th line data for the (K+1)-th through the N-th pixel rows received in a previous frame period; and a data correction circuit configured to correct the (K+1)-th line data for the (K+1)-th pixel row based on the current control value in the current frame period.

Abstract: A controllable lighting device may comprise a drive circuit characterized by one or more cycles and a control circuit configured to control the drive circuit to conduct a load current through a light source of the lighting device. The control circuit may be configured to determine one or more operating parameters of the lighting device during a present cycle of the drive circuit based on a feedback signal indicative of a peak magnitude of the load current conducted through the light source. The control circuit may be able to adjust an average magnitude of the load current conducted through the light source so as to adjust an intensity of the light source towards a target intensity based on the operating parameters.

Abstract: Self-identifying solid-state transducer (SST) modules and associated systems and methods are disclosed herein. In several embodiments, for example, an SST system can include a driver and at least one SST module electrically coupled to the driver. Each SST module can include an SST and a sense resistor. The sense resistors of each SST module can have at least substantially similar resistance values. The SSTs of the SST modules can be coupled in parallel across an SST channel to the driver, and the sense resistors of the SST modules can be coupled in parallel across a sense channel to the driver. The driver can be configured to measure a sense resistance across the sense resistors and deliver a current across the SSTs based on the sense resistance.

Abstract: A system and method for determining the current of a pixel circuit and an organic light emitting diode (OLED). The pixel circuit is connected to a source driver by a data line. The voltage (or current) supplied to the pixel circuit by the source driver. The current of the pixel and the OLED can be measured by a readout circuit. A value of a voltage from the measured current can be extracted and provided to a processor for further processing.

Abstract: A control circuit for a constant-current drive circuit, as well as a constant-current drive circuit are disclosed. The control circuit can obtain output information of the constant-current drive circuit and use it in combination with reference information to determine, according to an output condition corresponding to the current load of the constant-current drive circuit, a time point for the system to enter or exit a rapid drive mode. Therefore, it can be suitably used in various application scenarios to determine a time point for the system to entry into or exit from the rapid start mode. Compared with fast charging for a fixed period of time as used in the prior art, embodiments of the present invention can effectively overcome the problem of easy overshooting or inadequate acceleration during start as found in various applications.

Abstract: Embodiments of the present disclosure provide a driving circuit and a lamp comprising the same. The driving circuit comprises inputs connected to a mains supply; outputs connected to an LED load; an output capacitor connected in parallel with the LED load; an LED driving current source connected to the outputs, and configured to convert the mains supply at the inputs to current at the outputs in an illumination mode, such that the current flows through the LED load and charges the output capacitor; and a control circuit configured to receive a standby signal to enable a standby mode, and to control the mains supply to linearly charge the output capacitor in the standby mode, such that an output voltage at the output can be lower than a turn-on voltage of the LED load and is higher than a preset lowest voltage.

Abstract: An electronic substrate and a driving method thereof, and a display device. The electronic substrate includes a pixel drive chip which includes at least one signal terminal, a signal generation circuit, a data storage circuit, and an output circuit; at least one signal terminal is configured to be electrically connected to the light-emitting element; the signal generation circuit is connected to at least one signal terminal and configured to receive an input signal through the at least one signal terminal and generate a clock signal according to the input signal; the data storage circuit is configured to receive the clock signal and store the input signal according to the clock signal; and the output circuit is configured to output a current, which is generated according to the stored input signal and used for driving the light-emitting element, though at least one signal terminal.

Abstract: A lighting device driving circuit with high operating efficiency is provided, which includes a rectifying module, a constant-voltage module, an input signal collecting module, a constant-voltage signal collecting module and a constant-voltage control module. The rectifying module receives a power signal from a power source input terminal to generate a rectified voltage signal. The constant-voltage module receives the rectified voltage signal to generate a constant-voltage signal. The input signal collecting module receives the power signal or the rectified voltage signal to generate a first feedback signal. The constant-voltage signal collecting module receives the first feedback signal and the constant-voltage signal to generate a second feedback signal. The constant-voltage control module generates a control signal according to the second feedback signal so as to control the constant-voltage module to adjust the constant-voltage signal and drive a load.

Abstract: The invention provides an LED drive power supply and a controller thereof. The controller comprises a ground terminal, a sampling terminal, and a power supply terminal. The ground terminal and an output ground of a power supply module have different potentials. A drain of a power switching transistor is coupled to a positive output terminal of the power supply module, a source of the power switching transistor and the sampling terminal are coupled to a first terminal of a sampling resistor, and a second terminal of the sampling resistor is coupled to the ground terminal. The controller further includes a logic control circuit determining whether a sampling voltage input by the sampling terminal is zero; a driver generating a first driving signal to the power switching transistor; and a bias circuit configured to receive a power supply voltage.

Abstract: A semiconductor device that reduces variations in the characteristics of driving transistors and corrects image data is provided. The semiconductor device includes an image data retention portion, a correction data retention portion, a driver circuit portion, a display element, and a threshold voltage correction circuit portion. The image data retention portion has a function of retaining first image data, and the correction data retention portion has a function of retaining correction data, and a function of generating second image data corresponding to the first image data and the correction data when the first image data is retained in the image data retention portion. The driver circuit portion has a function of generating a current corresponding to the second image data and feeding the current to the display element, and the threshold voltage correction circuit portion has a function of correcting a threshold voltage of a driving transistor in the driver circuit portion.

Abstract: Disclosed is a power converter circuit and a method for operating the power converter circuit. The power converter circuit includes at least one converter stage and a control circuit. The at least one converter stage includes an input configured to receive an input power, an output configured to supply an output power, a first electronic switch, and a first inductor coupled to the first electronic switch. The control circuit includes a hysteresis controller configured to drive the first electronic switch based on a current measurement signal representing a current through the inductor, a first threshold signal, and a second threshold signal, and an operating point controller configured to detect an operating point of the converter stage to generate the first threshold signal and the second threshold signal based on the detected operating point.

Abstract: Disclosed is a phase-cut dimmer, comprising an AC switch coupled in series between an AC supply and a load; a DC power supply powered from a voltage across the switch; a zero-crossing detector of a phase-cut AC voltage across the switch; a timer generating a timing signal of a duty-cycle proportional to a variable fraction of a peak voltage of a sawtooth signal, wherein the sawtooth signal is synchronized to the zero-crossing detector; a blanking signal generator triggered by a duty-cycle detector to reduce the duty-cycle when the duty-cycle of the timing signal exceeds a predetermined maximum limit; and an operation mode selector activated by an output of an inductive load detector.

Abstract: A GFCI includes a current sensor system providing a current sensor signal indicating a leakage current of the AC power system. A magnitude detector is configured to provide a first channel signal indicating an RMS value of the current sensor signal. A reference signal generator is configured to provide a second channel signal indicating a trip reference value responsive to a frequency of the current sensor signal. A fault detector is configured to provide a fault trip signal indicating ground fault condition of the AC power system in response to the first channel signal and the second channel signal. A circuit breaker mechanism is configured to open a circuit of the AC power system in response to the fault trip signal.

Abstract: A lamp driver circuit for driving a lamp is provided. The lamp driver circuit includes: an under voltage protection circuit; a control circuit coupled to the under voltage protection circuit; and a driver transistor coupled to the control circuit for driving the lamp under the control of the control circuit. The under voltage protection circuit detects an operation voltage. When the operation voltage is lower than a threshold, the under voltage protection circuit outputs an enable signal. The control circuit receives the enable signal to shut down the control circuit and shut down the driver transistor.

Abstract: The present disclosure relates to PWM dimming circuit with low stand-by power. A lighting apparatus driver is provided, comprising: a power supplier to supply power to a lighting load; and a discrete PWM dimming circuit, the PWM dimming circuit is to receive PWM signal, and to control the switching of the power supplier based on the PWM signal, wherein the power supplier is capable of being turned off by the PWM dimming circuit.

Abstract: A LED driving circuit includes a DALI module, a linear voltage luminance adjusting module, a DIP luminance adjusting module, a control module, a power source, a constant current driving module and an output module. The DALI module generates a PWM signal. The linear voltage luminance adjusting module generates a second PWM signal. The DIP luminance adjusting module generates a switch signal. The control module generates a drive PWM signal using the first PWM signal, the second PWM signal and the switch signal. The power source provides power. The constant current driving module generates a constant-current drive voltage using the provided power and the drive PWM signal. The output module generates a drive current that responds to the constant-current drive voltage. And the output module drives an external LED device using the drive current.

Abstract: A voltage regulation system, a driving circuit, a display device and a voltage regulation method are disclosed. The voltage regulation system, applicable to an electronic device, including a power supply circuit, a determination circuit and a regulation circuit. The power supply circuit is connected with the regulation circuit, and the power supply circuit is configured to provide a reference voltage and provide a first voltage inputted into the electronic device; the determination circuit is connected with the power supply circuit, and the determination circuit is configured to, according to the reference voltage and the first voltage, output a compensation voltage; and the regulation circuit is connected with the determination circuit so as to receive the compensation voltage, and the regulation circuit is configured to output a third voltage, according to the compensation voltage and a second voltage, in a case where the compensation voltage is not within a preset range.

Abstract: A light-emitting diode (LED) luminaire comprising an emergency-operated portion is used to replace a luminaire operated only with alternate-current (AC) mains. The emergency-operated portion comprises a rechargeable battery with a terminal voltage, a self-diagnostic circuit, and a transceiver circuit. The LED luminaire can auto-switch from the AC mains to an emergency power or the other way around according to availability of the AC mains and whether a rechargeable battery test is initiated. The self-diagnostic circuit comprises a clock and is configured to initiate self-diagnostic tests and to auto-evaluate battery performance according to test schedules with the terminal voltage examined and test results stored. The LED luminaire further comprises a remote controller configured to initiate remote control signals with phase-shift keying (PSK) signals transmitted.

Abstract: A load control device may be configured to control an electrical load, such as a lighting load. The load control device may include a first terminal adapted to be coupled to an alternating-current (AC) power source, and a second terminal adapted to be coupled to the electrical load. The load control device may include a bidirectional semiconductor switch, a filter circuit, and a control circuit. The bidirectional semiconductor switch may be coupled in series between the first terminal and the second terminal, and be configured to provide a phase-control voltage to the electrical load. The filter circuit may be coupled between the first terminal and the second terminal. The control circuit may be configured to render the bidirectional semiconductor switch conductive and non-conductive to control an amount of power delivered to the electrical load, and be configured to adjust the impedance and/or filtering characteristics of the filter circuit.

Abstract: A stabilizing system includes an AC power supply, a TRIAC dimmer circuit, a load conversion circuit and a current controller. The TRIAC dimmer circuit dynamically generates a drive power. The load conversion circuit filters noises off the drive power and drives an external LED unit using the filtered drive power. The current controller detects an activating phase of the AC power supply's AC voltage from the drive power. The current controller keeps a sum of a buffer current of the current controller and a load current of the load conversion circuit to approximate a predetermined critical current value and to exceed an operating current of the TRIAC dimmer circuit in response to the detected activating phase of the AC voltage.

Abstract: System and method for voltage conversion to drive one or more light emitting diodes with at least a TRIAC dimmer. For example, the system includes: a phase detector configured to receive a first rectified voltage generated based at least in part on an AC input voltage processed by at least the TRIAC dimmer, the phase detector being further configured to generate a digital signal representing phase information associated with the first rectified voltage; a voltage generator configured to receive the digital signal and generate a DC voltage based at least in part on the digital signal; and a driver configured to receive the DC voltage and affect, based at least in part on the DC voltage, a current flowing through the one or more light emitting diodes; wherein the current changes with the phase information according to a predetermined function.

Abstract: A circuit arrangement for the electrical wiring of a light unit of a headlight for a vehicle, having a control unit which is connected to a power supply, the light unit having at least one semiconductor light source and a temperature measurer, wherein the semiconductor light source has a cathode and wherein the temperature measurer has a cathode, and wherein the light unit has an equipotential bonding contact. In the light unit, the cathodes are electrically connected to one another and/or at least one of the cathodes is electrically connected to the equipotential bonding contact in the light unit.

Abstract: A pixel-driving circuit includes: a write-compensation sub-circuit coupled to a signal scanning terminal, a data terminal and a driving sub-circuit, and configured to, controlled with voltage from the signal scanning terminal, provide voltages of the data terminal to the driving sub-circuit for compensation; the light-emission control sub-circuit is coupled with the light-emission terminal, the first power source terminal and the driving sub-circuit and configured to provide voltages of the first power source terminal to the first terminal of the driving transistor controlled with voltage from the light-emission control terminal; the reset sub-circuit is coupled with the reset signal terminal, the initial voltage terminal, and the driving sub-circuit and to provide voltages of the initial voltage terminal to the gate of the driving transistor controlled with voltage from the reset signal terminal, causing the driving transistor to be in ON and OFF states respectively during the first and second initialization

Abstract: System and method for controlling one or more light emitting diodes. For example, the system for controlling one or more light emitting diodes includes a current generator configured to generate a first current flowing through one or more light emitting diodes. The one or more light emitting diodes are configured to receive a rectified voltage generated by a rectifying bridge coupled to a TRIAC dimmer. Additionally, the system includes a bleeder configured to receive the rectified voltage, and a controller configured to receive a sensing voltage from the current generator and output a control signal to the bleeder. The sensing voltage indicates a magnitude of the first current.

Abstract: A split-type in-wall smart switch module comprises a switching signal generation unit, a mechanical switch, a switching signal receiving and processing unit, a wireless module unit, a switching unit and a load, wherein the switching signal generation unit is connected to a live wire in mains electricity, the mechanical switch and the switching signal receiving and processing unit, respectively; the switching signal receiving and processing unit is also connected to the wireless module unit and a neutral wire in mains electricity respectively; the other end of the wireless module unit is connected to the switching unit; the other end of the switching unit is connected to the load; and the other end of the load is connected to the neutral wire in mains electricity. The switch can realize the control of turning-on and turning-off by means of a switch panel.

Abstract: A light-emitting element driving device includes: a first amplifier configured, with respect to each of a plurality of light-emitting element strings, to control a first transistor connected in series with the light-emitting element string based on the current passing through the light-emitting element string; and a second amplifier configured, with respect to each of at least part of the plurality of light-emitting element strings, a second transistor, which is included in a series circuit composed of the second transistor and a first resistor and connected in parallel with the first transistor, based on the current passing through the light-emitting element string and the current passing through the second transistor.

Abstract: A display compensation circuit includes a driver circuit including a digital-to-analog converter (DAC), the driver circuit configured to drive pixels of a display panel; and a compensation circuit including a current-mode sensing circuit and a reference current generator circuit, the compensation circuit configured to determine a value to compensate for pixel variations across the display panel, the reference current generator circuit configured to generate a reference current using the DAC of the driver circuit.

Abstract: Examples to control timing for current-mode boost converters are disclosed. An example device to control timing includes a first input terminal to receive an input voltage of a current-mode boost converter a second input terminal to receive an output voltage of the current-mode boost converter, a generator to generate a first timing signal from the input voltage and the output voltage, a third input terminal to receive a second timing signal from the current-mode boost converter, a selector to select between the first on_off time signal and the second on_off time signal to generate a third on_off time signal based on a comparison of a first off time duration of the first on_off time signal and a second off time duration of the second on_off time signal, and an output terminal to control off times of the current-mode boost converter based on the third on_off time signal.

Abstract: Techniques for smart light and lighting drywall are provided. A system and/or method can comprise a smart light comprising at least one light bulb; and a lighting drywall comprising: a power source; a mesh configured to provide power from the power source using a wireless power transfer mechanism; wherein the smart light is removably attachable to a plurality of locations on the lighting drywall and configured to receive the power using the wireless power transfer mechanism at respective locations of the plurality of locations.

Abstract: Systems, methods, and computer program products for commissioning and controlling a lighting system, and tracking mobile devices. The lighting system comprises a plurality of system nodes including smart nodes and light fixtures. The smart nodes communicate with the mobile devices and the light fixtures to facilitate configuration and adjustment of the lighting system. The smart nodes may also receive signals from legacy control devices, and map the received control signals to control signals that are compatible with the light fixtures. The smart nodes may transmit beacon signals having unique identifiers that are received by the mobile devices. The mobile devices may in turn communicate received signal strengths for the beacon signals back to the smart nodes. The smart nodes may store this tracking data in a database to determine where and how long the mobile devices are in a location and to provide location-based services.

Abstract: The subject disclosure relates to power failure simulations, for example to test lighting systems, such as emergency lighting units or lighted signage. In some aspects, a method of the disclosed technology includes steps for receiving an interrupt command, terminating power delivery from a first power supply to a lighting array in response to the interrupt command, and measuring one or more power characteristics of the second power supply. Methods and machine-readable media are also provided.

Abstract: An audio/video power processor for an audio/video playback device, and an audio/video playback system. The audio/video power processor for an audio/video playback device includes: a box having a grounded metal shell; an electric power input port for receiving AC electric power, the electric power input port comprising a first live line terminal and a first null line terminal; an electric power output port for outputting electric power to the audio/video playback device, the electric power output port comprising a second live line terminal and a second null line terminal; a first capacitor unit electrically connected between the first live line terminal and the first null line terminal; a first inductor electrically connected between the first live line terminal and the second live line terminal; and a second inductor electrically connected between the first null line terminal and the second null line terminal.

Abstract: System controller and method for a lighting system according to certain embodiments. For example, the system controller includes a first controller terminal configured to receive a first signal, and a second controller terminal coupled to a first transistor terminal of a transistor. The transistor further includes a second transistor terminal and a third transistor terminal. The second transistor terminal is coupled to a first winding terminal of a winding, and the winding further includes a second winding terminal coupled to a capacitor. Additionally, the system controller includes a third controller terminal coupled to the third transistor terminal of the transistor, and a fourth controller terminal coupled to a resistor and configured to receive a second signal. The second signal represents a magnitude of a current flowing through at least the winding, the third controller terminal, the fourth controller terminal, and the resistor.

Abstract: A system includes multiple devices configured to emit and detect germicidal radiation. Each of the multiple devices operates in emitting mode when connected to a drive source in a forward bias configuration and operates in detecting mode when disconnected from the drive source or when connected to the drive source in a reverse bias configuration. Cycling circuitry generates a sequence of control signals that control switching circuitry to change the connections of the devices to the drive source in a cycle in which one or more of the multiple devices are switched to detecting mode and senses radiation emitted by one or more of the multiple devices simultaneously operating in emitting mode. Each device operating in detecting mode generates a signal in response to the sensed radiation. Detection circuitry detects signals of the devices operating in detecting mode and generates a detection output in response to the detected signals.

Abstract: A device and method are provided for saving power and electricity in a charging device including external power supplies and battery chargers having a primary circuit and a secondary circuit where a switch is located in the primary circuit and a current sensing device in the secondary circuit to sense when there is a drop in current in the secondary circuit or no current in the secondary circuit because the load such as a cell phone or tablet is charged and when this occurs the switch in the primary circuit is opened and the primary circuit no longer draws power from the source of power until the switch in the primary circuit is closed by either a user activating a switch to reenergize the charging device, where the switch may be powered by an on-board battery to close the primary circuit, or where a control circuit is activated by a program in the load or device to be charged, such that the charging device will cycle on and off according to an external app program residing on the device to be charged or some

Abstract: An emergency converter according to the invention is used in lighting applications for operation from an energy storage device in case of mains failure. The converter device comprises a charger circuit configured to charge the energy storage device and a microcontroller circuit configured to control the charger circuit. The driver circuit is preferably implemented in a coupled inductor boost circuit topology. The microcontroller circuit is further configured to control the switch based on a zero crossing of a measured inductor current.

Abstract: A single-stage driver for an LED device, configured to be coupled between a power supply and the LED device, comprises: a rectifier, a DC-to-DC converter, a resistor and a controller. The rectifier is configured to be coupled to the power supply and convert an alternating voltage from the power supply into a first direct voltage. The DC-to-DC converter, which comprises at least two switches, is coupled between the rectifier and the LED device and configured to receive the first direct voltage and provide a constant current to the LED device. The resistor is configured to be coupled in series with the LED device. The controller is coupled between the resistor and the at least two switches, and configured to keep the current through the LED device stable around a predetermined current value by controlling the switches based on a voltage across the resistor, wherein all the at least two switches are turned on or off synchronously.

Abstract: Systems for emergency exit LED lighting are described herein. The emergency exit lighting systems comprise structures for housing at least one LED light, an LED driver electronically coupled to the LED light(s), a continuous power source, a backup power source, and a test switch. The fixtures, in various configurations, may be mounted to an existing T-grid or to a wall or ceiling. The fixture may be tested remotely.

Abstract: A load control device coupled between an AC power source and an electrical load may operate in a three-wire mode or a two-wire mode based on whether the load control device is connected to a neutral side of the AC power source. The load control device may further comprise first and second zero-cross detect circuits to be respectively used in the two-wire mode or the three-wire mode, and a neutral wire detect circuit configured to generate a neutral wire detect signal indicating whether the load control device is connected to the neutral side of the AC power source. A control circuit of the load control device may determine whether the load control device should operate in the two-wire mode or in the three-wire mode in response to the neutral wire detect signal.

Abstract: A resonant power converter as disclosed herein, e.g., an LED driver, comprises first and second switches in a half-bridge arrangement and responsive at an operating frequency to controlled drive signals. A resonant circuit is coupled between the switch output and an isolation transformer. A negative feedback control loop provides an error signal for regulation of the output current. A reference control circuit is added to the feedback control loop, and configured to sense when the error signal exceeds a threshold value, and further configured in response to control a feedback reference signal wherein the error signal is reset to a value below the threshold value. By resetting the feedback control reference value, loop runaway may be prevented, e.g., for enough time that the LED load may warm up or otherwise stabilize. As a result the LED driver will always maintain negative current closed loop control, and restore normal operating mode.

Abstract: A circuit adapted to detect applied voltage and/or voltage based conditions. The circuit comprises a zero-cross detection circuit and a controller. The zero-cross detection circuit is adapted to output a zero-cross signal comprising zero-cross events based on an applied alternating current power signal. The controller is adapted to store a relationship between a pulse width delta, frequency, and voltage. The controller is adapted to sense the zero-cross signal from the zero-cross detection circuit to determine its frequency and pulse width delta by calculating a difference between a high-time and a low-time of the zero-cross signal, and determine the applied voltage based on the stored relationship. The controller can adjust at least one setting of the circuit based on the determined applied voltage, such as the timing of a dimming circuit. In another embodiment, the controller may directly detect voltage based conditions, such as zero-cross delays a dimmer circuit.

Abstract: Methods, devices, and systems for a current converter circuit for airfield ground lighting are described herein. In some examples, one or more embodiments include a bi-directional switch, an inductor to store energy in response to the bi-directional switch being on, and an output capacitor to discharge power to an LED, where the bi-directional switch can switch off to cause the inductor to discharge to the output capacitor in response to a voltage across the output capacitor being less than a threshold voltage.

Abstract: Methods, systems, and devices for inactivating microorganisms are disclosed. An example method comprises emitting, with a first light source, a first light comprising a first correlated color temperature (CCT), emitting, with a second light source, a second light comprising a second CCT and, varying respective power levels of the first light source and the second light source such that the first light and the second light combine to form white light comprising an intensity associated with light in a 380-420 nanometer (nm) wavelength range sufficient to initiate inactivation of microorganisms on the surface and a third CCT between the first CCT and the second CCT.

Abstract: A light emitting diode system allows for high current end user LED matrix applications while mitigating internal damage to control circuitry that may be caused by excess current flow. In one example, multiple switches operate in parallel across an LED. When an overvoltage condition is detected in a first switch, a logic circuit determines those switches programmed to operate in parallel and causes them to conduct current. This reduces the amount of current flowing through any one switch and mitigates harm to the device. The parallel configuration of switches may be driven by a single pulse width modulated current. This allows the drive current to be divided between parallel transistors, limiting the damaging effects that can be caused by high currents flowing through the transistors.

Abstract: An LED drive circuit with a SCR dimmer, a circuit module and a control method therefor are provided. In each cycle of the alternating current, the bleeding current during a time period for turning on the SCR dimmer is distinguished from the bleeding current in a time period from an instant at which the SCR dimmer is turned on to an instant at which the LED load is lit. The bleeder circuit is controlled to perform bleeding at the first current during the time period for turning on the SCR dimmer, and then perform bleeding at the second current which is less than the first current from the instant at which the SCR dimmer is turned on, so that an average bleeding current of the bleeder circuit in each cycle can be reduced, the bleed loss can be reduced, and the efficiency of the LED drive circuit can be improved.

Abstract: An active preload circuit includes: a rectifier configured to receive an AC input from a TRIAC dimmer and to generate DC power; a preload; and a phase angle controller configured to selectively couple the preload to the DC power.

Abstract: Methods of operating a dimmer switch interface are described. A method includes receiving a dimmer input voltage, providing a dimmer output signal based on the dimmer input voltage, and detecting a voltage level of the dimmer output signal. The voltage level of the dimmer output signal is compared with the threshold. A transformer is intermittently turned off when the voltage level of the dimmer output signal is below the threshold.

Abstract: System and method for controlling one or more light emitting diodes. For example, the system for controlling one or more light emitting diodes includes a current regulation circuit coupled to a cathode of one or more light emitting diodes. The one or more light emitting diodes include the cathode and an anode configured to receive a rectified voltage. Additionally, the system includes a control circuit coupled to the cathode of the one or more light emitting diodes. The control circuit is configured to receive a first voltage from the cathode of the one or more light emitting diodes, compare a second voltage and a threshold voltage, and generate a control signal based at least in part on the second voltage and the threshold voltage. The second voltage indicates a magnitude of the first voltage.

Abstract: A vehicle lamp includes: a first light source; a second light source; a first input terminal that receives a first turn-on instruction signal of the first light source; a second input terminal that receives a pulsed second turn-on instruction signal of the second light source; and a turn-on circuit that drives the first light source and the second light source based on the first turn-on instruction signal and the second turn-on instruction signal. The turn-on circuit includes: a drive circuit that becomes active based on the first turn-on instruction signal and the second turn-on instruction signal, and outputs a constant drive current from an output terminal; and a distribution circuit that forms a current path such that the drive current flows to the second light source, and forms a current path such that the drive current flows to the first light source.

Abstract: Provided is a smart matching step-down circuit, comprising an alternating current input terminal (10), a rectifier filter circuit (20), a switching circuit (30), a high voltage BUCK control step-down circuit (40), a floating zero potential control circuit (41), a voltage detection and feedback circuit (50), a PWM controller (52), a full-bridge DC/AC converter circuit (60), an alternating current output terminal (70), an output voltage detection circuit (62), and a conversion controller (80); the high voltage BUCK control step-down circuit comprises a step-down inductor (L1) and a step-down capacitor (C18); the first end of the step-down inductor is connected to the output terminal of the switching circuit; the second end of the step-down inductor is connected to the positive electrode of the step-down filter capacitor, and is used for stepping down and filtering the pulse voltage, then outputting a second current; the floating zero potential control circuit comprises a flyback diode (D11, D12); the cathode of