2524 results about "Led driver" patented technology

A LED driver circuit is disclosed that has the ability to drive a single series string of power LEDs. The LED driver circuit uses a single stage power converter to convert from a universal AC input to a regulated DC current. This single stage power converter current is controlled by a power factor correction unit. Furthermore, the LED driver circuit contains a galvanic isolation barrier that isolates an input, or primary, section from an output, or secondary, section. The LED driver circuit can also include a dimming function, a red, green, blue output function, and a control signal that indicates the LED current and is sent from the secondary to the primary side of the galvanic barrier.

A light-emitting diode (LED) driver is adapted to control either the magnitude of the current conducted through a LED light source or the magnitude of a voltage generated across the LED light source. The LED driver comprises a power converter circuit for generating a DC bus voltage, and an LED drive circuit for receiving the bus voltage and adjusting the magnitude of the current conducted through the LED light source. The LED driver is operable to dim the LED light source using either a pulse-width modulation technique or a constant current reduction technique. The LED drive circuit may comprise a controllable-impedance circuit, such as a linear regulator. The LED driver may be operable to control the magnitude of the bus voltage to optimize the efficiency and reduce the power dissipation in the LED drive circuit, as well ensuring that the load voltage and current do not have any ripple.

A light emitting diode (LED) lighting system includes a power factor correction (PFC) controller that determines at least one power factor correction control parameter from phase delays of a phase modulated signal. In at least one embodiment, a peak voltage of the phase modulated signal is a PFC control parameter used bit the PFC controller to control power factor correction and generation of a link voltage by a PFC LED driver circuit. The phase delays are related to a peak voltage of the phase modulated signal. Thus, in at least one embodiment, detecting the phase delay in one or more cycles of the phase modulated signal allows the PFC controller to determine the peak voltage of the phase modulated signal.

A LED driver is connectible to several series connected RGB LEDs which connect in series with a current generator. A plurality of LED switches are respectively connectible across one RGB LED. Each LED switch, operating in response to a binary signal is either open to permit electrical current to flow through the RGB LED, or closed to shunt current around that RGB LED. By varying respective duty cycles of the binary signals the LED driver is adapted for controlling operation of the combined RGB LEDs so they emit differing colors of light. An adaptive boost converter LED driver continuously adjusts voltage applied across the series connected RGB LEDs to be only that required for operating those LEDs through which open LED switches permit current to flow.

An AC LED package and circuits are disclosed along with an AC LED driver. The AC LED circuit may include as few as one LED or an array of anti-parallel LEDs driven with AC power sources and AC LED drivers at various voltages and frequencies. The AC LEDs are pre-packaged in various forms and materials and designed for mains or high frequency coupling in various forms to AC power sources, inverter type drivers or packages. The AC LED driver is a fixed frequency driver that provides a relatively constant voltage output to different size loads within the wattage limitation of the driver and in some cases is a direct mains power source.

An adaptive switch mode LED driver provides an intelligent approach to driving multiple strings of LEDs. The LED driver determines an optimal current level for each LED channel from a limited set of allowed currents. The LDO driver then determines a PWM duty cycle for driving the LEDs in each LED channel to provide precise brightness control over the LED channels. Beneficially, the LED driver minimizes the power dissipation in the LDO circuits driving each LED string, while also ensuring that the currents in each LED string are maintained within a limited range. A sample and hold LDO allows PWM control over extreme duty cycles with very fast dynamic response. Furthermore, fault protection circuitry ensures fault-free startup and operation of the LED driver.

A light-emitting diode (LED) driver according to the present invention consists of a voltage pre-regulator and multiple linear current regulators with an adaptively-controlled drive voltage. In this LED driver, the efficiency maximization is achieved by eliminating the sensing of the voltage drops across the linear regulators, i.e., by removing the external voltage feedback for the adjustment of the output voltage of the pre-regulator. In the LED driver of the present invention, the self-adjustment of drive voltage is achieved by relying on a relatively strong dependence between the gate-to-source and drain-to-source voltages of a current-regulating transistor, e.g., a MOSFET, operating in the linear region. The driver powers all LEDs in a string with a constant current and provides consistent illumination and optimum operating efficiency at low cost over a wide range of input / output voltage and temperature.

A current source generates, with high efficiency, a current that is substantially constant over a wide range of output voltages. This current is injected into the first end of a series-connected string (hereinafter referred to as string) of LEDs, with the second end of the string connected through a resistor to ground. The voltage developed across this resistor, which is a measure of current flow in the series string, is fed back to the current source, wherein feedback maintains nearly constant current output over a wide range of output voltages. A switch, such as a field effect transistor (FET) is placed in parallel with each LED in the string. A level shift gate driver couples a pulse width modulated control signal to the gate of each FET. When the FET across a particular LED is on, substantially all the current flows through the FET rather than the LED, and little or no light is emitted. Because the one resistance of the FET is very low, the power dissipated in the FET (current squared times resistance) is also very low. With the FET turned on, the forward voltage drop of the LED it is controlling drops to near zero, since little current is flowing through the LED. However, because the current source is designed to provide constant current over a wide range of output voltages, the current flow through the other LEDs in the series string changes little. When the FET is turned off, substantially all of the current flows through the associated LED, turning it on. By modulating the duty cycle of each FET, the brightness of each associated LED may be varied smoothly over its full range.

Prior applications disclosed power supply transmission voltage resulting in reduced line losses, with further energy conservation via luminous intensity control (dimming) of lamp(s) including LEDs. Additionally, an invertible, convertable luminaire, and upgraded control module design (comparable to a computer mainframe) comprised of function components including, for example, a microcontroller with programmable CPU, multiple LED driver(s), multiple independent lamp control(s), variable ON time segmentation(s) and variable ramp speed(s), voice actuation (s), security system(s), battery charge component(s), voltage drop (current) limiter(s), protection, ammeter(s), volt and watt meter(s); and voids for optional modules including but not limited to: clock timer(s); photocell(s); motion detector(s) of various function(s); push button(s); programming and function display(s); microphone(s); wireless transmitter(s) / receiver(s); fiber optic interconnection(s); remote control(s); integration to personal computer(s) or other central control system(s); speaker(s); camera(s); irrigation control(s); luminaire mountable laser module(s) and beacon(s); battery array(s); transmission voltage double isolation for nominal 15 volt maximum wet contact.

An LED driver for controlling the intensity of an LED light source includes a power converter circuit for generating a DC bus voltage, an LED drive circuit for receiving the bus voltage and controlling a load current through, and thus the intensity of, the LED light source, and a controller operatively coupled to the power converter circuit and the LED drive circuit. The LED drive circuit comprises a controllable-impedance circuit adapted to be coupled in series with the LED light source. The controller adjusts the magnitude of the bus voltage to a target bus voltage and generates a drive signal for controlling the controllable-impedance circuit. To adjust the intensity of the LED light source, the controller controls both the magnitude of the load current and the magnitude of the regulator voltage. The controller controls the magnitude of the regulator voltage by simultaneously maintaining the magnitude of the drive signal constant and adjusting the target bus voltage.

An LED lamp is provided in which the output light intensity of the LEDs in the LED lamp is adjusted based on the input voltage to the LED lamp. The LED lamp comprises one or more LEDs, and an LED driver configured to receive an input voltage and provide regulated current to said one or more LEDs, where the LED driver is configured to adjust the regulated current to said one or more LEDs according to the input voltage to adjust the output light intensity of said one or more LEDs. The LED lamp can be a direct replacement of conventional incandescent lamps in typical wiring configurations found in residential and commercial building lighting applications that use conventional dimmer switches that carry out dimming by changing the input voltage to the LED lamp.

LED lamp has LEDs aimed rearwards with either a concave mirror to the rear of each LED, or one concave mirror to the rear of two or more LEDs, collecting the light from the LEDs to form a forward projecting beam. LEDs may be high power types that require heatsinking. LED lamp may have a lens forward of each LED to collimate the radiation produced by the LEDs into a beam, where at least one lens has at least one aspheric curved surface. LED lamp may have a transparent reflective optic to collimate the radiation produced by each LED into a beam. For an inspection lamp, the LEDs typically have a peak wavelength of 395 to 415 naometers for seeing the area being irradiated but not so visible as to overwhelm fluorescence of fluorescent materials to be detected. Other wavelengths may be used. LED inspection lamp has a combination of LEDs of different wavelengths or a combination of at least one LED and at least one other light source such that the lamp produces radiation suitable for detection of materials to be detected and adequately illuminates the area being irradiated. LED lamp has LEDs that produce a beam of suitable radiation with a width of 10 degrees or less without additional optics. LED inspection lamp has head attached to a flexible member, with head serving as heatsink for one or more high power LEDs. Current regulator circuits are also disclosed.

An LED down light replacement apparatus is disclosed for insertion into a recessed-light housing can, which includes an LED light source, a means for mounting said LED light source within the housing can, an LED driver circuit electrically connected to the LED light source, a heat sink in thermal contact with the LED light source, and means for removing heat generated by the LED light source. The means for removing heat generated by the LED light source can include a fan and / or ventilation holes in the top of the housing can.

An exemplary aircraft anticollision beacon is constructed around a faceted aluminum support cylinder and base. The support cylinder has an outside surface with ten vertically oriented substantially planar faces. An array of LEDs is mounted in thermally conductive relationship on each face of the support cylinder. Each LED is partially surrounded by a trough-shaped reflecting surface that re-directs off axis light into a horizontal plane. Axially aligned, radially adjacent reflecting troughs combine to form the circumferential reflecting troughs. The support cylinder and base are connected in thermally conductive relationship to define a thermal pathway from the LEDs to a heat radiation surface on the base. The base is also configured to act as a heat sink for heat generating components of the LED driver circuits. The exemplary beacon employs a distributed energizing circuit in which each driver is configured to energize two of the ten arrays of LEDs.

LED driver circuits containing voltage reducing devices, voltage regulating devices, and voltage converting devices are disclosed as the main components to provide power to LEDs. The LED driver circuits are designed to work with a ballast, mains alternating current voltage, direct current voltage, and electromagnetic induction power. The voltage regulating devices can be a resistor in series with at least one zener diode or a voltage regulator both in parallel with and providing power to the LEDs. The LEDs can also be anti-parallel diode pairs consisting of one diode and one LED or two LEDs, or the LEDs can be anti-parallel diode string pairs consisting of diodes and LEDs or all LEDs. The LED driver circuits will be incorporated into LED replacement lamps, and in particular to LED lamps to replace fluorescent lamps for use with existing ballasts and other power sources where the ballast may be removed or bypassed.

A LED driver is disclosed. The LED driver includes a high frequency inverter and an impedance circuit. The high frequency inverter operates to produce a high frequency voltage source whereby the impedance circuit directs a flow of alternating current through a LED array including one or more anti-parallel LED pairs, one or more anti-parallel LED strings, and / or one or more anti-parallel LED matrixes. A transistor can be employed to divert the flow of the alternating current from the LED array, or to vary the flow of the alternating current through LED array.

Electronic circuitry for color-mixing in an LED light fixture during AC power dimming is disclosed to achieve adjustable color temperature. According to one embodiment, a dimmable LED light fixture has first, second, and third LED light sources, the first and second LED light sources producing white light, the third LED light source producing colored light, the LED driver configured to power the LED light sources by providing a single-channel variable-DC current source having two output terminals, and a current regulator for maintaining the current in the third LED light source path substantially constant as the LED driver output current is decreased when the AC power is reduced by the dimmer module, thereby altering the color of the light produced by the combination of the LED light sources.

A buck converter LED driver circuit is provided. The driver circuit includes a buck power stage, a rectified AC voltage source, a voltage waveform sampler, and a control circuit. The buck power stage includes at least one LED and provides a first signal directly proportional to the current through the LED. The rectified AC voltage source is coupled to the buck power stage for driving the buck power stage. The voltage waveform sampler is coupled to the rectified AC voltage source for providing a second signal directly proportional to the voltage provided by the rectified AC voltage source. The control circuit is coupled to the voltage waveform sampler and the buck power stage for turning on and turning off the buck power stage according to a comparison between the first signal and the second signal.

An LED floodlight fixture including a housing that forms a substantially water / air-tight chamber, electronic LED driver(s) within the chamber, and an LED assembly secured with respect to the housing adjacent thereto in non-water / air-tight condition, the LED assembly having at least one LED-array module mounted on an LED heat sink. In certain preferred embodiments the housing is a perimetrical structure such that the substantially water-tight chamber substantially surrounds the LED assembly.

A programmable LED constant current driver circuit for driving LEDs at constant current and dimming the LEDs using standard, off-the-shelf dimmers is provided. The current driver circuit of the present disclosure includes a temperature compensation feature which controls the on time for the LEDs based on a measured temperature of the current driver and associated circuits. In another embodiment, the current driver circuit is designed to receive a 24 VAC input and drive one or more LEDs in a transformer-based system dimming system.

Systems and methods are described that provide an efficient and cost-effective LED driver for controlling strings of LEDs. Embodiments described include an LED driver that comprises an adaptive boost converter and current source that cooperate to provide a desired light output from energized LEDs. Systems and methods are also described that modulate the excitation of the LEDs using a pulsed signal to obtain brightness control. Techniques are described for controlling the operation of individual LEDs in a string of LEDs such that a desired level of light output can be achieved. Embodiments are described in which multicolored LEDs can be included in strings of LEDs and excitation of the individual LEDs can be controlled to obtained a desired color of output.

The disclosure is directed at a configurable light emitting diode (LED) driver / dimmer for controlling a set of light fixture loads comprising: a power circuit; a primary digital controller for controlling the power circuit; a set of output current drivers, each of the set of output current drivers connected to one of the set of light fixture loads for controlling the associated light fixture load; a secondary digital controller for controlling the set of output current drivers; wherein the secondary controller transmits LED control information to control outputs of the set of output current drivers; and wherein the secondary digital controller provides digital feedback control information to the primary digital controller.

A luminaire includes an Edison type electrical base, an optic, and a heat sink disposed between the base and the optic. An LED driver circuit is disposed at least partially within the heat sink, and is disposed in electrical communication with the base. An LED assembly is disposed in thermal communication with a surface of the heat sink, and in electrical communication with the driver circuit, the LED assembly includes an LED. The driver circuit includes circuitry that converts an AC signal at the base to a DC signal and provides the DC signal to the LED assembly, the circuitry includes holding current circuitry that produces a holding current for an electrical dimmer disposed upstream of the base in response to a current to the LED assembly being reduced for light dimming purposes.

A configurable light-emitting diode (LED) driver is adapted to control a plurality of different LED light sources, which may be rated to operate using different load control techniques, different dimming techniques, and different magnitudes of load current and voltage. The LED driver comprises a power converter circuit for generating a DC bus voltage, and an LED drive circuit for receiving the bus voltage and adjusting either the magnitude of the current conducted through the LED light source or the magnitude of the voltage across the LED light source. The LED driver is operable to dim the LED light source using either a pulse-width modulation technique or a constant current reduction technique, and may be configured using a programming device and a personal computer.