Impedance Or Current Regulator In The Supply Circuit Patents (Class 315/224)
  • Patent number: 8941314
    Abstract: In a light emitting device, luminance irregularities caused by fluctuation in threshold of TFTs for supplying a current to EL elements among pixels hinder the light emitting device from improving the image quality. A voltage equal to the threshold of a TFT 110 is held in capacitor means 111 in advance. When a video signal is inputted from a source signal line, the voltage held in the capacitor means is added to the signal, which is then applied to a gate electrode of the TFT 110. Even when threshold is fluctuated among pixels, each threshold is held in the capacitor means 111 of each pixel, and therefore, influence of the threshold fluctuation can be removed. Since the threshold is stored in the capacitor means 111 alone and the voltage between two electrodes is not changed while a video signal is written, fluctuation in capacitance value has no influence.
    Type: Grant
    Filed: November 1, 2012
    Date of Patent: January 27, 2015
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventor: Hajime Kimura
  • Patent number: 8941325
    Abstract: The present invention discloses a current splitter circuit for splitting a supply current to multiple light emitting device strings of a light emitting device array. The current splitter circuit includes: a minimum selector circuit coupled to the multiple light emitting device strings to generate a minimum signal which indicates a minimum voltage of the light emitting device strings; and multiple current source circuits each including a first current source end coupled to a corresponding light emitting device string, a second current source end coupled to ground, and a current source control end receiving a current control signal related to the minimum signal, so as to control currents through the corresponding light emitting device string.
    Type: Grant
    Filed: September 6, 2011
    Date of Patent: January 27, 2015
    Assignee: Richtek Technologies Corporation, R.O.C.
    Inventors: Jing-Meng Liu, Chiawei Liao
  • Patent number: 8937439
    Abstract: In various embodiments, a control system for an electronic circuit iteratively applies voltage to and senses current from a load to regulate operation of the load.
    Type: Grant
    Filed: May 7, 2014
    Date of Patent: January 20, 2015
    Assignee: Cooledge Lighting Inc.
    Inventors: Michael A. Tischler, William P. Coetzee, Paul Jungwirth
  • Patent number: 8937437
    Abstract: A ballast comprises an inverter circuit for providing an oscillating current signal for energizing the at least one lamp. The inverter circuit comprises a first switching component and a second switching component each having a collector terminal, a base terminal, and an emitter terminal. And, each switching component is configured for alternately operating between a conductive state and a non-conductive state. A first collector-emitter circuit is connected between the collector terminal and the emitter terminal of the first switching component, wherein the first collector-emitter circuit has a first resistance of zero or more Ohms. A second collector-emitter circuit is connected between the collector terminal and the emitter terminal of the second switching component, wherein the second collector-emitter circuit has a second resistance of zero or more Ohms and the first resistance and the second resistance are unequal.
    Type: Grant
    Filed: June 13, 2013
    Date of Patent: January 20, 2015
    Assignee: Osram Syvlania Inc.
    Inventors: Nitin Kumar, Shashank Bakre
  • Patent number: 8937436
    Abstract: To prevent biased consumption of electrodes in a discharge lamp and to prevent biased precipitation of the electrode material, a light source is provided. The light source device has a discharge lamp that emits light by discharge between a first electrode and a second electrode; and a driver that supplies alternating current to the first and the second electrodes so as to maintain the discharge, and changes duty ratio of the alternating current in accordance with predetermined pattern. The predetermined pattern includes a plurality of section periods for which the duty ratio maintains mutually different values for a predetermined period.
    Type: Grant
    Filed: May 11, 2012
    Date of Patent: January 20, 2015
    Assignee: Seiko Epson Corporation
    Inventors: Kentaro Yamauchi, Tetsuo Terashima, Takeshi Takezawa, Kazuo Okawa, Shigeyasu Soma
  • Patent number: 8937435
    Abstract: Aspects of the disclosure provide a circuit that includes a first circuit, a second circuit and a bridge circuit. The first circuit is coupled to a magnetic component to receive electric energy transferred via the magnetic component and thus configured to store the electric energy and generate a supply voltage. The second circuit is also coupled to the magnetic component. The second circuit is switchable and is configured to deplete a portion of the electric energy when the second circuit is switched on. The bridge circuit is coupled between the first circuit and the second circuit to provide a charge flow path when the second circuit is switched off.
    Type: Grant
    Filed: August 27, 2013
    Date of Patent: January 20, 2015
    Assignee: Marvell International Ltd.
    Inventors: Sehat Sutardja, Wanfeng Zhang
  • Publication number: 20150015160
    Abstract: A converter, for feeding a load via an inductor with a current having a controlled intensity between a maximum and a minimum level, includes a switch to permit or prevent, respectively, current towards said inductor, a first current sensor sensitive to the current flowing through switch when the switch is on, a second current sensor sensitive to the current flowing through said inductor when the switch is off, drive circuitry to turn the switch off and on upon receiving a first and a second logic signal, respectively, and comparison circuitry coupled to the first and the second current sensors to generate first and the second logic signals when, respectively: the current intensity detected by the first current sensor is offset a given amount with respect to the maximum level, and the current intensity detected by the second current sensor is offset a given amount with respect to the minimum level.
    Type: Application
    Filed: December 17, 2012
    Publication date: January 15, 2015
    Inventors: Francesco Angelin, Paolo De Anna
  • Publication number: 20150015159
    Abstract: An LED driver having one end coupled with an LED module and another end coupled to a ground, being capable of generating a duty current and a duty in response to a dropout voltage across the LED driver in a way that, the duty current will increase and the duty will decrease when the dropout voltage exceeds a first threshold, and the duty current will decrease and the duty will increase when the dropout voltage falls below a second threshold.
    Type: Application
    Filed: July 15, 2013
    Publication date: January 15, 2015
    Inventors: Shih Yu WANG, Hui Teng TSAI, Mao Feng LAN, Tien Pao LEE
  • Publication number: 20150015161
    Abstract: A medical light-source device for securing a long illumination time required for operations in the medical field, has an LED illumination section including an LED element; a holder to put the LED illumination section on a head of the operator; a battery power supply section that supplies power to the LED illumination section; a charger having an AC adaptor capable of being connected to a commercial power supply for charging the battery power supply section; and a battery holding belt to put the battery power supply section and the charger on the body of the operator. The battery holding belt has a switch section to switch on/off the LED illumination section and to adjust intensity of illumination of the LED element; and a control section to control a constant current, which is associated with the intensity of illumination, supplied to the LED illumination section.
    Type: Application
    Filed: September 30, 2014
    Publication date: January 15, 2015
    Applicants: ACP JAPAN CO., LTD.
    Inventor: Shoichi NAKAMURA
  • Patent number: 8933639
    Abstract: In various embodiments, a device for dimming a light source is provided. The device may include a two-wire power supply line having interposed therein a switch for controlling transfer of the power supply towards the light source; a capacitance located downstream of the switch being traversed by a charge current as the switch is switched on; and a pre-charge stage interposed between the switch and the capacitance; the pre-charge stage being configured to limit to a given value the charge current.
    Type: Grant
    Filed: February 25, 2010
    Date of Patent: January 13, 2015
    Assignee: OSRAM Gesellschaft mit beschraenkter Haftung
    Inventors: Francesco Bianco, Alessandro Bizzotto, Paolo De Anna, Alessandro Scordino, Nicola Zanforlin
  • Patent number: 8933640
    Abstract: A current driver circuit for regulating a light emitting diode (LED) is disclosed. An example driver circuit uses one input node of the driver circuit for controlling both maximum brightness and dimming of an LED coupled to an output node of the driver circuit. The driver circuit supplies a reference voltage (VREF) to its input node. A microcontroller is coupled through a resistor or other resistive component to the input node of the driver circuit and provides the input current, where the input current is adjustable by the resistor value. The driver circuit is configured to drive multiple times the input current from its output node. By adjusting the resistor value the output current of the LED is adjusted. The microcontroller is configured to provide pulse width modulation (PWM). By reducing the duty cycle of the PWM waveform the dimming of the LED can be controlled.
    Type: Grant
    Filed: January 7, 2013
    Date of Patent: January 13, 2015
    Assignee: Atmel Corporation
    Inventor: Armin Noller
  • Patent number: 8933642
    Abstract: A driver for an LED lamp assembly includes a rectifier configured to receive an AC power and produce a first DC power and a switching regulator coupled to the rectifier. The switching regulator is configured to receive the first DC power and produce an output DC power. The driver also includes a current controller coupled between the rectifier and the switching regulator. The current controller is configured to damp and stabilize an electric current flowing between the switching regulator and the rectifier.
    Type: Grant
    Filed: March 30, 2012
    Date of Patent: January 13, 2015
    Assignee: General Electric Company
    Inventor: Mohamed Cherif Ghanem
  • Publication number: 20150008839
    Abstract: A light emitting diode (LED) backlight driving circuit includes a power supply, an LED lightbar coupled to the power supply, and a constant current driving chip coupled to a control end of the power supply and coupled to a cathode of the LED lightbar. The constant current driving chip includes an adjusting dimming unit coupled to the cathode of the LED lightbar, and the adjusting dimming unit adjusts an external pulse-width modulation (PWM) dimming signal. A controllable switch unit is connected in series between an output end of the power supply and the constant current driving chip, and logical operation of the controllable switch unit is relative to logical operation of the adjusting dimming unit. The controllable switch unit turns off when the adjusting dimming unit turns off or before the adjusting dimming unit turns off, and the controllable switch unit turns on when the adjusting dimming unit turns on or after the adjusting dimming unit turns on.
    Type: Application
    Filed: July 5, 2013
    Publication date: January 8, 2015
    Applicant: SHENZHEN CHINA STAR OPTOELECTRONICS TECHNOLOGY CO., LTD.
    Inventor: Hua Zhang
  • Patent number: 8928256
    Abstract: A system and method for operating one or more light emitting devices is disclosed. In one example, the light emitting devices may be deactivated in response to a rate of temperature rise of the light emitting devices. The system and method further include a way of reducing false positive indications of light emitting device.
    Type: Grant
    Filed: May 8, 2013
    Date of Patent: January 6, 2015
    Assignee: Phoseon Technology, Inc.
    Inventor: Jeff Smith
  • Patent number: 8928238
    Abstract: A supplemental dimming circuit for an electronic led driver comprising a universal control section has a VCC3 startup and low conduction period circuit for providing a current during start-up and during low conduction periods; a CC hold current circuit for providing a hold current for the dimmer at low conduction periods; a latch circuit for providing a current draw latch on; and a PWM synchronized dimming circuit for providing a PWM signal dependent on the conduction period of the dimmer in real time. The supplemental dimming circuit also has a socket and a plug. The universal control section is on a daughter board that is pluggable to the socket. The VCC3 startup and low conduction period circuit creates a low AC voltage dummy load, which is a resistive load. The CC hold current circuit creates a low AC current dummy load that is a constant current load.
    Type: Grant
    Filed: January 6, 2012
    Date of Patent: January 6, 2015
    Assignee: Eptronics, Inc.
    Inventor: Thomas O'Neil
  • Patent number: 8928255
    Abstract: A dynamic step dimming interface is provided that allows a ballast to energize a lamp in a dim mode or a normal mode. The ballast includes a lamp controller that energizes the lamp using an oscillating current. The oscillating current is also provided to a voltage monitor, which indicates the voltage level of the oscillating current, and to a rectifier, which provides an output indicative of the oscillating current. The rectifier is responsive to user input indicating whether the dim mode or the normal mode is to be used. A processing circuit receives the voltage level from the voltage monitor and provides a mode command to the ballast, indicating the lamp mode, based on inputs received, and provides a reference voltage to a comparator. The comparator receives the rectifier output and the reference voltage, and generates a voltage indicative of a power level of the lamp for the processing circuit.
    Type: Grant
    Filed: February 25, 2014
    Date of Patent: January 6, 2015
    Assignee: OSRAM SYLVANIA Inc.
    Inventors: Arturo Hernandez Lopez, Markus Ziegler, Carlos Daniel Ortega Jaramillo
  • Patent number: 8928239
    Abstract: A backlight driver includes current sources that are connected between LED strings and a number of bias voltages. There can be any number of different bias voltages, each at a ground potential or higher voltage. The bias voltage is selected for a particular LED string in order to reduce a current drop across the current source. This reduces the power consumption of the current source and LED string. Heat dissipation is also reduced.
    Type: Grant
    Filed: June 24, 2014
    Date of Patent: January 6, 2015
    Assignee: IML International
    Inventor: Alberto Viviani
  • Patent number: 8928237
    Abstract: A luminaire according to one embodiment includes a DC power supply circuit, a switching power supply, and a lighting load. The DC power supply circuit converts an AC voltage controlled in phase to a DC voltage. The switching power supply is connected to the DC power supply circuit, and is controlled so that an input current becomes a constant current. The lighting load is connected as a load circuit of the switching power supply.
    Type: Grant
    Filed: December 28, 2012
    Date of Patent: January 6, 2015
    Assignee: Toshiba Lighting & Technology Corporation
    Inventors: Hirokazu Otake, Fumihiko Nagasaki, Takuro Hiramatsu, Katsuya Ooto
  • Patent number: 8928248
    Abstract: Provided is a step up/down converter, in which the inductor current can be easily detected by a simple configuration in any connecting mode of the switches.
    Type: Grant
    Filed: February 8, 2013
    Date of Patent: January 6, 2015
    Assignee: Panasonic Corporation
    Inventors: Takuya Ishii, Takeshi Azuma
  • Patent number: 8922130
    Abstract: In a conventional example, even if a duty cycle of the burst dimming is changed during an OFF-period of a switching element, current flowing to an LED is maintained constant. On the other hand, in the present embodiment, an accumulated value of ON-periods of a switching element is increased or decreased so as to be linked to a minimum variation width for a duty cycle (a dimming level) of a dimming signal, regardless of a timing of when the duty cycle is changed. Therefore, a lighting system (an LED drive device) according to the present embodiment can change smoothly a light output of a solid-state light-emitting element (a light source) with respect to a change in a duty cycle of the burst dimming while preventing the switching frequency from increasing.
    Type: Grant
    Filed: September 3, 2013
    Date of Patent: December 30, 2014
    Assignee: Panasonic Intellectual Property Management Co., Ltd.
    Inventors: Masahiro Naruo, Sana Esaki, Kenichi Fukuda
  • Patent number: 8922138
    Abstract: A first driver switches on and off a driving current ILED according to a first pulse signal which is pulse-width modulated according to an externally supplied target luminance level of a light emitting element. An oscillator generates a cyclic signal SOSC having a predetermined frequency. A pulse modulator generates a second pulse signal which is switched to an on level that corresponds to the on state of a switching transistor in synchronization with the cyclic signal SOSC, and which is switched to an off level that corresponds to the off state according to a feedback voltage. A second driver switches on and off the switching transistor according to the second pulse signal. The oscillator is configured to be reset according to a first edge which is transition of the first pulse signal from a first level that corresponds to the off state to a second level that corresponds to the on state.
    Type: Grant
    Filed: October 29, 2013
    Date of Patent: December 30, 2014
    Assignee: Rohm Co., Ltd.
    Inventor: Yoshikazu Sasaki
  • Patent number: 8922129
    Abstract: In one general aspect, a dimmer power supply circuit is disclosed for use with single-pole dimmers that includes a first AC mains input line, second AC mains input line, and a rectification circuit responsive to the first and second AC mains input lines. A positive LED supply terminal responsive to the rectification circuit, and a negative LED supply terminal is responsive to the rectification circuit. At least one preload resistor is operatively connected in a first intermittent loading circuit path between two supply rails in the dimmer power supply circuit, and a peak detector is responsive to the first and second AC mains input lines.
    Type: Grant
    Filed: July 6, 2010
    Date of Patent: December 30, 2014
    Assignee: Solais Lighting, Inc.
    Inventor: Edward Rodriguez
  • Publication number: 20140375226
    Abstract: In one embodiment, method of signal processing can include: (i) determining a high level sampling pulse amount by counting a number of pulses of a first clock signal during a high level portion of a period of a first PWM; (ii) generating a first pulse signal based on a second clock signal and the high level sampling pulse amount; (iii) determining a low level sampling pulse amount by counting a number of pulses of the first clock signal during a low level portion of the period of the first PWM signal; (iv) generating a second pulse signal based on the second clock signal and the low level sampling pulse amount; and (v) generating a second PWM signal based on the first and second pulse signals.
    Type: Application
    Filed: June 18, 2014
    Publication date: December 25, 2014
    Inventors: Yunlong Han, Huiqiang Chen
  • Patent number: 8917030
    Abstract: An electronic ballast for a lighting unit may include a Power Factor Correction (PFC) circuit, an inverter, and a control circuit for controlling startup of the inverter, wherein the control circuit is coupled between the PFC circuit and the inverter and includes a switching device coupled in a startup loop for the inverter; a unidirectional conductive device coupled between a PFC power supply circuit for providing an operation current to a PFC controller of the PFC circuit and an input of the PFC controller for preventing a startup current flowing through the PFC circuit from triggering the switching device; and a triggering device coupled to the switching device and a connection point between the unidirectional conductive device and the PFC power supply circuit for controlling switch-on and switch-off of the switching device.
    Type: Grant
    Filed: August 25, 2011
    Date of Patent: December 23, 2014
    Assignee: OSRAM GmbH
    Inventors: Hong Dai, Yuancheng Guo, Wei Gao, Changsong Ma
  • Patent number: 8917029
    Abstract: A light-emitting diode (LED) driver is provided. The LED driver, providing a drive voltage for driving an LED circuit according to an input voltage, includes a current regulator, a dimming signal generator, and a boost converter. In response to a pulse width modulation (PWM) dimming signal, the current regulator enables the LED circuit in a first PWM period and disables the LED circuit outside the first PWM period. The dimming generator generates a prolonged PWM dimming signal according to the PWM dimming signal. The prolonged PWM dimming signal has a prolonged period, a length of which is associated with a level of an input voltage. In response to the prolonged PWM dimming signal, the boost converter is enabled in a second PWM period and maintains a level of the drive voltage according to the input voltage.
    Type: Grant
    Filed: May 30, 2012
    Date of Patent: December 23, 2014
    Assignee: Raydium Semiconductor Corporation
    Inventors: Chih-Wei Chu, Yu-Nan Yen
  • Patent number: 8917027
    Abstract: Driver device and a corresponding driving method for driving a load, in particular an LED assembly comprising one or more LEDs. To provide a better performance, better cost-efficiency, improved power factor and reduced losses, a driver device (1,1?, 2, 2?) is provided comprising a rectifier unit (10) for rectifying a received AC supply voltage (VS), load terminals (20) for providing a drive voltage (VL) and/or a drive current (IL) for driving said load, a capacitive storage unit (30) coupled between said rectifier unit and said load terminals for storing electrical energy provided by said rectifier unit and providing electrical energy to said load, and a bridge switching unit (40) coupled between said rectifier unit and said load for switching said capacitive storage unit into a load current path from said rectifier unit to said load terminals with a desired polarity and for switching said capacitive storage unit out of said load current path.
    Type: Grant
    Filed: March 28, 2012
    Date of Patent: December 23, 2014
    Assignee: Koninklijke Philips N.V.
    Inventors: Harald Josef Gunther Radermacher, Pieter Gerrit Blanken, Yifeng Qiu, Haimin Tao, Ronald Van Langevelde, Ralph Kurt
  • Publication number: 20140368122
    Abstract: The invention relates to an operating circuit for illuminants, in particular one or more LED sections (17), comprising an actively clocked PFC circuit (11), which can be supplied by an AC voltage (UAC) and optionally also a DC voltage (UDC) and the output voltage of which is directly or indirectly supplied through the illuminant (17) to a unit (19) for generating a PWM-modulated current. The operating circuit also has a control unit (16) that detects a residual ripple in the voltage (UPFC) in the supply chain before (18a), in (18b) or after (18c) the PFC circuit (11) and causes the frequency of the PWM modulation of the current through the illuminant (17) to be selected as a function of the frequency of the residual ripple.
    Type: Application
    Filed: December 20, 2012
    Publication date: December 18, 2014
    Applicant: TRIDONIC GMBH & CO KG
    Inventors: Andre Mitterbacher, Markus Mayrhofer
  • Patent number: 8912726
    Abstract: Light emitting devices. A light emitting device including a power source; and a plurality of light emitting diode (LED) arrays coupled to the power source unit; and at least one delay unit. Each delay unit is coupled to a corresponding light emitting diode array of the light emitting diode arrays.
    Type: Grant
    Filed: March 7, 2013
    Date of Patent: December 16, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jong Ho Lee, Sung Tae Kim, Chan Mook Lim, Jin Hwan Kim
  • Patent number: 8912731
    Abstract: An LED backlight driving circuit has a voltage converting unit having an output terminal connected to a positive electrode of an LED to provide a driving voltage required by the LED, a driving unit to control the voltage converting unit to achieve a voltage conversion, and a protection unit connected in series between a negative electrode of the LED and the driving unit. A maximum allowable power of the protection unit is less than a power when the driving voltage of the LED is directly applied to the protection unit. The circuit also includes a control unit for outputting a control signal for stopping working to the driving unit when the protection unit forms an open circuit. Thus, the circuit parts can be protected, and the short-circuit protection function is more safe and reliable.
    Type: Grant
    Filed: April 2, 2013
    Date of Patent: December 16, 2014
    Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd.
    Inventors: Hua Zhang, Xianming Zhang
  • Patent number: 8912723
    Abstract: A method for driving light adjustments, a device therefor and a light adjustable lamp including the device are disclosed. The device includes a light source driving circuit, an MCU and a temporary power supplying circuit. The MCU includes a current detecting module, an analyzing and processing module and a storage module. The analyzing and processing module obtains a connecting signal or a disconnecting signal of the light source driving circuit and thereafter extracts a stored firmware program of gradually varying brightness of a light source or stored information about a constant brightness state of the light source from the storage module for analyzing and processing, so as to generate a controlling signal of adjusting the brightness of the light source and send the controlling signal into the light source driving circuit. Then the light source driving circuit adjusts the brightness of the light source according to the controlling signal.
    Type: Grant
    Filed: June 28, 2010
    Date of Patent: December 16, 2014
    Inventors: Yingwen Liao, Lin Feng, Xiaoyu Wang
  • Patent number: 8912729
    Abstract: A backlight module and a liquid crystal display (LCD) device thereof are proposed. The backlight module includes a DC/DC converter producing a positive/negative voltage level. The backlight module can output the positive and negative levels of driving voltage from an output end of the inverter to drive LEDs through alternately switching. Besides, a constant current can be obtained with designs of power on/off periods and energy-storing inductors to prevent LEDs employing current limiting resistors from having too low current efficiency and from being burnt out.
    Type: Grant
    Filed: September 1, 2010
    Date of Patent: December 16, 2014
    Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd.
    Inventors: Chengming He, Chingyuan Yang
  • Publication number: 20140361705
    Abstract: Circuits and methods for detecting the presence of a leading-edge phase-cut dimmer. The dimmer detector comprises an edge detector, a pulse stretcher and a filter. The edge detector detects whether an input signal has a rapidly rising edge and generates an output signal pulse if a rapidly rising edge is detected. If the edge detector outputs a signal pulse, the pulse stretcher generates a stretched pulse having a duration that is longer than the signal pulse received from the edge detector. The filter produces a dimmer detect signal that indicates whether a leading-edge phase-cut dimmer is detected. If the pulse stretcher output signal comprises at least a predetermined number of stretched pulses within a predetermined amount of time, the dimmer signal signals the presence of a leading-edge phase-cut dimmer.
    Type: Application
    Filed: May 7, 2014
    Publication date: December 11, 2014
    Applicant: Texas Instruments Incorporated
    Inventors: Irwin Nederbragt, Steven Barrow
  • Patent number: 8907579
    Abstract: When an operator operates an operation tool of a dimming operation terminal device in order to set the brightness of a lighting load to desired brightness, an energization electric signal, for example, a voltage level detected by a dimming control section changes. The dimming control section generates a dimming signal modulated according to the voltage level. Power supply to the dimming control section is performed by an insulated auxiliary power supply. Transmission of the dimming signal is performed via an insulating section.
    Type: Grant
    Filed: December 31, 2013
    Date of Patent: December 9, 2014
    Assignee: Toshiba Lighting & Technology Corporation
    Inventors: Masahiko Kamata, Kenji Takanashi
  • Patent number: 8907584
    Abstract: An apparatus for controlling the constant current for multi-channel LEDs includes: a plurality of LED channels each comprising an LED array, a transistor, and a variable emitter resistor; a feedback sensing circuit for sensing the collector or drain voltage of a transistor of each of the LED channels; and a controller for increasing the variable emitter resistance of an LED channel in which the collector voltage of the transistor is higher than those of the other LED channels, in response to a feedback sensing result input from the feedback sensing circuit.
    Type: Grant
    Filed: November 8, 2012
    Date of Patent: December 9, 2014
    Assignee: LG Display Co., Ltd.
    Inventors: Seongho Lim, Eungkyu Kim, Taewoo Kim
  • Patent number: 8907582
    Abstract: A method for providing a kickstart pulse to a dimmer circuit for a light source that is slow starting. The method includes receiving an initial power signal for a light source electrically coupled to a dimmer circuit, and generating, using the initial power signal, a pulse signal. The method also includes sending, for a period of time, the pulse signal to a load control circuit for the light source. In such a case, the light source is illuminated by the pulse signal for the period of time, and the magnitude of the pulse signal is greater than the magnitude of a steady-state signal generated by the dimmer circuit for the light source. The method can be performed using discrete components, integrated circuits, software, some other electrical device, or any combination thereof. A kickstart circuit and a dimmer circuit, using substantially the method described above, is also disclosed herein.
    Type: Grant
    Filed: August 28, 2012
    Date of Patent: December 9, 2014
    Assignee: Cooper Technologies Company
    Inventors: Oscar Lewis Neundorfer, Carlos Eduardo Restrepo, Rohit Sumerchand Dodal
  • Patent number: 8907583
    Abstract: An LED driving device includes: a rectifying circuit for outputting a DC voltage to a string of M LED units; (M?1) first switching circuits each coupled between a corresponding one of first to (M?1)th LED units and ground; and a second switching circuit coupled between an Mth LED unit and ground. When the DC voltage is sufficient to turn on first to kth LED units, where 1?k?M, the kth LED unit is coupled to ground through first and second conductive paths provided by a resistor unit, and a corresponding first switching circuit or the second switching circuit, and each of the first to (k?1)th LED units is coupled to ground through a third conductive path provided by a corresponding first switching circuit and the resistor unit.
    Type: Grant
    Filed: October 29, 2013
    Date of Patent: December 9, 2014
    Assignee: Richtek Technology Corp.
    Inventors: Chih-Feng Huang, Kuo-Chin Chiu
  • Patent number: 8907585
    Abstract: A method of driving a light source includes receiving an alternating current (“AC”) voltage from outside, generating a first direct current (“DC”) voltage based on the AC voltage, generating a second DC voltage, corresponding to a difference between a driving voltage of a light source part and the first DC voltage, based on the first DC voltage, and outputting a sum of the first DC voltage and the second DC voltage to the light source part.
    Type: Grant
    Filed: September 23, 2011
    Date of Patent: December 9, 2014
    Assignee: Samsung Display Co., Ltd.
    Inventors: Seung-Wan Kim, Won-Sik Oh, Young-Sup Kwon, Hwan-Woong Lee
  • Publication number: 20140354169
    Abstract: A lighting device includes an electrical circuit for energizing an LED light source having a variable illuminating resistance. The electrical circuit includes at least one target parameter, at least one target relationship and is configured for energizing the LED light source with an energizing waveform for the LED light source having a plurality of operating parameters. The operating parameters change in response to changes in ambient conditions thereby changing the performance characteristics of the LED light source. The circuit determines at least one operating parameter, compares the operating parameter with the target parameter and changes the energizing waveform applied to the LED light source for changing the effective power applied to the LED light source for maintaining the operating parameter in conformance with a target relationship with the target parameter.
    Type: Application
    Filed: May 31, 2013
    Publication date: December 4, 2014
    Inventor: Kevin McDermott
  • Publication number: 20140354170
    Abstract: A load control device for controlling the intensity of a lighting load, such as a light-emitting diode (LED) light source, may include a power converter circuit operable to receive a rectified AC voltage and to generate a DC bus voltage, a load regulation circuit operable to receive the bus voltage and to control the magnitude of a load current conducted through the lighting load, and a control circuit operatively coupled to the load regulation circuit for pulse width modulating or pulse frequency modulating the load current to control the intensity of the lighting load to a target intensity. The control circuit may control the intensity of the lighting load by pulse width modulating the load current when the target intensity is above a predetermined threshold and control the intensity of the lighting load by pulse frequency modulating the load current when the target intensity is below the predetermined threshold.
    Type: Application
    Filed: May 29, 2014
    Publication date: December 4, 2014
    Applicant: Lutron Electronics Co., Inc.
    Inventors: Timothy P. Gredler, Matthew R. Zartman
  • Patent number: 8901821
    Abstract: An apparatus for driving a fluorescent lamp is provided. The provided apparatus includes a power switching circuit, an LC resonator and an automatic frequency tracing circuit. The power switching circuit is coupled between an input voltage and a ground potential, and configured for switching and outputting the input voltage and the ground potential in response to two output signals with a phase difference of 180 degrees so as to generate a square signal. The LC resonator is configured for receiving and converting the square signal, so as to generate a sinusoidal driving signal for driving the fluorescent lamp. The automatic frequency tracing circuit is configured for generating and adjusting the two output signals according to a current feedback signal relating to the sinusoidal driving signal, so as to make the frequency of the sinusoidal driving signal automatically follow the resonant frequency of the LC resonator.
    Type: Grant
    Filed: May 29, 2012
    Date of Patent: December 2, 2014
    Assignee: Beyond Innovation Technology Co., Ltd.
    Inventors: Kuang-Yu Jung, Shih-Chung Huang
  • Patent number: 8901841
    Abstract: The disclosure relates to an AC LED dimmer and dimming method thereof. The AC LED dimmer includes a rectifier receiving AC voltage from an AC voltage source and full-wave rectifying the AC voltage; a direct current (DC)/DC converter receiving the full-wave rectified voltage from the rectifier, generating a full-wave rectified stepped-up voltage, and generating a pulse enable signal; a pulse width modulation controller receiving the full-wave rectified stepped-up voltage and generating a pulse width modulation signal to dim an AC LED in response to the pulse enable signal; a switch driving the AC LED under control of the pulse width modulation signal, and an electromagnetic interference (EMI) filter to be connected between the AC voltage source and the switch to eliminate electromagnetic interference from the AC voltage source. Accordingly, the dimmer can perform an efficient and linear dimming function and suppress harmonics.
    Type: Grant
    Filed: December 3, 2012
    Date of Patent: December 2, 2014
    Assignee: Seoul Semiconductor Co., Ltd.
    Inventors: Byung Hoon Choi, In Kyu Park
  • Patent number: 8901830
    Abstract: A method for controlling a current of a power supply system includes following steps. First, the power supply is started to produce an output current and the output current is increased. Afterward, the output current is decreased when the output current increases to a rated output current value. Finally, the output current is maintained at a typical output current value when the output current decreases to the typical output current value.
    Type: Grant
    Filed: September 7, 2012
    Date of Patent: December 2, 2014
    Assignee: Delta Electronics, Inc.
    Inventors: Hsiang-Chen Wu, Chao-Pin Chen
  • Patent number: 8901840
    Abstract: A lamp ignition system and a lamp ignition method are disclosed, where the lamp ignition system includes a converter, a transformer and a driving circuit. The converter converts an input voltage into an operating voltage for a gas discharge lamp. The transformer has a primary winding and a secondary winding, and the secondary winding is connected to the gas discharge lamp in series. The driving circuit is electrically connected to the primary winding for driving the transformer, so that the secondary winding of the transformer can output a high-frequency voltage to ignite the gas discharge lamp.
    Type: Grant
    Filed: September 13, 2012
    Date of Patent: December 2, 2014
    Assignee: Delta Electronics, Inc.
    Inventors: Wei-Qiang Zhang, Xiao-Peng Wang, Jian-Ping Ying
  • Patent number: 8901854
    Abstract: Disclosed is a multi-segment LED driving circuit used in an AC operating mode for outputting a drive current to drive a plurality of serially connected LED strings. The LED driving circuit includes at least one detection part, at least one comparison part and at least one adjusting part. The detection part detects an input voltage and an output voltage at both ends of each string and its next string to form a detected value provided for the comparison part to compare the detected value with a reference value to turn on or off the adjusting part so as to control the strings through which the drive current passes and then sequentially drives the strings to emit light. The LED driving circuit can adjust the load of the circuit immediately based on the change of voltage value of the AC power to ensure the stability of the drive current.
    Type: Grant
    Filed: May 8, 2013
    Date of Patent: December 2, 2014
    Assignee: Anwell Semiconductor Corp.
    Inventors: Shao-Wei Chiu, Chun-Chieh Kuo, Cheng-Po Hsiao, Shih-Ping Tu
  • Patent number: 8896226
    Abstract: A power supply apparatus for applying a method of supplying a loading with an electric power within a predetermined range of a default power, which includes a driving unit, a voltage sensing unit, and a feedback control unit. The driving unit receives power from a power source, and supplies the loading with a working voltage and a working current; the voltage sensing unit detects the working voltage; the feedback control unit keeps a plurality of reference voltages, wherein each two neighboring reference voltages are defined to have a voltage section therebetween. The feedback control unit sends a current signal to the driving unit according to the working voltage and a slope parameter of the voltage section which the working voltage falls in, and the driving unit supplies the working current according to the current signal to maintain the electric power in the predetermined range of the default power.
    Type: Grant
    Filed: January 27, 2014
    Date of Patent: November 25, 2014
    Assignees: Hep Tech Co., Ltd.
    Inventor: Ming-Feng Lin
  • Patent number: 8896221
    Abstract: A lighting device for a semiconductor light emitting element includes a series circuit of two switching elements which are alternately turned on, the series circuit being connected to a direct current (DC) input power source and a reactance circuit connected between a connection node of the two switching elements and one end of the DC input power source through a capacitor, an output of the reactance circuit being supplied to the semiconductor light emitting element through a rectifier circuit. A dimming operation of the semiconductor light emitting element is performed by varying a ratio of ON periods of the two switching elements.
    Type: Grant
    Filed: March 29, 2012
    Date of Patent: November 25, 2014
    Assignee: Panasonic Corporation
    Inventors: Sana Esaki, Akinori Hiramatu
  • Patent number: 8896230
    Abstract: The present invention provides an LED backlight drive circuit, which includes a first power supply module, an electrical inductor, a rectifier diode, a MOS transistor, an electrolytic capacitor, an LED light string, a voltage division module, a voltage comparator, a second power supply module, and an LED constant-current drive chip. The LED backlight drive circuit is arranged to include a voltage comparator in an external circuit of the LED constant-current drive chip to detect output voltage of the drive circuit so that high voltage, the voltage comparator is caused to supply a low voltage level to forcibly pull down a PWM dimming signal or an ENA enabling signal of the LED constant-current drive chip to achieve an over-voltage protection function and also enable removal of over-voltage protection module from a conventional LED constant-current drive chip.
    Type: Grant
    Filed: March 5, 2013
    Date of Patent: November 25, 2014
    Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd.
    Inventor: Hua Zhang
  • Patent number: 8896223
    Abstract: A LED driving device comprises a rectification circuit, a holding current circuit and a driving circuit to drive and linearly regulates an illumination brightness of at least one LED by utilizing level variation of current magnitude. The rectification circuit rectifies and outputs a rectified voltage to the holding current circuit and the driving circuit by filtering impulses via a filter after receiving an alternating current voltage. The driving circuit outputs a driving current filtered by a filter capacitor to the LED, and the driving current is sensed by a sensing resistor to allow the holding current circuit outputting a holding current to the rectification circuit such that the whole circuit power can be improved to reduce problems of noise interference and twinkling.
    Type: Grant
    Filed: September 14, 2012
    Date of Patent: November 25, 2014
    Assignee: Unity Opto Technology Co., Ltd.
    Inventors: Chih-Hsien Wu, Wei Chang, Kai-Cheng Chuang
  • Patent number: 8896234
    Abstract: A power supply apparatus and a display apparatus including the same are provided. The power supply apparatus according to an exemplary embodiment includes a power factor correction circuit unit which corrects a power factor of input power and outputs the corrected power factor and a controller which controls whether to operate the power factor correction circuit unit according to an input status of a first signal indicating a status of power supplied to the display apparatus and an input status of a second signal indicating an operation status of a display unit included in the display apparatus.
    Type: Grant
    Filed: September 25, 2011
    Date of Patent: November 25, 2014
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Chang-kwun Kwak, Du-seong Kang
  • Patent number: 8890429
    Abstract: A solid-state light-emitting element drive device includes a switching regulator and a control circuit. The switching regulator includes a series circuit of a switching element and an inductor, a regenerative element configured to allow a regenerative current to flow therethrough from the inductor when the switching element is turned off, and output terminals configured so that a solid-state light-emitting element is connected therebetween. The control circuit is configured to control a switching operation of the switching element of the switching regulator. The control circuit is configured to suppress an output power of the switching regulator if a parameter obtained from at least one of an ON-period and an OFF-period of the switching element is out of a prescribed range.
    Type: Grant
    Filed: September 10, 2013
    Date of Patent: November 18, 2014
    Assignee: Panasonic Corporation
    Inventors: Kenichi Fukuda, Masahiro Naruo, Sana Esaki