Patents Examined by David Hung Vu
  • Patent number: 8058811
    Abstract: A ballast circuit operable to drive a high intensity discharge lamp in accordance with an embodiment of the present applications includes an energy conversion circuit operable to convert an input voltage into a bus voltage and to provide the bus voltage to a DC bus, a first half bridge connected across the DC bus and operable to control an output voltage supplied to the lamp, a control circuit operable to control the half bridge such that a desired output voltage is provided to the lamp, a series inductor connected in series between the half bridge and the lamp; and a parallel capacitor resistor connected across the lamp. The control circuit operates the half bridge at a high frequency for a set period of time such that a high voltage is built up across the parallel resistor, and then reduces the frequency of the half bridge until it approaches a resonance frequency which ignites the lamp.
    Type: Grant
    Filed: March 26, 2008
    Date of Patent: November 15, 2011
    Assignee: International Rectifier Corporation
    Inventor: Peter Green
  • Patent number: 8054249
    Abstract: Provided is a field emission display (FED) capable of driving on the basis of current and preventing leakage current caused by thin film transistors (TFTs). The FED includes: a plurality of unit pixels including an emission element in which cathode luminescence of a phosphor occurs and a TFT for driving the emission element; a current source for applying a scan signal to each unit pixel; and a voltage source for applying a data signal to each unit pixel. Here, the on-current of the current source is high enough to take care of the load resistance and capacitance of a scan row within a given writing time, and the off-current of the current source is so low that the electron emission of each pixel can be ignored. In addition, the pulse amplitude or pulse width of the data signal applied from the voltage source is changed, and thereby the gray scale of the display is represented.
    Type: Grant
    Filed: November 27, 2006
    Date of Patent: November 8, 2011
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Yoon Ho Song, Dae Jun Kim, Jin Woo Jeong, Jin Ho Lee, Kwang Yong Kang
  • Patent number: 8054002
    Abstract: The present invention relates to a light emitting device. The light emitting device according to the present invention comprises a light emitting cell block having a plurality of light emitting cells; and a bridge rectifying circuit connected to input and output terminals of the light emitting cell block, wherein the bridge rectifying circuit includes a plurality of diodes between nodes. In manufacturing an AC light emitting device with a bridge rectifying circuit built therein, the present invention can provide a light emitting device capable of enhancing the reliability and luminance of the light emitting device by setting the size of diodes of the bridge rectifying circuit to be a certain size and controlling the number thereof.
    Type: Grant
    Filed: December 5, 2006
    Date of Patent: November 8, 2011
    Assignee: Seoul Opto Device Co., Ltd.
    Inventors: Jae Ho Lee, Yeo Jin Yoon, Eu Jin Hwang, Lacroix Yves
  • Patent number: 8049434
    Abstract: A lighting commissioning device and method including a lighting commissioning device for commissioning of a lighting device in a lighting system, the lighting commissioning device including an indication detector 142 responsive to indication from the lighting device and generating a lighting device indication signal 148, a change detector 144 responsive to the lighting device indication signal 148 and generating an indication detected signal 150, and a control unit 146 receiving the indication detected signal 150 and being operably connected to the lighting system.
    Type: Grant
    Filed: September 6, 2006
    Date of Patent: November 1, 2011
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Kent E. Crouse, Ling Wang, William L. Keith, James Cai
  • Patent number: 8040071
    Abstract: In one embodiment, a driving circuit includes an AC/DC converter which converts an AC voltage to a DC voltage and a DC/DC linear regulator which regulates a current through, e.g., an LED light source, according to a first current reference if a monitoring signal indicating the DC voltage is within a predetermined range, and regulates the current according to a second current reference less than the first current reference if the monitoring signal is beyond the predetermined range. In another embodiment, a controller controlling power to an LED light source turns on a first plurality of LEDs and turns off a second plurality of LEDs if a monitoring signal indicative of a DC voltage received by the LED light source is within a predetermined range, and turns on both first and second plurality of LEDs if the monitoring signal is beyond the predetermined range.
    Type: Grant
    Filed: December 14, 2010
    Date of Patent: October 18, 2011
    Assignee: O2Micro, Inc.
    Inventors: Yung Lin Lin, Sterling Du
  • Patent number: 8040069
    Abstract: A method and apparatus for maintaining a maximum sustained flash current over the whole length of a flash using a programmable current drive in a handheld portable device powered by a battery. The method involves measuring the battery voltage before and after a flash is initiated and calculating the equivalent series resistance (ESR) of the battery. The calculated ESR is then used to adjust the flash current. The process may be repeated to correct for errors in the flash current.
    Type: Grant
    Filed: November 17, 2009
    Date of Patent: October 18, 2011
    Assignee: Research In Motion Limited
    Inventors: Marc Drader, Ryan Geris, Lyall Winger
  • Patent number: 8035310
    Abstract: A light source driving circuit including a driving module, a plurality of first switches, a detecting unit, and a control unit is provided. The plurality of first switches is respectively coupled to corresponding light sources and these light sources are driven by the driving module. The detecting unit is coupled to the driving module to detect a working parameter of each light source and transmit the working parameter to the control unit. When the detecting unit detects some of these light sources are broken down, the control unit sequentially turns on the first switches to find out the failed light source. Moreover, the first switch coupled to the failed light source is remained on, and the driving signal is regulated according to the number of the failed light source, such that the brightness of the panel does not decrease.
    Type: Grant
    Filed: April 22, 2008
    Date of Patent: October 11, 2011
    Assignee: Chunghwa Picture Tubes, Ltd.
    Inventors: Pi-Lun Chang, Hung-Hsiang Chen, Yi-Nan Chu
  • Patent number: 8030854
    Abstract: Waveform management systems and methods for ballasts are provided. The system includes a lamp, a ballast, a first interface, a storage unit, and a processing unit. The processing unit obtains at least one first waveform from the storage unit, and writes the first waveform to the ballast via the first interface. The processing unit transmits an illumination signal to the ballast via the first interface, such that the ballast controls the illumination of the lamp according to the first waveform.
    Type: Grant
    Filed: October 13, 2008
    Date of Patent: October 4, 2011
    Assignee: Coretronic Corporation
    Inventors: Chih-Heng Fan Chiang, Hsin-Chi Chen
  • Patent number: 8022636
    Abstract: Control of delivery of current through one or more discharge lamps. Methods include alternately switching on and off switching elements that control a fluorescent lamp, in response to receiving input, until the brightness of the lamp decreases to a threshold. Further, methods include providing control signals at complementary duty cycles to further decrease the brightness and alternating the duty cycles of the signals applied to the filaments of the fluorescent lamp.
    Type: Grant
    Filed: May 22, 2008
    Date of Patent: September 20, 2011
    Assignee: Marvell International Ltd.
    Inventors: Hubertus Notohamiprodjo, Radu Pitigoi-Aron
  • Patent number: 8018165
    Abstract: An end of life (EOL) detection circuit for a gas discharge lamp. The circuit includes a comparator for comparing an input voltage to first and second threshold voltages and providing an EOL signal; a sensing circuit for sensing a DC offset in the lamp-voltage during the EOL of the lamp; and a reference voltage setting circuit responsive to the DC offset including a reference diode for setting an adjustable reference voltage as said input voltage to the comparator.
    Type: Grant
    Filed: October 14, 2008
    Date of Patent: September 13, 2011
    Assignee: International Rectifier Corporation
    Inventor: Peter Bredemeier
  • Patent number: 8018172
    Abstract: A dimmable LED driver provides accurate full range dimming for LED lighting. The driver utilizes the timing of an AC signal rather than its power output or other characteristics to accurately determine the level of light a user desires. In this manner, the driver provides accurate full range dimming without the need for calibration to specific AC power levels. The driver may detect the period of an AC signal allowing the driver to be used with various frequencies without the need for calibration. In one or more embodiments, the driver compares the pulse widths of a dimmed AC signal to the period of the AC signal to determine the desired light level. The driver may comprise a signal processor and controller in one or more embodiments.
    Type: Grant
    Filed: April 13, 2009
    Date of Patent: September 13, 2011
    Assignee: MAGTECH Industries Corporation
    Inventor: Itai Leshniak
  • Patent number: 8018171
    Abstract: A system and method modify phase delays of a periodic, phase modulated mains voltage to generate at least two independent items of information during each cycle of the periodic input signal. The independent items of information can be generated by, for example, independently modifying leading edge and trailing edge phase delays of each half cycle phase modulated mains voltage. Modifying phase delays for the leading and trailing edges of each half cycle of the phase modulated mains voltage can generate up to four independent items of data. The items of data can be converted into independent control signals to, for example, control drive currents to respective output devices such as light sources to provide multiple items of information per cycle.
    Type: Grant
    Filed: March 12, 2008
    Date of Patent: September 13, 2011
    Assignee: Cirrus Logic, Inc.
    Inventors: John L. Melanson, John J. Paulos
  • Patent number: 8018158
    Abstract: An output circuit for a microwave tube is provided that has generally high interaction impedance for good efficiency, has high average power capability, and is physically large for a given operating frequency. The output circuit is designed to operate in conjunction with an off-axis, bunched electron beam. Electromagnetic fields are applied to the region in which the electron beam propagates to impart an azimuthal velocity to the bunched electron beam. The electron bunches then interact synchronously with a resonant output structure to excite radio-frequency modes from which energy can be extracted and applied to a load.
    Type: Grant
    Filed: April 18, 2008
    Date of Patent: September 13, 2011
    Assignee: L-3 Communications Corporation
    Inventors: Richard Donald Kowalczyk, Mark Frederick Kirshner, Craig Bisset Wilsen, Chad Daniel Marchewka
  • Patent number: 8018174
    Abstract: A safety circuit is provided for a ballast of an electro-luminescent (EL) lamp. The EL lamp had an electrical ground shield on at least a portion thereof and has a separate ground lead. The ballast is an isolated ballast with a line input being isolated from an output. The ballast is constructed and arranged to be electrically connected with the separate ground lead. The circuit includes a current sensing structure constructed and arranged to connect between the separate ground lead and a potential ground of the ballast. In the event a user contacts the EL lamp to replace the EL lamp or contacts a defective EL lamp, the ballast is shut down based on a value of current sensed by the current sensing structure.
    Type: Grant
    Filed: November 20, 2008
    Date of Patent: September 13, 2011
    Assignee: Ceelite LLC
    Inventors: Chih-Ping Liang, Chang-Yi Liu
  • Patent number: 8004217
    Abstract: The present invention provides, in one embodiment, a gas discharge lamp ballast with an integral shutdown timer. The ballast includes a circuit for receiving AC power, a converter circuit for converting the AC power to DC power and a square wave oscillator powered from the DC power. A resonant circuit powered by the square wave oscillator supplies power to at least one gas discharge lamp. A time-delay circuit disables the square wave oscillator, without interrupting the DC power supplied to the oscillator, upon the passage of a predetermined period of time from power-up of the AC power. The ballast can be realized with only a marginal increase in cost and size of the ballast.
    Type: Grant
    Filed: January 11, 2008
    Date of Patent: August 23, 2011
    Assignee: Robertson Worldwide, Inc.
    Inventors: George William Mortimer, Robert William Wisbey
  • Patent number: 8004209
    Abstract: The invention relates to a method of controlling a temporal variation of light emitted by an illumination system. The light emitted by the illumination system varies from light having a start color point (14) to light having a target color point (12). The start and target color point are defined in a first color space (XYZ, RGBvid, RGBill), which is perceptually non-uniform. The method according to the invention converts the start and target color point from the first color space to a second color space (Lab, Lch), which is more uniform to the human visual system than the first color space. The method further comprises a step of generating an intermediate color point (34, I1, I2) located on a transition-path (p, p?) within the second color space, an intermediate distance (d) between the start color point in the second color space and the intermediate color point in the second color space not being larger than a threshold distance (26).
    Type: Grant
    Filed: October 2, 2007
    Date of Patent: August 23, 2011
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Dragan Sekulovski, Ramon Antoine Wiro Clout
  • Patent number: 8004202
    Abstract: An apparatus for driving a backlight includes a controller for driving a lamp; a limiter for preventing the controller from driving the lamp during a contact condition of the lamp; and means for disabling the limiter during a first time of the controller, wherein the controller drives the lamp from a zero condition to the contact condition during the first time of the controller.
    Type: Grant
    Filed: March 1, 2010
    Date of Patent: August 23, 2011
    Assignee: LG Display Co., Ltd.
    Inventor: Changho Lee
  • Patent number: 7999481
    Abstract: After startup, a lighting method for a high-pressure discharge lamp is to light the lamp at a rated frequency without switching the frequency for 120 seconds (S12, S13), and thereafter to switch from the rated frequency to a more audible frequency in accordance with a change in voltage value (S21 to S23).
    Type: Grant
    Filed: July 10, 2008
    Date of Patent: August 16, 2011
    Assignee: Panasonic Corporation
    Inventors: Syunsuke Ono, Minoru Ozasa, Masahiro Yamamoto, Go Yamada
  • Patent number: 7994728
    Abstract: The present invention discloses a boost driver circuit which converts an input voltage to an output voltage and supplies it to a load, the boost driver circuit comprising: a power transistor electrically connected with a node between the input voltage and the output voltage; a pulse width modulation driver circuit for controlling the operation of the power transistor; an output node electrically connected with the output voltage; a feedback node electrically connected with the load; a low voltage transistor electrically connected with the feedback node; and a clamp and fast discharge circuit electrically connected with the feedback node for discharging the feedback node when the voltage at the feedback node is higher than a predetermined voltage.
    Type: Grant
    Filed: April 1, 2009
    Date of Patent: August 9, 2011
    Assignee: Richtek Technology Corporation
    Inventors: Kwan-Jen Chu, Nien-Hui Kung, Tzu-Huan Chiu, Chien-Ping Lu
  • Patent number: 7988346
    Abstract: A headlamp for a vehicle (air, land or sea) providing a planar array of infrared (IR) light-emitting diodes (LEDs) and visible light LEDs, and arranged and mounted within a housing so as to provide for cooling of the LEDs without forced convection, by conducting heat from the LEDs to protruding cooling fins. A switch system is also provided, for enabling either the visible light or the infrared light, and for selecting a high-beam or low-beam pattern. The beam pattern is provided in some embodiments so as to meet US Federal Motor Vehicle standards.
    Type: Grant
    Filed: March 19, 2009
    Date of Patent: August 2, 2011
    Assignee: Ibis Tek, LLC
    Inventors: James M. Helms, Mark R. Barie, John A. Lowrey, III