Application number: 20050057179
Title: Driver circuit for LED vehicle lamp
A first vehicle lamp driver circuit for a light emitting diode (LED) array, the LED array having a first string of four LEDs in series and a second string of four LEDs in series. A first LED driver drives the first LED string and a second LED driver drives the second LED string. In a STOP mode of operation, the current to both LED strings is controlled by the LED driver in series with the LED string. In a TAIL mode of operation, the current is provided to only one LED string via a series connected diode and resistor. When there is reduced input voltage, operation of the LED strings is provided by switching circuits that short-out one LED in each LED string. A second vehicle lamp driver circuit comprises a first LED string and a second LED string in series with a control switch having a feedback circuit for maintaining constant current regulation to control the sum of the current in each LED string and reduce switching noise.
Inventors: Madhani, Vipin; (Burlington, MA) ; Johnsen, Andrew O.; (Danvers, MA)
Assignee: OSRAM SYLVANIA INC., Danvers, MA
Filed: August 26, 2004
Application number: 20050057187
Title: Universal light emitting illumination device and method
Disclosed is a method and apparatus for providing a light emitting diode and driving circuitry integrated into a component module that will retrofit common incandescent lightbulb applications. The disclosed embodiments will perform with high efficiency at a wide operating voltage range with a very small size allowing for the incorporation within the envelope and form of existing lightbulb bases. Therefore, a single universal LED light bulb module can be used to replace the dozens of conventional LED and incandescent lights currently being used. The electronic circuitries used to drive the LEDs are extremely compact and consequently can be incorporated in nearly any standard bulb base.
Inventors: Catalano, Anthony; (Boulder, CO)
Assignee: Technology Assessment Group Inc., Boulder, CO
Filed: April 8, 2004
Application number: 20050057554
Title: Light emission control circuit uniformly and non-uniformly controlling a plurality of light-emitting elements
A booster converter outputs a boosted voltage. A plurality of LEDs emit light of respective colors. The transistors establish or shut connection between the LEDs and a main driving circuit. A variable current circuit feeds a current to drive the LEDs. A PWM control unit effects control to cause the LEDs to emit light with respective tones of color. A PWM circuit executes PWM modulation in accordance with an instruction from the PWM control unit. A setting control unit 138 controls the magnitude of the driving current fed by the variable current circuit in accordance with an instruction from a second light emission control unit. In an image pickup mode, an additional driving circuit feeds a driving current to the LEDs so that the LEDs operate as an electronic flash.
Inventors: Yamamoto, Isao; (Ukyo-Ku, JP) ; Miyanaga, Koichi; (Ukyo-Ku, JP)
Filed: July 15, 2004
Foreign Application Data: JP2003-322293 filed Sep 12, 2003
Application number: 20050057929
Title: Led lamp
An LED lamp includes: a substrate; a cluster of LEDs, which are arranged two-dimensionally on the substrate; and an interconnection circuit, which is electrically connected to the LEDs. The LEDs include a first group of LEDs, which are located around the outer periphery of the cluster, and a second group of LEDs, which are located elsewhere in the cluster. The interconnection circuit has an interconnection structure for separately supplying drive currents to at least one of the LEDs in the first group and to at least one of the LEDs in the second group separately from each other.
Inventors: Yano, Tadashi; (Soraku-gun, JP) ; Shimizu, Masanori; (Kyotanabe-shi, JP)
Assignee: Matsushita Electric Industrial Co., Ltd.
Filed: September 14, 2004
Foreign Application Data: JP2003-322645 filed Sep 16, 2003