Patents by Inventor Tom William Thornton

Tom William Thornton has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8686668
    Abstract: Apparatus for maintaining at least a holding current in a leading-edge phase-cut dimmer during a period of transient voltage variations, the apparatus connectable to the dimmer and connectable to a load connected to draw current from the dimmer. The apparatus may comprise an edge detector connected to receive a voltage from the dimmer and generate a leading-edge signal in response to a leading-edge of a phase-cut waveform, and a current offset circuit connected to receive the leading-edge signal and draw a supplementary offset current in response to the leading-edge signal, wherein the supplementary offset current is sufficient to maintain at least a holding current in the dimmer during the period of transient voltage variations. The current offset circuit may comprise a holding current circuit which also draws supplementary current in response to an instantaneous value of load current.
    Type: Grant
    Filed: April 25, 2011
    Date of Patent: April 1, 2014
    Assignee: Koninklijke Philips N.V.
    Inventors: Miroslaw Marek Grotkowski, Milen Moussakov, Gregory Bernard Sheehan, Tom William Thornton, Thomas George Foxall
  • Patent number: 8598804
    Abstract: An illumination apparatus comprises a plurality of LEDs and a control system connected to receive dimmer-modulated AC line voltage and control the LEDs. The control system is configured to operate in a plurality of different modes wherein changes in dimmer-modulated AC line voltage adjust various characteristic of the LEDs.
    Type: Grant
    Filed: April 25, 2011
    Date of Patent: December 3, 2013
    Assignee: Light-Based Technologies Incorporated
    Inventors: Thomas George Foxall, Miroslaw Marek Grotkowski, Stephen Christian Wilson, Tom William Thornton, Brent York
  • Patent number: 8441202
    Abstract: An illumination apparatus comprises a plurality of LEDs and a control system connected to receive dimmer-modulated AC line voltage and control the LEDs. The control system is configured to operate in a plurality of different modes wherein changes in dimmer-modulated AC line voltage adjust various characteristic of the LEDs.
    Type: Grant
    Filed: May 21, 2010
    Date of Patent: May 14, 2013
    Assignee: Light-Based Technologies Incorporated
    Inventors: Stephen Christian Wilson, Tom William Thornton, Thomas George Foxall, Miroslaw Marek Grotkowski
  • Patent number: 8339066
    Abstract: Holding current circuits in light sources controlled by a dimmer are operated in a coordinated manner to maintain proper operation of the dimmer without wasting energy. A plurality of light sources each including a separate holding current circuit may be controlled by a dimmer. The holding current units are selectively disabled and/or a maximum holding current drawn by the holding current units are selectively adjusted to maintain a desired current draw.
    Type: Grant
    Filed: March 25, 2011
    Date of Patent: December 25, 2012
    Assignee: Light-Based Technologies Incorporated
    Inventors: Tom William Thornton, Milen Moussakov, Gregory Bernard Sheehan
  • Patent number: 8283875
    Abstract: Holding current circuits and lighting assemblies comprising same are provided. Holding current circuits may be connected to loads to ensure that the load and holding current circuit together draw at least a holding current from a dimmer when the dimmer is in conduction. A holding current circuit may comprise a controlled current source configured to selectively draw current from a dimmer. The controlled current source draws current according to a control signal based on the conduction state of the dimmer and the sum of the currents in a load and the controlled current source. The control signal is generated by a current controller configured to generate the control signal to cause the controlled current source to draw a supplementary current at least as great as the difference between the holding current and the load current when the dimmer is in conduction and the load current is less than the holding current.
    Type: Grant
    Filed: October 26, 2010
    Date of Patent: October 9, 2012
    Inventors: Miroslaw Marek Grotkowski, Milen Moussakov, Gregory Bernard Sheehan, Tom William Thornton, Thomas George Foxall
  • Publication number: 20120161665
    Abstract: A method of controlling an illumination apparatus comprises monitoring a dimmer modulated control voltage, controlling the illumination apparatus in a normal mode wherein changes in the dimmer modulated control voltage adjust a light output of the illumination apparatus within a normal range until the dimmer modulated control voltage manifests a first mode change condition, and, when the dimmer modulated control voltage manifests the first mode change condition, switching from the normal mode to a deep dimming mode wherein changes in the dimmer modulated control voltage adjust the light output of the illumination apparatus within a deep dimming range which is smaller than the normal range.
    Type: Application
    Filed: December 23, 2010
    Publication date: June 28, 2012
    Inventor: Tom William Thornton
  • Publication number: 20120098454
    Abstract: Apparatus for maintaining at least a holding current in a leading-edge phase-cut dimmer during a period of transient voltage variations, the apparatus connectable to the dimmer and connectable to a load connected to draw current from the dimmer. The apparatus may comprise an edge detector connected to receive a voltage from the dimmer and generate a leading-edge signal in response to a leading-edge of a phase-cut waveform, and a current offset circuit connected to receive the leading-edge signal and draw a supplementary offset current in response to the leading-edge signal, wherein the supplementary offset current is sufficient to maintain at least a holding current in the dimmer during the period of transient voltage variations. The current offset circuit may comprise a holding current circuit which also draws supplementary current in response to an instantaneous value of load current.
    Type: Application
    Filed: April 25, 2011
    Publication date: April 26, 2012
    Applicant: LIGHT-BASED TECHNOLOGIES INCORPORATED
    Inventors: Miroslaw Marek Grotkowski, Milen Moussakov, Gregory Bernard Sheehan, Tom William Thornton, Thomas George Foxall
  • Publication number: 20120062138
    Abstract: An illumination apparatus comprises a plurality of LEDs and a control system connected to receive dimmer-modulated AC line voltage and control the LEDs. The control system is configured to operate in a plurality of different modes wherein changes in dimmer-modulated AC line voltage adjust various characteristic of the LEDs.
    Type: Application
    Filed: April 25, 2011
    Publication date: March 15, 2012
    Applicant: LIGHT-BASED TECHNOLOGIES INCORPORATED
    Inventors: Stephen Christian Wilson, Tom William Thornton, Thomas George Foxall, Miroslaw Marek Grotkowski, Brent York
  • Publication number: 20110266974
    Abstract: Holding current circuits in light sources controlled by a dimmer are operated in a coordinated manner to maintain proper operation of the dimmer without wasting energy. A plurality of light sources each including a separate holding current circuit may be controlled by a dimmer. The holding current units are selectively disabled and/or a maximum holding current drawn by the holding current units are selectively adjusted to maintain a desired current draw.
    Type: Application
    Filed: March 25, 2011
    Publication date: November 3, 2011
    Inventors: Tom William Thornton, Milen Moussakov, Gregory Bernard Sheehan
  • Publication number: 20110241557
    Abstract: Holding current circuits and lighting assemblies comprising same are provided. Holding current circuits may be connected to loads to ensure that the load and holding current circuit together draw at least a holding current from a dimmer when the dimmer is in conduction. A holding current circuit may comprise a controlled current source configured to selectively draw current from a dimmer. The controlled current source draws current according to a control signal based on the conduction state of the dimmer and the sum of the currents in a load and the controlled current source. The control signal is generated by a current controller configured to generate the control signal to cause the to cause the controlled current source to draw a supplementary current at least as great as the difference between the holding current and the load current when the dimmer is in conduction and the load current is less than the holding current.
    Type: Application
    Filed: October 26, 2010
    Publication date: October 6, 2011
    Applicant: LIGHT-BASED TECHNOLOGIES INCORPORATED
    Inventors: Miroslaw Marek GROTKOWSKI, Milen MOUSSAKOV, Gregory Bernard SHEEHAN, Tom William THORNTON, Thomas George FOXALL
  • Publication number: 20110095703
    Abstract: An illumination apparatus comprises a plurality of LEDs and a control system connected to receive dimmer-modulated AC line voltage and control the LEDs. The control system is configured to operate in a plurality of different modes wherein changes in dimmer-modulated AC line voltage adjust various characteristic of the LEDs.
    Type: Application
    Filed: May 21, 2010
    Publication date: April 28, 2011
    Inventors: Stephen Christian Wilson, Tom William Thornton, Thomas George Foxall, Miroslaw Marek Grotkowski