Patents by Inventor Robert Douglas Christie

Robert Douglas Christie 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: 9780706
    Abstract: A driver circuit is provided for driving a load, such as a multi-phase motor. The driver circuit includes a gate driver for providing a control signal to switching elements coupled to the driver circuit. A first switching element is coupled between a high supply voltage and a switching node of the load, and a second switching element is coupled between the switching node and a low supply voltage. To detect zero crossings of a current through the load, a zero crossing detector includes a first counter coupled to the switching node and a second counter coupled to the control signal. The first counter and second counter count in a predetermined direction based on a detected voltage of the switching node and based on a detected voltage of the control signal, respectively. The zero crossing detector generates an output signal based upon the difference between the first and the second counter.
    Type: Grant
    Filed: February 5, 2016
    Date of Patent: October 3, 2017
    Assignee: Allegro MicroSystems, LLC
    Inventors: Gianluca Allegrini, Thomas Ross, James McIntosh, Robert Douglas Christie
  • Publication number: 20170229986
    Abstract: A driver circuit is provided for driving a load, such as a multi-phase motor. The driver circuit includes a gate driver for providing a control signal to switching elements coupled to the driver circuit. A first switching element is coupled between a high supply voltage and a switching node of the load, and a second switching element is coupled between the switching node and a low supply voltage. To detect zero crossings of a current through the load, a zero crossing detector includes a first counter coupled to the switching node and a second counter coupled to the control signal. The first counter and second counter count in a predetermined direction based on a detected voltage of the switching node and based on a detected voltage of the control signal, respectively. The zero crossing detector generates an output signal based upon the difference between the first and the second counter.
    Type: Application
    Filed: February 5, 2016
    Publication date: August 10, 2017
    Applicant: Allegro Microsystems, LLC
    Inventors: Gianluca Allegrini, Thomas Ross, James McIntosh, Robert Douglas Christie
  • Publication number: 20130314836
    Abstract: Circuits and methods for overcurrent fault detection using a debounce timer to qualify the presence of an overcurrent fault based on an overcurrent signal being asserted for at least a predetermined time interval. The debounce timer may be used in conjunction with state-qualified fault sensing and/or blank-time-qualified fault sensing.
    Type: Application
    Filed: May 24, 2012
    Publication date: November 28, 2013
    Applicant: ALLEGRO MICROSYSTEMS, INC.
    Inventor: Robert Douglas Christie