Patents by Inventor William Roger Fletcher

William Roger Fletcher 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).

  • Resonant transmission line to deliver precision RF voltage
    Patent number: 10600628
    Abstract: A system for conveying a time-varying voltage signal from a first subsystem to a second subsystem, and for monitoring and controlling the time-varying voltage signal, comprises a transmission line having a first end and a second end, extending from the first end at the first subsystem to the second end at the second subsystem. The transmission line is configured to be un-terminated, and have an electrical length substantially equal to a multiple of one half wavelength of the time-varying voltage signal. The system may further comprise an adaptive control configured to couple the time-varying voltage signal to the first end, and adjust a generator of the time-varying voltage signal based on a sampling of the time-varying voltage signal at the first end, and at least one transformer at the second subsystem electrically coupled to the second end and configured to increase an amplitude of the time-varying voltage signal.
    Type: Grant
    Filed: November 15, 2018
    Date of Patent: March 24, 2020
    Assignee: MKS Instruments, Inc.
    Inventor: William Roger Fletcher
  • Wide-dynamic range electrometer with a fast response
    Patent number: 8415942
    Abstract: A method and apparatus for measuring current includes sensing a first voltage at the output of an amplifier and computing a current based on the first voltage and the resistance of a first resistive element, which is electrically coupled between an inverting input of the amplifier and the output of the amplifier, if the first voltage is below a predetermined level. The method also includes sensing a second voltage at the output of a buffer and computing a current based on the first and second voltages and the resistances of the first resistive element and a second resistive element, which is electrically coupled between the inverting input of the amplifier and an input of the buffer and is also electrically coupled to the output of the amplifier through a at least one diode, if the voltage output from the amplifier is above the predetermined level.
    Type: Grant
    Filed: December 16, 2011
    Date of Patent: April 9, 2013
    Assignee: MKS Instruments, Inc.
    Inventor: William Roger Fletcher
  • Wide-dynamic range electrometer with a fast response
    Patent number: 8278909
    Abstract: A method and apparatus for measuring current includes sensing a first voltage at the output of an amplifier and computing a current based on the first voltage and the resistance of a first resistive element, which is electrically coupled between an inverting input of the amplifier and the output of the amplifier, if the first voltage is below a predetermined level. The method also includes sensing a second voltage at the output of a buffer and computing a current based on the first and second voltages and the resistances of the first resistive element and a second resistive element, which is electrically coupled between the inverting input of the amplifier and an input of the buffer and is also electrically coupled to the output of the amplifier through a at least one diode, if the voltage output from the amplifier is above the predetermined level.
    Type: Grant
    Filed: July 16, 2009
    Date of Patent: October 2, 2012
    Assignee: MKS Instruments, Inc.
    Inventor: William Roger Fletcher
  • WIDE-DYNAMIC RANGE ELECTROMETER WITH A FAST RESPONSE
    Publication number: 20120086434
    Abstract: A method and apparatus for measuring current includes sensing a first voltage at the output of an amplifier and computing a current based on the first voltage and the resistance of a first resistive element, which is electrically coupled between an inverting input of the amplifier and the output of the amplifier, if the first voltage is below a predetermined level. The method also includes sensing a second voltage at the output of a buffer and computing a current based on the first and second voltages and the resistances of the first resistive element and a second resistive element, which is electrically coupled between the inverting input of the amplifier and an input of the buffer and is also electrically coupled to the output of the amplifier through a at least one diode, if the voltage output from the amplifier is above the predetermined level.
    Type: Application
    Filed: December 16, 2011
    Publication date: April 12, 2012
    Applicant: MKS Instruments, Inc.
    Inventor: William Roger Fletcher
  • Wide-Dynamic Range Electrometer with a Fast Response
    Publication number: 20110012588
    Abstract: A method and apparatus for measuring current includes sensing a first voltage at the output of an amplifier and computing a current based on the first voltage and the resistance of a first resistive element, which is electrically coupled between an inverting input of the amplifier and the output of the amplifier, if the first voltage is below a predetermined level. The method also includes sensing a second voltage at the output of a buffer and computing a current based on the first and second voltages and the resistances of the first resistive element and a second resistive element, which is electrically coupled between the inverting input of the amplifier and an input of the buffer and is also electrically coupled to the output of the amplifier through a at least one diode, if the voltage output from the amplifier is above the predetermined level.
    Type: Application
    Filed: July 16, 2009
    Publication date: January 20, 2011
    Applicant: MKS Instruments, Inc.
    Inventor: William Roger Fletcher