Patents by Inventor James L. Brubaker

James L. Brubaker 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: 8330633
    Abstract: A differential current steering (CS) circuit uses feedback from the differential output nodes A and B to cause current steering devices (e.g., MOSFETs) to effectively exhibit an infinite output impedance when conducting. Therefore, the signal on the output nodes A or B does not significantly change the voltage at the common node, This is particularly useful when the differential output nodes are connected to differential output buses in a digital-to-analog converter. The circuit dynamically cancels, though feedback, the signal induced at the common node by the signal present at the “steered” output node. Therefore, the CS circuit effectively presents an infinite output impedance between the common node and the output nodes. In some cases, it may be desirable to not create a substantially infinite output impedance for the CS circuit but control the impedance to a predefined level to counter other distortions in the system.
    Type: Grant
    Filed: April 28, 2011
    Date of Patent: December 11, 2012
    Assignee: Linear Technology Corporation
    Inventors: James L. Brubaker, Florin A. Oprescu
  • Publication number: 20120274496
    Abstract: A differential current steering (CS) circuit uses feedback from the differential output nodes A and B to cause current steering devices (e.g., MOSFETs) to effectively exhibit an infinite output impedance when conducting. Therefore, the signal on the output nodes A or B does not significantly change the voltage at the common node, This is particularly useful when the differential output nodes are connected to differential output buses in a digital-to-analog converter. The circuit dynamically cancels, though feedback, the signal induced at the common node by the signal present at the “steered” output node. Therefore, the CS circuit effectively presents an infinite output impedance between the common node and the output nodes. In some cases, it may be desirable to not create a substantially infinite output impedance for the CS circuit but control the impedance to a predefined level to counter other distortions in the system.
    Type: Application
    Filed: April 28, 2011
    Publication date: November 1, 2012
    Applicant: LINEAR TECHNOLOGY CORPORATION
    Inventors: James L. Brubaker, Florin A. Oprescu
  • Patent number: 7532140
    Abstract: Digital to analog converter circuits and methods are provided for producing an analog output voltage indicative of a digital input signal with at least partial insensitivity to error gradients. Described are split-core resistive elements, which include a plurality of one-dimensional or multi-dimensional resistive strings, that may be used to reduce or substantially eliminate the effects that error gradients have on the linearity of the analog output voltages of a resistive string or interpolating amplifier DACs. The resistor strings that make up the split-core resistive elements are configured in such a manner that combining respective output voltages from each of the resistor strings results in an analog output voltage that is at least partially insensitive to the effects of error gradients.
    Type: Grant
    Filed: July 13, 2006
    Date of Patent: May 12, 2009
    Assignee: Linear Technology Corporation
    Inventors: William C Rempfer, Hassan Malik, James L Brubaker
  • Patent number: 6937178
    Abstract: Digital to analog converter circuits and methods are provided for producing an analog output voltage indicative of a digital input signal with at least partial insensitivity to error gradients. Described are split-core resistive elements, which include a plurality of one-dimensional or multi-dimensional resistive strings, that may be used to reduce or substantially eliminate the effects that error gradients have on the linearity of the analog output voltages of a resistive string or interpolating amplifier DACs. The resistor strings that make up the split-core resistive elements are configured in such a manner that combining respective output voltages from each of the resistor strings results in an analog output voltage that is at least partially insensitive to the effects of error gradients.
    Type: Grant
    Filed: May 15, 2003
    Date of Patent: August 30, 2005
    Assignee: Linear Technology Corporation
    Inventors: William C. Rempfer, Hassan Malik, James L. Brubaker
  • Patent number: 6492924
    Abstract: A signal processor circuit that buffers a ground-referred, signal-dependent, current. A ground-referred node in the circuit is preferably maintained at a ground level. The ground-referred, signal-dependent, current is preferably buffered such that the ground-referred node is preferably maintained at a ground level independent of changes to the ground-referred, signal-dependent, current.
    Type: Grant
    Filed: August 17, 2001
    Date of Patent: December 10, 2002
    Assignee: Linear Technology Corporation
    Inventors: Patrick P. Copley, William C. Rempfer, James L. Brubaker
  • Publication number: 20020063646
    Abstract: A signal processor circuit that buffers a ground-referred, signal-dependent, current. A ground-referred node in the circuit is preferably maintained at a ground level. The ground-referred, signal-dependent, current is preferably buffered such that the ground-referred node is preferably maintained at a ground level independent of changes to the ground-referred, signal-dependent, current.
    Type: Application
    Filed: August 17, 2001
    Publication date: May 30, 2002
    Inventors: Patrick P. Copley, William C. Rempfer, James L. Brubaker
  • Patent number: 6310567
    Abstract: A signal processor circuit which receives an input signal and two control words and is programmable to vary the level and the output voltage range of the output signal is provided. The signal processor includes a converter circuit and a level circuit which provide the output circuit with intermediate signals based on input control signals, e.g., input digital words. The output circuit receives an additional control signal and the intermediate signals and is programmable to modify the output voltage range and level of the output signal based on the additional control signal, e.g., a digital word.
    Type: Grant
    Filed: September 7, 1999
    Date of Patent: October 30, 2001
    Assignee: Linear Technology Corporation
    Inventors: Patrick P. Copley, William C. Rempfer, James L. Brubaker
  • Patent number: 6181263
    Abstract: A switch impedance insensitive signal processor is provided. A signal processor according to the present invention overcomes the problem of switch impedance by adding an individual buffer, e.g. a unity-gain amplifier, between the switch and the processor portion of the circuit. The buffer isolates the signal processor from the switch impedance.
    Type: Grant
    Filed: February 26, 1999
    Date of Patent: January 30, 2001
    Assignee: Linear Technology Corp.
    Inventors: Hassan Malik, William C. Rempfer, James L. Brubaker
  • Patent number: 4897657
    Abstract: Employed is a thermometer-code-to-one-of-n converter having a number of similar portions each of which includes gates each configured to detect a zero-zero-one pattern and to develop a one-of-n signal, gates each configured to detect a one-zero-zero pattern (an invalid pattern) and to develop an error signal, gates configured to combine the error signals, and gates configured to gate the error signals with the one-of-n pattern signals to block (inhibit) one-of-n signals.
    Type: Grant
    Filed: June 13, 1988
    Date of Patent: January 30, 1990
    Assignee: Integrated Device Technology, Inc.
    Inventor: James L. Brubaker
  • Patent number: 4465996
    Abstract: A high accuracy monolithic digital to analog converter (DAC) which employs an EPROM controlled correction DAC to correct for errors in the output of a primary DAC. The correction DAC empolys a non-binary bit weighting which permits the use of low accuracy components in the fabrication of the correction DAC. The output of the primary DAC is skewed so that the required correction is always in a single direction, thereby eliminating the need for a constant offset generator. Resistors necessary for bipolar operation are included on the chip, thereby eliminating the need for connection of any external resistors to achieve such operation.
    Type: Grant
    Filed: May 24, 1982
    Date of Patent: August 14, 1984
    Assignee: Intersil, Inc.
    Inventors: Ziya G. Boyacigiller, James L. Brubaker, Jerome C. Zis