Patents by Inventor Charles Parkhurst

Charles Parkhurst 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: 8390327
    Abstract: A system and method for radiation-tolerant level shifting are disclosed. In some embodiments, an integrated circuit may include a plurality of level shifters, where each of the plurality of level shifters configured receive a same logic level in a first voltage domain and to output candidate logic levels in a second voltage domain, and where at least one of the candidate logic levels subject to being different from another one of the candidate logic levels. The integrated circuit may also include a voting circuit coupled to the plurality of level shifters, where the voting circuit is configured to evaluate the candidate logic levels and output a selected logic level based, at least in part, upon the evaluation.
    Type: Grant
    Filed: August 19, 2011
    Date of Patent: March 5, 2013
    Assignee: Texas Instruments Incorporated
    Inventors: Charles Parkhurst, Mark Hamlyn
  • Publication number: 20130043903
    Abstract: A system and method for radiation-tolerant level shifting are disclosed. In some embodiments, an integrated circuit may include a plurality of level shifters, where each of the plurality of level shifters configured receive a same logic level in a first voltage domain and to output candidate logic levels in a second voltage domain, and where at least one of the candidate logic levels subject to being different from another one of the candidate logic levels. The integrated circuit may also include a voting circuit coupled to the plurality of level shifters, where the voting circuit is configured to evaluate the candidate logic levels and output a selected logic level based, at least in part, upon the evaluation.
    Type: Application
    Filed: August 19, 2011
    Publication date: February 21, 2013
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Charles Parkhurst, Mark Hamlyn
  • Patent number: 8228108
    Abstract: A level formatter is provided that has differentially coupled closed loop current sources, each configured to precisely establish a current proportional to a reference voltage. A bridge circuit is differentially coupled to two supplementary current sources and controlled to rapidly switch the current from the supplementary current sources to produce output voltages at respective outputs that are approximately equal to respective one of two reference voltages.
    Type: Grant
    Filed: October 5, 2010
    Date of Patent: July 24, 2012
    Assignee: Texas Instruments Incorporated
    Inventors: Hector Torres, Charles Parkhurst
  • Publication number: 20110095798
    Abstract: A level formatter is provided that has differentially coupled closed loop current sources, each configured to precisely establish a current proportional to a reference voltage. A bridge circuit is differentially coupled to two supplementary current sources and controlled to rapidly switch the current from the supplementary current sources to produce output voltages at respective outputs that are approximately equal to respective ones of two reference voltages.
    Type: Application
    Filed: October 5, 2010
    Publication date: April 28, 2011
    Inventors: Hector Torres, Charles Parkhurst
  • Patent number: 7362176
    Abstract: A linear amplifier is configured with a current-feedback amplifier followed by a voltage-feedback amplifier to drive a totem-pole output stage. The output stage includes a series arrangement of an npn transistor and a pnp transistor with their emitters coupled in series and to an output node. The voltage amplifier driving the output stage is also configured with totem-pole elements, wherein a conductive path between the voltage-feedback amplifier and an output transistor is included to reduce conduction of the output transistor when the opposing output transistor is driven to increase conduction as a result of a high-frequency input signal. A capacitor may be included between the collector and base of a transistor in the circuit path that drives an output transistor in the output stage to briefly reduce its conduction when the opposing output transistor is driven to increase conduction.
    Type: Grant
    Filed: February 18, 2005
    Date of Patent: April 22, 2008
    Assignee: Texas Instruments Incorporated
    Inventors: Maria-Flora Carreto, Charles Parkhurst
  • Patent number: 7307477
    Abstract: An apparatus for affecting operation of a signal treating device that is provided an operating voltage ranging between an upper voltage limit and a lower voltage limit for treating at least one input signal includes: a respective dynamic bias unit coupled with the signal treating device for each respective input signal of the at least one input signal; and a respective transconductance control unit coupled with each the respective dynamic bias unit. Each respective dynamic bias unit and transconductance control unit cooperates to operate the signal treating device responsive to the at least one input signal approaching at least one of the upper voltage limit and the lower voltage limit.
    Type: Grant
    Filed: February 8, 2006
    Date of Patent: December 11, 2007
    Assignee: Texas Instruments Incorporated
    Inventors: Maria-Flora Carreto, Charles Parkhurst
  • Patent number: 7265445
    Abstract: An IC package includes a package body of non-conductive material. A conductive heat-sink pad includes an interior pad portion located within an interior of the package body. An exterior pad portion is located external to the package body. The exterior pad portion includes at least two pad pieces that are spaced apart to define at least one channel that separates the at least two pad pieces, the at least two pad pieces being electrically connected with each other. The at least two pad pieces may be flush with an underside surface of the package body or one or more of the pad pieces may extend outwardly from the package body.
    Type: Grant
    Filed: March 23, 2005
    Date of Patent: September 4, 2007
    Assignee: Texas Instruments Incorporated
    Inventors: Dolly Wu, Charles Parkhurst
  • Publication number: 20070194851
    Abstract: An apparatus for affecting operation of a signal treating device that is provided an operating voltage ranging between an upper voltage limit and a lower voltage limit for treating at least one input signal includes: a respective dynamic bias unit coupled with the signal treating device for each respective input signal of the at least one input signal; and a respective transconductance control unit coupled with each the respective dynamic bias unit. Each respective dynamic bias unit and transconductance control unit cooperates to operate the signal treating device responsive to the at least one input signal approaching at least one of the upper voltage limit and the lower voltage limit.
    Type: Application
    Filed: February 8, 2006
    Publication date: August 23, 2007
    Inventors: Maria-Flora Carreto, Charles Parkhurst
  • Patent number: 7135927
    Abstract: The present invention achieves technical advantages as an operational amplifier (30) having both a high slew rate and a full power bandwidth with low distortion by providing resistors (R6, R7, R9, R10) in place of active loads coupled to a differential pair (Q22, Q25, and Q23, Q24) of transistors in a folded cascode input stage (34). By utilizing passive resistors instead of active loads, no saturation occurs during high slew rate signals. The present invention achieves technical advantages of higher slew rate and lower noise without sacrificing power consumption.
    Type: Grant
    Filed: December 15, 2003
    Date of Patent: November 14, 2006
    Assignee: Texas Instruments Incorporated
    Inventor: Charles Parkhurst
  • Publication number: 20060214285
    Abstract: An IC package includes a package body of non-conductive material. A conductive heat-sink pad includes an interior pad portion located within an interior of the package body. An exterior pad portion is located external to the package body. The exterior pad portion includes at least two pad pieces that are spaced apart to define at least one channel that separates the at least two pad pieces, the at least two pad pieces being electrically connected with each other. The at least two pad pieces may be flush with an underside surface of the package body or one or more of the pad pieces may extend outwardly from the package body.
    Type: Application
    Filed: March 23, 2005
    Publication date: September 28, 2006
    Inventors: Dolly Wu, Charles Parkhurst
  • Publication number: 20060186958
    Abstract: A linear amplifier is configured with a current-feedback amplifier followed by a voltage-feedback amplifier to drive a totem-pole output stage. The output stage includes a series arrangement of an npn transistor and a pnp transistor with their emitters coupled in series and to an output node. The voltage amplifier driving the output stage is also configured with totem-pole elements, wherein a conductive path between the voltage-feedback amplifier and an output transistor is included to reduce conduction of the output transistor when the opposing output transistor is driven to increase conduction as a result of a high-frequency input signal. A capacitor may be included between the collector and base of a transistor in the circuit path that drives an output transistor in the output stage to briefly reduce its conduction when the opposing output transistor is driven to increase conduction.
    Type: Application
    Filed: February 18, 2005
    Publication date: August 24, 2006
    Inventors: Maria-Flora Carreto, Charles Parkhurst
  • Patent number: 7078962
    Abstract: A dynamic current generator 30 is disclosed in which a common-mode input range is provided which is asymmetric toward the bottom rail VEE. An embodiment of the invention is also disclosed used in an asymmetrical dynamically biased amplifier system 34.
    Type: Grant
    Filed: April 23, 2003
    Date of Patent: July 18, 2006
    Assignee: Texas Instruments Incorporated
    Inventor: Charles Parkhurst
  • Patent number: 7009450
    Abstract: A voltage feedback (“VF”) operational amplifier (“op-amp”) that includes a circuit operable to dynamically bias pre-driver transistors at the op amp output stage. This arrangement provides a dynamic bias from a common base gain stage (302) to the pre-drivers (338, 339) of the output stage (303) so that higher slew rate is achieved with minimal discontinuity in the signal.
    Type: Grant
    Filed: December 11, 2003
    Date of Patent: March 7, 2006
    Assignee: Texas Instruments Incorporated
    Inventors: Charles Parkhurst, Muhammad Islam
  • Publication number: 20050128000
    Abstract: The present invention achieves technical advantages as an operational amplifier (30) having both a high slew rate and a full power bandwidth with low distortion by providing resistors (R6, R7, R9, R10) in place of active loads coupled to a differential pair (Q22, Q25, and Q23, Q24) of transistors in a folded cascode input stage (34). By utilizing passive resistors instead of active loads, no saturation occurs during high slew rate signals. The present invention achieves technical advantages of higher slew rate and lower noise without sacrificing power consumption.
    Type: Application
    Filed: December 15, 2003
    Publication date: June 16, 2005
    Inventor: Charles Parkhurst
  • Publication number: 20050127999
    Abstract: A voltage feedback (“VF”) operational amplifier (“op-amp”) that includes a circuit operable to dynamically bias pre-driver transistors at the op amp output stage. This arrangement provides a dynamic bias from a common base gain stage (302) to the pre-drivers (338, 339) of the output stage (303) so that higher slew rate is achieved with minimal discontinuity in the signal.
    Type: Application
    Filed: December 11, 2003
    Publication date: June 16, 2005
    Inventors: Charles Parkhurst, Muhammad Islam
  • Publication number: 20040212425
    Abstract: A dynamic current generator 30 is disclosed in which a common-mode input range is provided which is asymmetric toward the bottom rail VEE. An embodiment of the invention is also disclosed used in an asymmetrical dynamically biased amplifier system 34.
    Type: Application
    Filed: April 23, 2003
    Publication date: October 28, 2004
    Inventor: Charles Parkhurst
  • Patent number: 6784736
    Abstract: An apparatus for indicating a difference between a first voltage and a second voltage includes: (a) an input unit for receiving the first voltage at a first locus and receiving the second voltage at a second locus; the input unit quanitifying the difference; (b) an output unit coupled with the input unit and cooperating with the input unit to generate an output signal for effecting the indicating; and (c) a signal treating unit coupled with the output unit, the first locus and the second locus, and employing at least one algorithmic relation with at least one of the first voltage and the second voltage to generate at least one bias current for effecting a substantially balanced response by said output section in said generating said output signal as said difference varies. The at least one drive current has nonnegative values as the difference ranges in value.
    Type: Grant
    Filed: November 12, 2002
    Date of Patent: August 31, 2004
    Assignee: Texas Instruments Incorporated
    Inventor: Charles Parkhurst
  • Publication number: 20040090270
    Abstract: An apparatus for indicating a difference between a first voltage and a second voltage includes: (a) an input unit for receiving the first voltage at a first locus and receiving the second voltage at a second locus; the input unit quanitifying the difference; (b) an output unit coupled with the input unit and cooperating with the input unit to generate an output signal for effecting the indicating; and (c) a signal treating unit coupled with the output unit, the first locus and the second locus, and employing at least one algorithmic relation with at least one of the first voltage and the second voltage to generate at least one bias current for effecting a substantially balanced response by said output section in said generating said output signal as said difference varies. The at least one drive current has nonnegative values as the difference ranges in value.
    Type: Application
    Filed: November 12, 2002
    Publication date: May 13, 2004
    Inventor: Charles Parkhurst
  • Patent number: 6710655
    Abstract: An emitter coupled pair transconductor circuit includes: an emitter couple pair 20 and 21; and a tail current source coupled to the emitter couple pair wherein the tail current source provides a tail current that is a hyperbolic cosine function relative to a differential input signal. This solution transforms the output current of an emitter couple pair transconductor from a hyperbolic tangent to a hyperbolic sine by using a hyperbolic cosine comparator for the biasing. By doing this, the transconductor has a similar speed behavior to a second-generation current conveyor and is more precise. This transformation makes a regular transconductor very fast without changing its parameters.
    Type: Grant
    Filed: May 13, 2002
    Date of Patent: March 23, 2004
    Assignee: Texas Instruments Incorporated
    Inventors: Charles Parkhurst, Julio E. Acosta
  • Patent number: 6710654
    Abstract: The present invention (800) comprises an operational amplifier with a first stage comparator circuit (801) for biasing a second stage folded cascode amplifier circuit (802). The result is that the input differential voltage signal to output current signal is transformed from a tanh function to a sinh function. The present invention provides the low noise, low distortion, high gain, wide bandwidth and good DC performance characteristics of the folded cascode op-amp configuration, with much improved slew rate.
    Type: Grant
    Filed: November 15, 2001
    Date of Patent: March 23, 2004
    Assignee: Texas Instruments Incorporated
    Inventors: Charles Parkhurst, Julio E. Acosta