Patents by Inventor Thomas K. Johnston

Thomas K. Johnston 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: 7917875
    Abstract: An adjustable buffer including a series of P-channel devices having current paths coupled between a first voltage supply and at least one output node, and a series of N-channel devices having current paths coupled between the output node and a second voltage supply. The control electrodes of the P- and N-channel devices are coupled to a selected one of an input node and a corresponding voltage supply collectively forming first and second sets of selectable connections. The first and second sets of selectable connections are made to adjust delay from the input node to the output node. The selectable connections may be defined in an integrated circuit mask or may be electronic switches. The P- and N-channel devices may be in a balanced configuration or an imbalanced configuration. The P- and N-channel devices may form an inverting buffer or a non-inverting buffer.
    Type: Grant
    Filed: February 23, 2009
    Date of Patent: March 29, 2011
    Assignee: Freescale Semiconductor, Inc.
    Inventor: Thomas K. Johnston
  • Patent number: 7571406
    Abstract: An adjustable buffer including a first series of P-channel devices having current electrodes coupled in series between a first voltage supply and a first output node, and a first series of N-channel devices having current electrodes coupled in series between the first output node and a second voltage supply. The control electrodes of the P- and N-channel devices are coupled to a selected one of an input node and a corresponding voltage supply collectively forming first and second sets of selectable connections. The first and second sets of selectable connections are made to adjust delay from the input node to the first output node. A clock distribution system including multiple uniform adjustable buffers coupled between at least one root node and multiple destination nodes, where each uniform adjustable buffer is adjustable between a minimum delay and a maximum delay.
    Type: Grant
    Filed: August 4, 2005
    Date of Patent: August 4, 2009
    Assignee: Freescale Semiconductor, Inc.
    Inventor: Thomas K. Johnston
  • Patent number: 6877123
    Abstract: Embodiments of the present invention relate generally to scan clock waveform generation. One embodiment utilizes global and local circular shift registers to provide a series of shift/capture pulses at a manageable frequency for the tester and launch pulses that are phase shifted in order to provide for at-speed testing. Therefore, scan test patterns may be shifted in or out of state elements at lower frequencies as compared to the normal operating frequency of the integrated circuit being tested, while still allowing for at-speed testing. An alternate embodiment utilizes a circular shift register in combination with static storage devices and waveform generators to provide the shift/capture pulses and launch pulses. Embodiments of the present invention also allow for clock inversion where the clock and clock bar signals are dependent during normal mode and independent during scan test mode.
    Type: Grant
    Filed: December 19, 2001
    Date of Patent: April 5, 2005
    Assignee: Freescale Semiconductors, Inc.
    Inventors: Thomas K. Johnston, Frank Frederick
  • Publication number: 20030115524
    Abstract: Embodiments of the present invention relate generally to scan clock waveform generation. One embodiment utilizes global and local circular shift registers to provide a series of shift/capture pulses at a manageable frequency for the tester and launch pulses that are phase shifted in order to provide for at-speed testing. Therefore, scan test patterns may be shifted in or out of state elements at lower frequencies as compared to the normal operating frequency of the integrated circuit being tested, while still allowing for at-speed testing. An alternate embodiment utilizes a circular shift register in combination with static storage devices and waveform generators to provide the shift/capture pulses and launch pulses. Embodiments of the present invention also allow for clock inversion where the clock and clock bar signals are dependent during normal mode and independent during scan test mode.
    Type: Application
    Filed: December 19, 2001
    Publication date: June 19, 2003
    Inventors: Thomas K. Johnston, Frank Frederick
  • Patent number: 6167484
    Abstract: A method and apparatus that improves either power savings and/or DRAM system access bandwidth in an embedded DRAM device. The apparatus (200, 800, or 900) contains embedded DRAM memory devices (212, 802, or 902) which require refresh operations in order to retain data. As the memory devices (212, 802, or 902) are accessed by read and write system operations and by refresh operations, a set of history bits (204, 808, 904) are continually updated to indicate a level of freshness for the charge stored in various DRAM memory rows. When scheduled refresh opportunities arrive for each memory row in the embedded DRAM devices, the history bits (204, 808, 904) are accessed to determine if the refresh operation of a row of memory should be performed or if the refresh operation should be postponed until a subsequent refresh time period.
    Type: Grant
    Filed: May 12, 1998
    Date of Patent: December 26, 2000
    Assignee: Motorola, Inc.
    Inventors: John Mark Boyer, William Clayton Bruce, Jr., Grady Lawrence Giles, Thomas K. Johnston, Bernard J. Pappert, John J. Vaglica
  • Patent number: 5748949
    Abstract: A counter (200) generates signals which have an average period of a non-integer multiple of an input clock period. Through the use of this non-integer multiple period, non-integer division operations are executed and used in circuits such as pulse width modulators (800) and phase lock loops (900). Additionally, when the counter (200') is used with a Gray coded counter, the average duty cycle of all bits is exactly equal to 50%.
    Type: Grant
    Filed: July 2, 1996
    Date of Patent: May 5, 1998
    Assignee: Motorola Inc.
    Inventor: Thomas K. Johnston
  • Patent number: 5135594
    Abstract: The present invention discloses a hot melt sealant comprising a thermosetting styrene butadiene diblock copolymer and a styrene butadiene terpolymer. The composition is capable of flowing, expanding and curing at temperatures below 300.degree. F. Also disclosed is a method of making the sealant and a method of using the sealant.
    Type: Grant
    Filed: February 11, 1991
    Date of Patent: August 4, 1992
    Assignee: United Technologies Automotive Inc.
    Inventor: Thomas K. Johnston
  • Patent number: 5017653
    Abstract: The present invention discloses a hot melt sealant comprising a thermosetting styrene butadiene diblock copolymer and a styrene butadiene terpolymer. The composition being capable of flowing, expanding and curing at temperatures below 300.degree. F. Also disclosed is a method of making the sealant and a method of using the sealant.
    Type: Grant
    Filed: January 16, 1990
    Date of Patent: May 21, 1991
    Assignee: United Technologies Automotive Inc.
    Inventor: Thomas K. Johnston
  • Patent number: 4978474
    Abstract: The present invention discloses a heat pumpable expandable weld through sealant comprising a combination of a terpolymer and a copolymer, a curing agent, electrically conductive particles and a blowing agent. Also disclosed is a method of bonding two metal components using this sealant.
    Type: Grant
    Filed: July 24, 1987
    Date of Patent: December 18, 1990
    Assignee: United Technologies Automotive Inc.
    Inventor: Thomas K. Johnston