Patents by Inventor John Fifield
John Fifield 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).
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Publication number: 20040001382Abstract: A writeback and refresh circuit for a direct sense architecture memory wherein a plurality of primary sense amps are connected to a global data line and also to bitlines, each of which is coupled to an array of memory storage cells which are selected for write and read operations by a plurality of wordlines. A single secondary sense amp receives analog level data from the primary sense amps over the global data line, and includes a restore/writeback circuit which digitizes the data and then returns the digitized data over the global data line to the primary sense amp and back into the memory. A 2-cycle read/writeback operation is used for each memory read cycle, a first cycle read operation, and a second cycle writeback operation. The 2-cycle destructive read architecture eliminates the need for a cache and complex caching algorithms.Type: ApplicationFiled: July 1, 2002Publication date: January 1, 2004Applicant: International Business Machines CorporationInventors: Ciaran J. Brennan, John A. Fifield, Jeremy K. Stephens, Daniel W. Storaska
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Patent number: 6667633Abstract: A multiple finger off chip driver (OCD) has a single level translator for each of a plurality of PFET fingers and NFET fingers which allow the impedance of the OCD to be varied to match the impedance of a driven load. A plurality of PFET and NFET finger selection devices are used to select various combinations of output FETS and ballast resistor finger combinations to drive an output signal at a desired impedance level. The ballast resistors are scaled in ohmic value to the size of the output finger it is connected to. In this configuration, a constant ratio of FET impedance to ballast resistance is maintained in each drive stage (finger). By selecting various combinations of fingers various driver impedances can be selected.Type: GrantFiled: March 7, 2002Date of Patent: December 23, 2003Assignees: International Business Machines Corporation, Infineon Technologies North America CorporationInventors: John A. Fifield, Wolfgang Hokenmaier
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Publication number: 20030193828Abstract: A localized direct sense architecture circuit includes a large number (e.g. 8) of microcells, each having a primary sense amp PSA, coupled to one global data line which is coupled to one secondary sense amp SSA. Each PSA includes its own bias current device, which supplies bias current to sense devices in the PSA and is also used for precharge, such that the bias current does not flow along the highly capacitive global data line. With this technical approach, the size of each bias current supply device can be substantially reduced, and the number of PSAs on one global data line can be increased for increased layout density.Type: ApplicationFiled: April 12, 2002Publication date: October 16, 2003Applicant: International Business Machines CorporationInventors: Ciaran J. Brennan, John A. Fifield
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Patent number: 6631503Abstract: The present invention provides a temperature programmable timing delay system utilizing circuitry for generating a band-gap reference and for sensing the on-chip temperature of an integrated circuit chip. The circuitry outputs the sensed temperature as a binary output which is received by a programmable table circuit of the timing delay system. The programmable table circuit outputs a binary output corresponding to the received binary output. The timing delay system further includes a temperature dependent timing delay circuit having inputs for receiving the binary output of the programmable table circuit and an output for outputting a timing delay signal for delaying a clock by a timing delay corresponding to the binary output of the programmable table circuit. The band-gap reference can be a temperature independent band-gap reference voltage having a constant-voltage value or a temperature dependent band-gap reference current having a constant-current value.Type: GrantFiled: January 5, 2001Date of Patent: October 7, 2003Assignee: IBM CorporationInventors: Louis L. Hsu, Rajiv V. Joshi, John A. Fifield
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Patent number: 6621324Abstract: An antifuse structure for improved programming efficiency is disclosed wherein the antifuse structure including a first node providing a first voltage, a plurality of antifuse elements, and a plurality of first switches. The plurality of antifuse elements are commonly connected to the first node. The plurality of first switches are sequentially activated during a program mode to individually apply the first voltage to each antifuse element. The antifuse structure may include a second node to which a second voltage is provided. Each of the plurality of first switches may be coupled between the second node and a corresponding one of the plurality of antifuse elements. The antifuse structure may also include a third node to which a fuse latch is connected. A plurality of second switches may be coupled between the third node and a corresponding one of the plurality antifuse elements. The plurality of second switches may be simultaneously activated during a read mode.Type: GrantFiled: February 19, 2002Date of Patent: September 16, 2003Assignee: International Business Machines CorporationInventors: John A. Fifield, William R. Tonti
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Publication number: 20030167716Abstract: An insulative panel with transverse fiber reinforcements is provided and which is adopted for use with a plurality of building materials such as concrete to create a lightweight, high strength building panel having superior insulative properties.Type: ApplicationFiled: May 17, 2002Publication date: September 11, 2003Inventors: Harold G. Messenger, Thomas G. Harmon, John A. Fifield, John M. Carson
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Publication number: 20030169069Abstract: A multiple finger off chip driver (OCD) has a single level translator for each of a plurality of PFET fingers and NFET fingers which allow the impedance of the OCD to be varied to match the impedance of a driven load. A plurality of PFET and NFET finger selection devices are used to select various combinations of output FETS and ballast resistor finger combinations to drive an output signal at a desired impedance level. The ballast resistors are scaled in ohmic value to the size of the output finger it is connected to. In this configuration, a constant ratio of FET impedance to ballast resistance is maintained in each drive stage (finger). By selecting various combinations of fingers various driver impedances can be selected.Type: ApplicationFiled: March 7, 2002Publication date: September 11, 2003Applicant: International Business Machines CorporationInventors: John A. Fifield, Wolfgang Hokenmaier
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Publication number: 20030155961Abstract: An antifuse structure for improved programming efficiency is disclosed wherein the antifuse structure including a first node providing a first voltage, a plurality of antifuse elements, and a plurality of first switches. The plurality of antifuse elements are commonly connected to the first node. The plurality of first switches are sequentially activated during a program mode to individually apply the first voltage to each antifuse element. The antifuse structure may include a second node to which a second voltage is provided. Each of the plurality of first switches may be coupled between the second node and a corresponding one of the plurality of antifuse elements. The antifuse structure may also include a third node to which a fuse latch is connected. A plurality of second switches may be coupled between the third node and a corresponding one of the plurality antifuse elements. The plurality of second switches may be simultaneously activated during a read mode.Type: ApplicationFiled: February 19, 2002Publication date: August 21, 2003Applicant: International Business Machines CorporationInventors: John A. Fifield, William R. Tonti
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Publication number: 20030115819Abstract: An extruded concrete interlocking roof tile has upper and under surfaces, upper and lower edges, two opposite side edges, with the upper surface having a recess extending transversely between the two opposite side edges adjacent the upper edge for receiving a lower edge region of an adjacent tile in overlapping relationship, and in that integral spacer means acts between the recess floor and the undersurface of the adjacent tile.Type: ApplicationFiled: November 21, 2002Publication date: June 26, 2003Inventor: John Fifield
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Patent number: 6577154Abstract: A compensated driver for maintaining constant impedance during data transfer from an integrated circuit comprises an output portion having an output device to transfer data from the integrated circuit and a mimic circuit portion having a sample output device scaled to a fraction of the output device adapted to accept a reference current and generate a sample voltage. A mimic circuit portion has a sample output device scaled to a fraction of the output device adapted to accept a reference current and generate a sample voltage. A differential amplifier portion is adapted to generate a control voltage in response to a reference voltage and the sample voltage. A predrive portion applies either a ground or the predetermined control voltage from the differential amplifier portion to the output stage portion in response to an input, the control voltage regulating the output device in the output stage portion to achieve a more constant impedance.Type: GrantFiled: May 3, 2001Date of Patent: June 10, 2003Assignee: International Business Machines CorporationInventors: John A. Fifield, Russell J. Houghton
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Publication number: 20030084386Abstract: An ECC based system and method within an integrated circuit memory for self-repair of a failed memory element is disclosed. The method includes processing, within the integrated circuit, data and check bits retrieved from addressed memory locations therein. The locations of memory failures are automatically recorded within the integrated circuit. Logic circuits within the integrated circuit automatically identify failure patterns based on the locations. Based on the identified failure patterns, logic circuits within the integrated circuit then permanently replace a failed memory element with an appropriate redundancy element, using devices such as electronic fuse or antifuse. In this manner, the integrated circuit automatically identifies and effects self repair of a failed memory element therein.Type: ApplicationFiled: October 25, 2001Publication date: May 1, 2003Inventors: John E. Barth, Wayne F. Ellis, John A. Fifield
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Patent number: 6552944Abstract: A single bitline direct sensing architecture employs a 4 transistor sense amplifier circuit located in each memory array, wherein the transistors function to selectively transfer data bits from either a true bitline or a complement bitline of the bitline pair to a data line. The data line is preferably arranged over a plurality of memory arrays. The data line may or may not be shared for the read and write operations. One current source is additionally used to precharge the datalines in a read mode, performing the function of a digital sensing scheme by detecting a resistance ratio between the current source and the transistor driven by the bitline for the corresponding array. A simple inverter may be used for detecting a level of the data line determined by the resistance ratio. The bitline pair is sensed in a single ended fashion, eliminating the need for a cross-coupled pair of CMOS devices, and thus reducing the required layout area.Type: GrantFiled: May 31, 2001Date of Patent: April 22, 2003Assignee: International Business Machines CorporationInventors: John A. Fifield, Toshiaki Kirihata, Wing K. Luk, Jeremy K. Stephens, Daniel W. Storaska
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Patent number: 6538932Abstract: A semiconductor memory is disclosed, the memory comprising: a memory cell adapted to store a bit; a wordline and a bitline coupled to the memory cell; a primary sense amplifier coupled to the bitline to receive a signal representing the stored bit when the wordline is active; a wordline driver coupled to activate the wordline; and a primary delay device adapted to produce a first delay selected from a range of selectable delays, the primary delay device adapted to compensate for signal propagation delay along the wordline.Type: GrantFiled: June 13, 2001Date of Patent: March 25, 2003Assignee: International Business Machines CorporationInventors: Wayne F. Ellis, John A. Fifield, Louis L. Hsu
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Patent number: 6518827Abstract: A method and system are disclosed for adjusting the threshold in MOS devices, in particular for devices used in DRAM sense amplifiers. The effects of process and temperature variations on the threshold are compensated by a back-bias voltage. A comparison of an indicating voltage and a reference voltage is used to generate the back-bias voltage. The direction of back-bias voltage may be either in the backward, or in the forward bias direction.Type: GrantFiled: July 27, 2001Date of Patent: February 11, 2003Assignee: International Business Machines CorporationInventors: John A. Fifield, Robert H. Dennard, Russell J. Houghton, Toshiaki Kirihara, Wing Luk
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Publication number: 20030021161Abstract: A method and system are disclosed for adjusting the threshold in MOS devices, in particular for devices used in DRAM sense amplifiers. The effects of process and temperature variations on the threshold are compensated by a back-bias voltage. A comparison of an indicating voltage and a reference voltage is used to generate the back-bias voltage. The direction of back-bias voltage may be either in the backward, or in the forward bias direction.Type: ApplicationFiled: July 27, 2001Publication date: January 30, 2003Inventors: John A. Fifield, Robert H. Dennard, Russell J. Houghton, Toshiaki Kirihara, Wing Luk
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Publication number: 20020194539Abstract: A test methodology is used to conduct an automatic chip timing analysis in coarse and fine resolution steps. Timing adjustment circuits implement coarse timing adjustment and fine timing adjustment for chip timing analysis. Timings such as clock, address and control inputs to a memory system can be digitally adjusted with respect to each other. A timer circuit is provided with a counter so that an incremental or decremental timing analysis can be carried out with a specific timing step. An algorithm is implemented which provides an effective, low-cost and accurate timing analysis. A nested loop is set up in the BIST where all possibilities of timing relationships between two or more signals can be applied to a device under test, and weaknesses, or failing timing conditions, can be found.Type: ApplicationFiled: April 5, 2001Publication date: December 19, 2002Applicant: International Business Machines CorporationInventors: Wayne F. Ellis, John A. Fifield, Louis Hsu, William V. Huott
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Publication number: 20020191448Abstract: A semiconductor memory is disclosed, the memory comprising: a memory cell adapted to store a bit; a wordline and a bitline coupled to the memory cell; a primary sense amplifier coupled to the bitline to receive a signal representing the stored bit when the wordline is active; a wordline driver coupled to activate the wordline; and a primary delay device adapted to produce a first delay selected from a range of selectable delays, the primary delay device adapted to compensate for signal propagation delay along the wordline.Type: ApplicationFiled: June 13, 2001Publication date: December 19, 2002Applicant: International Business Machines CorporationInventors: Wayne F. Ellis, John A. Fifield, Louis L. Hsu
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Patent number: 6496037Abstract: An automatic driver adjuster and methods using the same are provided that modify off-chip drivers based on load characteristics. The preferred embodiments are preferably automatic and require little or no human intervention. Preferred embodiments of the current invention analyze and determine the impedance of a node and adjust a number of output drivers in response to the impedance of the node, or analyze a resultant waveform of the node, caused by an input waveform, and adjust a number of output drivers in response to the resultant waveform of the node.Type: GrantFiled: June 6, 2000Date of Patent: December 17, 2002Assignee: International Business Machines CorporationInventors: Claude L. Bertin, John A. Fifield, Thomas M. Maffitt, Wilbur D. Pricer, William R. Tonti
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Publication number: 20020181307Abstract: A single bitline direct sensing architecture employs a 4 transistor sense amplifier circuit located in each memory array, wherein the transistors function to selectively transfer data bits from either a true bitline or a complement bitline of the bitline pair to a data line. The data line is preferably arranged over a plurality of memory arrays. The data line may or may not be shared for the read and write operations. One current source is additionally used to precharge the datalines in a read mode, performing the function of a digital sensing scheme by detecting a resistance ratio between the current source and the transistor driven by the bitline for the corresponding array. A simple inverter may be used for detecting a level of the data line determined by the resistance ratio. The bitline pair is sensed in a single ended fashion, eliminating the need for a cross-coupled pair of CMOS devices, and thus reducing the required layout area.Type: ApplicationFiled: May 31, 2001Publication date: December 5, 2002Applicant: International Business Machines CorporationInventors: John A. Fifield, Toshiaki Kirihata, Wing K. Luk, Jeremy K. Stephens, Daniel W. Storaska
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Patent number: D478179Type: GrantFiled: March 5, 2002Date of Patent: August 5, 2003Assignee: Westile, Inc.Inventor: John Fifield