Patents Represented by Attorney, Agent or Law Firm Jeanette S. Harms
  • Patent number: 6526466
    Abstract: An apparatus and method for enabling hot swapping of programmable logic devices (PLDs) and boards containing PLDs is provided. If the hot swap capability is desired, a hot swap terminal on the PLD is set to facilitate a floating state on the input/output pad of the PLD. Further, the input buffer and the output buffer of the PLD are disabled. In one embodiment, a predetermined voltage is provided on the output terminal of the input buffer. In this configuration, the hot swap circuit eliminates any leakage current, ensures no static current occurs, and provides appropriate signals to the internal circuits of the PLD.
    Type: Grant
    Filed: November 12, 1999
    Date of Patent: February 25, 2003
    Assignee: Xilinx, Inc.
    Inventors: Scott O. Frake, James L. McManus, David P. Schultz, Wilson K. Yee
  • Patent number: 6523162
    Abstract: Layout processing can be applied to an integrated circuit (IC) layout using a shape-based system. A shape can be defined by a set of associated edges in a specified configuration. A catalog of shapes is defined and layout processing actions are associated with the various shapes. Each layout processing action applies a specified layout modification to its associated shape. A shape-based rule system advantageously enables efficient formulation and precise application of layout modifications. Shapes/actions can be provided as defaults, can be retrieved from a remote source, or can be defined by the user. The layout processing actions can be compiled in a bias table. The bias table can include both rule-based and model-based actions, and can also include single-edge shapes for completeness. The scanning of the IC layout can be performed in order of increasing or decreasing complexity, or can be specified by the user.
    Type: Grant
    Filed: August 2, 2000
    Date of Patent: February 18, 2003
    Assignee: Numerical Technologies, Inc.
    Inventors: Deepak Agrawal, Fang-Cheng Chang, Hyungjip Kim, Yao-Ting Wang, Myunghoon Yoon
  • Patent number: 6512289
    Abstract: An integrated circuit (I/C) assembly includes a dedicated voltage sensor line for determining with a high degree of accuracy the operating voltage at a predetermined sensor point on the IC die. The dedicated voltage sensor line connects the sensor point to an input/output (I/O) structure of the IC die, which in turn is connected to a voltage sense pin on the package of the IC assembly. In this manner, an end user can accurately monitor the operating voltage at the voltage sensor point on the IC. Additionally, an end user can connect a control circuit to the voltage sensor pin to control either the supply voltage or secondary parameters.
    Type: Grant
    Filed: May 9, 2000
    Date of Patent: January 28, 2003
    Assignee: Xilinx, Inc.
    Inventor: John S. Elward
  • Patent number: 6509739
    Abstract: A test structure provides defect information rapidly and accurately. The test structure includes a plurality of lines provided in a parallel orientation, a decoder coupled to the plurality of lines for selecting one of the plurality of lines, and a sense amplifier coupled to the selected line. To analyze an open, a line in the test structure is coupled to the sense amplifier. A high input signal is provided to the line. To determine the resistance of the open, a plurality of reference voltages are then provided to the sense amplifier. A mathematical model of the resistance of the line based on the reference voltage provided to the sense amplifier is generated. Using this mathematical model, the test structure can quickly detect and characterize defect levels down to a few parts-per-million at minimal expense.
    Type: Grant
    Filed: November 8, 2000
    Date of Patent: January 21, 2003
    Assignee: Xilinx, Inc.
    Inventors: Martin L. Voogel, Leon Ly Nguyen, Narasimhan Vasudevan
  • Patent number: 6510548
    Abstract: A method for providing a core for a programmable logic device (PLD) is provided. In this method, a vendor can designate the size and ports of a core. Using this information, a user can generate a top-level design that can accommodate the core. The user can then submit that top-level design to the vendor, or a third party designated by the vendor, to generate a complete configuration bitstream for the PLD. The user can use this configuration bitstream to program the PLD, thereby implementing the top-level design including the core. The number of bits in this configuration bitstream is typically large enough to render reverse engineering economically unfeasible. Thus, the method allows vendors to retain control over their proprietary core IP and discourages undetectable use of this IP.
    Type: Grant
    Filed: August 3, 2001
    Date of Patent: January 21, 2003
    Assignee: Xilinx, Inc.
    Inventor: David B. Squires
  • Patent number: 6496416
    Abstract: A memory cell comprises a multilayer gate heating structure formed over a channel region between source and drain regions. The multilayer gate heating structure comprises polysilicon and metal silicide layers stacked over a similarly shaped gate oxide. The gate heating structure includes a fusible portion in the metal silicide layer formed over the channel region. In an unprogrammed state, the memory cell operates as a conventional MOS transistor, with current flow between the source and drain regions being controlled by a control voltage applied to the metal silicide layer. However, when a programming voltage is applied across the metal silicide, layer, the fusible portion agglomerates, generating intense localized heating. In an embodiment of the invention, the memory cell is an NMOS device. Tie heating causes segregation of the channel dopant atoms towards the source and drain regions, lowering the threshold voltage of the device.
    Type: Grant
    Filed: December 19, 2000
    Date of Patent: December 17, 2002
    Assignee: Xilinx, Inc.
    Inventor: Kevin T. Look
  • Patent number: 6487648
    Abstract: A programmable logic device (PLD) implementing an SDRAM controller is provided. The configurable logic of the PLD forms an interface between the system and the SDRAM, as well as a state machine to operate the controller and the interface. In this manner, many functions of the SDRAM controller can be selectively controlled and easily changed by reprogramming the PLD. The configurable logic of the PLD also forms a state machine to operate the controller and the interface. In accordance with the present invention, dedicated circuits of the PLD optimize performance of the SDRAM controller. These dedicated circuits include two delay locked loops (DLLs) which eliminate skew between the system clock, a global clock in the PLD, and the SDRAM clock.
    Type: Grant
    Filed: December 15, 1999
    Date of Patent: November 26, 2002
    Assignee: Xilinx, Inc.
    Inventor: Joseph H. Hassoun
  • Patent number: 6480954
    Abstract: A programmable logic device (PLD) comprises at least one configurable element, and a plurality of programmable logic elements for configuring the configurable element(s). Alternatively, a PLD comprises an interconnect structure and a plurality of programmable logic elements for configuring the interconnect structure. In either embodiment, at least one of the programmable logic elements includes N memory cells. A predetermined one of the N memory cells forms part of a memory slice, wherein at least a portion of each slice of the programmable logic device is allocated to either configuration data or user data memory. Typically, one memory slice provides one configuration of the programmable logic device. In accordance with one embodiment, a memory access port is coupled between at least one of the N memory cells and either one configurable element or the interconnect, thereby facilitating loading of new configuration data into other memory slices during the one configuration.
    Type: Grant
    Filed: June 6, 2001
    Date of Patent: November 12, 2002
    Assignee: Xilinx Inc.
    Inventors: Stephen M. Trimberger, Richard A. Carberry, Robert Anders Johnson, Jennifer Wong
  • Patent number: 6470409
    Abstract: A multi-channel data transfer circuit and method which provides an interface between a computer system and a multi-channel communication controller. The data transfer circuit is programmable to provide a selectable number of communication channels between the computer system and the communication controller. The data transfer circuit is further programmable to provide a selectable number of entries in each of the communication channels. In a particular embodiment, FIFO memories within the data transfer circuit are logically partitioned to provide the desired number of communication channels and the desired number of entries per channel. The data transfer circuit includes a multi-channel transmit circuit for providing data values from the computer system to the communication controller, and a multi-channel receive circuit for providing data values from the computer communication controller to the computer system.
    Type: Grant
    Filed: November 26, 1996
    Date of Patent: October 22, 2002
    Assignee: Xilinx Inc.
    Inventor: David J. Ridgeway
  • Patent number: 6469929
    Abstract: A method for sensing the state of a memory cell includes both dynamic and static clamping of the bit line coupled to a memory cell. This dual clamping configuration/operation ensures a quick charge of the bit line while eliminating overcharging of the bit line. Thus, sensing the state of the memory cell is substantially independent of the size of the memory array. A sensing system for sensing the state of a memory cell can include a system bit line coupled to a terminal of the memory cell, a charge initiation device for activating a charge operation on the system bit line, and a control unit connected between the system bit line and the charge initiation device. The control unit includes a static clamp to charge the system bit line to a first predetermined voltage and a dynamic clamp to charge the system bit line to a second predetermined voltage.
    Type: Grant
    Filed: August 21, 2001
    Date of Patent: October 22, 2002
    Assignee: Tower Semiconductor Ltd.
    Inventors: Alexander Kushnarenko, Oleg Dadashev
  • Patent number: 6453457
    Abstract: Techniques for fabricating a device include forming a fabrication layout such as a mask layout, for a physical design layer, such as a design for an integrated circuit, and identifying evaluation points on an edge of a polygon corresponding to the design layer for correcting proximity effects. Included are techniques that correct for proximity effects associated with an edge in a layout corresponding to a design layer. An evaluation point is determined for the edge based on a profile of amplitudes output from a proximity effects model along a transect. The transect includes a target edge in the design layer corresponding to the edge. It is then determined how to correct at least a portion of the edge for proximity effects based on an analysis at the evaluation point. In other techniques, a dissection length parameter is derived based on a profile of amplitudes output by a proximity effects model along a transect. The transect includes a second edge in a second layout.
    Type: Grant
    Filed: September 29, 2000
    Date of Patent: September 17, 2002
    Assignee: Numerical Technologies, Inc.
    Inventors: Christophe Pierrat, Youping Zhang
  • Patent number: 6437598
    Abstract: A scalable pterm generator provides enhanced programming flexibility in logic devices such as PLAs. A scalable pterm generator includes both wide AND logic and alternative OR logic that enables efficient implementation of functions not requiring the full wide AND logic. According to an embodiment of the invention, a scalable pterm generator comprises a wide AND gate, an alternative logic circuit, and an output control circuit. The alternative logic circuit includes OR logic, thereby providing an alternative to the pure AND functionality of the wide AND gate. A set of logic input lines connects to both the inputs of the wide AND gate and the inputs of the alternative logic circuit. An output control circuit selects the final output of the scalable pterm generator. According to an embodiment of the invention, the output control circuit comprises a programmable circuit. According to another embodiment of the invention, the output control circuit comprises a multiplexer.
    Type: Grant
    Filed: February 15, 2001
    Date of Patent: August 20, 2002
    Assignee: Xilinx, Inc.
    Inventor: Shi-dong Zhou
  • Patent number: 6432808
    Abstract: A method of forming a bond pad area for an integrated circuit provides FSG in the dielectric layer while at the same time minimizes bond pad lift off. The method includes forming a first dielectric layer of fluorinated silicon glass (FSG) on a substrate, then forming an FSG barrier layer on the first dielectric layer. A second, non-FSG dielectric layer is formed on the FSG barrier layer. A barrier metal layer is then formed on the second dielectric layer. Finally, a metal layer is formed on the barrier metal layer. This metal layer provides the surface for adhesion to the bonding wire. The FSG barrier layer absorbs the atoms of fluorine diffused from the first dielectric layer. In this manner, fluorine is prevented from penetrating the second dielectric layer, thereby minimizing bond pad lift off between the second dielectric layer and the barrier metal layer. In one embodiment, the FSG barrier layer includes titanium and/or aluminum.
    Type: Grant
    Filed: December 3, 1999
    Date of Patent: August 13, 2002
    Assignee: Xilinx, Inc.
    Inventors: Michael J. Hart, James Karp
  • Patent number: 6429686
    Abstract: An output driver on an integrated circuit (IC) includes at least one transistor that has a thicker gate oxide than other standard transistors in the IC. In one embodiment, the output driver includes two pull-up transistors. A first pull-up transistor has a thicker gate oxide than standard transistors on the IC to provide a wide range of output voltages on the pad. A second pull-up transistor has a standard, i.e. thin, gate oxide thickness to ensure a fast low-to-high voltage transition on the pad. The other transistors in the output driver have standard gate oxide thicknesses. Illustrative thicknesses include 150 Angstroms for the first pull-up transistor and 50 Angstroms for the second pull-up transistor.
    Type: Grant
    Filed: June 16, 2000
    Date of Patent: August 6, 2002
    Assignee: Xilinx, Inc.
    Inventor: Hy V. Nguyen
  • Patent number: 6421817
    Abstract: An FPGA configuration provides a virtual instruction. In a generic computation, the output pattern of a first instruction is compared to the input pattern of a second instruction. If the input and output patterns of the first and second instructions do not match, then a pattern manipulation instruction is inserted between the first and second instructions. At this point, the input and output patterns of the first and second instructions should match and the computation task can be completed. The method of providing virtual instructions is applicable to any FPGA. In a standard FPGA, the data stored in the storage elements of the FPGA, such as flip-flops, is retained for the next configuration of the FPGA. In this manner, successive configurations can communicate data using the patterns of the storage elements, thereby allowing standard FPGAs to implement virtual instructions. Alternatively, a standard FPGA could write out data to an external memory using a predetermined pattern of addresses.
    Type: Grant
    Filed: April 3, 2000
    Date of Patent: July 16, 2002
    Assignee: Xilinx, Inc.
    Inventors: Sundararajarao Mohan, Stephen M. Trimberger
  • Patent number: 6421748
    Abstract: The inventive system and method simulate the actions of a selected output device driver, and then record all the request and information for the document output. The quality and size of the document output are optimized according to the properties of the selected output device driver and supported resources before it is sent to the selected remote output device. When the document output data is sent to the remote site, it is restored and converted to a format acceptable by the selected output device driver for outputting a document of desired format and quality. The inventive method and system for the universal output driver facilitate the operations of network outputting so that a local host does not have to install the driver of the selected driver. Moreover, the invention can optimize the document output in accordance to the properties of the selected output device, thereby to ensure the quality of the document output and increase the transmission speed.
    Type: Grant
    Filed: March 4, 1998
    Date of Patent: July 16, 2002
    Assignee: Nadio.com, Inc.
    Inventors: Jo-Tsen Lin, Wei-Chuan Li, Chang-Chen Chen, Chien-Wen Chen, Hsin-Yu Lin, Wang-Hsing Huang
  • Patent number: 6370052
    Abstract: A ternary dynamic CAM cell compatible with a standard logic process includes two ratio-independent 4-transistor (4T) SRAM cells. Each 4T SRAM cell includes a pair of cross-coupled driver transistors for storing data value, and a pair of access transistors. The driver transistors are sized to not be stronger than the access transistors. In one embodiment, the driver and access transistors are PMOS and NMOS, respectively, and are all substantially the same size. A match circuit for each 4T SRAM cell includes a pair of pass transistors serially coupled between a match line and a supply voltage. If the comparand and stored data bits do not match, both pass transistors are turned on, pulling the match line to the supply voltage. “A DON'T CARE” state is created by writing the same logic value to both 4T SRAM cells, so that both match circuits remain off for all input comparands.
    Type: Grant
    Filed: July 19, 2000
    Date of Patent: April 9, 2002
    Assignee: Monolithic System Technology, Inc.
    Inventors: Fu-Chieh Hsu, Wingyu Leung
  • Patent number: 6370576
    Abstract: A system and method for obstacle-free network communication allows two host computers to share data and resources freely without worrying about the restriction of the security systems in their networks. The system and method mainly comprise three software modules namely, Agent module, Initiator module, and Acceptor module. The Agent module is implemented in a computer server for receiving and storing connection requests and data from networks. The Initiator module is implemented in a host computer for sending connection requests and data to the Agent module of the computer server. The Acceptor module is implemented in another host computer for periodically querying the Agent module of the computer server to fetch the connection requests and the data from the Agent module of the computer server. Consequently, even when no direct connection can be established between the two host computers, their communication is still available via the Agent module.
    Type: Grant
    Filed: May 27, 1999
    Date of Patent: April 9, 2002
    Assignee: Nadio.com, Inc.
    Inventor: Cheng-San Huang
  • Patent number: 6370601
    Abstract: The Intelligent DMA Controller (IDMAC) significantly reduces system latency by replacing one or more layers of software with hardware. The IDMAC uses controlwise and datawise intelligence. The controlwise intelligence of the IDMAC is given specific knowledge of the structure of certain pieces of memory or hardware registers, (e.g. parameter blocks), used for Inter Process Communication. This specific knowledge can be imparted during the design phase of the IDMAC, or dynamically provided during its operation as system requirements dictate. The IDMAC achieves its DMA controlwise intelligence by understanding parameter blocks (PBs). The IDMAC reads the structure of the PB from memory directly, gets all of its PB parameters directly from memory, dereferencing as required, and then begins transferring data between the source and destination as instructed by the PB(s). Examples of PB parameters are source address, destination address, transfer length, and data intelligence opcode.
    Type: Grant
    Filed: November 3, 2000
    Date of Patent: April 9, 2002
    Assignee: Xilinx, Inc.
    Inventor: Glenn A. Baxter
  • Patent number: 6362648
    Abstract: The invention allows the implementation of common wide logic functions using only two function generators of a field programmable gate array. One embodiment of the invention provides a structure for implementing a wide AND-gate in an FPGA configurable logic element (CLE) or portion thereof that includes no more than two function generators. First and second function generators are configured as AND-gates, the output signals (first and second AND signals) being combined in a 2-to-1 multiplexer controlled by the first AND signal, “0” selecting the first AND signal and “1” selecting the second AND signal. Therefore, a wide AND-gate is provided having a number of input signals equal to the total number of input signals for the two function generators. In another embodiment, a wide OR-gate is provided by configuring the function generators as OR-gates and controlling the multiplexer using the second OR signal.
    Type: Grant
    Filed: November 13, 2000
    Date of Patent: March 26, 2002
    Assignee: Xilinx, Inc.
    Inventors: Bernard J. New, Steven P. Young, Shekhar Bapat, Kamal Chaudhary, Trevor J. Bauer, Roman Iwanczuk