Patents Represented by Attorney, Agent or Law Firm Jonathan H. Schafer
  • Patent number: 6285212
    Abstract: An FPGA architecture has top, middle and low levels. The top level of the architecture is an array of the B16×16 tiles arranged in a rectangular array and enclosed by I/O blocks on the periphery. On each of the four sides of a B16×16 tile, and also associated with each of the I/O blocks is a freeway routing channel. A B16×16 tile in the middle level of hierarchy is a sixteen by sixteen array of B1 blocks. The routing resources in the middle level of hierarchy are expressway routing channels M1, M2, and M3 including groups of interconnect conductors. At the lowest level of the semi-hierarchical FPGA architecture, there are block connect (BC) routing channels, local mesh (LM) routing channels, and direct connect (DC) interconnect conductors to connect the logic elements to further routing resources.
    Type: Grant
    Filed: March 6, 2000
    Date of Patent: September 4, 2001
    Assignee: Actel Corporation
    Inventor: Sinan Kaptanoglu
  • Patent number: 6272655
    Abstract: The present invention provides for a method of testing an FPGA using NVM memory cells for programmable interconnects. The NVM memory cells are arranged as a memory array of rows and columns. User-configurable logic elements and interconnections, which are programmed by the stored states of the memory cells, are organized into identical and/or differing tiles. The tiles are organized into an array of rows and columns superimposed upon the memory array. The testing method includes: selecting test circuit configurations by which identical tiles are identically programmed as much as possible; and simultaneously programming and simultaneously erasing pluralities of the memory rows corresponding to the tiles into the test circuit configurations. Additionally, the test circuit configurations programmed into the FPGA are tested at a lower supply voltage than that of normal operation.
    Type: Grant
    Filed: June 11, 1998
    Date of Patent: August 7, 2001
    Assignee: Actel Corporation
    Inventors: Volker Hecht, Timothy Saxe
  • Patent number: 6268743
    Abstract: An FPGA architecture has top, middle and low levels. The top level of the architecture is an array of the B16×16 tiles arranged in a rectangular array and enclosed by I/O blocks on the periphery. On each of the four sides of a B16×16 tile, and also associated with each of the I/O blocks is a freeway routing channel. A B16×16 tile in the middle level of hierarchy is a sixteen by sixteen array of B1 blocks. The routing resources in the middle level of hierarchy are expressway routing channels M1, M2, and M3 including groups of interconnect conductors. At the lowest level of the semi-hierarchical FPGA architecture, there are block connect (BC) routing channels, local mesh (LM) routing channels, and direct connect (DC) interconnect conductors to connect the logic elements to further routing resources. Each B1 block includes four clusters of devices. Each of the four clusters includes first and second LUT3s, a LUT2, and a DFF .
    Type: Grant
    Filed: March 6, 2000
    Date of Patent: July 31, 2001
    Assignee: Acatel Corporation
    Inventor: Sinan Kaptanoglu
  • Patent number: 6252273
    Abstract: A programmable interconnect cell for selectively connecting circuit nodes of a field programmable integrated circuit array in a semiconductor substrate includes a switch field effect transistor, a sense field effect transistor, and an electron tunneling device with the transistors and electron tunneling device having interconnected floating gates and interconnected control gates. The floating gates comprise a first polysilicon layer which is restricted to each cell, and the control gates comprise a second polysilicon layer which extends to adjacent cells in the row. The source/drain regions of the sense transistor extend to source/drain regions of sense amplifiers in adjacent rows. Programming and erasing of the switch transistor is effected entirely by electron tunneling in the electron tunneling device.
    Type: Grant
    Filed: August 24, 1998
    Date of Patent: June 26, 2001
    Assignee: Actel Corporation
    Inventors: Robert M. Salter, III, Robert J. Lipp, Kyung Joon Han, Jack Zezhong Peng
  • Patent number: 6237124
    Abstract: A method for detecting an error in data stored in configuration SRAM and user assignable SRAM in a FPGA comprises the steps of providing a serial data stream into the FPGA from an external source, loading data from the serial data stream into the configuration SRAM in response to address signals generated by row column counters, loading data from the serial data stream into the user assignable SRAM in response to address signals generated by row and column counters, loading a seed and signature from the serial data stream into a cyclic redundancy checking circuit, cycling data out of the configuration SRAM and the user assignable SRAM by the row and column counters; performing error checking on the data that has been cycled out of the configuration SRAM and out of the user assignable SRAM by the cyclic redundancy checking circuit, and generating an error signal when an error is detected by the error checking circuit.
    Type: Grant
    Filed: March 16, 1998
    Date of Patent: May 22, 2001
    Assignee: Actel Corporation
    Inventor: William C. Plants
  • Patent number: 6160420
    Abstract: A user-programmable interconnect architecture, which may be used for logic arrays for digital and analog system design, is disclosed. In one embodiment, a plurality of logic cells or modules in a matrix are connected by vertical and horizontal wiring channels. The wiring channels may in turn be programmed by the user to interconnect the various logic cells to implement the required logic function. The wiring channels comprise wiring segments connected by normally open programmable. Elements situated at the intersection of any two segments to be connected.
    Type: Grant
    Filed: November 12, 1996
    Date of Patent: December 12, 2000
    Assignee: Actel Corporation
    Inventors: Abbas El Gamal, Khaled A. El-Avat, Amr Mohsen
  • Patent number: 6150837
    Abstract: An enhanced performance field programmable gate array integrated circuit comprises a field programmable gate array and other functional circuitry such as a mask-programmable gate array in the same integrated circuit. A circuit interface provides communication between the field programmable gate array, the mask-programmable gate array and the integrated circuit I/O.
    Type: Grant
    Filed: February 28, 1997
    Date of Patent: November 21, 2000
    Assignee: Actel Corporation
    Inventors: Samuel W. Beal, Sinan Kaptonoglu, Jung-Cheun Lien, William Shu, King W. Chan, William C. Plants
  • Patent number: 6124193
    Abstract: An antifuse comprises a lower electrode formed from a metal layer in a microcircuit. A interlayer dielectric layer is disposed over the lower electrode and has an aperture formed therein. A conductive plug, formed from a material such as tungsten, is formed in the aperture. The upper surface of the interlayer dielectric is etched back to create a raised portion of the plug. The upper edges of the plug are rounded. An antifuse layer, preferably comprising a silicon nitride, amorphous silicon, silicon nitride sandwich incorporating a thin silicon dioxide layer above or below the amorphous silicon layer or such a sandwich structure covered by a titanium nitride layer, is disposed above the plug. An upper electrode, preferably comprising a metal layer is disposed over the antifuse layer.
    Type: Grant
    Filed: April 17, 1998
    Date of Patent: September 26, 2000
    Assignee: Actel Corporation
    Inventors: Frank W. Hawley, John L. McCollum, Ying Go, Abdelshafy Eltoukhy
  • Patent number: 6111302
    Abstract: The present invention relates to a high performance, high reliability antifuse using conductive electrodes. The problem of switch-off of the programmed antifuses is solved by reducing the thermal conductivity of the conductive electrodes. This is achieved by using lower thermal conductivity conductors for the electrodes or by using thinner electrodes to increase thermal resistance. According to a first aspect of the present invention, the problem of switch-off in conductor-to-conductor antifuses is solved by utilizing conductive electrode materials having a relatively lower thermal conductivity than prior art electrode materials. According to a second aspect of the present invention, the problem of switch-off in conductor-to-conductor antifuses is solved by utilizing relatively thin electrodes, thus increasing their thermal resistance.
    Type: Grant
    Filed: August 30, 1995
    Date of Patent: August 29, 2000
    Assignee: Actel Corporation
    Inventors: Guobiao Zhang, Chenming Hu, Steve S. Chiang
  • Patent number: 6049487
    Abstract: A dual ported (simultaneous read/write) SRAM block with an additional load port that interacts with the circuitry employed in the loading and testing of the configuration data of the FPGA core is disclosed. Each SRAM block contains circuits in both the read port and the write port that permit the SRAM blocks to be connected into deeper and wider configurations by without any additional logic as required by the prior art. An address collision detector is provided such that when both read and write ports in the SRAM block access the same address simultaneously a choice between the data being read can be made between the data presently in the SRAM block or the new data being written to the SRAM block.
    Type: Grant
    Filed: March 16, 1998
    Date of Patent: April 11, 2000
    Assignee: Actel Corporation
    Inventors: William C. Plants, James Dean Joseph, Antony G. Bell
  • Patent number: 6038627
    Abstract: An SRAM bus architecture includes pass-through interconnect conductors. Each of the pass-through interconnect conductors is connected to routing channels of the general interconnect architecture of the FPGA through an element which includes a pass transistor connected in parallel with a tri-state buffer. The pass transistors and tri-state buffers are controlled by configuration SRAM bits. Some of the pass-through interconnect conductors are connected by programmable elements to the address, data and control signal lines of the SRAM blocks, while other pass through the SRAM blocks without being further connected to the SRAM bussing architecture.
    Type: Grant
    Filed: March 16, 1998
    Date of Patent: March 14, 2000
    Assignee: Actel Corporation
    Inventor: William C. Plants
  • Patent number: RE37048
    Abstract: A field programmable, digital signal processing integrated circuit is formed in a semiconductor die and includes an array of arithmetic logic (ALU) circuits. A user programmable interconnect architecture is superimposed on the array of ALU circuits. One or more interface circuits comprising digital-to-analog (D/A) converters or analog-to-digital (A/D) converters are may be provided on the integrated circuit to interface to off-chip analog input signals and provide off-chip analog output signals. Circuitry is provided to program the interconnections between the interface circuits and the ALU circuits and between individual ones of the ALU circuits, as well as to define the specific functions of the individual ALU circuits.
    Type: Grant
    Filed: October 8, 1997
    Date of Patent: February 6, 2001
    Assignee: Actel Corporation
    Inventor: John L. McCollum