Patents Assigned to Actel Corporation, a California Corporation
  • Publication number: 20070139998
    Abstract: In an integrated circuit, a radiation tolerant static random access memory device comprising a first inverter having an input and an output, a second inverter having an input and an output. A first resistor is coupled between the output of the first inverter and the input of the second inverter. A second resistor is coupled between the output of the second inverter and the input of the first inverter. A first write transistor is coupled to the output of the first inverter and has a gate coupled to a source of a first set of write-control signals and a second write transistor is coupled to the output of the second inverter and has a gate coupled to said source of a second set of write-control signals. Finally, a pass transistor has a gate coupled to the output of on of the first and second inverters.
    Type: Application
    Filed: February 16, 2007
    Publication date: June 21, 2007
    Applicant: ACTEL CORPORATION, a California Corporation
    Inventor: John McCollum
  • Publication number: 20060284666
    Abstract: An integrated temperature-compensated RC oscillator circuit includes an inverter having an input and an output. An RC network is coupled between the inverter and a pair of comparators. A first comparator has an inverting input coupled to a first reference voltage, a non-inverting input coupled to the RC network, and an output. A second comparator has an inverting input coupled to the RC network, a non-inverting input coupled to a second reference voltage, and an output. A set-reset flip-flop has a set input coupled to the output of the first comparator, a reset input coupled to the output of the second comparator, and an output coupled to the input of the inverter. Differential amplifiers in the comparators each have a diode-connected p-channel MOS transistor controlling a mirrored p-channel MOS transistor whose channel width is less than that of the diode-connected p-channel current mirror transistor.
    Type: Application
    Filed: August 25, 2006
    Publication date: December 21, 2006
    Applicant: ACTEL CORPORATION, a California Corporation
    Inventor: Gregory Bakker
  • Publication number: 20040237021
    Abstract: A method for detecting an error in data stored in configuration SRAM and user assignable SRAM in a FPGA comprises providing 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 configuration SRAM and 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: Application
    Filed: June 24, 2004
    Publication date: November 25, 2004
    Applicant: Actel Corporation, a California Corporation
    Inventor: William C. Plants
  • Publication number: 20040199689
    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 s 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 with out being further connected to the SRAM bussing architecture.
    Type: Application
    Filed: March 16, 2004
    Publication date: October 7, 2004
    Applicant: Actel Corporation, a California Corporation
    Inventor: William C. Plants
  • Publication number: 20030218479
    Abstract: An apparatus includes a field-programmable gate array (FPGA). The FPGA includes a first FPGA tile, and the first FPGA tile includes a plurality of functional groups (FGs), a third set of routing conductors, in addition to a first set of routing conductors and a second set of routing conductors and a plurality of interface groups (IGs). The plurality of FGs are arranged in rows and columns with each of the FGs being configured to receive tertiary input signals as well as regular input signals, perform a logic operation, and generate regular output signals. The third set of routing conductors is coupled to the first set of output ports of the FGs and configured to receive signals, route signals within the first FPGA tile, and provide input signals to the third set of input ports of the FGs. The plurality of IGs surround the plurality of FGs such that one IG is positioned at each end of each row and column.
    Type: Application
    Filed: April 30, 2003
    Publication date: November 27, 2003
    Applicant: Actel Corporation, a California Corporation
    Inventors: Sheng Feng, Jung-Cheun Lien, Eddy C. Huang, Chung-Yuan Sun, Tong Liu, Naihui Liao, Weidong Xiong
  • Publication number: 20030201792
    Abstract: An antifuse based FPGA architecture is partitioned into repeatable blocks of logic modules to reduce the programming time of the array and to minimize parasitic capacitance and current leakage in the array. With repeatable blocks the size of the FPGA may be made larger with minimal changes to the architecture. Disposed along the edges of each repeatable block are bidirectional buffer banks for connecting to adjacent blocks and to an interconnect matrix that is connectable to blocks other than adjacent blocks. Disposed at regular intervals in the interconnect matrix are repeater buffers to limit the number of antifuses on a given track of the interconnect matrix, to minimize RC delay, and to avoid violating the Ipeak limit.
    Type: Application
    Filed: April 11, 2003
    Publication date: October 30, 2003
    Applicant: Actel Corporation, a California Corporation
    Inventor: Reza Asayeh
  • Publication number: 20030121020
    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. Each BC routing channel is coupled to an expressway tab to provide access for each B1 block to the expressway routing channels M1, M2, and M3, respectively.
    Type: Application
    Filed: November 5, 2002
    Publication date: June 26, 2003
    Applicant: Actel Corporation, a California Corporation
    Inventor: Sinan Kaptanoglu