Patents by Inventor Kanad Chakraborty

Kanad Chakraborty 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: 9728273
    Abstract: In one embodiment, a BIST (built-in self-test) engine performs BIST testing of embedded memory in an integrated circuit device (e.g., an FPGA) via an (e.g., hard-wired, dedicated, low-latency) bus from the configuration bitstream engine. During BIST testing, data is written into the embedded memory at-speed, which may require the bitstream engine to produce a higher frequency than originally used for configuration. Between consecutive write operations, the BIST engine is capable of reading the previously written set of data from the embedded memory and comparing that read-back data with the corresponding original set of data to determine whether a BIST error has occurred. By performing back-to-back write/read-back operations faster than the configuration speed and using a dedicated W/RB bus, BIST testing can be optimally performed without false-positive-invoking delays and undesirable resource utilization.
    Type: Grant
    Filed: May 21, 2014
    Date of Patent: August 8, 2017
    Assignee: Lattice Semiconductor Corporation
    Inventors: Kanad Chakraborty, Naveen Purushotham
  • Patent number: 9618579
    Abstract: In certain embodiments, an integrated circuit has scan-test circuitry that performs scan testing on circuitry under scan test (CUST) within the IC, where the scan-test circuitry is susceptible to a defect. In order to enable the defect to be corrected after it occurs, the scan-test circuitry includes a set of programmable circuitry connected to provide a signal to other circuitry (e.g., a scan chain) within the scan-test circuitry, where the set of programmable circuitry includes one or more configurable memory cells connected to control the programming of the set of programmable circuitry. The memory cell(s) can be configured to program the set of programmable circuitry to enable the scan testing to be performed without modification. The memory cell(s) can also be configured to program the set of programmable circuitry to modify the scan testing to correct the defect in the scan-test circuitry.
    Type: Grant
    Filed: April 28, 2015
    Date of Patent: April 11, 2017
    Assignee: Lattice Semiconductor Corporation
    Inventor: Kanad Chakraborty
  • Patent number: 9530486
    Abstract: In one embodiment, a memory array has a pair of bit lines for each column of 1-bit SRAM cells and a word line for each row of cells, where, during a memory read operation, the bit value stored in each cell is detectable by sensing a voltage difference developed between the corresponding bit line pair. A first signal-development circuit is coupled to one bit line to accelerate draining that bit line of charge if a first bit value is stored in the cell, and a second signal-development circuit is coupled to the other bit line to accelerate draining that other bit line of charge if a second, different bit value is stored in the cell. Pulldown devices are provided to ensure that the signal-development circuit operate properly during the pre-charge and voltage difference development phases of the memory read operation, which is now faster due to the signal-development circuits.
    Type: Grant
    Filed: October 7, 2015
    Date of Patent: December 27, 2016
    Assignee: LATTICE SEMICONDUCTOR CORPORATION
    Inventor: Kanad Chakraborty
  • Publication number: 20160320448
    Abstract: In certain embodiments, an integrated circuit has scan-test circuitry that performs scan testing on circuitry under scan test (OUST) within the IC, where the scan-test circuitry is susceptible to a defect. In order to enable the defect to be corrected after it occurs, the scan-test circuitry includes a set of programmable circuitry connected to provide a signal to other circuitry (e.g., a scan chain) within the scan-test circuitry, where the set of programmable circuitry includes one or more configurable memory cells connected to control the programming of the set of programmable circuitry. The memory cell(s) can be configured to program the set of programmable circuitry to enable the scan testing to be performed without modification. The memory cell(s) can also be configured to program the set of programmable circuitry to modify the scan testing to correct the defect in the scan-test circuitry.
    Type: Application
    Filed: April 28, 2015
    Publication date: November 3, 2016
    Inventor: Kanad Chakraborty
  • Publication number: 20150340103
    Abstract: In one embodiment, a BIST (built-in self-test) engine performs BIST testing of embedded memory in an integrated circuit device (e.g., an FPGA) via an (e.g., hard-wired, dedicated, low-latency) bus from the configuration bitstream engine. During BIST testing, data is written into the embedded memory at-speed, which may require the bitstream engine to produce a higher frequency than originally used for configuration. Between consecutive write operations, the BIST engine is capable of reading the previously written set of data from the embedded memory and comparing that read-back data with the corresponding original set of data to determine whether a BIST error has occurred. By performing back-to-back write/read-back operations faster than the configuration speed and using a dedicated W/RB bus, BIST testing can be optimally performed without false-positive-invoking delays and undesirable resource utilization.
    Type: Application
    Filed: May 21, 2014
    Publication date: November 26, 2015
    Applicant: Lattice Semiconductor Corporation
    Inventors: Kanad Chakraborty, Naveen Purushotham
  • Publication number: 20150310933
    Abstract: In certain embodiment, built-in self-test (BIST) circuitry for multiport memory comprises a configurable address generator and a configurable data generator. The configurable address generator can be configured to concurrently generate first and second logical memory addresses corresponding to physically neighboring first and second memory cells of the multiport memory for any selected memory mode of a plurality of available memory modes having different column-multiplexing schemes. The configurable data generator can be configured to concurrently generate two sets of data for the selected memory mode, such that (i) the first set of data is written into and read from the multiport memory via a first memory port using the first logical memory address and (ii) the second set of data is written into and read from the multiport memory via a second memory port using the second logical memory address. The BIST circuitry enables efficient, physically aware built-in self-testing.
    Type: Application
    Filed: September 10, 2014
    Publication date: October 29, 2015
    Inventors: Naveen Purushotham, Kanad Chakraborty, Daniel Ratchen
  • Patent number: 8977917
    Abstract: In one embodiment, an integrated circuit chip has an input/output (I/O) interface and programmable fabric. The I/O interface restricts access to scan testing of the chip by requiring (1) a specific scan-testing instruction, (2) a specific manufacturing key, and (3) a specific fabric pattern value from a specific set of registers in the programmed fabric. In addition or alternatively, the I/O interface has circuitry that enables scan testing of most of the logic of the I/O interface itself, including the logic being driven by the JTAG TAP state register.
    Type: Grant
    Filed: April 8, 2013
    Date of Patent: March 10, 2015
    Assignee: Lattice Semiconductor Corporation
    Inventors: Wei Han, Zheng Chen, Eric Lee, Jie Qin, Shankar Durgamahanthi, Kanad Chakraborty, Dan Ratchen
  • Publication number: 20140136914
    Abstract: In one embodiment, an integrated circuit chip has an input/output (I/O) interface and programmable fabric. The I/O interface restricts access to scan testing of the chip by requiring (1) a specific scan-testing instruction, (2) a specific manufacturing key, and (3) a specific fabric pattern value from a specific set of registers in the programmed fabric. In addition or alternatively, the I/O interface has circuitry that enables scan testing of most of the logic of the I/O interface itself, including the logic being driven by the JTAG TAP state register.
    Type: Application
    Filed: April 8, 2013
    Publication date: May 15, 2014
    Applicant: Lattice Semiconductor Corporation
    Inventors: Wei Han, Zheng Chen, Eric Lee, Jie Qin, Shankar Durgamahanthi, Kanad Chakraborty, Dan Ratchen
  • Patent number: 7511535
    Abstract: A power management circuit is provided for controlling power dissipation in at least one combinational logic circuit. The power management circuit includes a detector operative to receive at least a first input signal to the combinational logic circuit and to detect a transition of the first input signal between a first logic state and a second logic state. The detector generates a control signal indicative of whether or not a transition of the first input signal has occurred.
    Type: Grant
    Filed: February 28, 2007
    Date of Patent: March 31, 2009
    Assignee: Agere Systems Inc.
    Inventors: Kanad Chakraborty, Steven E. Strauss, Bingxiong Xu
  • Publication number: 20080204124
    Abstract: A power management circuit is provided for controlling power dissipation in at least one combinational logic circuit. The power management circuit includes a detector operative to receive at least a first input signal to the combinational logic circuit and to detect a transition of the first input signal between a first logic state and a second logic state. The detector generates a control signal indicative of whether or not a transition of the first input signal has occurred.
    Type: Application
    Filed: February 28, 2007
    Publication date: August 28, 2008
    Inventors: Kanad Chakraborty, Steven E. Strauss, Bingxiong Xu
  • Patent number: 7409659
    Abstract: A static latch circuit is used to suppress crosstalk glitch in a synchronous digital integrated circuit. A static latch is inserted into a selected victim net, and the net is examined if crosstalk glitch induced in the selected victim net is sufficiently suppressed. If not, then the selected victim net is examined to check whether the crosstalk glitch is primarily due to propagated noise from an earlier stage or due to noise injected in the selected victim net. If the crosstalk glitch is propagated from an earlier stage, then a second static latch is inserted before the state in which the first static latch is inserted. Alternatively, another static latch may be inserted in the selected victim net. Cell libraries including a variety of static latch circuit architectures can be designed.
    Type: Grant
    Filed: November 12, 2004
    Date of Patent: August 5, 2008
    Assignee: Agere Systems Inc.
    Inventors: Kanad Chakraborty, Thaddeus J. Gabara, Kevin R. Stiles, Bingxiong Xu
  • Publication number: 20070194453
    Abstract: An integrated circuit includes a first semiconductor chip including one or more circuits thereon performing substantially core logic functions, the first semiconductor chip including multiple signal pads for providing electrical connection to the one or more circuits. The integrated circuit further includes at least a second semiconductor chip including one or more circuits thereon performing substantially input/output interface functions, the second semiconductor chip including multiple signal pads for providing electrical connection to the one or more circuits on the first semiconductor chip. The signal pads on the second semiconductor chip are substantially aligned with and electrically connected to corresponding signal pads on the first semiconductor chip.
    Type: Application
    Filed: January 27, 2006
    Publication date: August 23, 2007
    Inventors: Kanad Chakraborty, Bingxiong Xu, Xingling Zhou
  • Publication number: 20060107245
    Abstract: A static latch circuit is used to suppress crosstalk glitch in a synchronous digital integrated circuit. A static latch is inserted into a selected victim net, and the net is examined if crosstalk glitch induced in the selected victim net is sufficiently suppressed. If not, then the selected victim net is examined to check whether the crosstalk glitch is primarily due to propagated noise from an earlier stage or due to noise injected in the selected victim net. If the crosstalk glitch is propagated from an earlier stage, then a second static latch is inserted before the state in which the first static latch is inserted. Alternatively, another static latch may be inserted in the selected victim net. Cell libraries including a variety of static latch circuit architectures can be designed.
    Type: Application
    Filed: November 12, 2004
    Publication date: May 18, 2006
    Inventors: Kanad Chakraborty, Thaddeus Gabara, Kevin Stiles, Bingxiong Xu
  • Patent number: 7047163
    Abstract: A method (and system) of applying transforms for modifying a plurality of domains concurrently in a design space, includes creating a sequence of more and less granular placement and netlist modification transforms. A converging design process flow is created by a flexible mechanism in which a select combination of fine-grained transforms are applied to optimize the netlist and placement of a design.
    Type: Grant
    Filed: March 13, 2000
    Date of Patent: May 16, 2006
    Assignee: International Business Machines Corporation
    Inventors: Kanad Chakraborty, Wilm Ernst Donath, Prabhakar Nandavar Kudva, Lakshmi Narasimha Reddy, Leon Stok, Andrew James Sullivan, Paul Gerard Villarrubia
  • Patent number: 6532578
    Abstract: A method of configuring partitions for different circuit or other operational areas on an integrated circuit initially identifies points representing components of an integrated circuit with respect to a coordinate system having a horizontal axis and a vertical axis, and subsequently creates a first isothetic rectangular partition containing all of the identified points of the integrated circuit. The method then continues by subdividing the first isothetic rectangular partition with respect to the horizontal axis by creating a plurality of isothetic rectangular sub-partitions collectively containing all of the identified points of the integrated circuit. Each of the isothetic rectangular sub-partitions is separated by a line parallel to the horizontal axis. These isothetic rectangular sub-partitions collectively encompass a minimum area containing all of the identified points.
    Type: Grant
    Filed: May 16, 2001
    Date of Patent: March 11, 2003
    Assignee: International Business Machines Corporation
    Inventors: Kanad Chakraborty, Maharaj Mukherjee
  • Publication number: 20020174410
    Abstract: A method of configuring partitions for different circuit or other operational areas on an integrated circuit initially identifies points representing components of an integrated circuit with respect to a coordinate system having a horizontal axis and a vertical axis, and subsequently creates a first isothetic rectangular partition containing all of the identified points of the integrated circuit. The method then continues by subdividing the first isothetic rectangular partition with respect to the horizontal axis by creating a plurality of isothetic rectangular sub-partitions collectively containing all of the identified points of the integrated circuit. Each of the isothetic rectangular sub-partitions is separated by a line parallel to the horizontal axis. These isothetic rectangular sub-partitions collectively encompass a minimum area containing all of the identified points.
    Type: Application
    Filed: May 16, 2001
    Publication date: November 21, 2002
    Applicant: International Business Machines Corporation
    Inventors: Kanad Chakraborty, Maharaj Mukherjee