Patents by Inventor Krishna Chakravadhanula

Krishna Chakravadhanula 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: 11947887
    Abstract: A system includes a memory that stores instructions and receives a circuit netlist, and includes a processing unit that accesses the memory and executes the instructions. The instructions include an EDA application that includes a test-point flop allocation module that is configured to evaluate the circuit netlist to determine compatibility of the test-point nodes in the circuit netlist. The test-point flop allocation module can further allocate each of the test-point flops to a test-point sharing group comprising a plurality of compatible test-point nodes. The EDA application also includes a circuit layout module configured to generate a circuit layout associated with the circuit design, the circuit layout comprising the functional logic and scan-chains comprising the test-point flops allocated to the test-point sharing groups in response to the circuit netlist. The circuit layout is employable to fabricate an integrated circuit (IC) chip.
    Type: Grant
    Filed: September 27, 2022
    Date of Patent: April 2, 2024
    Assignee: Cadence Design Systems, Inc.
    Inventors: Krishna Chakravadhanula, Brian Foutz, Prateek Kumar Rai, Sarthak Singhal, Christos Papameletis, Vivek Chickermane
  • Patent number: 10996270
    Abstract: Systems and methods for multiple device diagnostics are disclosed herein. Exemplary embodiments provide for a multiple device diagnostic system having a plurality of electronic devices selected for diagnosis based on at least one selection criterion, a diagnosis engine in data communication with a failure database, and a diagnosis results database in data communication with the diagnosis engine. Embodiments further provide that the failure database contains grouped failure data from at least one previously diagnosed electronic device, that the wherein the processor diagnoses defects in one or more of the plurality of electronic devices using the grouped failure data, and that the processor outputs the diagnosis results to the diagnosis results database.
    Type: Grant
    Filed: September 11, 2018
    Date of Patent: May 4, 2021
    Assignee: CADENCE DESIGN SYSTEMS, INC.
    Inventors: Sameer Chillarige, Joe Swenton, Anil Malik, Krishna Chakravadhanula
  • Patent number: 9170301
    Abstract: A method and apparatus for hierarchical compaction of test patterns to be applied to an integrated circuit during test is disclosed. The embodiments apply a hierarchical strategy for categorizing test patterns for compaction. A test pattern is considered against a series of criteria for a compacted test pattern. Where all the criteria are met the test pattern is merged into a compacted test pattern. If the criteria are not all met the test patterns are considered against each of the compacted test patterns in turn. This is repeated for each test pattern to create a set of compacted test patterns conforming to the requirements of the criteria. This method and apparatus provides for fine grained control of low power constraints when testing integrated circuits, and includes benefits such as preventing damage during test from burnout and hot spots, and avoiding failures due to IR drop.
    Type: Grant
    Filed: February 20, 2013
    Date of Patent: October 27, 2015
    Assignee: CADENCE DESIGN SYSTEMS, INC.
    Inventors: Patrick Gallagher, Krishna Chakravadhanula, Rajesh Khurana
  • Patent number: 8904256
    Abstract: A method and apparatus to apply compressed test patterns using a very pin-limited test apparatus to a chip design for use in semiconductor manufacturing test is disclosed. Compression circuitry is inserted into the circuit design and the compressed signals manipulated for communication over a serial interface. On a test apparatus, ATPG may be run, assuming a parallel test interface, resulting in test patterns that may be compressed into a parallel format and then converted into a serial signal. On chip, the serial signal is parallelized, decompressed, and then shifted into the scan chains. An inserted controller generates clocks and various control signals. Conventional test patterns from ATPG may be generated and applied during testing without the need to modify the ATPG program saving time and resources. Hierarchical testing of integrated circuits built with a multiplicity of cores, each having its own embedded compression logic, is also supported.
    Type: Grant
    Filed: November 9, 2012
    Date of Patent: December 2, 2014
    Assignee: Cadence Design Systems, Inc.
    Inventors: Krishna Chakravadhanula, Vivek Chickermane, Dale Meehl
  • Patent number: 8650524
    Abstract: A method and apparatus to apply compressed test patterns using a very pin-limited test apparatus to a chip design for use in semiconductor manufacturing test is disclosed. Compression circuitry is inserted into the circuit design and the compressed signals manipulated for communication over a serial interface. On a test apparatus, ATPG may be run, assuming a parallel test interface, resulting in test patterns that may be compressed into a parallel format and then converted into a serial signal. On chip, the serial signal is parallelized, decompressed, and then shifted into the scan chains. An inserted controller generates clocks and various control signals. Conventional test patterns from ATPG may be generated and applied during testing without the need to modify the ATPG program saving time and resources. Hierarchical testing of integrated circuits built with a multiplicity of cores, each having its own embedded compression logic, is also supported.
    Type: Grant
    Filed: November 9, 2012
    Date of Patent: February 11, 2014
    Assignee: Cadence Design Systems, Inc.
    Inventors: Krishna Chakravadhanula, Vivek Chickermane, Dale Meehl
  • Patent number: 8615692
    Abstract: A system, method, and computer program product is disclosed that recycle digital assertions for analyzing the test vectors to quickly and accurately calculate the switching activity at each test clock pulse or scan cycle. According to some approaches, load vector data and unload vector data are analyzed to determine toggle counts and switching activity, without requiring simulation to be performed.
    Type: Grant
    Filed: December 15, 2009
    Date of Patent: December 24, 2013
    Assignee: Cadence Design Systems, Inc.
    Inventors: Rajesh Khurana, Krishna Chakravadhanula, Vivek Chickermane
  • Patent number: 8296703
    Abstract: A method for modeling state-retention logic includes: specifying a circuit that includes an arrangement of circuit elements, wherein a portion of the circuit is organized into a power domain with a power-domain control for effecting power variations within the power domain, and the power domain includes a state-retention cell that includes a retention element with a retention-element control for saving state-retention-cell values in the retention element during power variations in the power domain; determining one or more pattern faults for detecting defects in state-retention operation of the circuit by associating circuit element values with values for the power-domain control or the retention-element control; and saving one or more values for the one or more pattern faults.
    Type: Grant
    Filed: December 19, 2008
    Date of Patent: October 23, 2012
    Assignee: Cadence Design Systems, Inc.
    Inventors: Krishna Chakravadhanula, Steven L. Gregor, Brion L. Keller, Vivek Chickermane
  • Patent number: 8271226
    Abstract: A method of testing an Integrated Circuit (IC) includes: loading a sequence of data into a chain of circuit elements that hold data values, where outputs of at least some circuit elements are connected to inputs of adjacent circuit elements so values move sequentially through the chain between a chain input for loading values and a chain output for unloading values, and a first circuit element includes a retention element for saving values during power variations related to the IC. The method further includes: saving a value from the data sequence in the retention element; and accessing the retention element for verifying an accuracy of the saved value from the data sequence.
    Type: Grant
    Filed: June 26, 2008
    Date of Patent: September 18, 2012
    Assignee: Cadence Design Systems, Inc.
    Inventors: Krishna Chakravadhanula, Patrick Gallagher, Vivek Chickermane, Steven L. Gregor, Puneet Arora
  • Publication number: 20120124423
    Abstract: A method and system for providing on-product clocks for domains compatible with compression is disclosed. According to one embodiment, a base signal received from automated test equipment has a frequency for testing a plurality of clock domains and programming instruction for first and second clock domains of a plurality of clock domains. First and second clock signals are generated from the base clock signal based on the programming instruction. A first delay for the first clock signal and a second delay for the second clock signal are determined from the programming instruction. A test sequence is provided to test a first clock domain and a second clock domain. The test sequence comprises the first clock signal delayed by the first delay and the second clock signal delayed by the second delay. The first clock drives the first clock domain and the second clock derives the second clock domain.
    Type: Application
    Filed: November 16, 2010
    Publication date: May 17, 2012
    Inventors: KRISHNA CHAKRAVADHANULA, Brion Keller, Ramana Malneedi
  • Publication number: 20090326854
    Abstract: A method of testing an Integrated Circuit (IC) includes: loading a sequence of data into a chain of circuit elements that hold data values, where outputs of at least some circuit elements are connected to inputs of adjacent circuit elements so values move sequentially through the chain between a chain input for loading values and a chain output for unloading values, and a first circuit element includes a retention element for saving values during power variations related to the IC. The method further includes: saving a value from the data sequence in the retention element; and accessing the retention element for verifying an accuracy of the saved value from the data sequence.
    Type: Application
    Filed: June 26, 2008
    Publication date: December 31, 2009
    Applicant: CADENCE DESIGN SYSTEMS, INC.
    Inventors: Krishna CHAKRAVADHANULA, Patrick Gallagher, Vivek Chickermane, Steven L. Gregor, Puneet Arora