Patents by Inventor Rajit Chandra

Rajit Chandra 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: 7587692
    Abstract: A method and apparatus for full-chip thermal analysis of semiconductor chip designs is provided. One embodiment of a novel method for performing thermal analysis of a semiconductor chip design comprises receiving at least one input relating to a semiconductor chip design to be analyzed. The input is then processed to produce a three-dimensional thermal model of the semiconductor chip design. In another embodiment, thermal analysis of the semiconductor chip design is performed by calculating power dissipated by transistors and interconnects included in the semiconductor chip design and distributing power dissipated by the interconnects.
    Type: Grant
    Filed: January 29, 2007
    Date of Patent: September 8, 2009
    Assignee: Gradient Design Automation, Inc.
    Inventor: Rajit Chandra
  • Publication number: 20090077508
    Abstract: Improved techniques for accelerated life testing of a sample of semiconductor chips advantageously enable more effective testing and better estimation of lifetime. Full-chip temperature maps are computed at sets of operating and testing conditions. Evaluating the temperature maps enables operations such as: temperature-aware design changes, including adding and/or configuring heating elements, cooling elements, thermal diodes, or sensors; determination of accelerated testing conditions; avoidance of harmful conditions during accelerated testing; and the better estimation of lifetime. Iteration of the computing and the evaluating refines the accelerated testing conditions. Measuring actual testing conditions and computing a full-chip temperature map using the actual testing conditions enables the estimation of lifetime to account for the actual testing conditions. A lifetime acceleration factor map based, at least in part, on the temperature maps is used to produce the estimated lifetime.
    Type: Application
    Filed: August 19, 2008
    Publication date: March 19, 2009
    Inventors: Daniel I. Rubin, Rajit Chandra, Earl T. Cohen
  • Publication number: 20090048801
    Abstract: Temperature aware testing enables computation of thermal test vectors that are applied, via a tester, to a Device Under Test (DUT) to place various internal elements of the DUT at respective temperature operating points. The respective temperature operating points are selected to sensitize the DUT to measurements of selected temperature-dependent critical parameters, including frequency, leakage current behaviors, voltage drops, power profiles, thermal gradients, and absolute temperature. In operation, the thermal test vectors are applied to the DUT for a sufficient time for the DUT to reach thermal equilibrium, or alternatively for the internal elements to reach the respective temperature operating points. Subsequently critical parameter vectors are applied to enable measurement of one or more of the critical parameters.
    Type: Application
    Filed: December 23, 2005
    Publication date: February 19, 2009
    Inventor: Rajit Chandra
  • Publication number: 20090044156
    Abstract: A method and apparatus for normalizing thermal gradients over semiconductor chip designs is provided. One embodiment of a novel method for normalizing an expected thermal gradient includes determining a location of the thermal gradient in the semiconductor chip design and inserting at least one supplemental heat source into the semiconductor chip design such that the thermal gradient is normalized by heat dissipated by the supplemental heat source.
    Type: Application
    Filed: October 24, 2008
    Publication date: February 12, 2009
    Inventors: Rajit Chandra, Daniel I. Rubin
  • Publication number: 20090024969
    Abstract: A thermally aware design automation suite integrates system-level thermal awareness into the design of semiconductor chips. A thermal analysis engine performs fine-grain thermal simulations of the semiconductor chip based on thermal models and boundary conditions for all thermally significant structures in the chip and the adjacent system that impact the temperature of the semiconductor chip. The thermally aware design automation suite uses the simulations of the thermal analysis engine to repair or otherwise modify the thermally significant structures to equalize temperature variations across the chip, impose specified design assertions on selected portions of the chip, and verify overall chip performance and reliability over designated operating ranges and manufacturing variations. The thermally significant structures are introduced or modified via one or more of: change in number, change in location, and change in material properties.
    Type: Application
    Filed: December 23, 2005
    Publication date: January 22, 2009
    Inventor: Rajit Chandra
  • Publication number: 20090024347
    Abstract: A thermally aware design automation suite integrates system-level thermal awareness into design of semiconductor chips, performing fine-grain static and/or transient thermal simulations of the chips based on thermal models and boundary conditions. The thermal simulations are performed in accordance with one or more grids, with boundaries and/or resolutions being determined by adaptive and/or hierarchical multi-dimensional techniques. The adaptive grid techniques include material-boundary, rate-of-change, and convergence-information heuristics. For example, a finer grid is used in a region having higher temperature gradients compared to a region having lower temperature gradients. The hierarchical grid techniques are based on critical, intermediate, and boundary regions specified manually or automatically, each region having a respective grid resolution.
    Type: Application
    Filed: June 2, 2008
    Publication date: January 22, 2009
    Inventors: Rajit Chandra, John Yanjiang Shu, Adi Srinivasan, Paolo Carnevali
  • Publication number: 20090019411
    Abstract: In a first variation, a thermally aware design automation suite integrates system-level thermal awareness into design of semiconductor chips, performing fine-grain thermal simulations of the chips based on thermal models and boundary conditions. The suite uses results of the simulations to modify thermally significant structures to achieve desired thermal variations across a chip, meet design assertions on selected portions of the chip, and verify overall performance and reliability of the chip over designated operating ranges and manufacturing variations. In a second variation, a discretization approach models chip temperature distributions using heuristics to adaptively grid space in three dimensions. Adaptive and locally variable grid spacing techniques are used to efficiently and accurately converge for steady state and/or transient temperature solutions.
    Type: Application
    Filed: June 16, 2008
    Publication date: January 15, 2009
    Inventors: Rajit Chandra, Adi Srinivasan, Nanda Gopal
  • Patent number: 7472363
    Abstract: A thermally aware design automation suite integrates system-level thermal awareness into the design of semiconductor chips. A thermal analysis engine performs fine-grain thermal simulations of the semiconductor chip based on thermal models and boundary conditions for all thermally significant structures in the chip and the adjacent system that impact the temperature of the semiconductor chip. The thermally aware design automation suite uses the simulations of the thermal analysis engine to repair or otherwise modify the thermally significant structures to equalize temperature variations across the chip, impose specified design assertions on selected portions of the chip, and verify overall chip performance and reliability over designated operating ranges and manufacturing variations. The thermally significant structures are introduced or modified via one or more of: change in number, change in location, and change in material properties.
    Type: Grant
    Filed: December 23, 2005
    Date of Patent: December 30, 2008
    Assignee: Gradient Design Automation Inc.
    Inventor: Rajit Chandra
  • Patent number: 7458052
    Abstract: A method and apparatus for normalizing thermal gradients over semiconductor chip designs is provided. One embodiment of a novel method for normalizing an expected thermal gradient includes determining a location of the thermal gradient in the semiconductor chip design and inserting at least one supplemental heat source into the semiconductor chip design such that the thermal gradient is normalized by heat dissipated by the supplemental heat source.
    Type: Grant
    Filed: August 29, 2005
    Date of Patent: November 25, 2008
    Assignee: Gradient Design Automation, Inc.
    Inventors: Rajit Chandra, Daniel I. Rubin
  • Publication number: 20080243461
    Abstract: A method and apparatus for modeling and thermal analysis of semiconductor chip designs is provided. One embodiment of a novel method for performing thermal testing of a semiconductor chip design includes calculating full-chip temperatures over the semiconductor chip design (e.g., to identify steep thermal gradients) and modeling the full-chip temperatures in accordance with a geometric multi-grid technique. The geometric multi-grid technique is tailored to determine temperatures within the semiconductor chip design based at least in part on the physical attributes or geometry of the design.
    Type: Application
    Filed: June 11, 2008
    Publication date: October 2, 2008
    Inventors: Peng Li, Larry Pileggi, Mehdi Asheghi, Rajit Chandra
  • Patent number: 7401304
    Abstract: A method and apparatus for modeling and thermal analysis of semiconductor chip designs is provided. One embodiment of a novel method for performing thermal testing of a semiconductor chip design includes calculating full-chip temperatures over the semiconductor chip design (e.g., to identify steep thermal gradients) and modeling the full-chip temperatures in accordance with a geometric multi-grid technique. The geometric multi-grid technique is tailored to determine temperatures within the semiconductor chip design based at least in part on the physical attributes or geometry of the design.
    Type: Grant
    Filed: July 13, 2005
    Date of Patent: July 15, 2008
    Assignee: Gradient Design Automation Inc.
    Inventors: Peng Li, Larry Pileggi, Mehdi Asheghi, Rajit Chandra
  • Publication number: 20080163135
    Abstract: A method and apparatus for optimizing cooling system performance using full-chip thermal analysis of semiconductor chip designs is provided. One embodiment of a novel method for optimizing the cooling of an electronic system incorporating at least one semiconductor chip includes receiving full-chip temperature data for the semiconductor chip(s) and configuring the cooling system for dissipating heat from the electronic system in accordance with the full-chip temperature data.
    Type: Application
    Filed: March 11, 2008
    Publication date: July 3, 2008
    Inventor: RAJIT CHANDRA
  • Publication number: 20080141192
    Abstract: A method and apparatus for using full-chip thermal analysis of semiconductor chip designs to compute thermal conductivity is disclosed. One embodiment of a novel method for analyzing the conductivity of a semiconductor chip design that comprises a plurality of physical layers includes defining at least one thermal layer within the plurality of physical layers, where the thermal layer(s) represents a variance in thermal conductivity relative to a remainder of the semiconductor chip design, and computing a thermal conductivity of the thermal layer(s). As the thermal layer(s) represents variances in thermal conductivity over the semiconductor chip design, the thermal layer(s) does not necessarily correspond one-to-one to the physical layers of the semiconductor chip design. Thus, the thermal conductivities within the semiconductor chip design can be computed from the thermal layers.
    Type: Application
    Filed: January 18, 2008
    Publication date: June 12, 2008
    Inventors: RAJIT CHANDRA, Adi Srinivasan
  • Patent number: 7383520
    Abstract: A method and apparatus for optimizing cooling system performance using full-chip thermal analysis of semiconductor chip designs is provided. One embodiment of a novel method for optimizing the cooling of an electronic system incorporating at least one semiconductor chip includes receiving full-chip temperature data for the semiconductor chip(s) and configuring the cooling system for dissipating heat from the electronic system in accordance with the full-chip temperature data.
    Type: Grant
    Filed: August 5, 2005
    Date of Patent: June 3, 2008
    Assignee: Gradient Design Automation Inc.
    Inventor: Rajit Chandra
  • Patent number: 7353471
    Abstract: A method and apparatus for using full-chip thermal analysis of semiconductor chip designs to compute thermal conductivity is disclosed. One embodiment of a novel method for analyzing the conductivity of a semiconductor chip design that comprises a plurality of physical layers includes defining at least one thermal layer within the plurality of physical layers, where the thermal layer(s) represents a variance in thermal conductivity relative to a remainder of the semiconductor chip design, and computing a thermal conductivity of the thermal layer(s). As the thermal layer(s) represents variances in thermal conductivity over the semiconductor chip design, the thermal layer(s) does not necessarily correspond one-to-one to the physical layers of the semiconductor chip design. Thus, the thermal conductivities within the semiconductor chip design can be computed from the thermal layers.
    Type: Grant
    Filed: August 5, 2005
    Date of Patent: April 1, 2008
    Assignee: Gradient Design Automation Inc.
    Inventors: Rajit Chandra, Adi Srinivasan
  • Publication number: 20080066022
    Abstract: A method and apparatus for optimizing cooling system performance using full-chip thermal analysis of semiconductor chip designs is provided. One embodiment of a novel method for optimizing the cooling of an electronic system incorporating at least one semiconductor chip includes receiving full-chip temperature data for the semiconductor chip(s) and configuring the cooling system for dissipating heat from the electronic system in accordance with the full-chip temperature data.
    Type: Application
    Filed: August 5, 2005
    Publication date: March 13, 2008
    Inventor: Rajit Chandra
  • Publication number: 20070157137
    Abstract: A method and apparatus for retrofitting semiconductor chip performance analysis tools with full-chip thermal analysis capabilities is provided. One embodiment of a novel method for performing performance analysis of a semiconductor chip design includes receiving at least one input calculated in accordance with an actual (e.g., purposefully calculated rather than assumed or estimated) temperature of a semiconductor device and/or an interconnects in the semiconductor ship design. This input is then used to assess at least one temperature-dependent performance parameter of the semiconductor chip design.
    Type: Application
    Filed: February 28, 2007
    Publication date: July 5, 2007
    Inventor: RAJIT CHANDRA
  • Publication number: 20070120239
    Abstract: A method and apparatus for full-chip thermal analysis of semiconductor chip designs is provided. One embodiment of a novel method for performing thermal analysis of a semiconductor chip design comprises receiving at least one input relating to a semiconductor chip design to be analyzed. The input is then processed to produce a three-dimensional thermal model of the semiconductor chip design. In another embodiment, thermal analysis of the semiconductor chip design is performed by calculating power dissipated by transistors and interconnects included in the semiconductor chip design and distributing power dissipated by the interconnects.
    Type: Application
    Filed: January 29, 2007
    Publication date: May 31, 2007
    Inventor: Rajit Chandra
  • Patent number: 7203920
    Abstract: A method and apparatus for retrofitting semiconductor chip performance analysis tools with full-chip thermal analysis capabilities is provided. One embodiment of a novel method for performing performance analysis of a semiconductor chip design includes receiving at least one input calculated in accordance with an actual (e.g., purposefully calculated rather than assumed or estimated) temperature of a semiconductor device and/or an interconnects in the semiconductor ship design. This input is then used to assess at least one temperature-dependent performance parameter of the semiconductor chip design.
    Type: Grant
    Filed: January 20, 2005
    Date of Patent: April 10, 2007
    Assignee: Gradient Design Automation Inc.
    Inventor: Rajit Chandra
  • Patent number: 7194711
    Abstract: A method and apparatus for full-chip thermal analysis of semiconductor chip designs is provided. One embodiment of a novel method for performing thermal analysis of a semiconductor chip design comprises receiving at least one input relating to a semiconductor chip design to be analyzed. The input is then processed to produce a three-dimensional thermal model of the semiconductor chip design. In another embodiment, thermal analysis of the semiconductor chip design is performed by calculating power dissipated by transistors and interconnects included in the semiconductor chip design and distributing power dissipated by the interconnects.
    Type: Grant
    Filed: November 3, 2004
    Date of Patent: March 20, 2007
    Assignee: Gradient Design Automation Inc.
    Inventor: Rajit Chandra