Patents by Inventor Rahul M. Rao

Rahul M. Rao 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).

  • Publication number: 20090309625
    Abstract: An electronic circuit includes an output terminal and at least a first measuring FET. The second drain-source terminals of a plurality of FETS to be tested are interconnected with the first drain-source terminal of the first measuring FET and the output terminal. The second drain-source terminal of the first measuring FET is interconnected with a first biasing terminal. The first drain-source terminals of the FETS to be tested are interconnected with a second biasing terminal. A state machine is coupled to the gates of the FETS to be tested and the gate of the first measuring FET. The state machine is configured to energize the gate of the first measuring FET and to sequentially energize the gates of the FETS to be tested, so that an output voltage appears on the output terminal. Circuitry to compare the output voltage to a reference value is also provided.
    Type: Application
    Filed: August 17, 2009
    Publication date: December 17, 2009
    Applicant: International Business Machines Corporation
    Inventors: Keith A. Jenkins, Jae-Joon Kim, Rahul M. Rao
  • Publication number: 20090189703
    Abstract: A ring oscillator has an odd number of NOR-gates greater than or equal to three, each with first and second input terminals, a voltage supply terminal, and an output terminal. The first input terminals of all the NOR-gates are interconnected, and each of the NOR-gates has its output terminal connected to the second input terminal of an immediately adjacent one of the NOR-gates. During a stress mode, a voltage supply and control block applies a stress enable signal to the interconnected first input terminals, and an increased supply voltage to the voltage supply terminals. During a measurement mode, this block grounds the interconnected first input terminals, and applies a normal supply voltage to the voltage supply terminals.
    Type: Application
    Filed: January 29, 2008
    Publication date: July 30, 2009
    Applicant: International Business Machines Corporation
    Inventors: Ching-Te K. Chuang, Jae-Joon Kim, Tae-Hyoung Kim, Pong-Fei Lu, Saibal Mukhopadhyay, Rahul M. Rao, Shao-yi Wang
  • Publication number: 20090185409
    Abstract: A memory circuit includes a plurality of bit line structures (each including a true and a complementary bit line), a plurality of word line structures intersecting the plurality of bit line structures to form a plurality of cell locations and a plurality of cells located at the plurality of cell locations. Each of the cells includes a logical storage element, a first access transistor selectively coupling a given one of the true bit lines to the logical storage element, and a second access transistor selectively coupling a corresponding given one of the complementary bit lines to the logical storage element. One or both of the first and second access transistors are configured with asymmetric current characteristics to enable independent enhancement of READ and WRITE margins. Also included within the 6-T scope are one or more design structures embodied in a machine readable medium, comprising circuits as set forth herein.
    Type: Application
    Filed: January 22, 2008
    Publication date: July 23, 2009
    Applicant: International Business Machines Corporation
    Inventors: Aditya Bansal, Ching-Te K. Chuang, Jae-Joon Kim, Shih-Hsien Lo, Rahul M. Rao
  • Patent number: 7550987
    Abstract: A method and circuits for measuring operating and leakage current of individual blocks within an array of test circuit blocks provides measurement free of error due to leakage currents through non-selected circuit blocks, without requiring an independent test facility for each circuit block. The circuit includes a pair of power supply grids and selection circuits at each test circuit block to select between a test power grid and a “rest” power grid used to supply current to the non-selected circuits. The leakage currents through the non-selected circuits are thus sourced from the rest grid and error that would otherwise be introduced in the test grid current measurement is avoided. The test circuit blocks may be ring oscillators, and the measured current may be the operating and/or leakage current of the ring oscillator. The circuit blocks may also include individual devices for IV (current-voltage) characterization using an additional gate input grid.
    Type: Grant
    Filed: February 27, 2007
    Date of Patent: June 23, 2009
    Assignee: International Business Machines Corporation
    Inventors: Dhruva J. Acharyya, Sani R. Nassif, Rahul M. Rao
  • Patent number: 7548822
    Abstract: Determining a slew rate of a signal from an integrated circuit under test by comparing the signal with a first reference voltage, comparing the signal with a second reference voltage different from the first reference voltage, generating an output pulse having a pulse width indicative of a slew rate of the signal, and integrating the output pulse over time to generate an output voltage proportional to the pulse width; wherein the output voltage is indicative of the slew rate of the signal produced by the integrated circuit.
    Type: Grant
    Filed: July 13, 2007
    Date of Patent: June 16, 2009
    Assignee: International Business Machines Corporation
    Inventors: Ching-Te K. Chuang, Amlan Ghosh, Jae-Joon Kim, Rahul M. Rao
  • Publication number: 20090147592
    Abstract: In a memory circuit, data from all cells along a selected word line is read. Then, the read data is written back to half-selected cells and new data is written to the selected cells in the next cycle. In cases where a READ bit line (RBL) and WRITE bit line (WBL) are decoupled, RBL and WBL can be accessed simultaneously. Hence, the WRITE in the n-th cycle can be delayed to the n+1-th cycle as far as there is no data hazard such as reading data from memory before correct data are actually written to memory. As a result, there is no bandwidth loss, although the latency of the WRITE operation increases. WRITE stability issues in previous configurations with decoupled RBL and WBL are thus addressed.
    Type: Application
    Filed: December 5, 2008
    Publication date: June 11, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Rajiv V. Joshi, Jae-Joon Kim, Rahul M. Rao
  • Patent number: 7495969
    Abstract: In a memory circuit, data from all cells along a selected word line is read. Then, the read data is written back to half-selected cells and new data is written to the selected cells in the next cycle. In cases where a READ bit line (RBL) and WRITE bit line (WBL) are decoupled, RBL and WBL can be accessed simultaneously. Hence, the WRITE in the n-th cycle can be delayed to the n+1-th cycle as far as there is no data hazard such as reading data from memory before correct data are actually written to memory. As a result, there is no bandwidth loss, although the latency of the WRITE operation increases. WRITE stability issues in previous configurations with decoupled RBL and WBL are thus addressed.
    Type: Grant
    Filed: January 30, 2007
    Date of Patent: February 24, 2009
    Assignee: International Business Machines Corporation
    Inventors: Rajiv V. Joshi, Jae-Joon Kim, Rahul M. Rao
  • Publication number: 20090018787
    Abstract: Determining a slew rate of a signal from an integrated circuit under test by comparing the signal with a first reference voltage, comparing the signal with a second reference voltage different from the first reference voltage, generating an output pulse having a pulse width indicative of a slew rate of the signal, and integrating the output pulse over time to generate an output voltage proportional to the pulse width; wherein the output voltage is indicative of the slew rate of the signal produced by the integrated circuit.
    Type: Application
    Filed: July 13, 2007
    Publication date: January 15, 2009
    Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Ching-Te K. Chuang, Amlan Ghosh, Jae-Joon Kim, Rahul M. Rao
  • Publication number: 20080315907
    Abstract: An electronic circuit includes an output terminal and at least a first measuring FET. The second drain-source terminals of a plurality of FETS to be tested are interconnected with the first drain-source terminal of the first measuring FET and the output terminal. The second drain-source terminal of the first measuring FET is interconnected with a first biasing terminal. The first drain-source terminals of the FETS to be tested are interconnected with a second biasing terminal. A state machine is coupled to the gates of the FETS to be tested and the gate of the first measuring FET. The state machine is configured to energize the gate of the first measuring FET and to sequentially energize the gates of the FETS to be tested, so that an output voltage appears on the output terminal. Circuitry to compare the output voltage to a reference value is also provided.
    Type: Application
    Filed: August 28, 2008
    Publication date: December 25, 2008
    Applicant: International Business Machines Corporation
    Inventors: Keith A. Jenkins, Jae-Joon Kim, Rahul M. Rao
  • Patent number: 7439755
    Abstract: An electronic circuit includes an output terminal and at least a first measuring FET. The second drain-source terminals of a plurality of FETS to be tested are interconnected with the first drain-source terminal of the first measuring FET and the output terminal. The second drain-source terminal of the first measuring FET is interconnected with a first biasing terminal. The first drain-source terminals of the FETS to be tested are interconnected with a second biasing terminal. A state machine is coupled to the gates of the FETS to be tested and the gate of the first measuring FET. The state machine is configured to energize the gate of the first measuring FET and to sequentially energize the gates of the FETS to be tested, so that an output voltage appears on the output terminal. Circuitry to compare the output voltage to a reference value is also provided.
    Type: Grant
    Filed: January 31, 2007
    Date of Patent: October 21, 2008
    Assignee: International Business Machines Corporation
    Inventors: Keith A. Jenkins, Jae-Joon Kim, Rahul M. Rao
  • Publication number: 20080209285
    Abstract: A method and circuits for measuring operating and leakage current of individual blocks within an array of test circuit blocks provides measurement free of error due to leakage currents through non-selected circuit blocks, without requiring an independent test facility for each circuit block. The circuit includes a pair of power supply grids and selection circuits at each test circuit block to select between a test power grid and a “rest” power grid used to supply current to the non-selected circuits. The leakage currents through the non-selected circuits are thus sourced from the rest grid and error that would otherwise be introduced in the test grid current measurement is avoided. The test circuit blocks may be ring oscillators, and the measured current may be the operating and/or leakage current of the ring oscillator. The circuit blocks may also include individual devices for IV (current-voltage) characterization using an additional gate input grid.
    Type: Application
    Filed: February 27, 2007
    Publication date: August 28, 2008
    Inventors: Dhruva J. Acharyya, Sani R. Nassif, Rahul M. Rao
  • Publication number: 20080180134
    Abstract: An electronic circuit includes an output terminal and at least a first measuring FET. The second drain-source terminals of a plurality of FETS to be tested are interconnected with the first drain-source terminal of the first measuring FET and the output terminal. The second drain-source terminal of the first measuring FET is interconnected with a first biasing terminal. The first drain-source terminals of the FETS to be tested are interconnected with a second biasing terminal. A state machine is coupled to the gates of the FETS to be tested and the gate of the first measuring FET. The state machine is configured to energize the gate of the first measuring FET and to sequentially energize the gates of the FETS to be tested, so that an output voltage appears on the output terminal. Circuitry to compare the output voltage to a reference value is also provided.
    Type: Application
    Filed: January 31, 2007
    Publication date: July 31, 2008
    Applicant: International Business Machines Corporation
    Inventors: Keith A. Jenkins, Jae-Joon Kim, Rahul M. Rao
  • Publication number: 20080181029
    Abstract: In a memory circuit, data from all cells along a selected word line is read. Then, the read data is written back to half-selected cells and new data is written to the selected cells in the next cycle. In cases where a READ bit line (RBL) and WRITE bit line (WBL) are decoupled, RBL and WBL can be accessed simultaneously. Hence, the WRITE in the n-th cycle can be delayed to the n+1-th cycle as far as there is no data hazard such as reading data from memory before correct data are actually written to memory. As a result, there is no bandwidth loss, although the latency of the WRITE operation increases. WRITE stability issues in previous configurations with decoupled RBL and WBL are thus addressed.
    Type: Application
    Filed: January 30, 2007
    Publication date: July 31, 2008
    Applicant: International Business Machines Corporation
    Inventors: Rajiv V. Joshi, Jae-Joon Kim, Rahul M. Rao
  • Publication number: 20080121948
    Abstract: A fin-type field effect transistor (FINFET) includes a plurality of fins forming drain-source regions and a gate region disposed about the fins. At least a first one of the fins has a first crystal orientation, and at least a second one of the fins has a second crystal orientation that is different from the first crystal orientation. The second crystal orientation is selected to be different from the first crystal orientation to reduce a drive strength quantization error of the transistor. Circuits using such FETS and methods for designing such circuits are also presented.
    Type: Application
    Filed: August 16, 2006
    Publication date: May 29, 2008
    Applicant: International Business Machines Corporation
    Inventors: Jae-Joon Kim, Rahul M. Rao
  • Publication number: 20080069558
    Abstract: A static pulse bus circuit and method having dynamic power supply rail selection reduces static and dynamic power consumption over that of static pulse bus designs with fixed power supply rail voltages. Every other (even) bus repeater is operated with a selectable power supply rail voltage that is selected in conformity with a state of the input signal of the bus repeater. The odd bus repeaters are operated from the lower of the selectable power supply voltages supplied to the even repeaters. The odd bus repeaters may also be operated from a selectable power supply rail voltage opposite the selectable-voltage power supply rail provided to the even bus repeaters, in which case the opposing rail of the even bus repeaters is set to the higher of the voltages selectable in the odd bus repeaters.
    Type: Application
    Filed: September 1, 2006
    Publication date: March 20, 2008
    Inventors: Harmander Singh Deogun, Kevin J. Nowka, Rahul M. Rao, Robert M. Senger
  • Patent number: 7088141
    Abstract: A multi-threshold complementary metal-oxide semiconductor (MTCMO) bus circuit reduces bus power consumption via a reduced circuit leakage standby and pulsed control of standby mode so that the advantages of MTCMOS repeater design are realized in dynamic operation. A pulse generator pulses the high-threshold voltage power supply rail standby switching devices in response to changes detected at the bus circuit inputs. The delay penalty associated with leaving the standby mode is overcome by reducing cross-talk induced delay via a cross-talk noise minimization encoding and decoding scheme. A subgroup of bus wires is encoded and decoded, simplifying the encoding, decoding and change detection logic and results in the bus subgroup being taken out of standby mode only when changes occur in one or more of the subgroup inputs, further reducing the power consumption of the overall bus circuit.
    Type: Grant
    Filed: October 14, 2004
    Date of Patent: August 8, 2006
    Assignee: International Business Machines Corporation
    Inventors: Harmander Singh Deogun, Kevin John Nowka, Rahul M. Rao
  • Patent number: 6791361
    Abstract: A method and circuit for mitigating gate leakage during a sleep state. An input pattern may be applied to one or more of a plurality of devices in a circuit, e.g., static circuit, dynamic circuit, during a sleep state. In response to the application of the input pattern, a majority of the devices in the circuit may have a substantially identical voltage at each of its terminals, i.e., the source, gate and drain terminal, thereby mitigating gate leakage.
    Type: Grant
    Filed: December 12, 2002
    Date of Patent: September 14, 2004
    Assignee: International Business Machines Corporation
    Inventors: Elad Alon, Jeffrey L. Burns, Kevin J. Nowka, Rahul M. Rao
  • Publication number: 20040113657
    Abstract: A method and circuit for mitigating gate leakage during a sleep state. An input pattern may be applied to one or more of a plurality of devices in a circuit, e.g., static circuit, dynamic circuit, during a sleep state. In response to the application of the input pattern, a majority of the devices in the circuit may have a substantially identical voltage at each of its terminals, i.e., the source, gate and drain terminal, thereby mitigating gate leakage.
    Type: Application
    Filed: December 12, 2002
    Publication date: June 17, 2004
    Applicant: International Business Machines Corporation
    Inventors: Elad Alon, Jeffrey L. Burns, Kevin J. Nowka, Rahul M. Rao