Patents by Inventor Makeshwar Kothandaraman

Makeshwar Kothandaraman 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: 8125267
    Abstract: A method includes controllably generating a first bias voltage from a supply voltage to be within an upper tolerable limit of an operating voltage of one or more constituent active circuit element(s) of an Input/Output (IO) core device of an integrated circuit (IC) to be interfaced with an IO pad, and controllably generating a second bias voltage from an external voltage supplied through the IO pad to be within the upper tolerable limit of the operating voltage of the one or more constituent active circuit element(s) of the IO core device to be interfaced with the IO pad. The method also includes controllably utilizing a control signal generated by the IO core to derive an output bias voltage from the first bias voltage during a driver mode of operation or the second bias voltage during a failsafe mode of operation and a tolerant mode of operation.
    Type: Grant
    Filed: September 24, 2010
    Date of Patent: February 28, 2012
    Assignee: LSI Corporation
    Inventors: Pankaj Kumar, Pramod E Parameswaran, Makeshwar Kothandaraman, Vani Deshpande, John Kriz
  • Patent number: 8089739
    Abstract: An ESD protection circuit includes a first voltage clamp, connected between a first voltage supply node and a second voltage supply node of the circuit, and a second voltage clamp, connected between the second voltage supply node and a voltage return of the circuit. The first voltage supply node is adapted to receive a first voltage which is greater than a prescribed gate oxide reliability potential of the circuit. The second voltage supply node is operative to receive a second voltage which is less than the first voltage. The first voltage clamp is operative to clamp the first voltage on the first voltage supply node to a first value during an ESD event between the first and second voltage supply nodes, and the second voltage clamp is operative to clamp the second voltage on the second voltage supply node to a second value during an ESD event between the second voltage supply node and the voltage return.
    Type: Grant
    Filed: October 30, 2007
    Date of Patent: January 3, 2012
    Assignee: Agere Systems Inc.
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris, Yehuda Smooha
  • Publication number: 20110187431
    Abstract: A voltage translator circuit (320) includes an input stage (322) adapted for receiving an input signal referenced to a first voltage supply (VDD core), a latch (326) adapted for connection to a second voltage supply (VDD33) and operative to at least temporarily store a logic state of the input signal, and a voltage clamp (324) coupled between the input stage (322) and the latch (326). The voltage clamp (322) is operative to set a maximum voltage across the latch (326) to a first prescribed level and to set a maximum voltage across the input stage to a second prescribed level. The voltage translator circuit (320) generates a first output signal (II) at a junction between the latch (326) and the voltage clamp (324). The voltage translator circuit generates a second output signal (15) at a junction between the voltage clamp (324) and the input stage (322).
    Type: Application
    Filed: December 29, 2008
    Publication date: August 4, 2011
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman
  • Publication number: 20110102046
    Abstract: A method includes controllably generating a first bias voltage from a supply voltage to be within an upper tolerable limit of an operating voltage of one or more constituent active circuit element(s) of an Input/Output (IO) core device of an integrated circuit (IC) to be interfaced with an IO pad, and controllably generating a second bias voltage from an external voltage supplied through the IO pad to be within the upper tolerable limit of the operating voltage of the one or more constituent active circuit element(s) of the IO core device to be interfaced with the IO pad. The method also includes controllably utilizing a control signal generated by the IO core to derive an output bias voltage from the first bias voltage during a driver mode of operation or the second bias voltage during a failsafe mode of operation and a tolerant mode of operation.
    Type: Application
    Filed: October 31, 2009
    Publication date: May 5, 2011
    Inventors: PANKAJ KUMAR, Pramod Elamannu Parameswaran, Makeshwar Kothandaraman, Vani Deshpande, John Kriz
  • Publication number: 20110102048
    Abstract: A method includes controllably generating a first bias voltage from a supply voltage to be within an upper tolerable limit of an operating voltage of one or more constituent active circuit element(s) of an Input/Output (IO) core device of an integrated circuit (IC) to be interfaced with an IO pad, and controllably generating a second bias voltage from an external voltage supplied through the IO pad to be within the upper tolerable limit of the operating voltage of the one or more constituent active circuit element(s) of the IO core device to be interfaced with the IO pad. The method also includes controllably utilizing a control signal generated by the IO core to derive an output bias voltage from the first bias voltage during a driver mode of operation or the second bias voltage during a failsafe mode of operation and a tolerant mode of operation.
    Type: Application
    Filed: September 24, 2010
    Publication date: May 5, 2011
    Applicant: LSI Corporation
    Inventors: Pankaj Kumar, Pramod Elamannu Parameswaran, Makeshwar Kothandaraman, Vani Deshpande, John Kriz
  • Publication number: 20110102045
    Abstract: A method includes controllably generating a first bias voltage from a supply voltage to be within an upper tolerable limit of an operating voltage of an IO receiver, and controllably generating a second bias voltage from an external voltage supplied through an IO pad to be within the upper tolerable limit of the operating voltage of the IO receiver. The method also includes deriving an output voltage from the first bias voltage during a normal condition and a tolerant condition, and deriving the output voltage from the second bias voltage during a failsafe condition. The tolerant condition is a mode of operation where the external voltage supplied through the IO pad varies from zero to a value higher than the supply voltage, and the failsafe condition is a mode of operation where the supply voltage is zero.
    Type: Application
    Filed: October 31, 2009
    Publication date: May 5, 2011
    Inventors: PANKAJ KUMAR, Pramod Elamannu Parameswaran, Makeshwar Kothandaraman, Vani Deshpande, John Kriz
  • Patent number: 7936209
    Abstract: Described embodiments provide for protecting from DC and transient over-voltage conditions an input/output (“I/O”) buffer having first and second I/O transistors. The first I/O transistor is coupled to a first over-voltage protection circuit adapted to prevent an over-voltage condition on at least the first I/O transistor. The second I/O transistor is coupled to a second over-voltage protection circuit adapted to prevent an over-voltage condition on at least the second I/O transistor. First and second bias voltages are generated from an operating voltage of the buffer. A third bias voltage is generated from either i) the first bias voltage, or ii) an output signal voltage of the buffer and a fourth bias voltage is generated from either i) the second bias voltage, or ii) the output signal voltage of the buffer. The third and fourth bias voltages are provided to the first and second over-voltage protection circuits, respectively.
    Type: Grant
    Filed: April 23, 2009
    Date of Patent: May 3, 2011
    Assignee: LSI Corporation
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John Kriz, Jeffrey Nagy, Yehuda Smooha, Pankaj Kumar
  • Patent number: 7902904
    Abstract: Disclosed is a bias circuit with a first resistor connected between the supply voltage and a feedback node. Resistors are connected in series between the feedback node and the reference supply voltage. The connections between the resistors define at least one bias voltage. A second resistor is connected between the feedback node and a first drain node. A first field-effect transistor has a first gate node, the first drain node, and a first source node. The gate node is connected to the first supply voltage. A second field-effect transistor has a second gate node, a second drain node, and a second source node. The second drain node is connected to the first source node. The second gate node is connected to the bias voltage. The second source node is connected to an output signal node. The output signal node capable of experiencing an overshoot voltage.
    Type: Grant
    Filed: December 9, 2008
    Date of Patent: March 8, 2011
    Assignee: LSI Corporation
    Inventors: Pankaj Kumar, Makeshwar Kothandaraman, Dipankar Bhattacharya, John Kriz, Jeffrey J. Nagy, Pramod Elamannu Parameswaran
  • Patent number: 7876132
    Abstract: A circuit includes a first comparator block configured to output a voltage equal to a higher of a supply voltage and a bias voltage, a second comparator block configured to output a voltage equal to a higher of the bias voltage and an external voltage supplied through an Input/Output (IO) pad, and a third comparator block configured to output a voltage equal to a higher of the output of the first comparator block and the output of the second comparator block. A voltage across one or more constituent active element(s) of each of the first comparator block, the second comparator block, and the third comparator block is within an upper tolerable limit thereof during each of a normal operation, a failsafe operation, and a tolerant operation.
    Type: Grant
    Filed: October 16, 2009
    Date of Patent: January 25, 2011
    Assignee: LSI Corporation
    Inventors: Pankaj Kumar, Pramod Elamannu Parameswaran, Makeshwar Kothandaraman, Vani Deshpande, John Kriz
  • Patent number: 7834653
    Abstract: A method includes controllably utilizing a control signal generated by an Input/Output (IO) core to isolate a current path from an external voltage supplied through an IO pad to a supply voltage by transmitting a same voltage at an input terminal of a transistor, configured to be part of a number of cascaded transistors of an IO driver of an interface circuit, to an output terminal thereof during a failsafe mode of operation and a tolerant mode of operation. The method also includes feeding back an appropriate voltage to a floating node created by the isolation of the current path, and controlling a voltage across each transistor of the number of cascaded transistors to be within an upper tolerable limit thereof through an application of a gate voltage to each transistor derived from the supply voltage or the external voltage supplied through the IO pad.
    Type: Grant
    Filed: October 31, 2009
    Date of Patent: November 16, 2010
    Assignee: LSI Corporation
    Inventors: Pankaj Kumar, Pramod Elamannu Parameswaran, Makeshwar Kothandaraman, Vani Deshpande
  • Publication number: 20100271118
    Abstract: Described embodiments provide for protecting from DC and transient over-voltage conditions an input/output (“I/O”) buffer having first and second I/O transistors. The first I/O transistor is coupled to a first over-voltage protection circuit adapted to prevent an over-voltage condition on at least the first I/O transistor. The second I/O transistor is coupled to a second over-voltage protection circuit adapted to prevent an over-voltage condition on at least the second I/O transistor. First and second bias voltages are generated from an operating voltage of the buffer. A third bias voltage is generated from either i) the first bias voltage, or ii) an output signal voltage of the buffer and a fourth bias voltage is generated from either i) the second bias voltage, or ii) the output signal voltage of the buffer. The third and fourth bias voltages are provided to the first and second over-voltage protection circuits, respectively.
    Type: Application
    Filed: April 23, 2009
    Publication date: October 28, 2010
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John Kriz, Jeffrey Nagy, Yehuda Smooha, Pankaj Kumar
  • Publication number: 20100232078
    Abstract: An ESD protection circuit includes a first voltage clamp, connected between a first voltage supply node and a second voltage supply node of the circuit, and a second voltage clamp, connected between the second voltage supply node and a voltage return of the circuit. The first voltage supply node is adapted to receive a first voltage which is greater than a prescribed gate oxide reliability potential of the circuit. The second voltage supply node is operative to receive a second voltage which is less than the first voltage. The first voltage clamp is operative to clamp the first voltage on the first voltage supply node to a first value during an ESD event between the first and second voltage supply nodes, and the second voltage clamp is operative to clamp the second voltage on the second voltage supply node to a second value during an ESD event between the second voltage supply node and the voltage return.
    Type: Application
    Filed: October 30, 2007
    Publication date: September 16, 2010
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris, Yehuda Smooha
  • Publication number: 20100141334
    Abstract: Disclosed is a bias circuit with a first resistor connected between the supply voltage and a feedback node. Resistors are connected in series between the feedback node and the reference supply voltage. The connections between the resistors define at least one bias voltage. A second resistor is connected between the feedback node and a first drain node. A first field-effect transistor has a first gate node, the first drain node, and a first source node. The gate node is connected to the first supply voltage. A second field-effect transistor has a second gate node, a second drain node, and a second source node. The second drain node is connected to the first source node. The second gate node is connected to the bias voltage. The second source node is connected to an output signal node. The output signal node capable of experiencing an overshoot voltage.
    Type: Application
    Filed: December 9, 2008
    Publication date: June 10, 2010
    Inventors: Pankaj Kumar, Makeshwar Kothandaraman, Dipankar Bhattacharya, John Kriz, Jeffrey J. Nagy, Pramod Elamannu Parameswaran
  • Patent number: 7642807
    Abstract: A compensated buffer circuit operative in one of at least a first mode and a second mode includes a plurality of output blocks and a plurality of predrivers, each of the predrivers having an output connected to an input of a corresponding one of the output blocks. Respective outputs of the output blocks are connected together and form an output of the buffer circuit. The output blocks are arranged in a sequence and are binary weighted such that a drive strength of a given one of the output blocks is about twice as large as a drive strength of an output block immediately preceding the given output block. Each of the predrivers selectively enables the corresponding output block connected thereto as a function of a control signal supplied to the predriver for compensating the buffer circuit for PVT variations to which the buffer circuit may be subjected.
    Type: Grant
    Filed: June 26, 2007
    Date of Patent: January 5, 2010
    Assignee: Agere Systems Inc.
    Inventors: Dipankar Bhattacharya, Gregg R. Harleman, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris
  • Patent number: 7551020
    Abstract: A compensation circuit for compensating an output impedance of at least a first MOS device over PVT variations to which the first MOS device may be subjected includes a first current source generating a first current having a value which is substantially constant and a second current source generating a second current having a value which is programmable as a function of at least one control signal presented to the second current source. A comparator is connected to respective outputs of the first and second current sources and is operative to measure a difference between the respective values of the first and second currents and to generate an output signal indicative of relative magnitudes of the first current and the second current. A processor connected in a feedback arrangement between the comparator and the second current source receives the output signal generated by the comparator and generates the control signal for controlling the second current as a function of the output signal.
    Type: Grant
    Filed: May 31, 2007
    Date of Patent: June 23, 2009
    Assignee: Agere Systems Inc.
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John C. Kriz, Antonio M. Marques, Bernard L. Morris
  • Patent number: 7529071
    Abstract: A circuit for selectively bypassing a capacitive element includes at least one NMOS device selectively connectable across the capacitive element to be bypassed, and at least first and second PMOS devices. The PMOS devices are selectively connectable together in series across the capacitive element to be bypassed. The NMOS device provides a first bypass path and the first and second PMOS devices collectively provide a second bypass path.
    Type: Grant
    Filed: September 27, 2006
    Date of Patent: May 5, 2009
    Assignee: Agere Systems Inc.
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris, Yehuda Smooha
  • Patent number: 7511550
    Abstract: An IC having improved reliability includes at least first and second circuit blocks and at least first and second power domains, the first circuit block being connected to the first power domain and the second circuit block being connected to the second power domain. The IC further includes at least one control circuit configured to generate at least first and second control signals. The first control signal is operative to selectively connect the first power domain to a first voltage supply, and the second control signal is operative to selectively connect the second power domain to a second voltage supply. The IC includes at least first and second clamp circuits, the first clamp circuit being connected to the first power domain, the second clamp circuit being connected to the second power domain. Each of the clamp circuits is operative to prevent a voltage on a corresponding power domain from rising above a prescribed voltage level for the corresponding power domain.
    Type: Grant
    Filed: September 26, 2006
    Date of Patent: March 31, 2009
    Assignee: Agere Systems Inc.
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris, Yehuda Smooha
  • Patent number: 7498860
    Abstract: A buffer circuit is selectively operative in one of at least a first mode and a second mode as a function of a first control signal supplied to the buffer circuit. The buffer circuit includes interface circuitry operative to receive at least second and third control signals referenced to a first voltage level, and to generate an output signal referenced to a second voltage level, the second voltage level being greater than the first voltage level. The output signal is a function of the second control signal in the first mode and is a function of the third control signal in the second mode. The buffer circuit further includes at least first and second circuit portions coupled to the interface circuitry, each of the first and second circuit portions including at least one control input operative to receive the output signal generated by the interface circuitry.
    Type: Grant
    Filed: March 27, 2007
    Date of Patent: March 3, 2009
    Assignee: Agere Systems Inc.
    Inventors: Dipankar Bhattacharya, Carol A. Huber, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris
  • Publication number: 20090002017
    Abstract: A compensated buffer circuit operative in one of at least a first mode and a second mode includes a plurality of output blocks and a plurality of predrivers, each of the predrivers having an output connected to an input of a corresponding one of the output blocks. Respective outputs of the output blocks are connected together and form an output of the buffer circuit. The output blocks are arranged in a sequence and are binary weighted such that a drive strength of a given one of the output blocks is about twice as large as a drive strength of an output block immediately preceding the given output block. Each of the predrivers selectively enables the corresponding output block connected thereto as a function of a control signal supplied to the predriver for compensating the buffer circuit for PVT variations to which the buffer circuit may be subjected.
    Type: Application
    Filed: June 26, 2007
    Publication date: January 1, 2009
    Inventors: Dipankar Bhattacharya, Gregg R. Harleman, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris
  • Publication number: 20080297226
    Abstract: A compensation circuit for compensating an output impedance of at least a first MOS device over PVT variations to which the first MOS device may be subjected includes a first current source generating a first current having a value which is substantially constant and a second current source generating a second current having a value which is programmable as a function of at least one control signal presented to the second current source. A comparator is connected to respective outputs of the first and second current sources and is operative to measure a difference between the respective values of the first and second currents and to generate an output signal indicative of relative magnitudes of the first current and the second current. A processor connected in a feedback arrangement between the comparator and the second current source receives the output signal generated by the comparator and generates the control signal for controlling the second current as a function of the output signal.
    Type: Application
    Filed: May 31, 2007
    Publication date: December 4, 2008
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John C. Kriz, Antonio M. Marques, Bernard L. Morris