Patents by Inventor Dipankar Bhattacharya

Dipankar Bhattacharya 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: 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
  • Patent number: 7495873
    Abstract: An ESD protection circuit for protecting a circuit from an ESD event occurring between a first voltage supply node and a second voltage supply node associated with the circuit to be protected includes an MOS device having a gate terminal, a first source/drain terminal and a second source/drain terminal. The first source/drain terminal is connected to the first voltage supply node and the second source/drain terminal is connected to the second voltage supply node. The ESD protection circuit further includes a trigger circuit coupled to the gate terminal of the MOS device. The trigger circuit is configured to generate a control signal at the gate terminal of the MOS device for activating the MOS device during the ESD event.
    Type: Grant
    Filed: October 29, 2004
    Date of Patent: February 24, 2009
    Assignee: Agere Systems Inc.
    Inventors: Dipankar Bhattacharya, John C. Kriz, Bernard L. Morris, Yehuda Smooha
  • 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
  • Patent number: 7432762
    Abstract: A circuit having an enhanced input signal range includes a differential amplifier operative to receive at least first and second signals and to generate a difference signal at an output thereof which is a function of the difference between the first and second signals. The differential amplifier includes an input stage having at least first and second transistors having a first threshold voltage associated therewith and being operative to receive the first and second signals, respectively, and a load including at least third and fourth transistors having a second threshold voltage associated therewith, the first threshold voltage being greater than the second threshold voltage. The circuit further includes an output stage coupled to the differential amplifier and operative to receive the difference signal and to generate an output signal of the circuit that is indicative of the difference signal and is referenced to the supply voltage of the circuit.
    Type: Grant
    Filed: March 30, 2006
    Date of Patent: October 7, 2008
    Assignee: Agere Systems Inc.
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris
  • Publication number: 20080238399
    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: Application
    Filed: March 27, 2007
    Publication date: October 2, 2008
    Inventors: Dipankar Bhattacharya, Carol A. Huber, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris
  • Patent number: 7430100
    Abstract: A buffer circuit having enhanced overvoltage protection includes core buffer circuitry couplable to a first voltage source having a first voltage level. The core buffer circuitry is configured to receive a first signal and to generate a second signal which is a function of the first signal. The buffer circuit further includes a protection circuit coupled between the core buffer circuitry and a signal pad. The protection circuit is operative: (i) to clamp the first signal to about the first voltage level when a third signal received at the signal pad exceeds the first voltage level by a first amount; and (ii) to generate the first signal being substantially equal to the third signal when the third signal is less than or substantially equal to the first voltage level.
    Type: Grant
    Filed: June 28, 2005
    Date of Patent: September 30, 2008
    Assignee: Agere Systems Inc.
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris
  • Patent number: 7397279
    Abstract: A voltage level translator circuit for translating an input signal referenced to a first voltage supply to an output signal referenced to a second voltage supply includes an input stage for receiving the input signal, the input stage including at least one transistor device having a first threshold voltage associated therewith. The voltage level translator circuit further includes a latch circuit operative to store a signal representative of a logic state of the input signal, the latch circuit including at least one transistor device having a second threshold voltage associated therewith, the second threshold voltage being greater than the first threshold voltage. A voltage clamp circuit is connected between the input stage and the latch circuit. The voltage clamp circuit is operative to limit a voltage across the input stage, an amplitude of the voltage across the input stage being controlled as a function of a voltage difference between the first and second voltage supplies.
    Type: Grant
    Filed: January 27, 2006
    Date of Patent: July 8, 2008
    Assignee: Agere Systems Inc.
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris, Joseph E. Simko
  • Patent number: 7391825
    Abstract: A comparator circuit having reduced pulse width distortion includes a differential amplifier operative to receive at least first and second signals and to amplify a difference between the first and second signals. The differential amplifier generates a difference signal at an output thereof which is a function of the difference between the first and second signals. An output stage is included in the comparator circuit for receiving the difference signal and for generating an output signal of the comparator circuit, the output signal being representative of the difference signal, the output stage having a switching point associated therewith. The comparator circuit further includes a voltage source coupled to the output of the differential amplifier. The voltage source is operative to generate a reference signal for establishing a common-mode voltage of the difference signal generated by the differential amplifier.
    Type: Grant
    Filed: January 31, 2005
    Date of Patent: June 24, 2008
    Assignee: Agere Systems Inc.
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris
  • Patent number: 7382168
    Abstract: A buffer circuit operative at multiple power supply voltage levels includes first and second buffers, the first buffer being configured for operation with a first voltage source and the second buffer being operative with a second voltage source. The buffer circuit further includes a controllable isolation circuit. An output of the first buffer connects to an external pad of the buffer circuit, and an output of the second buffer connects to the pad via the isolation circuit. The buffer circuit is selectively operative in at least a first mode or a second mode in response to at least a first control signal. The isolation circuit is operative in the first mode to substantially isolate the second buffer from the external pad and is operative in the second mode to connect the output of the second buffer to the external pad.
    Type: Grant
    Filed: August 30, 2005
    Date of Patent: June 3, 2008
    Assignee: Agere Systems Inc.
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris, Yehuda Smooha
  • Patent number: 7369489
    Abstract: The present invention defines a method of unbiased policing of data flow in a network device. According to an embodiment of the present invention, the token bucket policer of the network device ‘permits’ (forwards) incoming packets even when the size of the token bucket is less than the size of the incoming packets. Permitting incoming packets that are larger than the token bucket ensures that incoming packets are not dropped because of the size of the incoming packets. Incoming packets are policed by TBP when the magnitude comparison of the token bucket and a predetermined constant value does not comply with the policing scheme defined for the incoming packets. When a packet is ‘permitted’ (forwarded), the size of the token bucket is reduced by an amount equal to the size of the packet.
    Type: Grant
    Filed: March 12, 2002
    Date of Patent: May 6, 2008
    Assignee: Cisco Technology, Inc.
    Inventors: Dipankar Bhattacharya, Ketan A. Padwekar
  • Publication number: 20080074171
    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: Application
    Filed: September 26, 2006
    Publication date: March 27, 2008
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris, Yehuda Smooha
  • Publication number: 20080074814
    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: Application
    Filed: September 27, 2006
    Publication date: March 27, 2008
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris, Yehuda Smooha
  • Patent number: 7350020
    Abstract: Methods, apparatus, and other mechanisms are disclosed for merging lookup results, such as from one or more associative memory banks and/or memory devices. In one exemplary implementation, multiple associative memories or associative memory banks are configured to substantially simultaneously generate a plurality of lookup results based on a lookup value. Multiple memories are each configured to generate a corresponding result based on the lookup result generated by its corresponding associative memory or associative memory bank. A combiner is configured to receive and merge these corresponding results generated substantially simultaneously in order to identify the merged lookup result.
    Type: Grant
    Filed: August 1, 2006
    Date of Patent: March 25, 2008
    Assignee: Cisco Technology, Inc.
    Inventors: Bhushan Mangesh Kanekar, Venkateshwar Rao Pullela, Dileep Kumar Devireddy, Gyaneshwar S. Saharia, Dipankar Bhattacharya, Qizhong Chen
  • Publication number: 20070229157
    Abstract: A circuit having an enhanced input signal range includes a differential amplifier operative to receive at least first and second signals and to amplify a difference between the first and second signals. The differential amplifier generates a difference signal at an output thereof which is a function of the difference between the first and second signals. The differential amplifier includes an input stage having at least first and second transistors operative to receive the first and second signals, respectively, each of the first and second transistors having a first threshold voltage associated therewith, and a load including at least third and fourth transistors having a second threshold voltage associated therewith, the first threshold voltage being greater than the second threshold voltage.
    Type: Application
    Filed: March 30, 2006
    Publication date: October 4, 2007
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John Kriz, Bernard Morris
  • Patent number: 7276957
    Abstract: A circuit for defining a voltage potential of a floating well in which is formed at least one metal-oxide-semiconductor device includes a sense circuit operative to detect a voltage at a node to which the floating well is connected and to generate a control signal indicative of whether the voltage at the node is substantially within a voltage range. A lower value of the voltage range is substantially equal to a threshold voltage below a first supply voltage of the circuit. An upper value of the voltage range is substantially equal to a threshold voltage above the first supply voltage. The circuit for defining the voltage potential of the floating well further includes a voltage generator circuit operative to receive the control signal and to generate a bias signal for setting a voltage potential of the well in response to the control signal, the bias signal being controlled throughout the voltage range.
    Type: Grant
    Filed: September 30, 2005
    Date of Patent: October 2, 2007
    Assignee: Agere Systems Inc.
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John C. Kriz, Duane J. Loeper, Bernard L. Morris, Yehuda Smooha
  • Publication number: 20070176635
    Abstract: A voltage level translator circuit for translating an input signal referenced to a first voltage supply to an output signal referenced to a second voltage supply includes an input stage for receiving the input signal, the input stage including at least one transistor device having a first threshold voltage associated therewith. The voltage level translator circuit further includes a latch circuit operative to store a signal representative of a logic state of the input signal, the latch circuit including at least one transistor device having a second threshold voltage associated therewith, the second threshold voltage being greater than the first threshold voltage. A voltage clamp circuit is connected between the input stage and the latch circuit. The voltage clamp circuit is operative to limit a voltage across the input stage, an amplitude of the voltage across the input stage being controlled as a function of a voltage difference between the first and second voltage supplies.
    Type: Application
    Filed: January 27, 2006
    Publication date: August 2, 2007
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John Kriz, Bernard Morris, Joseph Simko
  • Patent number: 7248079
    Abstract: A differential buffer circuit includes a current source, a current sink, and a switching circuit connected to the current source at a first node and connected to the current sink at a second node. The switching circuit is operative to selectively control a direction of current flowing through differential outputs of the buffer circuit in response to at least a first control signal. The buffer circuit further includes a common mode detection circuit and a common mode control circuit. The common mode detection circuit is operative to detect an output common mode voltage of the buffer circuit and to generate a second control signal representative of the output common mode voltage. The common mode control circuit includes a first terminal connected to the current source and a second terminal connected to the current sink. The common mode control circuit is operative to selectively control the output common mode voltage of the buffer circuit as a function of the second control signal.
    Type: Grant
    Filed: November 23, 2005
    Date of Patent: July 24, 2007
    Assignee: Agere Systems Inc.
    Inventors: Dipankar Bhattacharya, Makeshwar Kothandaraman, John C. Kriz, Bernard L. Morris