Patents by Inventor Prabhansu Chakrabarti

Prabhansu Chakrabarti 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: 8018738
    Abstract: A voltage regulator. The voltage regulator includes an interposer having, on a first side, a plurality of electrical connections suitable for coupling to a printed circuit board (PCB). The interposer also includes at least one power plane and at least one ground plane, wherein each of the power and ground planes is coupled to one or more of the electrical connections. The voltage regulator further includes a DC-DC converter that is electro-mechanically attachable to and detachable from the interposer. The interposer includes a socket, on a second side, that is suitable to receive two or more electro-mechanical connecting members of the DC-DC converter. When the DC-DC converter is attached to the interposer, at least one of the electromechanical connecting members is electrically coupled to a power plane of the interposer, while at least one other one of the electromechanical connecting members is electrically coupled to the ground plane.
    Type: Grant
    Filed: June 2, 2008
    Date of Patent: September 13, 2011
    Assignee: Oracle America, Inc.,
    Inventors: Drew G. Doblar, Prabhansu Chakrabarti, Michael J. Bushue
  • Publication number: 20090296360
    Abstract: A voltage regulator. The voltage regulator includes an interposer having, on a first side, a plurality of electrical connections suitable for coupling to a printed circuit board (PCB). The interposer also includes at least one power plane and at least one ground plane, wherein each of the power and ground planes is coupled to one or more of the electrical connections. The voltage regulator further includes a DC-DC converter that is electro-mechanically attachable to and detachable from the interposer. The interposer includes a socket, on a second side, that is suitable to receive two or more electro-mechanical connecting members of the DC-DC converter. When the DC-DC converter is attached to the interposer, at least one of the electromechanical connecting members is electrically coupled to a power plane of the interposer, while at least one other one of the electromechanical connecting members is electrically coupled to the ground plane.
    Type: Application
    Filed: June 2, 2008
    Publication date: December 3, 2009
    Inventors: Drew G. Doblar, Prabhansu Chakrabarti, Michael J. Bushue
  • Patent number: 7394260
    Abstract: A method of tuning a test trace that is capacitively coupled to a number of signal traces. A method for determining a configuration of a device comprising signal traces and a capacitively coupled test trace may include selecting a test frequency of a test signal to be driven on selected signal traces during a test mode of device operation, and tuning circuit characteristics of the test trace to generate a bandpass frequency response including a passband and a stopband, where a detection frequency corresponding either to the test frequency or a selected harmonic of the test frequency is included in the passband. Tuning of circuit characteristics may include selecting a degree of capacitive coupling between the test trace and the signal traces such that, within a specified constraint for signal degradation on the signal traces, the bandpass frequency response of the given test trace satisfies a specified transmission requirement at the detection frequency.
    Type: Grant
    Filed: May 24, 2006
    Date of Patent: July 1, 2008
    Assignee: Sun Microsystems, Inc.
    Inventors: Margaret H. Wang, Prabhansu Chakrabarti
  • Publication number: 20070273386
    Abstract: A method of tuning a test trace that is capacitively coupled to a number of signal traces. A method for determining a configuration of a device comprising signal traces and a capacitively coupled test trace may include selecting a test frequency of a test signal to be driven on selected signal traces during a test mode of device operation, and tuning circuit characteristics of the test trace to generate a bandpass frequency response including a passband and a stopband, where a detection frequency corresponding either to the test frequency or a selected harmonic of the test frequency is included in the passband. Tuning of circuit characteristics may include selecting a degree of capacitive coupling between the test trace and the signal traces such that, within a specified constraint for signal degradation on the signal traces, the bandpass frequency response of the given test trace satisfies a specified transmission requirement at the detection frequency.
    Type: Application
    Filed: May 24, 2006
    Publication date: November 29, 2007
    Applicant: Sun Microsystems, Inc.
    Inventors: Margaret H. Wang, Prabhansu Chakrabarti
  • Patent number: 7296104
    Abstract: A method and apparatus for automated calibration of I/O over a multi-variable eye window is provided. A transmitter may conduct data transmissions to a receiver of an integrated circuit (IC) over a plurality of signal lines. The data transmissions may be conducted according to a certain parameters or sets of parameters. Parameters may include voltage levels at which signals are transmitted or timing delays. The receiver may determine whether the correct data value was received over each signal line. The results may be recorded in a storage mechanism in the same IC as the receiver. The storage mechanism may, for each signal line, store a pass/fail result corresponding to the particular parameters for the data transmission. The system may select the parameters which subsequent transmissions are to be conducted over each of the plurality of signal lines from the storage mechanism.
    Type: Grant
    Filed: September 12, 2005
    Date of Patent: November 13, 2007
    Assignee: Sun Microsystems, Inc.
    Inventors: Brian L. Smith, Jue Wu, Jyh-Ming Jong, Wai Fong, Leo Yuan, Prabhansu Chakrabarti
  • Patent number: 7292020
    Abstract: A remote voltage regulator module (VRM) for high-current, low voltage applications. In one embodiment, an electronic system includes a VRM configured to provide a DC output voltage. The VRM is coupled to a load board via a first bus bar and a second bus bar. The VRM includes a first capacitance of a first amount, while the load board includes a second capacitance of a second amount. A loop between the VRM and the load board is formed by the first and second bus bars and first and second capacitances. The loop is characterized by a transfer function that is second order or less.
    Type: Grant
    Filed: March 1, 2005
    Date of Patent: November 6, 2007
    Assignee: Sun Microsysytems, Inc.
    Inventors: Lawrence D. Smith, Prabhansu Chakrabarti, William H. Schwartz
  • Publication number: 20060009931
    Abstract: A method and apparatus for automated calibration of I/O over a multi-variable eye window is provided. A transmitter may conduct data transmissions to a receiver of an integrated circuit (IC) over a plurality of signal lines. The data transmissions may be conducted according to a certain parameters or sets of parameters. Parameters may include voltage levels at which signals are transmitted or timing delays. The receiver may determine whether the correct data value was received over each signal line. The results may be recorded in a storage mechanism in the same IC as the receiver. The storage mechanism may, for each signal line, store a pass/fail result corresponding to the particular parameters for the data transmission. The system may select the parameters which subsequent transmissions are to be conducted over each of the plurality of signal lines from the storage mechanism.
    Type: Application
    Filed: September 12, 2005
    Publication date: January 12, 2006
    Inventors: Brian Smith, Jue Wu, Jyh-Ming Jong, Wai Fong, Leo Yuan, Prabhansu Chakrabarti
  • Patent number: 6965648
    Abstract: A system may perform interconnect BIST (IBIST) testing on source synchronous links. The system may perform, at normal operating frequency, a source synchronous link test that tests a victim line on the source synchronous link using a transition weave pattern. The transition weave pattern causes interaction between a data transition on the victim line, previous transitions on the victim line, and transitions on the other lines of the link (the “aggressor” lines). The interaction caused may be: (i) a first crossing pulse on the victim line; (ii) a second crossing pulse of the opposite polarity on each aggressor line concurrent with the first crossing pulse on the victim line; and (iii) a reflection in the opposite direction of the first transition of the first crossing pulse, wherein the reflection results from a previous transition on the victim line.
    Type: Grant
    Filed: May 4, 2000
    Date of Patent: November 15, 2005
    Assignee: Sun Microsystems, Inc.
    Inventors: Brian L. Smith, Prabhansu Chakrabarti
  • Patent number: 6944692
    Abstract: A method and apparatus for automated calibration of I/O over a multi-variable eye window is provided. A transmitter may conduct data transmissions to a receiver of an integrated circuit (IC) over a plurality of signal lines. The data transmissions may be conducted according to a certain parameters or sets of parameters. Parameters may include voltage levels at which signals are transmitted or timing delays. The receiver may determine whether the correct data value was received over each signal line. The results may be recorded in a storage mechanism in the same IC as the receiver. The storage mechanism may, for each signal line, store a pass/fail result corresponding to the particular parameters for the data transmission. The system may select the parameters which subsequent transmissions are to be conducted over each of the plurality of signal lines from the storage mechanism.
    Type: Grant
    Filed: September 13, 2001
    Date of Patent: September 13, 2005
    Assignee: Sun Microsystems, Inc.
    Inventors: Brian L. Smith, Jue Wu, Jyh-Ming Jong, Wai Fong, Leo Yuan, Prabhansu Chakrabarti
  • Patent number: 6937680
    Abstract: A method and apparatus for operating a source synchronous receiver. In one embodiment, a source synchronous receiver may include a clock receiver comprising a clock detector and a clock signal buffer. The clock detector may be configured to detect a first clock signal and assert a clock detect signal responsive to detecting the first clock signal. The clock buffer may receive the first clock signal and produce a second clock signal, which may be driven to a digital locked loop (DLL) circuit, where the second clock signal is regenerated and driven to a data buffer of the source synchronous receiver. The clock detect signal may be received by a clock verification circuit. The clock verification circuit may be configured to initiate a reset of the source synchronous receiver upon a failure to receive the clock detect signal.
    Type: Grant
    Filed: April 24, 2001
    Date of Patent: August 30, 2005
    Assignee: Sun Microsystems, Inc.
    Inventors: Wai Fong, Jyh-Ming Jong, Leo Yuan, Brian Smith, Prabhansu Chakrabarti
  • Publication number: 20040136462
    Abstract: A system and method for training a receiver circuit. In one embodiment, a first integrated circuit (IC) may be coupled to a plurality of signal lines. One or more of the signal lines may be coupled to a second IC as well. The first IC may include a plurality of transmitters, while the second IC may include one or more receivers. On a first signal line, a transmitter of the first IC may transmit a first bit pattern to a receiver in the second IC. On a first plurality of signal lines (not including the first signal line), transmitters in the first IC may transmit a second bit pattern. The receiver in the second IC, responsive to receiving the bit pattern, may be configured (i.e. trained) to lock onto bits transmitted to it over the signal line.
    Type: Application
    Filed: January 13, 2003
    Publication date: July 15, 2004
    Inventors: Albert Chen, Gary M. Rigsby, Prabhansu Chakrabarti
  • Patent number: 6737892
    Abstract: One embodiment of the present invention provides a system for detecting a valid clock signal at a clock receiver. The system operates by receiving a clock signal at the clock receiver, and directing the clock signal into a control input of a voltage-controlled variable resistor. Next, the system uses the voltage-controlled variable resistor to control a first current. A current mirror is then employed to create a second current from the first current. This second current passes through a resistor to produce a control voltage, which is amplified to produce a validity signal indicating whether or not the clock signal is valid. In one embodiment of the present invention, the system additionally uses at least one capacitor to filter out periodic fluctuations in the validity signal.
    Type: Grant
    Filed: December 18, 2000
    Date of Patent: May 18, 2004
    Assignee: Sun Microsystems, Inc.
    Inventors: Jyh-Ming Jong, Chung-Hsiao Wu, Prabhansu Chakrabarti, Leo Yuan
  • Patent number: 6542026
    Abstract: An on-chip DC voltage generator providing a marginable reference voltage signal is described. The present invention is a CMOS-based integrated circuit that generates a marginable reference voltage level. The present invention provides a process insensitive reference voltage signal and may be configured so as to generate a ground-bounce-noise free signal.
    Type: Grant
    Filed: August 15, 2001
    Date of Patent: April 1, 2003
    Assignee: Sun Microsystems, Inc.
    Inventors: Chung-Hsiao R. Wu, Jyh-Ming Jong, Prabhansu Chakrabarti, Leo Yuan
  • Publication number: 20030051086
    Abstract: A method and apparatus for automated calibration of I/O over a multi-variable eye window is provided. A transmitter may conduct data transmissions to a receiver of an integrated circuit (IC) over a plurality of signal lines. The data transmissions may be conducted according to a certain parameters or sets of parameters. Parameters may include voltage levels at which signals are transmitted or timing delays. The receiver may determine whether the correct data value was received over each signal line. The results may be recorded in a storage mechanism in the same IC as the receiver. The storage mechanism may, for each signal line, store a pass/fail result corresponding to the particular parameters for the data transmission. The system may select the parameters which subsequent transmissions are to be conducted over each of the plurality of signal lines from the storage mechanism.
    Type: Application
    Filed: September 13, 2001
    Publication date: March 13, 2003
    Inventors: Brian L. Smith, Jue Wu, Jyh-Ming Jong, Wai Fong, Leo Yuan, Prabhansu Chakrabarti
  • Publication number: 20030034829
    Abstract: An on-chip DC voltage generator providing a marginable reference voltage signal is described. The present invention is a CMOS-based integrated circuit that generates a marginable reference voltage level. The present invention provides a process insensitive reference voltage signal and may be configured so as to generate a ground-bounce-noise free signal.
    Type: Application
    Filed: August 15, 2001
    Publication date: February 20, 2003
    Inventors: Chung-Hsiao R. Wu, Jyh-Ming Jong, Prabhansu Chakrabarti, Leo Yuan
  • Patent number: 6521846
    Abstract: A method for assigning power and ground pins in array packages in order to enhance next level routing is provided. In one embodiment, the method comprises arranging connections of a semiconductor array package, the semiconductor package having an integrated circuit with power, ground, and signal connections, in 2×3 connection grids. Each connection grid includes a power connection and a ground connection which is adjacent to the power connection. The 2×3 connection grids are arranged so that each connection at the periphery is a signal connection. A 4:1:1 signal:power:ground connection ratio is maintained in the arrangement, wherein no more than four signal connections are present for each power connection, and no more than four signal connections are present for each ground connection.
    Type: Grant
    Filed: January 7, 2002
    Date of Patent: February 18, 2003
    Assignee: Sun Microsystems, Inc.
    Inventors: Michael C. Freda, Prabhansu Chakrabarti
  • Patent number: 6518792
    Abstract: A method and circuitry for pre-emphasizing transmitted logic signals. The method and circuitry may be applied to single-ended center-taped terminated I/O lines. In one embodiment, a driver circuit may be configured for monitoring the logic values (i.e. logic 0, logic 1, or logic low, logic high) of signals transmitted by the driver circuit. The driver circuit may compare the logic value of a next logic signal to be transmitted with a first previously transmitted signal and a second previously transmitted signal. Pre-emphasis of the next logic signal may occur based on the logic value of the next logic signal to be transmitted as well as the logic values of the first and second logic signals. If the first and second logic signals have the same logic value, and the next logic signal has a different value, the next logic value may be pre-emphasized.
    Type: Grant
    Filed: June 11, 2001
    Date of Patent: February 11, 2003
    Assignee: Sun Microsystems, Inc.
    Inventors: Jyh-Ming Jong, Prabhansu Chakrabarti, Leo Yuan
  • Publication number: 20020186056
    Abstract: A method and circuitry for pre-emphasizing transmitted logic signals. The method and circuitry may be applied to single-ended center-taped terminated I/O lines. In one embodiment, a driver circuit may be configured for monitoring the logic values (i.e. logic 0, logic 1, or logic low, logic high) of signals transmitted by the driver circuit. The driver circuit may compare the logic value of a next logic signal to be transmitted with a first previously transmitted signal and a second previously transmitted signal. Pre-emphasis of the next logic signal may occur based on the logic value of the next logic signal to be transmitted as well as the logic values of the first and second logic signals. If the first and second logic signals have the same logic value, and the next logic signal has a different value, the next logic value may be pre-emphasized.
    Type: Application
    Filed: June 11, 2001
    Publication date: December 12, 2002
    Inventors: Jyh-Ming Jong, Prabhansu Chakrabarti, Leo Yuan
  • Publication number: 20020154718
    Abstract: A method and apparatus for operating a source synchronous receiver. In one embodiment, a source synchronous receiver may include a clock receiver comprising a clock detector and a clock signal buffer. The clock detector may be configured to detect a first clock signal and assert a clock detect signal responsive to detecting the first clock signal. The clock buffer may receive the first clock signal and produce a second clock signal, which may be driven to a digital locked loop (DLL) circuit, where the second clock signal is regenerated and driven to a data buffer of the source synchronous receiver. The clock detect signal may be received by a clock verification circuit. The clock verification circuit may be configured to initiate a reset of the source synchronous receiver upon a failure to receive the clock detect signal.
    Type: Application
    Filed: April 24, 2001
    Publication date: October 24, 2002
    Inventors: Wai Fong, Jyh-Ming Jong, Leo Yuan, Brian Smith, Prabhansu Chakrabarti
  • Publication number: 20020078392
    Abstract: One embodiment of the present invention provides a system for detecting a valid clock signal at a clock receiver. The system operates by receiving a clock signal at the clock receiver, and directing the clock signal into a control input of a voltage-controlled variable resistor. Next, the system uses the voltage-controlled variable resistor to control a first current. A current mirror is then employed to create a second current from the first current. This second current passes through a resistor to produce a control voltage, which is amplified to produce a validity signal indicating whether or not the clock signal is valid. In one embodiment of the present invention, the system additionally uses at least one capacitor to filter out periodic fluctuations in the validity signal.
    Type: Application
    Filed: December 18, 2000
    Publication date: June 20, 2002
    Inventors: Jyh-Ming Jong, Chung-Hsiao Wu, Prabhansu Chakrabarti, Leo Yuan