Patents by Inventor Stefanos Sidiropoulos

Stefanos Sidiropoulos 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: 20040076192
    Abstract: A system includes a first integrated circuit device and a second integrated circuit device. The first device transmits a data sequence to the second integrated circuit device, and the second device samples the data sequence to produce receiver data. The second device then transmits the receiver data back to the first device. Within the first integrated circuit device, a comparison between the data sequence and the receiver data is performed, and based on the comparison, the first device generates information representative of a calibrated timing offset. The first device uses the information representative of the calibrated timing offset to adjust timing associated with transferring write data from the first integrated circuit to the second integrated circuit.
    Type: Application
    Filed: October 13, 2003
    Publication date: April 22, 2004
    Applicant: Rambus Inc.
    Inventors: Jared LeVan Zerbe, Kevin S. Donnelly, Stefanos Sidiropoulos, Donald C. Stark, Mark A. Horowitz, Leung Yu, Roxanne Vu, Jun Kim, Bruno W. Garlepp, Tsyr-Chyang Ho, Benedict Chung-Kwong Lau
  • Patent number: 6643787
    Abstract: A bus system comprising a master connected to one or more slave devices via a bus is disclosed. The bus system is able to effectively communicate control information during a calibration phase and to individually determine appropriate timing and/or voltage offsets for each slave device. The offsets are used to optimize transfer timing (including duty cycle characteristics), signal equalization, and voltage levels for data exchanged between the master and the slave devices.
    Type: Grant
    Filed: October 19, 1999
    Date of Patent: November 4, 2003
    Assignee: Rambus Inc.
    Inventors: Jared LeVan Zerbe, Kevin S. Donnelly, Stefanos Sidiropoulos, Donald C. Stark, Mark A. Horowitz, Leung Yu, Roxanne Vu, Jun Kim, Bruno W. Garlepp, Tsyr-Chyang Ho, Benedict Chung-Kwong Lau
  • Patent number: 6618786
    Abstract: A current-mode bus line driver includes a primary current source and a supplemental current source. The primary current source is an open-drain NMOS transistor, whose output current decreases at low output voltages. The supplemental current source is responsive to low output voltages to provide a supplemental output current, in addition to the output current of the primary current source. The supplemental current source consists of an inverter and a current mirror. The inverter produces a correction current that is inversely related to the voltage output of the primary current source. This correction current is amplified by the current mirror to produce the supplemental output current. The current mirror is self-limiting, in that its current output falls off at very low output voltages.
    Type: Grant
    Filed: August 28, 2000
    Date of Patent: September 9, 2003
    Assignee: Rambus Inc.
    Inventors: Stefanos Sidiropoulos, Yingxuan Li
  • Publication number: 20030122621
    Abstract: A reconfigurable dual-mode multiple stage operational amplifier circuit includes a configurable portion that can be selectively configured to operate in either a one-pole mode or a two-pole mode. Different exemplary operational amplifier circuits are provided, some of which employ a compensation portion that can be selectively coupled to the configurable portion. For example, in the one-pole operating mode the compensation portion is decoupled from an output of the configurable portion. Conversely, in the two-pole operating mode the compensation portion is coupled to the output. The compensation portion is configured to stabilize a signal on the output. The configurable portion switches between operational modes in response to at least one control signal. The operational amplifier may include a pulse generating portion that is coupled to operatively control the configurable portion in response to the at least one control signal. Such an implementation negates the need for a compensation portion.
    Type: Application
    Filed: February 18, 2003
    Publication date: July 3, 2003
    Inventors: Stefanos Sidiropoulos, Yingxuan Li
  • Publication number: 20030107418
    Abstract: Dual loop phase lock loops having a high loop bandwidth with low power consumption are described. Each loop is provided with a voltage supply regulator circuit which regulates the voltage of a portion of each loop. In one embodiment, the outer loop employs a regulation circuit comprising a two stage operational amplifier which is compensated by a compensation circuit that is configured to ensure that the dominant pole of the operational amplifier is associated with the first stage of the operational amplifier.
    Type: Application
    Filed: January 3, 2003
    Publication date: June 12, 2003
    Inventors: Kun-Yung Ken Chang, Yingxuan Li, Stefanos Sidiropoulos
  • Patent number: 6573779
    Abstract: Disclosed herein is a process-tracking clock duty cycle integrator. Common mode feedback is used to set a common mode output voltage that varies with the voltage threshold of MOS elements that implement the circuit. In addition, a buffer is used to control the common mode input voltage to the differential amplifier circuit, and to vary the common mode input voltage with the voltage threshold.
    Type: Grant
    Filed: May 25, 2001
    Date of Patent: June 3, 2003
    Assignee: Rambus Inc.
    Inventors: Stefanos Sidiropoulos, Yingxuan Li
  • Patent number: 6553452
    Abstract: A synchronous dynamic random access memory device having an array of dynamic memory cells. The memory device includes input receiver circuitry to sample a value that is representative of a range of temperatures. In addition, the memory device includes a programmable register, coupled to the input receiver circuitry, to store the value that is representative of the range of temperatures.
    Type: Grant
    Filed: January 18, 2002
    Date of Patent: April 22, 2003
    Assignee: Rambus Inc.
    Inventors: Bruno Werner Garlepp, Pak Shing Chau, Kevin S. Donnelly, Clemenz Portmann, Donald C. Stark, Stefanos Sidiropoulos, Richard M. Barth, Paul G. Davis, Ely K. Tsern
  • Publication number: 20030061447
    Abstract: A memory system architecture/interconnect topology that includes at least one point-to-point link between a master, and at least one memory subsystem. The memory subsystem includes a buffer device coupled to a plurality of memory devices. The memory system may be upgraded through dedicated point-to-point links and corresponding memory subsystems.
    Type: Application
    Filed: October 15, 2002
    Publication date: March 27, 2003
    Inventors: Richard E. Perego, Stefanos Sidiropoulos, Ely Tsern
  • Patent number: 6522199
    Abstract: A reconfigurable dual-mode multiple stage operational amplifier circuit includes a configurable portion that can be selectively configured to operate in either a one-pole mode or a two-pole mode. Different exemplary operational amplifier circuits are provided, some of which employ a compensation portion that can be selectively coupled to the configurable portion. For example, in the one-pole operating mode the compensation portion is decoupled from an output of the configurable portion. Conversely, in the two-pole operating mode the compensation portion is coupled to the output. The compensation portion is configured to stabilize a signal on the output. The configurable portion switches between operational modes in response to at least one control signal. The operational amplifier may include a pulse generating portion that is coupled to operatively control the configurable portion in response to the at least one control signal. Such an implementation negates the need for a compensation portion.
    Type: Grant
    Filed: May 18, 2001
    Date of Patent: February 18, 2003
    Assignee: Rambus, Inc.
    Inventors: Stefanos Sidiropoulos, Yingxuan Li
  • Patent number: 6513103
    Abstract: A method and apparatus for adjusting the performance of a memory system is provided. A memory system comprises a master device and a slave device. A memory channel couples the master device to the slave device such that the slave device receives the system operating information from the master device via the memory channel. The slave device further includes means for tuning circuitry within the slave device such that the performance of the memory system is improved.
    Type: Grant
    Filed: October 10, 1997
    Date of Patent: January 28, 2003
    Assignee: Rambus Inc.
    Inventors: Bruno Werner Garlepp, Pak Shing Chau, Kevin S. Donnelly, Clemenz Portmann, Donald C. Stark, Stefanos Sidiropoulos, Richard M. Barth, Paul G. Davis, Ely K. Tsern
  • Patent number: 6504438
    Abstract: Dual loop phase lock loops having a high loop bandwidth with low power consumption are described. Each loop is provided with a voltage supply regulator circuit which regulates the voltage of a portion of each loop. In one embodiment, the outer loop employs a regulation circuit comprising a two stage operational amplifier which is compensated by a compensation circuit that is configured to ensure that the dominant pole of the operational amplifier is associated with the first stage of the operational amplifier.
    Type: Grant
    Filed: September 17, 2001
    Date of Patent: January 7, 2003
    Assignee: Rambus, Inc.
    Inventors: Kun-Yung Ken Chang, Yingxuan Li, Stefanos Sidiropoulos
  • Patent number: 6502161
    Abstract: A memory system architecture/interconnect topology that includes at least one point-to-point link between a master, and at least one memory subsystem. The memory subsystem includes a buffer device coupled to a plurality of memory devices. The memory system may be upgraded through dedicated point-to-point links and corresponding memory subsystems. The master communicates to the plurality of memory devices in each memory subsystem through the respective buffer device via each point-to-point link.
    Type: Grant
    Filed: January 5, 2000
    Date of Patent: December 31, 2002
    Assignee: Rambus Inc.
    Inventors: Richard E. Perego, Stefanos Sidiropoulos, Ely Tsern
  • Publication number: 20020175739
    Abstract: Disclosed herein is a process-tracking clock duty cycle integrator. Common mode feedback is used to set a common mode output voltage that varies with the voltage threshold of MOS elements that implement the circuit. In addition, a buffer is used to control the common mode input voltage to the differential amplifier circuit, and to vary the common mode input voltage with the voltage threshold.
    Type: Application
    Filed: May 25, 2001
    Publication date: November 28, 2002
    Inventors: Stefanos Sidiropoulos, Yingxuan Li
  • Publication number: 20020171487
    Abstract: A reconfigurable dual-mode multiple stage operational amplifier circuit includes a configurable portion that can be selectively configured to operate in either a one-pole mode or a two-pole mode. Different exemplary operational amplifier circuits are provided, some of which employ a compensation portion that can be selectively coupled to the configurable portion. For example, in the one-pole operating mode the compensation portion is decoupled from an output of the configurable portion. Conversely, in the two-pole operating mode the compensation portion is coupled to the output. The compensation portion is configured to stabilize a signal on the output. The configurable portion switches between operational modes in response to at least one control signal. The operational amplifier may include a pulse generating portion that is coupled to operatively control the configurable portion in response to the at least one control signal. Such an implementation negates the need for a compensation portion.
    Type: Application
    Filed: May 18, 2001
    Publication date: November 21, 2002
    Inventors: Stefanos Sidiropoulos, Yingxuan Li
  • Patent number: 6469555
    Abstract: A delay-locked loop circuit generates a first clock signal. The delay-locked loop circuit includes a first delay element coupled in a feedback path of the delay-locked loop circuit to advance the first clock signal relative to a reference clock signal by a first time period. A second delay element is coupled to receive the first clock signal from the delay-locked loop circuit. The second delay element also outputs a second clock signal that is delayed relative to the first clock signal by the first time period. The delay-locked loop circuit may include a phase detector to identify phase differences between the first clock signal and the reference clock signal. A third delay element may be coupled between the delay-locked loop circuit and the second delay element.
    Type: Grant
    Filed: August 18, 2000
    Date of Patent: October 22, 2002
    Assignee: Rambus, Inc
    Inventors: Benedict C. Lau, Stefanos Sidiropoulos
  • Publication number: 20020140473
    Abstract: A delay-locked loop circuit generates a first clock signal. The delay-locked loop circuit includes a first delay element coupled in a feedback path of the delay-locked loop circuit to advance the first clock signal relative to a reference clock signal by a first time period. A second delay element is coupled to receive the first clock signal from the delay-locked loop circuit. The second delay element also outputs a second clock signal that is delayed relative to the first clock signal by the first time period. The delay-locked loop circuit may include a phase detector to identify phase differences between the first clock signal and the reference clock signal. A third delay element may be coupled between the delay-locked loop circuit and the second delay element.
    Type: Application
    Filed: May 29, 2002
    Publication date: October 3, 2002
    Inventors: Benedict C. Lau, Stefanos Sidiropoulos
  • Patent number: 6448828
    Abstract: A duty cycle converter generating a pair of output signals whose cross-point duty cycle is substantially equal to the edge duty cycle of a pair of input signals. The duty cycle converter includes an edge detector and a signal generator. The edge detector detects and indicates a first transition of a first input signal and a second transition of a second input signal. The signal generator takes the outputs of the edge detector and generates a first output signal and a second output signal. The signal generator causes the cross-point duty cycle of the first output signal to substantially equal the edge duty cycle of the first input cycle. The signal generator does so by forcing a first time delay between adjacent crossover points of the first and second output signals to be substantially equal to a second time delay between the first transition and the second transition.
    Type: Grant
    Filed: October 15, 2001
    Date of Patent: September 10, 2002
    Assignee: Rambus Inc.
    Inventors: Donald C. Stark, Stefanos Sidiropoulos
  • Publication number: 20020087820
    Abstract: A method and apparatus for adjusting the performance of a memory system is provided. A memory control device comprises a master device including a frequency detector, a memory channel, and a memory device coupled to the master device via the memory channel. The memory device includes a decoder designed to receive a control signal from the master device. A clock recovery and alignment circuit receives the control signal from the decoder and adjusts the operating frequency of the memory device in response to the control signal.
    Type: Application
    Filed: January 18, 2002
    Publication date: July 4, 2002
    Inventors: Bruno Werner Garlepp, Pak Shing Chau, Kevin S. Donnelly, Clemenz Portmann, Donald C. Stark, Stefanos Sidiropoulos, Richard M. Barth, Paul G. Davis, Ely K. Tsern
  • Publication number: 20020017936
    Abstract: A duty cycle converter generating a pair of output signals whose cross-point duty cycle is substantially equal to the edge duty cycle of a pair of input signals. The duty cycle converter includes an edge detector and a signal generator. The edge detector detects and indicates a first transition of a first input signal and a second transition of a second input signal. The signal generator takes the outputs of the edge detector and generates a first output signal and a second output signal. The signal generator causes the cross-point duty cycle of the first output signal to substantially equal the edge duty cycle of the first input cycle. The signal generator does so by forcing a first time delay between adjacent crossover points of the first and second output signals to be substantially equal to a second time delay between the first transition and the second transition.
    Type: Application
    Filed: October 15, 2001
    Publication date: February 14, 2002
    Applicant: Rambus Inc..
    Inventors: Donald C. Stark, Stefanos Sidiropoulos
  • Patent number: 6323706
    Abstract: A duty cycle converter generating a pair of output signals whose cross-point duty cycle is substantially equal to the edge duty cycle of a pair of input signals. The duty cycle converter includes an edge detector and a signal generator. The edge detector detects and indicates a first transition of a first input signal and a second transition of a second input signal. The signal generator takes the outputs of the edge detector and generates a first output signal and a second output signal. The signal generator causes the cross-point duty cycle of the first output signal to substantially equal the edge duty cycle of the first input cycle. The signal generator does so by forcing a first time delay between adjacent cross-over points of the first and second output signals to be substantially equal to a second time delay between the first transition and the second transition.
    Type: Grant
    Filed: February 24, 2000
    Date of Patent: November 27, 2001
    Assignee: Rambus Inc.
    Inventors: Donald C. Stark, Stefanos Sidiropoulos