Patents Assigned to Rambus
  • Patent number: 8942319
    Abstract: A multi-phase partial response receiver supports various incoming data rates by sampling PrDFE output values at a selected one of at least two clock phases. The receiver includes a calibration circuit that performs a timing analysis of critical data paths in the circuit, and this analysis is then used to select the particular clock phase used to latch the output values. These techniques permit the multiplexer outputs from for each phase of the partial response receiver to directly drive selection of a multiplexer for the ensuing phase, i.e., by avoiding regions of instability or uncertainty in the respective multiplexer outputs.
    Type: Grant
    Filed: March 25, 2011
    Date of Patent: January 27, 2015
    Assignee: Rambus Inc.
    Inventors: Chintan S. Thakkar, Kun-Yung Chang, Ting Wu
  • Patent number: 8942297
    Abstract: In a data transmission system, one or more signal supply voltages for generating the signaling voltage of a signal to be transmitted are generated in a first circuit and forwarded from the first circuit to a second circuit. The second circuit may use the forwarded signal supply voltages to generate another signal to be transmitted back from the second circuit to the first circuit, thereby obviating the need to generate signal supply voltages separately in the second circuit. The first circuit may also adjust the signal supply voltages based on the signal transmitted back from the second circuit to the first circuit. The data transmission system may employ a single-ended signaling system in which the signaling voltage is referenced to a reference voltage that is a power supply voltage such as ground, shared by the first circuit and the second circuit.
    Type: Grant
    Filed: March 30, 2010
    Date of Patent: January 27, 2015
    Assignee: Rambus Inc.
    Inventors: Scott C. Best, John W. Poulton
  • Patent number: 8942056
    Abstract: In one embodiment, a memory device includes a memory core and input receivers to receive commands and data. The memory device also includes a register to store a value that indicates whether a subset of the input receivers are powered down in response to a control signal. A memory controller transmits commands and data to the memory device. The memory controller also transmits the value to indicate whether a subset of the input receivers of the memory device are powered down in response to the control signal. In addition, in response to a self-fresh command, the memory device defers entry into a self-refresh operation until receipt of the control signal that is received after receiving the self-refresh command.
    Type: Grant
    Filed: February 15, 2012
    Date of Patent: January 27, 2015
    Assignee: Rambus Inc.
    Inventors: Wayne F. Ellis, Wayne S. Richardson, Akash Bansal, Frederick A. Ware, Lawrence Lai, Kishore Ven Kasamsetty
  • Patent number: 8937994
    Abstract: A partial response decision feedback equalizer (PrDFE) includes a receiver including at least first and second comparators operative to compare an input signal representing a sequence of symbols against respective thresholds and to respectively generate first and second receiver outputs. A first selection stage is provided to select (a) between the first comparator output and a first resolved symbol according to a first timing signal, and (b) between the second comparator output and the first resolved symbol according to the first timing signal, to produce respective first and second selection outputs. A second selection stage selects between the first and second selection outputs according to a selection signal. The selection signal is dependent on a prior resolved symbol that precedes the first resolved symbol in the sequence.
    Type: Grant
    Filed: June 11, 2013
    Date of Patent: January 20, 2015
    Assignee: Rambus Inc.
    Inventors: Amir Amirkhany, Kambiz Kaviani, Aliazam Abbasfar
  • Patent number: 8938578
    Abstract: An integrated circuit memory device is disclosed. The memory device includes a memory core having a timing input to receive a clock signal. An interface couples to the memory core. The interface includes a receiver to receive a serial stream of write data bits and a sampler clocked by a strobe signal to generate serialized write data. The interface also includes a deserializer and control logic. The deserializer includes an input to receive the serialized write data and an output to generate parallel data responsive to a control signal generated by the control logic. In a first mode of operation, the control logic generates the control signal with respect to the clock signal. In a second mode of operation, the control logic generates the control signal with respect to the strobe signal.
    Type: Grant
    Filed: July 8, 2013
    Date of Patent: January 20, 2015
    Assignee: Rambus Inc.
    Inventors: Liji Gopalakrishnan, Renu Rangnekar
  • Patent number: 8935489
    Abstract: The disclosed embodiments relate to a system for processing memory references received from multiple processor cores. During operation, the system monitors the memory references to determine whether memory references from different processor cores are interfering with each other as the memory references are processed by a memory system. If memory references from different processor cores are interfering with each other, the system time-multiplexes the processing of memory references between processor cores, so that a block of consecutive memory references from a given processor core is processed by the memory system before memory references from other processor cores are processed.
    Type: Grant
    Filed: November 10, 2010
    Date of Patent: January 13, 2015
    Assignee: Rambus Inc.
    Inventors: Steven C. Woo, Trung A. Diep, Michael T. Ching
  • Patent number: 8934525
    Abstract: A receiver includes a continuous-time equalizer, a decision-feedback equalizer (DFE), data and error sampling logic, and an adaptation engine. The receiver corrects for inter-symbol interference (ISI) associated with the most recent data symbol (first post cursor ISI) by establishing appropriate equalization settings for the continuous-time equalizer based upon a measure of the first-post-cursor ISI.
    Type: Grant
    Filed: January 7, 2008
    Date of Patent: January 13, 2015
    Assignee: Rambus Inc.
    Inventors: Hae-Chang Lee, Brian S. Leibowitz, Jade M. Kizer, Thomas H. Greer, Akash Bansal
  • Patent number: 8933729
    Abstract: Differential receivers are “stacked” and independently calibrated to different common-mode voltages. The different common-mode voltages may correspond to the common-mode voltages of stacked transmission circuits. Multiple stacks of samplers are connected to the same channels. The clocking of each stack of sampler circuits is phased (timed) such that the samplers in a given stack are not resolving at the same time. Samplers in a different stack and receiving a different common-mode voltage resolve at the same time.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: January 13, 2015
    Assignee: Rambus Inc.
    Inventors: Xudong Shi, Reza Navid, Jason Chia-Jen Wei, Huy M. Nguyen, Kambiz Kaviani
  • Patent number: 8930779
    Abstract: The disclosed embodiments provide a dynamic memory device, comprising a set of dynamic memory cells and a set of replacement dynamic memory cells. The set of replacement dynamic memory cells includes data cells which contain replacement data bits for predetermined faulty cells in the set of dynamic memory cells, and address cells which contain address bits identifying the faulty cells, wherein each data cell is associated with a group of address cells that identify an associated faulty cell in the set of dynamic memory cells. The dynamic memory device also includes a remapping circuit, which remaps a faulty cell in the set of dynamic memory cells to an associated replacement cell in the set of replacement cells.
    Type: Grant
    Filed: November 10, 2010
    Date of Patent: January 6, 2015
    Assignee: Rambus Inc.
    Inventors: Frederick A. Ware, Ely Tsern, Thomas Vogelsang
  • Patent number: 8929159
    Abstract: A driver circuit includes pull-up and pull-down drivers driven by separate pre-drivers operating between different voltage rails. Data signals driving the pull-up driver and the pull-down driver are synchronized, and the pull-up driver and the pull-down driver are coupled together to produce an output signal having a voltage swing based on both the pull-up driver and the pull-down driver.
    Type: Grant
    Filed: April 5, 2012
    Date of Patent: January 6, 2015
    Assignee: Rambus Inc.
    Inventors: Manish Jain, Navin Kumar Mishra
  • Patent number: 8929496
    Abstract: A receiver device implements enhanced data reception with edge-based clock and data recovery such as with a flash analog-to-digital converter architecture. In an example embodiment, the device implements a first phase adjustment control loop, with for example, a bang-bang phase detector, that detects data transitions for adjusting sampling at an optimal edge time with an edge sampler by adjusting a phase of an edge clock of the sampler. This loop may further adjust sampling in received data intervals for optimal data reception by adjusting the phase of a data clock of a data sampler such a flash ADC. The device may also implement a second phase adjustment control loop with, for example, a baud-rate phase detector, that detects data intervals for further adjusting sampling at an optimal data time with the data sampler.
    Type: Grant
    Filed: January 30, 2009
    Date of Patent: January 6, 2015
    Assignee: Rambus Inc.
    Inventors: Hae-Chang Lee, Brian Leibowitz, Jaeha Kim, Jafar Savoj
  • Patent number: 8930740
    Abstract: This disclosure provides for adjustment of memory IO timing using a voltage controlled oscillator (VCO) and a register that generates a VCO control voltage directly used to vary memory IO timing. The register may be externally programmable by a controller and may be located on a memory device (IC, module or other device) or on an external voltage generator, which then provides an adjustable voltage to the memory device. This structure may be used to adjust memory timing so as to achieve a minimum target bitrate and thus minimize frequency of operation to minimize power. In one embodiment, each of several memory devices may be independently adjusted in this way to achieve a mesochronous memory system; in another embodiment, memory devices may be have their timing adjusted in parallel, with all memory devices equal to or greater than a target bitrate. Teachings presented herein provide a way to relax overdesign requirements and “tune” fast-fast and slow-slow devices to effectively operate as typical devices.
    Type: Grant
    Filed: November 16, 2010
    Date of Patent: January 6, 2015
    Assignee: Rambus Inc.
    Inventors: Jared L. Zerbe, Scott C. Best, Brian L. Leibowitz
  • Patent number: 8929424
    Abstract: A method and system that provides for execution of a first calibration sequence, such as upon initialization of a system, to establish an operation value, which utilizes an algorithm intended to be exhaustive, and executing a second calibration sequence from time to time, to measure drift in the parameter, and to update the operation value in response to the measured drift. The second calibration sequence utilizes less resources of the communication channel than does the first calibration sequence. In one embodiment, the first calibration sequence for measurement and convergence on the operation value utilizes long calibration patterns, such as codes that are greater than 30 bytes, or pseudorandom bit sequences having lengths of 2N?1 bits, where N is equal to or greater than 7, while the second calibration sequence utilizes short calibration patterns, such as fixed codes less than 16 bytes, and for example as short as 2 bytes long.
    Type: Grant
    Filed: January 1, 2014
    Date of Patent: January 6, 2015
    Assignee: Rambus Inc.
    Inventors: Craig E. Hampel, Frederick A. Ware, Richard E. Perego
  • Patent number: 8923467
    Abstract: A system and method for performing clock and data recovery. The system sets the phase of a recovered clock signal according to at least three estimates of the rate of change of an offset between the frequency of the data transmitter clock and the frequency of a receiver clock.
    Type: Grant
    Filed: November 12, 2012
    Date of Patent: December 30, 2014
    Assignee: Rambus Inc.
    Inventors: Hae-Chang Lee, Thomas H. Greer, III, Jade M. Kizer, Brian S. Leibowitz, Mark A. Horowitz
  • Patent number: 8923442
    Abstract: As single-ended signaling is implemented in higher-speed communications, accurate and consistent reading of the data signal becomes increasingly challenging. In particular, single-ended links can be limited by insufficient timing margins for sampling a received input signal. A single ended receiver provides for improved timing margins by adjusting a reference voltage used to sample the input signal. A calibration pattern is provided to the receiver as the input signal, and the reference voltage is adjusted toward a median value of the signal.
    Type: Grant
    Filed: December 28, 2012
    Date of Patent: December 30, 2014
    Assignee: Rambus Inc.
    Inventor: Srinivasaraman Chandrasekaran
  • Patent number: 8924680
    Abstract: A memory system includes a memory controller with a plurality N of memory-controller blocks, each of which conveys independent transaction requests over external request ports. The request ports are coupled, via point-to-point connections, to from one to N memory devices, each of which includes N independently addressable memory blocks. All of the external request ports are connected to respective external request ports on the memory device or devices used in a given configuration. The number of request ports per memory device and the data width of each memory device changes with the number of memory devices such that the ratio of the request-access granularity to the data granularity remains constant irrespective of the number of memory devices.
    Type: Grant
    Filed: April 11, 2008
    Date of Patent: December 30, 2014
    Assignee: Rambus Inc.
    Inventors: Richard E. Perego, Frederick A. Ware
  • Patent number: 8922245
    Abstract: In an asymmetrically terminated communication system, the power consumed to transmit a particular bit value is adjusted based on whether the bit being output is the second, third, fourth, etc. consecutive bit with the same value after a transition to output the particular bit value. The adjustment of the power consumed to transmit the two or more consecutive bits with the same value may be made by adjusting the driver strength during the second, or subsequent, consecutive bits with the same value. The adjustment of the power consumed is performed on the bit value that consumes the most DC power and the other value is typically not adjusted.
    Type: Grant
    Filed: August 9, 2013
    Date of Patent: December 30, 2014
    Assignee: Rambus Inc.
    Inventors: Kyung Suk Oh, Chi-Ming Yeung, David A. Secker
  • Publication number: 20140376324
    Abstract: Embodiments generally relate to integrated circuit devices having through silicon vias (TSVs). In one embodiment, an integrated circuit (IC) device includes a field of TSVs and an address decoder that selectably couples at least one of the TSVs to at least one of a test input and a test evaluation circuit. In another embodiment, a method includes selecting one or more TSVs from a field of TSVs in at least one IC device, and coupling each selected TS V to at least one of a test input and a test evaluation circuit.
    Type: Application
    Filed: August 31, 2012
    Publication date: December 25, 2014
    Applicant: Rambus Inc.
    Inventors: Thomas Vogelsang, William N. Ng, Frederick A. Ware
  • Patent number: 8918669
    Abstract: In a low-power signaling system, an integrated circuit device includes an open loop-clock distribution circuit and a transmit circuit that cooperate to enable high-speed transmission of information-bearing symbols unaccompanied by source-synchronous timing references. The open-loop clock distribution circuit generates a transmit clock signal in response to an externally-supplied clock signal, and the transmit circuit outputs a sequence of symbols onto an external signal line in response to transitions of the transmit clock signal. Each of the symbols is valid at the output of the transmit circuit for a symbol time and a phase offset between the transmit clock signal and the externally-supplied clock signal is permitted to drift by at least the symbol time.
    Type: Grant
    Filed: July 9, 2009
    Date of Patent: December 23, 2014
    Assignee: Rambus Inc.
    Inventors: Frederick A. Ware, Robert E. Palmer, John W. Poulton, Andrew M. Fuller
  • Patent number: 8917783
    Abstract: The frequency response of a first component signal path of a differential signaling link is adjusted to off-set a notch in the frequency response from a corresponding notch in the frequency response of a second component signal path of the differential signaling link.
    Type: Grant
    Filed: December 3, 2009
    Date of Patent: December 23, 2014
    Assignee: Rambus Inc.
    Inventors: Farshid Aryanfar, Aliazam Abbasfar, Amir Amirkhany