Patents Assigned to Rambus
  • 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
  • Patent number: 8918667
    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: 8908407
    Abstract: A content addressable memory device based on an extremely compact design, potentially as small as 16F2 per memory cell. One embodiment is based on cells having two memory storage elements, such as RRAM elements. Each RRAM element and a respective FET are connected in series between a common matchline and a respective bitline. Cell content for each cell is matched against a bit of a search word by applying voltages to the respective bitlines dependent upon bit value and causing one of the two RRAM elements for each cell to discharge the matchline over a low resistance path in event of mismatch between the cell content and the bit. If no “quick” discharge occurs for multiple cells of a row, then a match is detected. In addition, a matchline recharge path to a high voltage bitline is substantially eliminated by controlling the FETs with specific wordline voltages.
    Type: Grant
    Filed: July 13, 2012
    Date of Patent: December 9, 2014
    Assignee: Rambus Inc.
    Inventors: Brent Steven Haukness, Mark D. Kellam
  • Patent number: 8908466
    Abstract: A memory system includes a master device, such as a graphics controller or processor, and an integrated circuit memory device operable in a dual column addressing mode. The integrated circuit memory device includes an interface and column decoder to access a row of storage cells or a page in a memory bank. During a first mode of operation, a first row of storage cells in a first memory bank is accessible in response to a first column address. During a second mode of operation, a first plurality of storage cells in the first row of storage cells is accessible in response to a second column address during a column cycle time interval. A second plurality of storage cells in the first row of storage cells is accessible in response to a third column address during the column cycle time interval. The first and second pluralities of storage cells are concurrently accessible from the interface.
    Type: Grant
    Filed: April 11, 2013
    Date of Patent: December 9, 2014
    Assignee: Rambus Inc.
    Inventors: Frederick A. Ware, Lawrence Lai, Chad A. Bellows, Wayne S. Richardson
  • Patent number: 8908454
    Abstract: A hierarchical memory architecture includes an array of memory sub-arrays, each of which includes an array of memory cells. Each sub-array is supported by local wordlines, local column-select lines, and bitlines. The local wordlines are controlled using main wordlines that extend past multiple sub-arrays in a direction parallel to a first axis, whereas the local column-select lines are controlled using main column-select lines that extend between sub-arrays in a direction perpendicular to the first axis. At the direction of signals presented on the local wordlines and column-select lines, subsets of the bitlines in each sub-array are connected to main data lines that extend over a plurality of the sub-arrays in parallel with the second axis. Some embodiments include redundant data resources that are selected based on a decoding of row addresses.
    Type: Grant
    Filed: August 20, 2012
    Date of Patent: December 9, 2014
    Assignee: Rambus Inc.
    Inventors: Thomas Vogelsang, Brent Steven Haukness
  • Patent number: 8899813
    Abstract: A lighting assembly includes an edge-lit light guide and a light redirecting member. Light extracting elements at the light guide extract light from the light guide as intermediate light. Light redirecting elements at the light redirecting film are configured to redirect the intermediate light received from the light guide to illuminate a target surface in accordance with a defined illumination profile.
    Type: Grant
    Filed: July 26, 2012
    Date of Patent: December 2, 2014
    Assignee: Rambus Delaware LLC
    Inventors: Timothy A. McCollum, Robert M. Ezell, Jeffery R. Parker, Kurt R. Starkey, Ian Hardcastle, Fumitomo Hide
  • Patent number: 8903031
    Abstract: A clock recovery circuit includes a first phase detector for measuring the phase difference between a first clock signal from a voltage controlled oscillator (VCO) and a data signal. A phase shifter responsive to a control signal based on this phase difference adjusts the phase of an incoming clock signal to yield a second clock signal. The phase difference between the first clock signal and the second clock signal is measured and the resulting signal is low-pass filtered to derive a control signal for controlling the VCO. The phase locked loop including the VCO filters out jitter.
    Type: Grant
    Filed: May 17, 2013
    Date of Patent: December 2, 2014
    Assignee: Rambus Inc.
    Inventor: Carl W. Werner
  • Patent number: 8901975
    Abstract: The disclosed embodiments relate to a digital phase-locked loop (PLL) with dynamic gain control. This digital PLL includes a phase detector which receives a reference signal and a feedback signal as inputs and produces an output signal comprising up/down values. It also includes a digital loop filter which receives the phase-detector output signal as an input and produces an M-bit output signal. This digital loop filter is associated with a loop-parameter control unit (LPCU) which dynamically generates loop-filter parameters for the digital loop filter based on an observed pattern of up/down values from the phase-detector output over a specified period of time. A digitally controlled oscillator (DCO) receives the loop-filter output signal and produces a PLL output signal. Finally, a feedback path returns the PLL output signal to the phase detector.
    Type: Grant
    Filed: August 6, 2013
    Date of Patent: December 2, 2014
    Assignee: Rambus Inc.
    Inventor: Reza Navid
  • Publication number: 20140351629
    Abstract: A memory module is disclosed that includes a substrate, a memory device that outputs read data, and a buffer. The buffer has a primary interface for transferring the read data to a memory controller and a secondary interface coupled to the memory device to receive the read data. The buffer includes error logic to identify an error in the received read data and to identify a storage cell location in the memory device associated with the error. Repair logic maps a replacement storage element as a substitute storage element for the storage cell location associated with the error.
    Type: Application
    Filed: May 22, 2014
    Publication date: November 27, 2014
    Applicant: Rambus Inc.
    Inventors: Frederick A. Ware, Ely Tsern
  • Publication number: 20140351673
    Abstract: A memory device is disclosed that includes a row of storage locations to store a data word, and a spare row element. The data word is encoded via an error code for generating error information for correcting X bit errors or detecting Y bit errors, where Y is greater than X. The spare row element has substitute storage locations. The logic is responsive to detected errors to (1) enable correction of a data word based on the error information where there are no more than X bit errors, and (2) substitute the spare row element for a portion of the row where there are at least Y bit errors in the data word.
    Type: Application
    Filed: May 22, 2014
    Publication date: November 27, 2014
    Applicant: Rambus Inc.
    Inventors: Frederick A. Ware, Suresh Rajan, Brent Haukness, Scott C. Best, Wayne F. Ellis
  • Patent number: 8896355
    Abstract: A variable-frequency input clock signal and a reference clock signal are compared during a frequency-compare interval to generate a value that indicates a ratio of their frequencies. The frequency-ratio value is then applied to configure a wide-range frequency-locking oscillator for operation with a narrowed input frequency range. Because the narrowed input frequency range is targeted to the input clock frequency, the wide-range oscillator is able to rapidly lock to a frequency multiple of the input clock frequency. Because the frequency-compare interval is also brief, an extremely fast-locking, clock-multiplying operation may be effected over a relatively wide range of input clock frequencies.
    Type: Grant
    Filed: February 4, 2014
    Date of Patent: November 25, 2014
    Assignee: Rambus Inc.
    Inventors: Yue Lu, Jared L. Zerbe
  • Patent number: 8890580
    Abstract: A communication system includes a continuous-time linear equalizer in the clock forward path. The equalizer may be adjusted to minimize clock jitter, including jitter associated with the first few clock edges after the clock signal is enabled. Reducing early-edge jitter reduces the power and circuit complexity otherwise needed to turn the system on quickly.
    Type: Grant
    Filed: October 3, 2011
    Date of Patent: November 18, 2014
    Assignee: Rambus Inc.
    Inventors: Jared Zerbe, Teva Stone, Jihong Ren
  • Publication number: 20140333356
    Abstract: A signal distribution network has segments that each have a buffer circuit, a transmission line coupled to the buffer circuit, an inductor coupled to the buffer circuit through the transmission line, and a variable capacitance circuit coupled to the inductor and coupled to the buffer circuit through the transmission line. A capacitance of the variable capacitance circuit is set to determine a phase and an amplitude of a signal transmitted through the transmission line. A signal distribution network can include a phase detector, a loop filter circuit, and a resonant delay circuit. The phase detector compares a phase of a first periodic signal to a phase of a second periodic signal. The resonant delay circuit has a variable impedance circuit having an impedance that varies based on changes in an output signal of the loop filter circuit.
    Type: Application
    Filed: November 25, 2013
    Publication date: November 13, 2014
    Applicant: Rambus Inc.
    Inventors: Farshid Aryanfar, Hae-Chang Lee, Kun-Yung Chang, Ting Wu, Carl Werner, Masoud Koochakzadeh
  • Publication number: 20140333361
    Abstract: Duty cycle error vectors that indicate both the magnitude and direction of the duty cycle error relative to a desired duty cycle are generated within a duty cycle measurement circuit, enabling threshold-based determination of whether duty cycle adjustment is necessary, refraining from power-consuming adjustment and follow-up measurement in those cases where the duty cycle is within a target range. When duty cycle adjustment is deemed necessary, the magnitude of the duty cycle error indicated by the duty cycle error vector may be applied to effect proportional rather than incremental duty cycle adjustment, quickly returning the clock duty cycle to a target range.
    Type: Application
    Filed: November 16, 2012
    Publication date: November 13, 2014
    Applicant: Rambus Inc.
    Inventors: Pak Shing Chau, Wayne S. Richardson, Jun Kim
  • Patent number: 8885423
    Abstract: The disclosed embodiments provide a sense amplifier for a dynamic random-access memory (DRAM). This sense amplifier includes a bit line to be coupled to a cell to be sensed in the DRAM, and a complement bit line which carries a complement of a signal on the bit line. The sense amplifier also includes a p-type field-effect transistor (PFET) pair comprising cross-coupled PFETs that selectively couple either the bit line or the complement bit line to a high bit-line voltage. The sense amplifier additionally includes an n-type field effect transistor (NFET) pair comprising cross-coupled NFETs that selectively couple either the bit line or the complement bit line to ground. This NFET pair is lightly doped to provide a low threshold-voltage mismatch between NFETs in the NFET pair. In one variation, the gate material for the NFETs is selected to have a work function that compensates for a negative threshold voltage in the NFETs which results from the light substrate doping.
    Type: Grant
    Filed: November 19, 2010
    Date of Patent: November 11, 2014
    Assignee: Rambus Inc.
    Inventors: Thomas Vogelsang, Gary B. Bronner
  • Publication number: 20140329359
    Abstract: Multiple devices, including a first device and a second device, have operational circuitry and opposing first and second surfaces. First and second electrical contacts are formed at the first surface, while a third electrical contact is formed at the second surface opposite the first electrical contact. The first electrical contact is electrically connected to the operational circuitry, and the second electrical contact is electrically connected to the third electrical contact. The first device and the second device are subsequently stacked such that the first surface of the second device is located adjacent the second surface of the first device such that the first electrical contact of the second device is aligned with the third electrical contact of the first device. The first electrical contact of the second device is electrically connected to the third electrical contact of the first device.
    Type: Application
    Filed: May 7, 2014
    Publication date: November 6, 2014
    Applicant: Rambus Inc.
    Inventors: Frederick A. Ware, Ely K. Tsern, Ian P. Shaeffer
  • Patent number: 8880818
    Abstract: Embodiments of a memory controller are described. This memory controller includes signal connectors, which are electrically coupled to a communication path that includes multiple links, and an interface circuit, which is electrically coupled to the signal connectors. In a first operating mode, the interface circuit communicates with a first memory device via the communication path using spatial multiplexing, in which there are dedicated command/address links and dedicated data links in the communication path. Moreover, in a second operating mode, the interface circuit communicates with a second memory device via the communication path using time multiplexing, in which at least some of the links in the communication path time interleave command/address information and data.
    Type: Grant
    Filed: January 29, 2014
    Date of Patent: November 4, 2014
    Assignee: Rambus Inc.
    Inventors: Frederick A. Ware, John Eric Linstadt, Venu Madhav Kuchibholta
  • Patent number: 8878592
    Abstract: A data signal is transmitted from a first circuit to a second circuit, with noise and/or jitter added to the data signal by supply noise in the power distribution network in the first circuit and/or a second circuit being effectively canceled out by adjustment of the reference voltage and/or the phase of the sampling clock used for sampling of the data signal in a manner that effectively mimics such noise and/or jitter added to the data signal. The second circuit uses a filter that has the impedance profile and/or the jitter profile of such power distribution network. The bus weight and/or the number of switching bits in the data pattern transmitted from the first circuit to the second circuit is applied to the filter to determine the adjustment to be made to the reference voltage or the phase of the sampling clock.
    Type: Grant
    Filed: April 26, 2013
    Date of Patent: November 4, 2014
    Assignee: Rambus Inc.
    Inventor: Kyung Suk Oh
  • Patent number: 8879724
    Abstract: Information leaked from smart cards and other tamper resistant cryptographic devices can be statistically analyzed to determine keys or other secret data. A data collection and analysis system is configured with an analog-to-digital converter connected to measure the device's consumption of electrical power, or some other property of the target device, that varies during the device's processing. As the target device performs cryptographic operations, data from the A/D converter are recorded for each cryptographic operation. The stored data are then processed using statistical analysis, yielding the entire key, or partial information about the key that can be used to accelerate a brute force search or other attack.
    Type: Grant
    Filed: December 14, 2009
    Date of Patent: November 4, 2014
    Assignee: Rambus Inc.
    Inventors: Paul C. Kocher, Joshua M. Jaffe, Benjamin C. Jun
  • Patent number: 8873329
    Abstract: Row activation operations within a memory component are carried out with respect to patterns of storage cells that constitute a fraction of a row and that have been predicted or predetermined to yield a succession of page hits, thus reducing activation power consumption without significantly increasing memory latency. The patterns of activated storage cells may be predicted or predetermined statically, for example, in response to user input or configuration settings that specify activation patterns to be applied in response to memory request traffic meeting various criteria, or dynamically through run-time evaluation of sequences of memory access requests.
    Type: Grant
    Filed: January 14, 2013
    Date of Patent: October 28, 2014
    Assignee: Rambus Inc.
    Inventors: Hongzhong Zheng, Brent S. Haukness