Patents by Inventor Liji Gopalakrishnan

Liji Gopalakrishnan 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: 20170371827
    Abstract: A memory device or module selects between alternative command ports. Memory systems with memory modules incorporating such memory devices support point-to-point connectivity and efficient interconnect usage for different numbers of modules. The memory devices and modules can be of programmable data widths. Devices on the same module can be configured select different command ports to facilitate memory threading. Modules can likewise be configured to select different command ports for the same purpose.
    Type: Application
    Filed: July 12, 2017
    Publication date: December 28, 2017
    Inventors: Liji Gopalakrishnan, Ian Shaeffer, Yi Lu
  • Publication number: 20170337143
    Abstract: A transmitter is coupled to a command and address (CA) bus. The transmitter is configurable with dual-mode support to send commands over the CA bus in a first swing mode and a second swing mode. The transmitter is configurable to send a first command over the CA bus via the pins while in the first swing mode, initiate calibration of the master device to send commands over the CA bus in the second swing mode, and to send a second command over the CA bus via the pins while in the second swing mode.
    Type: Application
    Filed: June 7, 2017
    Publication date: November 23, 2017
    Inventors: Pravin Kumar Venkatesan, Liji Gopalakrishnan, Kashinath Prabhu, Makarand Shirasgaonkar
  • Patent number: 9734112
    Abstract: A memory device or module selects between alternative command ports. Memory systems with memory modules incorporating such memory devices support point-to-point connectivity and efficient interconnect usage for different numbers of modules. The memory devices and modules can be of programmable data widths. Devices on the same module can be configured select different command ports to facilitate memory threading. Modules can likewise be configured to select different command ports for the same purpose.
    Type: Grant
    Filed: February 23, 2016
    Date of Patent: August 15, 2017
    Assignee: Rambus Inc.
    Inventors: Liji Gopalakrishnan, Ian Shaeffer, Yi Lu
  • Patent number: 9715467
    Abstract: A single-ended receiver is coupled to an input-output (I/O) pin of a command and address (CA) bus. The receiver is configurable with dual-mode I/O support to operate the CA bus in a low-swing mode and a high-swing mode. The receiver is configurable to receive a first command on the I/O pin while in the high-swing mode, initiate calibration of the slave device to operate in the low-swing mode in response to the first command, switch the slave device to operate in the low-swing mode while the CA bus remains active, and to receive a second command on the I/O pin while in the low-swing mode.
    Type: Grant
    Filed: November 14, 2013
    Date of Patent: July 25, 2017
    Assignee: Rambus Inc.
    Inventors: Pravin Kumar Venkatesan, Liji Gopalakrishnan, Kashinath Prabhu, Makarand Shirasgaonkar
  • Patent number: 9704560
    Abstract: An integrated circuit includes a physical layer interface having a control timing domain and a data timing domain, and circuits that enable the control timing domain during a change in power conservation mode in response to a first event, and that enable the data timing domain in response to a second event. The control timing domain can include interface circuits coupled to a command and address path, and the data timing domain can include interface circuits coupled to a data path.
    Type: Grant
    Filed: August 19, 2016
    Date of Patent: July 11, 2017
    Assignee: Rambus Inc.
    Inventors: Ian Shaeffer, Lei Luo, Liji Gopalakrishnan
  • Publication number: 20170047108
    Abstract: An integrated circuit includes a physical layer interface having a control timing domain and a data timing domain, and circuits that enable the control timing domain during a change in power conservation mode in response to a first event, and that enable the data timing domain in response to a second event. The control timing domain can include interface circuits coupled to a command and address path, and the data timing domain can include interface circuits coupled to a data path.
    Type: Application
    Filed: August 19, 2016
    Publication date: February 16, 2017
    Inventors: Ian Shaeffer, Lei Luo, Liji Gopalakrishnan
  • Patent number: 9430027
    Abstract: An integrated circuit includes a physical layer interface having a control timing domain and a data timing domain, and circuits that enable the control timing domain during a change in power conservation mode in response to a first event, and that enable the data timing domain in response to a second event. The control timing domain can include interface circuits coupled to a command and address path, and the data timing domain can include interface circuits coupled to a data path.
    Type: Grant
    Filed: July 14, 2015
    Date of Patent: August 30, 2016
    Assignee: Rambus Inc.
    Inventors: Ian Shaeffer, Lei Luo, Liji Gopalakrishnan
  • Publication number: 20160170924
    Abstract: A memory device or module selects between alternative command ports. Memory systems with memory modules incorporating such memory devices support point-to-point connectivity and efficient interconnect usage for different numbers of modules. The memory devices and modules can be of programmable data widths. Devices on the same module can be configured select different command ports to facilitate memory threading. Modules can likewise be configured to select different command ports for the same purpose.
    Type: Application
    Filed: February 23, 2016
    Publication date: June 16, 2016
    Inventors: Liji Gopalakrishnan, Ian Shaeffer, Yi Lu
  • Patent number: 9287003
    Abstract: A memory controller includes logic to determine corresponding reference voltage values and delay values for one or more memory devices. The memory controller includes a command-address (CA) interface to send a command to a memory device to set a reference voltage value of the memory device to a test value, a data interface to write a data pattern to the memory device and read the data pattern from the memory device, and test reference voltage logic to perform a density check on at least a portion of the data pattern read from the memory device and determine whether the test value is a potential reference voltage value based on the density check. An operational reference voltage value selected from one or more potential reference voltage values may be used to determine a delay value.
    Type: Grant
    Filed: July 7, 2014
    Date of Patent: March 15, 2016
    Assignee: Rambus Inc.
    Inventors: Liji Gopalakrishnan, Mahabaleshwara Mahabaleshwara
  • Patent number: 9275699
    Abstract: A memory device or module selects between alternative command ports. Memory systems with memory modules incorporating such memory devices support point-to-point connectivity and efficient interconnect usage for different numbers of modules. The memory devices and modules can be of programmable data widths. Devices on the same module can be configured select different command ports to facilitate memory threading. Modules can likewise be configured to select different command ports for the same purpose.
    Type: Grant
    Filed: July 26, 2013
    Date of Patent: March 1, 2016
    Assignee: Rambus Inc.
    Inventors: Liji Gopalakrishnan, Ian Shaeffer, Yi Lu
  • Publication number: 20150348612
    Abstract: An integrated circuit includes a physical layer interface having a control timing domain and a data timing domain, and circuits that enable the control timing domain during a change in power conservation mode in response to a first event, and that enable the data timing domain in response to a second event. The control timing domain can include interface circuits coupled to a command and address path, and the data timing domain can include interface circuits coupled to a data path.
    Type: Application
    Filed: July 14, 2015
    Publication date: December 3, 2015
    Inventors: Ian Shaeffer, Lei Luo, Liji Gopalakrishnan
  • Publication number: 20150324309
    Abstract: A memory space of a module connected to a memory controller via a memory interface may be used as a command buffer. Commands received by the module via the command buffer are executed by the module. The memory controller may write to the command buffer out-of-order. The memory controller may delay or eliminate writes to the command buffer. Tags associated with commands are used to specify the order commands are executed. A status buffer in the memory space of the module is used to communicate whether commands have been received or executed. Information received via the status buffer can be used as a basis for a determination to re-send commands to the command buffer.
    Type: Application
    Filed: July 23, 2015
    Publication date: November 12, 2015
    Inventors: Liji Gopalakrishnan, Vlad Fruchter, Lawrence Lai, Pradeep Batra, Steven C. Woo, Wayne Frederick Ellis
  • Patent number: 9098209
    Abstract: A memory space of a module connected to a memory controller via a memory interface may be used as a command buffer. Commands received by the module via the command buffer are executed by the module. The memory controller may write to the command buffer out-of-order. The memory controller may delay or eliminate writes to the command buffer. Tags associated with commands are used to specify the order commands are executed. A status buffer in the memory space of the module is used to communicate whether commands have been received or executed. Information received via the status buffer can be used as a basis for a determination to re-send commands to the command buffer.
    Type: Grant
    Filed: October 27, 2013
    Date of Patent: August 4, 2015
    Assignee: Rambus Inc.
    Inventors: Liji Gopalakrishnan, Vlad Fruchter, Lawrence Lai, Pradeep Batra, Steven C. Woo, Wayne Frederick Ellis
  • Patent number: 9098281
    Abstract: An integrated circuit includes a physical layer interface having a control timing domain and a data timing domain, and circuits that enable the control timing domain during a change in power conservation mode in response to a first event, and that enable the data timing domain in response to a second event. The control timing domain can include interface circuits coupled to a command and address path, and the data timing domain can include interface circuits coupled to a data path.
    Type: Grant
    Filed: March 8, 2012
    Date of Patent: August 4, 2015
    Assignee: Rambus Inc.
    Inventors: Ian Shaeffer, Lei Luo, Liji Gopalakrishnan
  • Publication number: 20150162061
    Abstract: A memory controller includes logic to determine corresponding reference voltage values and delay values for one or more memory devices. The memory controller includes a command-address (CA) interface to send a command to a memory device to set a reference voltage value of the memory device to a test value, a data interface to write a data pattern to the memory device and read the data pattern from the memory device, and test reference voltage logic to perform a density check on at least a portion of the data pattern read from the memory device and determine whether the test value is a potential reference voltage value based on the density check. An operational reference voltage value selected from one or more potential reference voltage values may be used to determine a delay value.
    Type: Application
    Filed: July 7, 2014
    Publication date: June 11, 2015
    Inventors: Liji Gopalakrishnan, Mahabaleshwara Mahabaleshwara
  • Patent number: 8990490
    Abstract: Memory controller concepts are disclosed in which hardware resources of a memory controller can be re-used or re-configured to accommodate various different memory configurations. The memory configuration may be stored in mode register bits (228), settable by a host or operating system. By re-configuring or reallocating certain resources of a memory controller, for example command logic blocks (A, B, C, D in FIG. 1A), a single controller design can be used to interface efficiently with a variety of different memory components. Command logic blocks that support N×M memory ranks, for example, can be reconfigured to support N ranks and M threads for multi-threaded memories (FIG. 1A). Data buffer (232, 254) depth can be extended by reconfiguring the buffers responsive to the mode register bits (228). Request buffers can be shared across command logic blocks, for example to increase the request buffer depth (FIG. 3A). Unused circuits can be powered down to save power consumption (FIG. 4A).
    Type: Grant
    Filed: November 27, 2012
    Date of Patent: March 24, 2015
    Assignee: Rambus Inc.
    Inventors: Liji Gopalakrishnan, Vidhya Thyagarajan, Prasanna Kole, Gidda Reddy Gangula
  • 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
  • Publication number: 20140149618
    Abstract: A single-ended receiver is coupled to an input-output (I/O) pin of a command and address (CA) bus. The receiver is configurable with dual-mode I/O support to operate the CA bus in a low-swing mode and a high-swing mode. The receiver is configurable to receive a first command on the I/O pin while in the high-swing mode, initiate calibration of the slave device to operate in the low-swing mode in response to the first command, switch the slave device to operate in the low-swing mode while the CA bus remains active, and to receive a second command on the I/O pin while in the low-swing mode.
    Type: Application
    Filed: November 14, 2013
    Publication date: May 29, 2014
    Applicant: Rambus Inc.
    Inventors: Pravin Kumar Venkatesan, Liji Gopalakrishnan, Kashinath Prabhu, Makarand Shirasgaonkar
  • Publication number: 20140082234
    Abstract: A memory space of a module connected to a memory controller via a memory interface may be used as a command buffer. Commands received by the module via the command buffer are executed by the module. The memory controller may write to the command buffer out-of-order. The memory controller may delay or eliminate writes to the command buffer. Tags associated with commands are used to specify the order commands are executed. A status buffer in the memory space of the module is used to communicate whether commands have been received or executed. Information received via the status buffer can be used as a basis for a determination to re-send commands to the command buffer.
    Type: Application
    Filed: October 27, 2013
    Publication date: March 20, 2014
    Applicant: Rambus Inc.
    Inventors: Liji Gopalakrishnan, Vlad Fruchter, Lawrence Lai, Pradeep Batra
  • Publication number: 20140052934
    Abstract: A memory device or module selects between alternative command ports. Memory systems with memory modules incorporating such memory devices support point-to-point connectivity and efficient interconnect usage for different numbers of modules. The memory devices and modules can be of programmable data widths. Devices on the same module can be configured select different command ports to facilitate memory threading. Modules can likewise be configured to select different command ports for the same purpose.
    Type: Application
    Filed: July 26, 2013
    Publication date: February 20, 2014
    Applicant: Rambus Inc.
    Inventors: Liji Gopalakrishnan, Ian Shaeffer, Yi Lu