Patents Assigned to Silicon Access Networks, Inc.
  • Patent number: 6343029
    Abstract: A content addressable memory (CAM) with built-in power saving management. The CAM includes a comparator circuit region that is coupled to a match line (ML) as well as a swing line (SL). The comparator circuit region is coupled to CAM cells. The comparator region is adapted for comparing match data with stored data within the CAM cells. The ML has its ML voltage level pre-charged to a pre-charge voltage level (Vc). Additionally, the SL is pre-charged to ground. In turn, in response to a data mismatch detected by the comparator, the ML voltage level drops from Vc by a ML voltage swing (Vswing) while the SL charge shares with the Ml. Advantageously, in response to this data mismatch, the SL charge shares with the ML such that Vswing is approximately less or equal to Vc/2. That is, the charge sharing prevents the ML from discharging all the way to ground.
    Type: Grant
    Filed: February 13, 2001
    Date of Patent: January 29, 2002
    Assignee: Silicon Access Networks, Inc.
    Inventors: Subramani Kengeri, Steve Lim
  • Patent number: 6331961
    Abstract: A ternary state content addressable memory (CAM) cell that includes two DRAM cells. In addition to a port for controlling and transmitting data to the CAM, another port is exclusively used for refreshing the DRAM cells. A refresh word line is coupled to the two DRAM cells for performing DRAW cell refresh. A refresh bit line is coupled to the first of the two DRAM cells for refreshing this first DRAM cell. A refresh bit line is coupled to the second of the two DRAM cells for refreshing this second DRAM cell. Problematic power consumption and voltage swing found in a conventional CAM are overcome in the CAM. A swing line (SL) is coupled to said first and second DRAM cells and a local match line (LML) of said CAM cell, said SL having an adjustable voltage level for changing voltage swing in said LML to regulate trade-off between power consumption and speed of said CAM cell.
    Type: Grant
    Filed: June 9, 2000
    Date of Patent: December 18, 2001
    Assignee: Silicon Access Networks, Inc.
    Inventors: Subramani Kengeri, Hemraj K. Hingarh
  • Patent number: 6327197
    Abstract: A memory architecture is disclosed that employs multiple column redundancies which provide multiple options for replacing a defective global odd or even bit line. Each column memory has two multiplexers, one for selecting a global odd bit line and another for selecting a global even bit line. Two or more column redundancies are coupled to each of the multiplexer in the column memory. In a first embodiment, the global odd and even bit lines are connected through odd and even sense amps in a regular column. In a second embodiment, the global odd bit line in a regular column connects through odd sense amps, while the global even bit line in the regular column connects through even sense amps. In a third embodiment, two or more sets of redundancy columns are commonly coupled to a left adjacent regular column and a right adjacent regular column.
    Type: Grant
    Filed: September 13, 2000
    Date of Patent: December 4, 2001
    Assignee: Silicon Access Networks, Inc.
    Inventors: Juhan Kim, Hing Wong
  • Patent number: 6288922
    Abstract: The invention discloses a low-power ternary CAM by utilizing four encoded comparand datalines, C0, C1, C2, and C3 in a twin ternary cell. The twin ternary cell is a composite of two ternary CAM bits. The two binary CAM bits are coded so that only one of four comparand datalines is toggled during a compare operation. The encoded data is stored and used for comparison. In one embodiment, the four possible states for the 2 bit comparands are coded as 0001, 0010, 0100, and 1000.
    Type: Grant
    Filed: August 11, 2000
    Date of Patent: September 11, 2001
    Assignee: Silicon Access Networks, Inc.
    Inventors: Hing Wong, Subramani Kengeri
  • Patent number: 6262928
    Abstract: The present invention discloses a parallel test circuit and method for testing even bit line and odd bit line in a memory block simultaneously. The parallel test circuit comprises an even test circuit for testing an even bit line and an odd test circuit for testing an odd bit line. The parallel test circuit also includes a write circuit for writing data to a bit line, a read circuit including a data sense amp, an output buffer, and a comparator. Furthermore, the present invention provides the capability to conduct disturbance test in neighboring even and odd cells.
    Type: Grant
    Filed: September 13, 2000
    Date of Patent: July 17, 2001
    Assignee: Silicon Access Networks, Inc.
    Inventors: Juhan Kim, Hing Wong
  • Patent number: 6259634
    Abstract: A system and/or method for simultaneous read/write access of 1-Transistor (1-T) dynamic random access memory (DRAM), which does not rely on a dual-port DRAM to perform read and write accesses within single clock cycle. A single-port 1-T DRAM works with modified design of read sense amplifier to perform both read and write accesses within single clock cycle, thereby retaining high performance and compact size that characterize the 1-T DRAM while allowing simultaneous read/write access that characterizes dual-port memory. Hence, single-port 1-T DRAM constitutes a pseudo dual-port 1-T DRAM that emulates the dual-port DRAM's ability in performing simultaneous read/write memory access of 1-T DRAM.
    Type: Grant
    Filed: May 22, 2000
    Date of Patent: July 10, 2001
    Assignee: Silicon Access Networks, Inc.
    Inventors: Subramani Kengeri, Jawji Chen
  • Patent number: 6240008
    Abstract: A dynamic random access memory (DRAM) having a conventional cell layout and having its data access path adapted to access a ‘zero’ faster than a ‘one.’ The DRAM comprising two capacitors coupled respectively to two neighboring word lines. The two capacitors are also coupled respectively to two neighboring bit lines via two pass gates. Data is represented as complementary data bits on the two capacitors. In so doing, a ‘zero’ is ensured to be stored in either one of the two capacitors. A voltage level ‘zero’ is in turn ensured to be maintained on the bit line coupled to the capacitor that stores the ‘zero’ data bit. The sense amplifier and the write driver take advantage of the fact that a voltage level ‘zero’ is ensured to be maintained in either one of the two bit lines.
    Type: Grant
    Filed: June 9, 2000
    Date of Patent: May 29, 2001
    Assignee: Silicon Access Networks, Inc.
    Inventors: Subramani Kengeri, Hemraj K. Hingarh