Patents by Inventor Subramani Kengeri

Subramani Kengeri 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).

  • Patent number: 6292416
    Abstract: According to the first embodiment of the present invention, a pre-charge device is connected to the middle of each complementary bit line. Thus, once activated, the pre-charge device only drives a load equal to half of the RC impedance of the entire bit lines during the pre-charging operation. According to the second embodiment of the present invention, a first pre-charge device is connected to one end of each complementary bit lines and a second pre-charge device is connected approximately to the middle of each complementary bit lines. Once both devices are activated, each device drives a load equal to half of the RC impedance of the entire bit lines, thus reducing the pre-charge time of the bit lines.
    Type: Grant
    Filed: February 11, 1998
    Date of Patent: September 18, 2001
    Assignee: Alliance Semiconductor Corporation
    Inventors: Chitranjan N. Reddy, Subramani Kengeri
  • 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: 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
  • Patent number: 6141236
    Abstract: A word line stitch mechanism to be used in high-density DRAMs is presented herein. The word line stitch mechanism of the present invention eliminates the problem caused by using the conventional word line stitch methods of the prior art in the high-density DRAMs. In the present invention, the word lines are segmented with an space between the two adjacent word line segments. Thereafter, the contacts between the word line segments and the associated metal layers are established such that the contact overlap areas are completely adjacent to all or a portion of the spaces between the word line segments of the adjacent word lines.
    Type: Grant
    Filed: March 10, 1999
    Date of Patent: October 31, 2000
    Assignee: Alliance Semiconductor Corporation
    Inventor: Subramani Kengeri
  • Patent number: 6137746
    Abstract: The present invention provides an apparatus and a method of reducing the time to drive the I/O lines by the sense amplifiers. In one embodiment of the present invention, local sense amplifier segments and associated local I/O lines are provided. The I/O lines are short in length and are connected to the sense amplifiers in the associated sense amplifier segments. The reduction in the length of the local I/O lines reduce the effective RC impedance of the I/O lines. Thus, the local sense amplifiers are smaller and drive the local I/O lines much faster. The present invention further provides global I/O lines connected to the local I/O lines. In a second embodiment of the present invention, the global I/O lines are driven by a second stage amplifier. In a third embodiment of the present invention, one global I/O line is provided for every local I/O line.
    Type: Grant
    Filed: July 28, 1999
    Date of Patent: October 24, 2000
    Assignee: Alliance Semiconductor Corporation
    Inventors: Subramani Kengeri, Chitranjan N. Reddy
  • Patent number: 6108250
    Abstract: A high speed process for determining whether an externally applied address points to a memory cell or a redundant memory cell in a memory is disclosed. Identification information associated with redundant memory rows and columns is stored and compared with decoded information based upon a decoded externally applied address. This comparison determines if a memory cell of a redundant memory cell is addressed.
    Type: Grant
    Filed: April 15, 1999
    Date of Patent: August 22, 2000
    Assignee: Alliance Semiconductor Corporation
    Inventor: Subramani Kengeri
  • Patent number: 5872742
    Abstract: A static random access memory (SRAM) (10) operating in synchronism with an external clock is disclosed. The synchronous SRAM (10) includes a transparent address circuit (14) for decoding an external address in the set-up time prior to the rising edge of the external clock. A timing and control circuit (18) generates a word line enable (WLE) signal in synchronism with the rising edge of the external clock. When active, WLE activates a word line driver (34), when inactive, WLE equalizes the bit lines. WLE is applied to a first delay circuit (60) to generate a sense signal (SA). SA activates a sense circuit (46) and deactivates the WLE signal. Consecutive pipelined accesses are achieved such that, as an address is decoded, the bit lines are equalizing and the data from the previous address are propagating through a data I/O path (16).
    Type: Grant
    Filed: April 21, 1998
    Date of Patent: February 16, 1999
    Assignee: Alliance Semiconductor Corporation
    Inventors: Subramani Kengeri, Darryl G. Walker, Kenneth A. Poteet, Chitranjan N. Reddy
  • Patent number: 5831315
    Abstract: An SRAM array configuration is disclosed. SRAM cells (102) are arranged in rows and columns. Cell rows (104a-104f) are each driven by a particular word line (132). Cell row pairs (108a and 108b) are supplied with a low power supply voltage (Vss) by a number of Vss connections 116 disposed parallel to the cell rows (104a-104f). The word lines (132) and Vss connections 116 are "strapped" by low resistance word line straps (110b-110e) and Vss straps (112a-112b). Both the word line straps (110b-110e) and the Vss straps (112a-112b) are substantially offset with respect to their associated word lines (132) and Vss connections 116, respectively. The Vss strap offset is accomplished with the use of a Vss line 140 that makes contact with the Vss connections 116 and further includes landing portions 120 which extend in the column direction and make contact with the Vss straps (112a-112b).
    Type: Grant
    Filed: February 5, 1997
    Date of Patent: November 3, 1998
    Assignee: Alliance Semiconductor Corporation
    Inventors: Subramani Kengeri, Chitranjan N. Reddy
  • Patent number: 5808959
    Abstract: A static random access memory (SRAM) (10) operating in synchronism with an external clock is disclosed. The synchronous SRAM (10) includes a transparent address circuit (14) for decoding an external address in the set-up time prior to the rising edge of the external clock. A timing and control circuit (18) generates a word line enable (WLE) signal in synchronism with the rising edge of the external clock. When active, WLE activates a word line driver (34), when inactive, WLE equalizes the bit lines. WLE is applied to a first delay circuit (60) to generate a sense signal (SA). SA activates a sense circuit (46) and deactivates the WLE signal. Consecutive pipelined accesses are achieved such that, as an address is decoded, the bit lines are equalizing and the data from the previous address are propagating through a data I/O path (16).
    Type: Grant
    Filed: August 7, 1996
    Date of Patent: September 15, 1998
    Assignee: Alliance Semiconductor Corporation
    Inventors: Subramani Kengeri, Darryl G. Walker, Kenneth A. Poteet, Chitranjan N. Reddy
  • Patent number: 5717645
    Abstract: A random access memory (RAM) (10) is disclosed. A network of driver lines (28) extends over a number of core arrays (12a-12p) connecting a control bank 24 with column decode banks (26a and 26b), and the column decode banks (26a and 26b) with sense banks 46 within the core arrays (12a-12p). The driver lines 28 include predecode lines 30 and clock lines 32 for coupling predecode signals and clock signals from the control bank 24 to the column decode banks (26a and 26b). In addition, the driver lines 28 include column select lines 34 and sense driver lines 36 for coupling column select signals and sense amplifier enable signals from the column decode banks (26a and 26b) to the sense banks 46. The sense banks 46 include sense amplifiers 80 that are shared between array quadrants 42 by decoded transfer gate banks (70a and 70b). Advantageous placement of precharge circuits 82 and equalization circuits 86 provides a compact sense bank structure 46.
    Type: Grant
    Filed: February 7, 1997
    Date of Patent: February 10, 1998
    Assignee: Alliance Semiconductor Corporation
    Inventors: Subramani Kengeri, Chitranjan N. Reddy
  • Patent number: 5629646
    Abstract: In a DRAM unit in which the substrate bias voltage is maintained within predetermined limits by a of voltage detectors and a charge pump, a third voltage detector is provided which detects a intermediate substrate bias voltage level that is within the voltage range identified by the pair of voltage detectors. When the third voltage level detects that the intermediate substrate bias voltage has been traversed, the charge pump is activated at a reduced level to drive the substrate bias voltage to recross the intermediate substrate bias voltage level. This technique permits the DRAM unit to operate in a stand-by mode at a lower power level, especially in a standby mode of operation, than when the substrate bias voltage is maintained only by the two voltage limit detectors and a single power level charge pump.
    Type: Grant
    Filed: March 21, 1995
    Date of Patent: May 13, 1997
    Assignee: Texas Instruments Incorporated
    Inventors: Vinod J. Menezes, Subramani Kengeri, Raghava Madhu
  • Patent number: 5612635
    Abstract: A buffer circuit for converting logic signals generated by apparatus implemented in a TTL technology to logic signals processed by apparatus implemented by the CMOS technology includes an input stage (10, 11, 12, 13, 17), a voltage-control (14, 15) stage for causing the buffer circuit to vary the input voltage level required to switch the state of the buffer circuit output signal, and a hysteresis stage (16) for causing the switching of the output signal level to be different for the rising and falling edges of the input signal. The voltage-control stage (14, 15) provides a improvement in the noise margin of both the VTTL(High) switching level and the VTTL(Low) switching level.
    Type: Grant
    Filed: March 22, 1995
    Date of Patent: March 18, 1997
    Assignee: Texas Instruments Incorporated
    Inventors: Raghava Madhu, Subramani Kengeri