Patents by Inventor Yoshihiro Murashima

Yoshihiro Murashima 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: 5444662
    Abstract: A dynamic random access memory of the complementary MOS transistor type has memory cells connected between complementary bit lines on one side of a pair of transfer gates and a sense amplifier connected to nodes on the other side of the transfer gates, so that the sense amplifier can be connected to the bit lines and memory cells through the pair of transfer gates. A sense amplifier equalizing circuit and a bit line equalizing circuit are provided on opposite sides of the transfer gates so that the potentials on the bit lines can be equalized independently of equalization of the potentials on the nodes. Accordingly, there is no delay in the equalization due to the transfer gates connecting the nodes to the bit lines.
    Type: Grant
    Filed: June 8, 1994
    Date of Patent: August 22, 1995
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Takayuki Tanaka, Yoshimasa Sekino, Yoshihiro Murashima, Yasuhiro Tokunaga, Joji Ueno, Takeru Yonaga
  • Patent number: 5260903
    Abstract: A semiconductor memory device provided that first data is read out from a first memory cell within a first readout period; and second data is read out from the second memory cell within a second readout period; wherein an amplifier circuit receiving the first and second data, outputting first data signals having first electric potential level corresponding to the first and second data and outputting second data signal having second electric potential level; control circuit, in response to an external control signal, generating a first control signal in each of the first and second readout periods, the first control signal indicating first logic level during an enabling period of time within each of the first and second readout periods, otherwise the first control signal indicating second logic level; a first latch circuit latching the first data signals in the respective first and second readout periods and outputting a first latched data signal at the time of the first control signal indicating the first log
    Type: Grant
    Filed: February 12, 1992
    Date of Patent: November 9, 1993
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Junichi Suyama, Yoshihiro Murashima
  • Patent number: 5258950
    Abstract: In a semiconductor memory device having memory cells (21.sub.i, 21.sub.i+1) disposed at intersections of bit lines (BL, BL) and word lines (WL.sub.i, WL.sub.i+1) and operating on an internal power source voltage (V.sub.D) which is lower than an external power source voltage for the memory device, sense amplifiers (41) are activated by a voltage on a drive common node (NS), and a comparator (110) is activated by the control signal (PAS) and compares the voltage on the common node (PS) with the internal power source voltage (V.sub.D). The comparator has an output which is in a first state when the common node (PS) voltage is not higher than the reference voltage (V.sub.R) and which is in a second state when the common node (PS) voltage exceeds the reference voltage (V.sub.R).
    Type: Grant
    Filed: August 21, 1991
    Date of Patent: November 2, 1993
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Yoshihiro Murashima, Yoshimasa Sekino
  • Patent number: 5148401
    Abstract: In a dynamic random access memory comprising first and second memory cell arrays, and a plurality of word lines, each split into two sections extending through the first and the second memory cell arrays, respectively, word line drive circuits are divided into three blocks. The first block is disposed between the inner sides of the memory cell arrays and connected to the inner ends of the alternate word line sections. The second and the third blocks are disposed adjacent to the outer sides of the memory cell arrays and are connected to the outer ends of the intervening word line sections. Because the word line drive circuits for the respective word lines are disposed on both sides of each memory cell array, alternately, the area for the word line drive circuit for each word line can extend twice the pitch of the word lines. Thus, the pitch of the word lines can be reduced, or the size of the word line drive transistors can be increased, enabling a higher degree of integration.
    Type: Grant
    Filed: September 18, 1991
    Date of Patent: September 15, 1992
    Assignee: Oki Electric Industry Co., Ltd.
    Inventors: Yoshimasa Sekino, Yoshihiro Murashima