Patents Assigned to Rohm Corporation
  • Patent number: 5940325
    Abstract: A single transistor electrically erasable programmable memory device capable of being programmed and erased using Fowler-Nordheim tunneling and capable of being operated using low voltages. Portions of each of the source and drain regions overlap with the first gate dielectric layer, and the interpoly dielectric layer is chosen to have a high dielectric constant so as to maximize the capacitive coupling ratio between floating gate, control gate, source, and drain. The logical condition of cells in the array is set by first elevating a block of cells to a high voltage threshold and by individually lowering the voltage threshold of selected cells.
    Type: Grant
    Filed: November 17, 1997
    Date of Patent: August 17, 1999
    Assignee: Rohm Corporation
    Inventors: Shang-De Chang, Jai-Hwang Chang, Edwin Chow
  • Patent number: 5689459
    Abstract: A single transistor electrically erasable programmable memory device capable of being programmed and erased using Fowler-Nordheim tunneling and capable of being operated using low voltages. Portions of each of the source and drain regions overlap with the first gate dielectric layer, and the interpoly dielectric layer is chosen to have a high dielectric constant so as to maximize the capacitive coupling ratio between floating gate, control gate, source, and drain. The logical condition of cells in the array is set by first elevating a block of cells to a high voltage threshold and by individually lowering the voltage threshold of selected cells.
    Type: Grant
    Filed: November 5, 1996
    Date of Patent: November 18, 1997
    Assignee: Rohm Corporation
    Inventors: Shang-De Chang, Jia-Hwang Chang, Edwin Chow
  • Patent number: 5615147
    Abstract: A single transistor electrically erasable programmable memory device capable of being programmed and erased using Fowler-Nordheim tunneling and capable of being operated using low voltages. Portions of each of the source and drain regions overlap with the first gate dielectric layer, and the interpoly dielectric layer is chosen to have a high dielectric constant so as to maximize the capacitive coupling ratio between floating gate, control gate, source, and drain. The logical condition of cells in the array is set by first elevating a block of cells to a high voltage threshold and by individually lowering the voltage threshold of selected cells.
    Type: Grant
    Filed: September 27, 1995
    Date of Patent: March 25, 1997
    Assignee: Rohm Corporation
    Inventors: Shang-De Chang, Jia-Hwang Chang, Edwin Chow
  • Patent number: 5587947
    Abstract: A single transistor electrically erasable programmable memory device capable of being programmed and erased using Fowler-Nordheim tunneling and capable of being operated using low voltages. Portions of each of the source and drain regions overlap with the first gate dielectric layer, and the interpoly dielectric layer is chosen to have a high dielectric constant so as to maximize the capacitive coupling ratio between floating gate, control gate, source, and drain. The logical condition of cells in the array is set by first elevating a block of cells to a high voltage threshold and by individually lowering the voltage threshold of selected cells.
    Type: Grant
    Filed: September 27, 1995
    Date of Patent: December 24, 1996
    Assignee: Rohm Corporation
    Inventors: Shang-De Chang, Jia-Hwang Chang, Edwin Chow
  • Patent number: 5465062
    Abstract: A transition detection circuit is provided comprising input means receiving the signal to be monitored for generating a first pulse having a first predetermined pulsewidth when a transition occurs in the signal being monitored; and output means responsive to the first pulse from the input means for generating a second pulse having a second predetermined pulsewidth which is less than the first predetermined pulsewidth. The present invention permits a large number of signals to be monitored for transition yet provide a highly precise output pulsewidth, all with a minimum of circuitry. Preferably the input means include a plurality of input channels, each channel being assigned to a different signal being monitored and each channel providing the first predetermined pulsewidth using simple, non-precision time delay circuits. The output state employs a single, high precision time delay circuit to provide the second predetermined pulsewidth.
    Type: Grant
    Filed: February 3, 1994
    Date of Patent: November 7, 1995
    Assignee: Rohm Corporation
    Inventor: Vincent L. Fong
  • Patent number: 5097444
    Abstract: The present invention provides protection against the effects of overerasure while essentially maintaining a single transistor per memory cell through the use of an additional transistor for each row of memory cells. The added transistor is a positive voltage threshold device which is coupled between the connected sources of the floating gate transistors and a read input line to limit the threshold voltage. For programming, a second transistor with a negative voltage threshold is coupled in the same manner, but is coupled to a program input line. The positive threshold transistor prevents an unselected transistor from turning on during a read operation.
    Type: Grant
    Filed: November 29, 1989
    Date of Patent: March 17, 1992
    Assignee: Rohm Corporation
    Inventor: Vincent L. Fong