Patents by Inventor Shigekazu Yamada

Shigekazu Yamada 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: 20240135994
    Abstract: A system includes a memory device having one or more planes and a first set of voltage regulators coupled to each plane of the one or more planes, where the first set of voltage regulators is shared by the one or more planes. The system includes a second set of voltage regulators coupled to a plane of the one or more planes configured to supply a respective voltage to one or more conductive lines responsive to a memory access operation request. The system includes a switch, at the plane of the one or more planes, coupled with a first voltage regulator of the first set of voltage regulators, a second voltage regulator of the second set of voltage regulators, and a first conductive line, the switch configured to selectively couple the second voltage regulator of the second set of voltage regulators to the first conductive line.
    Type: Application
    Filed: October 17, 2023
    Publication date: April 25, 2024
    Inventors: Federica Paolini, Violante Moschiano, Marco Domenico Tiburzi, Leo Raimondo, Filippo Bruno, Shigekazu Yamada
  • Patent number: 11861236
    Abstract: A memory device includes a memory array comprising a plurality of planes, a primary plane driver circuit comprising components to support read operations, program operations, and erase operations on any of the plurality of planes, and a secondary plane driver circuit comprising components to support read operations on an associated one of the plurality of planes. The primary plane driver circuit is configured to perform a first read operation on a first plane of the plurality of planes and the secondary plane driver circuit is configured to perform a second read operation on a second plane of the plurality of planes concurrently with the first read operation.
    Type: Grant
    Filed: May 11, 2022
    Date of Patent: January 2, 2024
    Assignee: Micron Technology, Inc.
    Inventors: Kalyan Chakravarthy C. Kavalipurapu, Chang H. Siau, Shigekazu Yamada
  • Publication number: 20230307056
    Abstract: Some embodiments include apparatuses and methods using first and second data lines coupled to respective first and second memory cell strings; an access line shared by first and second memory cells of the first and second memory cell strings, respectively; and a control unit including circuitry to perform operations including charging the first data line to a first voltage during a first time interval of an operation performed on first and second memory cells; holding the second data line at a second voltage during the first time interval; charging the first data line to a third voltage during a second time interval of the operation; charging the second data line to a fourth voltage during the second time interval; and determining, during the second time interval of the operation, whether the first memory cell reaches a first threshold voltage and whether the second memory cell reaches a second threshold voltage.
    Type: Application
    Filed: April 28, 2023
    Publication date: September 28, 2023
    Inventor: Shigekazu Yamada
  • Patent number: 11688468
    Abstract: Devices and techniques are disclosed herein to provide a high-voltage bias signal in a standby state of the storage system without exceeding a limited maximum standby current allowance of the storage system. The high-voltage bias signal can enable a string driver circuit in the standby state to couple a global word line to a local word line, to provide a bias to, or sink a voltage from, a pillar of a string of memory cells of the storage system in the standby state, such as to reduce read disturbances in the storage system.
    Type: Grant
    Filed: August 16, 2021
    Date of Patent: June 27, 2023
    Assignee: Micron Technology, Inc.
    Inventors: Michele Piccardi, Xiaojiang Guo, Shigekazu Yamada
  • Patent number: 11670374
    Abstract: Some embodiments include apparatuses and methods using first and second data lines coupled to respective first and second memory cell strings; an access line shared by first and second memory cells of the first and second memory cell strings, respectively; and a control unit including circuitry to perform operations including charging the first data line to a first voltage during a first time interval of an operation performed on first and second memory cells; holding the second data line at a second voltage during the first time interval; charging the first data line to a third voltage during a second time interval of the operation; charging the second data line to a fourth voltage during the second time interval; and determining, during the second time interval of the operation, whether the first memory cell reaches a first threshold voltage and whether the second memory cell reaches a second threshold voltage.
    Type: Grant
    Filed: August 17, 2021
    Date of Patent: June 6, 2023
    Assignee: Micron Technology, Inc.
    Inventor: Shigekazu Yamada
  • Patent number: 11664076
    Abstract: Some embodiments include apparatuses and methods of operating the apparatuses. One of the apparatuses includes a first memory block including first word lines for respective first memory cells of the first memory block; a second memory block including second word lines for respective second memory cells of the second memory block; first diffusion regions coupled to the first word lines; second diffusion regions adjacent the first diffusion regions, the second diffusion regions coupled to the second word lines; and a circuit to apply a voltage to the second diffusion regions in a write operation performed on the first memory block.
    Type: Grant
    Filed: March 30, 2021
    Date of Patent: May 30, 2023
    Assignee: Micron Technology, Inc.
    Inventors: Go Shikata, Shigekazu Yamada
  • Publication number: 20230056107
    Abstract: Some embodiments include apparatuses and methods using first and second data lines coupled to respective first and second memory cell strings; an access line shared by first and second memory cells of the first and second memory cell strings, respectively; and a control unit including circuitry to perform operations including charging the first data line to a first voltage during a first time interval of an operation performed on first and second memory cells; holding the second data line at a second voltage during the first time interval; charging the first data line to a third voltage during a second time interval of the operation; charging the second data line to a fourth voltage during the second time interval; and determining, during the second time interval of the operation, whether the first memory cell reaches a first threshold voltage and whether the second memory cell reaches a second threshold voltage.
    Type: Application
    Filed: August 17, 2021
    Publication date: February 23, 2023
    Inventor: Shigekazu Yamada
  • Patent number: 11581043
    Abstract: Discussed herein are systems and methods for charging an access line to a non-volatile memory cell during a standby state, such as to prevent or mitigate standby-state charge loss. An embodiment of a memory device comprises a memory cell, a string driver circuit, and a charging circuit. The string driver circuit is coupled to the memory cell via a local word line, and has a common p-well. The charging circuit, in response to a voltage of a global word line of the memory device falling below a reference voltage during a standby state, couple a supply voltage to the common p-well of the string driver circuit to charge the global word line to a positive bias potential. The memory device includes a leakage compensation circuit to compensate for the junction leakage.
    Type: Grant
    Filed: September 17, 2021
    Date of Patent: February 14, 2023
    Assignee: Micron Technology, Inc.
    Inventor: Shigekazu Yamada
  • Publication number: 20220276806
    Abstract: A memory device includes a memory array comprising a plurality of planes, a primary plane driver circuit comprising components to support read operations, program operations, and erase operations on any of the plurality of planes, and a secondary plane driver circuit comprising components to support read operations on an associated one of the plurality of planes. The primary plane driver circuit is configured to perform a first read operation on a first plane of the plurality of planes and the secondary plane driver circuit is configured to perform a second read operation on a second plane of the plurality of planes concurrently with the first read operation.
    Type: Application
    Filed: May 11, 2022
    Publication date: September 1, 2022
    Inventors: Kalyan Chakravarthy C. Kavalipurapu, Chang H. Siau, Shigekazu Yamada
  • Patent number: 11380401
    Abstract: Discussed herein are systems and methods for protecting against transistor degradation in a high-voltage (HV) shifter to transfer an input voltage to an access line, such as a global wordline. An embodiment of a memory device comprises memory cells and a HV shifter circuit that includes a signal transfer circuit, and first and second HV control circuits. The signal transfer circuit includes a P-channel transistor to transfer a high-voltage input to an access line. The first HV control circuit couples a bias voltage to the P-channel transistor for a first time period, and the second HV control circuit couples a stress-relief signal to the P-channel transistor for a second time period, after the first time period, to reduce degradation of the P-channel transistor. The transferred high voltage can be used to charge the access line to selectively read, program, or erase memory cells.
    Type: Grant
    Filed: April 26, 2021
    Date of Patent: July 5, 2022
    Assignee: Micron Technology, Inc.
    Inventor: Shigekazu Yamada
  • Publication number: 20220208274
    Abstract: Some embodiments include apparatuses and methods of operating the apparatuses. One of the apparatuses includes a first memory block including first control gates for respective first memory cells of the first memory block; a second memory block including second control gates for respective second memory cells of the second memory block; first diffusion regions coupled to the first control gates; second diffusion regions adjacent the first diffusion regions, the second diffusion regions coupled to the second control gates; and a circuit to apply a voltage to the second diffusion regions in a write operation performed on the first memory block.
    Type: Application
    Filed: March 30, 2021
    Publication date: June 30, 2022
    Applicant: Micron Technology, Inc.
    Inventors: Go Shikata, Shigekazu Yamada
  • Patent number: 11354067
    Abstract: A memory device includes a memory array comprising a plurality of planes, a primary plane driver circuit comprising components to support read operations, program operations, and erase operations on any of the plurality of planes, and a secondary plane driver circuit comprising components to support read operations on an associated one of the plurality of planes. The primary plane driver circuit is configured to perform a first read operation on a first plane of the plurality of planes and the secondary plane driver circuit is configured to perform a second read operation on a second plane of the plurality of planes concurrently with the first read operation.
    Type: Grant
    Filed: August 5, 2020
    Date of Patent: June 7, 2022
    Assignee: MICRON TECHNOLOGY, INC.
    Inventors: Kalyan Chakravarthy C. Kavalipurapu, Chang H. Siau, Shigekazu Yamada
  • Patent number: 11355206
    Abstract: Discussed herein are systems and methods for compensating degradation of a transistor in a high-voltage (HV) shifter configured to transfer an input voltage to an access line, such as a global wordline. An embodiment of a memory device comprises a group of memory cells, and a HV shifter circuit including a signal transfer circuit and a compensator circuit. The signal transfer circuit includes a P-channel transistor to transfer a high-voltage input to an access line. The compensator circuit can provide a control signal to the signal transfer circuit by coupling a support voltage higher than a supply voltage (Vcc) to the signal transfer circuit for a specified time period to compensate for degradation of the P-channel transistor. The transferred high voltage is used to charge the access line to selectively read, program, or erase memory cells.
    Type: Grant
    Filed: March 12, 2021
    Date of Patent: June 7, 2022
    Assignee: Micron Technology, Inc.
    Inventor: Shigekazu Yamada
  • Publication number: 20220043597
    Abstract: A memory device includes a memory array comprising a plurality of planes, a primary plane driver circuit comprising components to support read operations, program operations, and erase operations on any of the plurality of planes, and a secondary plane driver circuit comprising components to support read operations on an associated one of the plurality of planes. The primary plane driver circuit is configured to perform a first read operation on a first plane of the plurality of planes and the secondary plane driver circuit is configured to perform a second read operation on a second plane of the plurality of planes concurrently with the first read operation.
    Type: Application
    Filed: August 5, 2020
    Publication date: February 10, 2022
    Inventors: Kalyan Chakravarthy C. Kavalipurapu, Chang H. Siau, Shigekazu Yamada
  • Publication number: 20220005530
    Abstract: Discussed herein are systems and methods for charging an access line to a non-volatile memory cell during a standby state, such as to prevent or mitigate standby-state charge loss. An embodiment of a memory device comprises a memory cell, a string driver circuit, and a charging circuit. The string driver circuit is coupled to the memory cell via a local word line, and has a common p-well. The charging circuit, in response to a voltage of a global word line of the memory device falling below a reference voltage during a standby state, couple a supply voltage to the common p-well of the string driver circuit to charge the global word line to a positive bias potential. The memory device includes a leakage compensation circuit to compensate for the junction leakage.
    Type: Application
    Filed: September 17, 2021
    Publication date: January 6, 2022
    Inventor: Shigekazu Yamada
  • Publication number: 20210375375
    Abstract: Devices and techniques are disclosed herein to provide a high-voltage bias signal in a standby state of the storage system without exceeding a limited maximum standby current allowance of the storage system. The high-voltage bias signal can enable a string driver circuit in the standby state to couple a global word line to a local word line, to provide a bias to, or sink a voltage from, a pillar of a string of memory cells of the storage system in the standby state, such as to reduce read disturbances in the storage system.
    Type: Application
    Filed: August 16, 2021
    Publication date: December 2, 2021
    Inventors: Michele Piccardi, Xiaojiang Guo, Shigekazu Yamada
  • Patent number: 11127463
    Abstract: Discussed herein are systems and methods for charging an access line to a non-volatile memory cell during a standby state, such as to prevent or mitigate standby-state charge loss. An embodiment of a memory device comprises a memory cell, a string driver circuit, and a charging circuit. The string driver circuit is coupled to the memory cell via a local word line, and has a common p-well. The charging circuit, in response to a voltage of a global word line of the memory device falling below a reference voltage during a standby state, couple a supply voltage to the common p-well of the string driver circuit to charge the global word line to a positive bias potential. The memory device includes a leakage compensation circuit to compensate for the junction leakage.
    Type: Grant
    Filed: February 3, 2021
    Date of Patent: September 21, 2021
    Assignee: Micron Technology, Inc.
    Inventor: Shigekazu Yamada
  • Patent number: 11125819
    Abstract: A device includes a comparator, a reference signal node, a plurality of test signal nodes, and control logic. The reference signal node receives a reference signal. The reference signal node is coupled to a first input of the comparator. Each of the plurality of test signal nodes receives a corresponding test signal. The control logic is configured to initiate a comparison of each test signal to the reference signal via the comparator.
    Type: Grant
    Filed: February 20, 2020
    Date of Patent: September 21, 2021
    Assignee: Micron Technology, Inc.
    Inventor: Shigekazu Yamada
  • Patent number: 11094385
    Abstract: Devices and techniques are disclosed herein to provide a high-voltage bias signal in a standby state of the storage system without exceeding a limited maximum standby current allowance of the storage system. The high-voltage bias signal can enable a string driver circuit in the standby state to couple a global word line to a local word line, to provide a bias to, or sink a voltage from, a pillar of a string of memory cells of the storage system in the standby state, such as to reduce read disturbances in the storage system.
    Type: Grant
    Filed: July 30, 2020
    Date of Patent: August 17, 2021
    Assignee: Micron Technology, Inc.
    Inventors: Michele Piccardi, Xiaojiang Guo, Shigekazu Yamada
  • Publication number: 20210249084
    Abstract: Discussed herein are systems and methods for protecting against transistor degradation in a high-voltage (HV) shifter to transfer an input voltage to an access line, such as a global wordline. An embodiment of a memory device comprises memory cells and a HV shifter circuit that includes a signal transfer circuit, and first and second HV control circuits. The signal transfer circuit includes a P-channel transistor to transfer a high-voltage input to an access line. The first HV control circuit couples a bias voltage to the P-channel transistor for a first time period, and the second H V control circuit couples a stress-relief signal to the P-channel transistor for a second time period, after the first time period, to reduce degradation of the P-channel transistor. The transferred high voltage can be used to charge the access line to selectively read, program, or erase memory cells.
    Type: Application
    Filed: April 26, 2021
    Publication date: August 12, 2021
    Inventor: Shigekazu Yamada