Patents Represented by Attorney Law Offices of Imam
  • Patent number: 6374337
    Abstract: A method and circuit for fast memory access (read or write) of the data to and from a memory array is disclosed. Architecture wise, the memory array control circuit provides for at least two address latches and two page registers. The first address latch contains a first data address and the second address latch contains a second data address. The first data address is decoded first and sent to the memory array to access (read or write) the corresponding data from the memory array. When the data of the first data address is being accessed, the decoding process will begin for a second data address. When the data of the first data address has been accessed, the second data address is ready for the memory array. Thus, there can be continuous fetching from or writing to the memory array. In the preferred embodiment, there are two page registers. In a read operation, the data read from the first data address is transferred to a first page register.
    Type: Grant
    Filed: November 16, 1999
    Date of Patent: April 16, 2002
    Assignee: Lexar Media, Inc.
    Inventor: Petro Estakhri
  • Patent number: 6262918
    Abstract: In accordance with an embodiment of the present invention, a method and apparatus is disclosed for use in a digital system having a host coupled to at least two nonvolatile memory devices. The host stores digital information in the nonvolatile memory devices and reads the stored digital information from the nonvolatile memory devices. The memory devices are organized into blocks of sectors of information. The method is for erasing digital information stored in the blocks of the nonvolatile memory devices and comprises assigning a predetermined number of blocks, in sequential order, to each of the nonvolatile memory devices, each block having a predetermined number of sectors.
    Type: Grant
    Filed: June 30, 2000
    Date of Patent: July 17, 2001
    Assignee: Lexar Media, Inc.
    Inventors: Petro Estakhri, Berhanu Iman, Min Guo
  • Patent number: 6230234
    Abstract: A nonvolatile semiconductor mass storage system and architecture can be substituted for a rotating hard disk. The system and architecture avoid an erase cycle each time information stored in the mass storage is changed. Erase cycles are avoided by programming an altered data file into an empty mass storage block rather than over itself as a hard disk would. Periodically, the mass storage will need to be cleaned up. These advantages are achieved through the use of several flags, and a map to correlate a logical block address of a block to a physical address of that block. In particular, flags are provided for defective blocks, used blocks, and old versions of a block. An array of volatile memory is addressable according to the logical address and stores the physical address.
    Type: Grant
    Filed: March 8, 2000
    Date of Patent: May 8, 2001
    Assignee: Lexar Media, Inc.
    Inventors: Petro Estakhri, Mamud Assar
  • Patent number: 6223308
    Abstract: A method and apparatus is disclosed for identifying a block being stored within flash memory devices using a cluster address for each block, the block being selectively erasable and having one or more sectors, the cluster address being stored in one of the sectors of the block. In an alternative embodiment, the cluster address is stored in at least two different sectors within the same block for ensuring that the information last written to the block is valid. Further disclosed is a novel way to use a defect flag for each block stored within the flash memory device for efficiently identifying non-defective blocks upon system power-up.
    Type: Grant
    Filed: March 7, 2000
    Date of Patent: April 24, 2001
    Assignee: Lexar Media, Inc.
    Inventors: Petro Estakhri, Berhanu Iman
  • Patent number: 6202138
    Abstract: In one embodiment of the present invention, a memory storage system for storing information organized in sectors within a nonvolatile memory bank is disclosed. The memory bank is defined by sector storage locations spanning across one or more rows of a nonvolatile memory device, each the sector including a user data portion and an overhead portion. The sectors being organized into blocks with each sector identified by a host provided logical block address (LBA). Each block is identified by a modified LBA derived from the host-provided LBA and said virtual PBA, said host-provided LBA being received by the storage device from the host for identifying a sector of information to be accessed, the actual PBA developed by said storage device for identifying a free location within said memory bank wherein said accessed sector is to be stored.
    Type: Grant
    Filed: January 20, 2000
    Date of Patent: March 13, 2001
    Assignee: Lexar Media, Inc
    Inventors: Petro Estakhri, Berhanu Iman
  • Patent number: 6175737
    Abstract: A cellular communication system having a plurality of wireless in-band channels and having a plurality of cells with a plurality of mobile stations in each cell where a base station (BTS) is the interface between mobile stations and a base station controller (BSC). The base station controller monitors and controls one or more base stations. A wireless trunk is established between the base station and the base station controller using selected ones of the allocated channels otherwise available for mobile station communications.
    Type: Grant
    Filed: November 15, 1996
    Date of Patent: January 16, 2001
    Inventor: Chiiming Kao
  • Patent number: 6172906
    Abstract: In one embodiment of the present invention, a memory storage system for storing information organized in sectors within a nonvolatile memory bank is disclosed. The memory bank is defined by sector storage locations spanning across one or more rows of a nonvolatile memory device, each the sector including a user data portion and an overhead portion. The sectors being organized into blocks with each sector identified by a host provided logical block address (LBA). Each block is identified by a modified LBA derived from the host-provided LBA and said virtual PBA, said host-provided LBA being received by the storage device from the host for identifying a sector of information to be accessed, the actual PBA developed by said storage device for identifying a free location within said memory bank wherein said accessed sector is to be stored.
    Type: Grant
    Filed: March 8, 2000
    Date of Patent: January 9, 2001
    Assignee: Lexar Media, Inc.
    Inventors: Petro Estakhri, Berhanu Iman
  • Patent number: 6151247
    Abstract: In accordance with an embodiment of the present invention, a solid state storage system and method is disclosed for reducing the number of write operations when re-writing a block of information that has been previously written by a host. The system includes a controller coupled to a host and a nonvolatile memory unit for controlling reading and writing of information organized in sectors from and to the nonvolatile memory unit, as commanded by the host. The controller maintains mapping of the sector information in an LUT stored in volatile memory the contents of which are lost if power is lost. Through the use of an address value and flag information maintained within each of the blocks of the nonvolatile memory unit, a block is re-written using a different number of write operations in various alternative embodiments of the present invention.
    Type: Grant
    Filed: March 7, 2000
    Date of Patent: November 21, 2000
    Assignee: Lexar Media, Inc.
    Inventors: Petro Estakhri, Berhanu Iman
  • Patent number: 6141249
    Abstract: An embodiment of the present invention includes a nonvolatile memory system for storing sector information in storage locations within nonvolatile memory organized into blocks, a plurality of blocks defining a super block and each block having a predetermined plurality of sectors. The nonvolatile memory system includes a controller for shifting sector information to a first and a second block of a particular super block and writing sector information to the first block of the particular super block, wherein shifting to the second block occurs entirely during the writing to the first block thereby decreasing the time required to perform write operations to blocks and increasing overall system performance.
    Type: Grant
    Filed: September 3, 1999
    Date of Patent: October 31, 2000
    Assignee: Lexar Media, Inc.
    Inventors: Petro Estakhri, Berhanu Iman
  • Patent number: 6134151
    Abstract: In accordance with an embodiment of the present invention, a method and apparatus is disclosed for use in a digital system having a host coupled to at least two nonvolatile memory devices. The host stores digital information in the nonvolatile memory devices and reads the stored digital information from the nonvolatile memory devices. The memory devices are organized into blocks of sectors of information. The method is for erasing digital information stored in the blocks of the nonvolatile memory devices and comprises assigning a predetermined number of blocks, in sequential order, to each of the nonvolatile memory devices, each block having a predetermined number of sectors.
    Type: Grant
    Filed: March 6, 2000
    Date of Patent: October 17, 2000
    Assignee: Lexar Media, Inc.
    Inventors: Petro Estakhri, Berhanu Iman, Min Guo
  • Patent number: 6125435
    Abstract: A digital system is disclosed for use with a host, the digital system including a controller and a nonvolatile memory unit having memory locations organized in blocks with each block having a plurality of sectors for storing information provided by the host in the form of non-user data files and user data files, the controller for controlling reading, writing and erasing operations performed on the nonvolatile memory, the host providing to the controller an address, identifying the starting location of the user file to the controller, and a user file identified by a starting sector address for storage within the nonvolatile memory unit. The controller finds a free block within the nonvolatile memory unit that is available for storage of information, and aligns the user file starting address with the beginning of the free block, and stores the user file within the free block starting with the beginning of the free block.
    Type: Grant
    Filed: November 24, 1997
    Date of Patent: September 26, 2000
    Assignee: Lexar Media, Inc.
    Inventors: Petro Estakhri, Berhau Imam
  • Patent number: 6115785
    Abstract: A nonvolatile semiconductor mass storage system and architecture can be substituted for a rotating hard disk. The system and architecture avoid an erase cycle each time information stored in the mass storage is changed. Erase cycles are avoided by programming an altered data file into an empty mass storage block rather than over itself as a hard disk would. Periodically, the mass storage will need to be cleaned up. These advantages are achieved through the use of several flags, and a map to correlate a logical block address of a block to a physical address of that block. In particular, flags are provided for defective blocks, used blocks, and old versions of a block. An array of volatile memory is addressable according to the logical address and stores the physical address.
    Type: Grant
    Filed: May 13, 1999
    Date of Patent: September 5, 2000
    Assignee: Lexar Media, Inc.
    Inventors: Petro Estakhri, Mamud Assar
  • Patent number: 6108801
    Abstract: A digital system for Bit Error Rate Testing (BERT) of test transmission lines and/or devices and including a test equipment coupled to at least one transmission line for transferring digital information between the test equipment and a company office, a bit error generator coupled to the transmission lines for generating test patterns, a device for storing a plurality of predetermined profiles, each profile having associated therewith at least one parameter for measuring the integrity of the test equipment or the transmission lines, the parameters including one of the generated test patterns.
    Type: Grant
    Filed: August 11, 1998
    Date of Patent: August 22, 2000
    Assignee: Cisco Systems, Inc.
    Inventors: Pankaj Malhotra, Michael Segal
  • Patent number: 6084483
    Abstract: An oscillator circuit residing internally to a semiconductor device for generating a clock signal for use by digital circuits. The oscillator circuit includes a voltage regulator circuit responsive to frequency selection signals for selecting a predetermined frequency and a supply voltage. The voltage regulator circuit is operative to generate a voltage reference signal having a voltage level being adjusted to compensate for variations due to temperature, process and supply voltage variations. The oscillator circuit further includes a ring oscillator circuit responsive to the voltage reference signal for generating a clock out signal having a particular frequency based upon the voltage level of the voltage reference signal. Wherein the frequency of the clock out signal remains substantially constant despite temperature, process and supply voltage variations in the semiconductor circuit.
    Type: Grant
    Filed: March 10, 1999
    Date of Patent: July 4, 2000
    Assignee: Lexar Media, Inc.
    Inventor: Parviz Keshtbod
  • Patent number: 6076137
    Abstract: In a digital system having a host, a controller device and at least one flash memory integrated circuit, a method and apparatus for storing location identification information regarding blocks of information within at least one of the flash memory integrated circuits wherein at least two buffers within the at least one of the flash memory integrated circuits are designated as primary and secondary buffers for storing the identification information in the primary buffer until the primary buffer is effectively full and storing additional identification information in the secondary buffer until it is effectively full, swapping buffer designation so that the primary buffer becomes the secondary buffer and the secondary buffer becomes the primary buffer, erasing the effectively-full buffer for re-use and in this manner, continuously swapping storage of identification information between the two buffers.
    Type: Grant
    Filed: December 11, 1997
    Date of Patent: June 13, 2000
    Assignee: Lexar Media, Inc.
    Inventor: Mehdi Asnaashari