Patents by Inventor Hock So

Hock So 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: 8406052
    Abstract: Non-volatile memory is programmed using source side hot electron injection. To generate a high voltage bit line for programming, the bit line corresponding to a selected memory cell is charged to a first level using a first low voltage. A second low voltage is applied to unselected bit lines adjacent to the selected bit line after charging. Because of capacitive coupling between the adjacent bit lines and the selected bit line, the selected bit line is boosted above the first voltage level by application of the second low voltage to the unselected bit lines. The column control circuitry for such a memory array does not directly apply the high voltage and thus, can be designed to withstand lower operating voltages, permitting low operating voltage circuitry to be used.
    Type: Grant
    Filed: February 16, 2011
    Date of Patent: March 26, 2013
    Assignee: SanDisk Technologies Inc.
    Inventors: Dana Lee, Hock So
  • Publication number: 20110134694
    Abstract: Non-volatile memory is programmed using source side hot electron injection. To generate a high voltage bit line for programming, the bit line corresponding to a selected memory cell is charged to a first level using a first low voltage. A second low voltage is applied to unselected bit lines adjacent to the selected bit line after charging. Because of capacitive coupling between the adjacent bit lines and the selected bit line, the selected bit line is boosted above the first voltage level by application of the second low voltage to the unselected bit lines. The column control circuitry for such a memory array does not directly apply the high voltage and thus, can be designed to withstand lower operating voltages, permitting low operating voltage circuitry to be used.
    Type: Application
    Filed: February 16, 2011
    Publication date: June 9, 2011
    Applicant: SanDisk Corporation
    Inventors: Dana Lee, Hock So
  • Patent number: 7894263
    Abstract: Non-volatile memory is programmed using source side hot electron injection. To generate a high voltage bit line for programming, the bit line corresponding to a selected memory cell is charged to a first level using a first low voltage. A second low voltage is applied to unselected bit lines adjacent to the selected bit line after charging. Because of capacitive coupling between the adjacent bit lines and the selected bit line, the selected bit line is boosted above the first voltage level by application of the second low voltage to the unselected bit lines. The column control circuitry for such a memory array does not directly apply the high voltage and thus, can be designed to withstand lower operating voltages, permitting low operating voltage circuitry to be used.
    Type: Grant
    Filed: September 28, 2007
    Date of Patent: February 22, 2011
    Assignee: SanDisk Corporation
    Inventors: Dana Lee, Hock So
  • Patent number: 7539060
    Abstract: A non-volatile storage device in which current sensing is performed for a non-volatile storage element. A voltage is applied to a selected word line of the first non-volatile storage element, and source and p-well voltages are applied to a source and a p-well, respectively, associated with the non-volatile storage element. The source and p-well voltages are regulated at respective positive DC levels to avoid a ground bounce, or voltage fluctuation, which would occur if the source voltage at least was regulated at a ground voltage. A programming condition of the non-volatile storage element is determined by sensing a current in a NAND string of the non-volatile storage element. The sensing can occur quickly since there is no delay in waiting for the ground bounce to settle.
    Type: Grant
    Filed: June 29, 2007
    Date of Patent: May 26, 2009
    Assignee: SanDisk Corporation
    Inventors: Hao Thai Nguyen, Seungpil Lee, Man Lung Mui, Shahzad Khalid, Hock So, Prashanti Govindu
  • Patent number: 7532516
    Abstract: A non-volatile storage device in which current sensing is performed for a non-volatile storage element with a negative threshold voltage. A control gate read voltage is applied to a selected word line of a non-volatile storage element, and source and p-well voltages are applied to a source and a p-well, respectively, associated with the non-volatile storage element. The source and p-well voltages exceed the control gate read voltage so that a positive control gate read voltage can be used. There is no need for a negative charge pump to apply a negative word line voltage even for sensing a negative threshold voltage. A programming condition of the non-volatile storage element is determined by sensing a voltage drop which is tied to a fixed current which flows in a NAND string of the non-volatile storage element.
    Type: Grant
    Filed: June 29, 2007
    Date of Patent: May 12, 2009
    Assignee: SanDisk Corporation
    Inventors: Hao Thai Nguyen, Seungpil Lee, Man Lung Mui, Shahzad Khalid, Hock So, Prashanti Govindu, Nima Mokhlesi, Deepak Chandra Sekar
  • Publication number: 20090086542
    Abstract: Non-volatile memory is programmed using source side hot electron injection. To generate a high voltage bit line for programming, the bit line corresponding to a selected memory cell is charged to a first level using a first low voltage. A second low voltage is applied to unselected bit lines adjacent to the selected bit line after charging. Because of capacitive coupling between the adjacent bit lines and the selected bit line, the selected bit line is boosted above the first voltage level by application of the second low voltage to the unselected bit lines. The column control circuitry for such a memory array does not directly apply the high voltage and thus, can be designed to withstand lower operating voltages, permitting low operating voltage circuitry to be used.
    Type: Application
    Filed: September 28, 2007
    Publication date: April 2, 2009
    Inventors: Dana Lee, Hock So
  • Patent number: 7489554
    Abstract: Current sensing is performed in a non-volatile storage device for a non-volatile storage element. A voltage is applied to a selected word line of the first non-volatile storage element, and source and p-well voltages are applied to a source and a p-well, respectively, associated with the non-volatile storage element. The source and p-well voltages are regulated at respective positive DC levels to avoid a ground bounce, or voltage fluctuation, which would occur if the source voltage at least was regulated at a ground voltage. A programming condition of the non-volatile storage element is determined by sensing a current in a NAND string of the non-volatile storage element. The sensing can occur quickly since there is no delay in waiting for the ground bounce to settle.
    Type: Grant
    Filed: June 29, 2007
    Date of Patent: February 10, 2009
    Assignee: SanDisk Corporation
    Inventors: Hao Thai Nguyen, Seungpil Lee, Man Lung Mui, Shahzad Khalid, Hock So, Prashanti Govindu
  • Patent number: 7447079
    Abstract: Current sensing is performed in a non-volatile storage device for a selected non-volatile storage element with a negative threshold voltage. A control gate read voltage is applied to a selected word line of a non-volatile storage element, and source and p-well voltages are applied to a source and a p-well, respectively, associated with the non-volatile storage element. The source and p-well voltages exceed the control gate read voltage so that a positive control gate read voltage can be used. There is no need for a negative charge pump to apply a negative word line voltage even for sensing a negative threshold voltage. A programming condition of the non-volatile storage element is determined by sensing a voltage drop which is tied to a fixed current which flows in a NAND string of the non-volatile storage element.
    Type: Grant
    Filed: June 29, 2007
    Date of Patent: November 4, 2008
    Assignee: SanDisk Corporation
    Inventors: Hao Thai Nguyen, Seungpil Lee, Man Lung Mui, Shahzad Khalid, Hock So, Prashanti Govindu, Nima Mokhlesi, Deepak Chandra Sekar
  • Publication number: 20080247228
    Abstract: A non-volatile storage device in which current sensing is performed for a non-volatile storage element with a negative threshold voltage. A control gate read voltage is applied to a selected word line of a non-volatile storage element, and source and p-well voltages are applied to a source and a p-well, respectively, associated with the non-volatile storage element. The source and p-well voltages exceed the control gate read voltage so that a positive control gate read voltage can be used. There is no need for a negative charge pump to apply a negative word line voltage even for sensing a negative threshold voltage. A programming condition of the non-volatile storage element is determined by sensing a voltage drop which is tied to a fixed current which flows in a NAND string of the non-volatile storage element.
    Type: Application
    Filed: June 29, 2007
    Publication date: October 9, 2008
    Inventors: Hao Thai Nguyen, Seungpil Lee, Man Lung Mui, Shahzad Khalid, Hock So, Prashanti Govindu, Nima Mokhlesi, Deepak Chandra Sekar
  • Publication number: 20080247238
    Abstract: Current sensing is performed in a non-volatile storage device for a selected non-volatile storage element with a negative threshold voltage. A control gate read voltage is applied to a selected word line of a non-volatile storage element, and source and p-well voltages are applied to a source and a p-well, respectively, associated with the non-volatile storage element. The source and p-well voltages exceed the control gate read voltage so that a positive control gate read voltage can be used. There is no need for a negative charge pump to apply a negative word line voltage even for sensing a negative threshold voltage. A programming condition of the non-volatile storage element is determined by sensing a voltage drop which is tied to a fixed current which flows in a NAND string of the non-volatile storage element.
    Type: Application
    Filed: June 29, 2007
    Publication date: October 9, 2008
    Inventors: Hao Thai Nguyen, Seungpil Lee, Man Lung Mui, Shahzad Khalid, Hock So, Prashanti Govindu, Nima Mokhlesi, Deepak Chandra Sekar
  • Publication number: 20080247229
    Abstract: A non-volatile storage device in which current sensing is performed for a non-volatile storage element. A voltage is applied to a selected word line of the first non-volatile storage element, and source and p-well voltages are applied to a source and a p-well, respectively, associated with the non-volatile storage element. The source and p-well voltages are regulated at respective positive DC levels to avoid a ground bounce, or voltage fluctuation, which would occur if the source voltage at least was regulated at a ground voltage. A programming condition of the non-volatile storage element is determined by sensing a current in a NAND string of the non-volatile storage element. The sensing can occur quickly since there is no delay in waiting for the ground bounce to settle.
    Type: Application
    Filed: June 29, 2007
    Publication date: October 9, 2008
    Inventors: Hao Thai Nguyen, Seungpil Lee, Man Lung Mui, Shahzad Khalid, Hock So, Prashanti Govindu
  • Publication number: 20080247239
    Abstract: Current sensing is performed in a non-volatile storage device for a non-volatile storage element. A voltage is applied to a selected word line of the first non-volatile storage element, and source and p-well voltages are applied to a source and a p-well, respectively, associated with the non-volatile storage element. The source and p-well voltages are regulated at respective positive DC levels to avoid a ground bounce, or voltage fluctuation, which would occur if the source voltage at least was regulated at a ground voltage. A programming condition of the non-volatile storage element is determined by sensing a current in a NAND string of the non-volatile storage element. The sensing can occur quickly since there is no delay in waiting for the ground bounce to settle.
    Type: Application
    Filed: June 29, 2007
    Publication date: October 9, 2008
    Inventors: Hao Thai Nguyen, Seungpil Lee, Man Lung Mui, Shahzad Khalid, Hock So, Prashanti Govindu
  • Publication number: 20080049498
    Abstract: Techniques are used to store information in a medium such as the memory cells of an integrated circuit, and also retrieval of information from the medium. The integrated circuit includes nonvolatile memory cells (416) capable of multilevel or analog voltage level storage. The integrated circuit may store or record information in analog or digital form, or both. Information is stored in and retrieved from the integrated circuit using a user-selected sampling frequency. The user's selection of the sampling frequency is stored within the integrated circuit.
    Type: Application
    Filed: October 22, 2007
    Publication date: February 28, 2008
    Inventors: Carl Werner, Andreas Haeberli, Leon Wong, Cheng-Yuan Wang, Hock So, Sau Wong
  • Publication number: 20070104004
    Abstract: A multibit-per-cell non-volatile memory divides the suitable threshold voltages of memory cells into ranges corresponding to allowed states for storage of data and ranges corresponding to forbidden zones indicating a data error. A read process in accordance automatically checks whether a threshold voltage is in a forbidden zone. In an alternative embodiment, a refresh process includes reprogramming the threshold voltage into an allowed state. In the case of a flash memory, a refresh reads a sector of the memory and saves corrected data from the sector in a buffer or another sector. The corrected data from the buffer or other sector can be written back in the original sector, or the corrected data can be left in the other sector with addresses of the original sector being mapped to the other sector.
    Type: Application
    Filed: January 5, 2007
    Publication date: May 10, 2007
    Inventors: Hock So, Sau Wong
  • Publication number: 20060285374
    Abstract: A content addressable memory cell may include a non-volatile memory storage transistor coupled to an enhancement transistor. In some embodiments, the enhancement transistor may be a select cell. In some embodiments, the storage transistor may use substrate hot electron injection. Through the use of the enhancement transistor, overerasing and read disturb problems may be mitigated.
    Type: Application
    Filed: June 16, 2005
    Publication date: December 21, 2006
    Inventors: Clement Szeto, Hock So, Ting-Wah Wong, Masaharu Shinya
  • Publication number: 20060256626
    Abstract: Techniques are used to store information in a medium such as the memory cells of an integrated circuit, and also retrieval of information from the medium. The integrated circuit includes nonvolatile memory cells (416) capable of multilevel or analog voltage level storage. The integrated circuit may store or record information in analog or digital form, or both. Information is stored in and retrieved from the integrated circuit using a user-selected sampling frequency. The user's selection of the sampling frequency is stored within the integrated circuit.
    Type: Application
    Filed: July 27, 2006
    Publication date: November 16, 2006
    Inventors: Carl Werner, Andreas Haeberli, Leon Wong, Cheng-Yuan Wang, Hock So, Sau Wong
  • Publication number: 20050174844
    Abstract: A multibit-per-cell non-volatile memory divides the suitable threshold voltages of memory cells into ranges corresponding to allowed states for storage of data and ranges corresponding to forbidden zones indicating a data error. A read process in accordance automatically checks whether a threshold voltage is in a forbidden zone. In an alternative embodiment, a refresh process includes reprogramming the threshold voltage into an allowed state. In the case of a flash memory, a refresh reads a sector of the memory and saves corrected data from the sector in a buffer or another sector. The corrected data from the buffer or other sector can be written back in the original sector, or the corrected data can be left in the other sector with addresses of the original sector being mapped to the other sector.
    Type: Application
    Filed: April 7, 2005
    Publication date: August 11, 2005
    Inventors: Hock So, Sau Wong