Patents by Inventor Man Lung Mui

Man Lung Mui 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: 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
  • Publication number: 20090003068
    Abstract: Bit line-to-bit line noise is discharged in a NAND string prior to sensing a programming condition of a selected non-volatile storage element in the NAND string. A source voltage is applied which boosts the voltage in conductive NAND strings. The voltage boost results in capacitive coupling of noise to neighboring NAND strings. A current pull down device is used to discharge each NAND string prior to performing sensing. After each NAND string is coupled to a discharge path for a predetermined amount of time, bit lines of the NAND string are coupled to voltage sense components for sensing the programming condition of the selected non-volatile storage elements based on a potential of the bit lines. The selected non-volatile storage elements may have a negative threshold voltage. Further, a word line associated with the selected non-volatile storage elements may be set at ground.
    Type: Application
    Filed: June 29, 2007
    Publication date: January 1, 2009
    Inventors: Seungpil Lee, Hao Thai Nguyen, Man Lung Mui
  • Publication number: 20090003069
    Abstract: A NAND string in which bit line-to-bit line noise is discharged prior to sensing a programming condition of a selected non-volatile storage element in the NAND string. A source voltage is applied which boosts the voltage in conductive NAND strings. The voltage boost results in capacitive coupling of noise to neighboring NAND strings. A current pull down device is used to discharge each NAND string prior to performing sensing. After each NAND string is coupled to a discharge path for a predetermined amount of time, bit lines of the NAND string are coupled to voltage sense components for sensing the programming condition of the selected non-volatile storage elements based on a potential of the bit lines. The selected non-volatile storage elements may have a negative threshold voltage. Further, a word line associated with the selected non-volatile storage elements may be set at ground.
    Type: Application
    Filed: June 29, 2007
    Publication date: January 1, 2009
    Inventors: Seungpil Lee, Hao Thai Nguyen, Man Lung Mui
  • Patent number: 7471567
    Abstract: Bit line-to-bit line noise is discharged in a NAND string prior to sensing a programming condition of a selected non-volatile storage element in the NAND string. A source voltage is applied which boosts the voltage in conductive NAND strings. The voltage boost results in capacitive coupling of noise to neighboring NAND strings. A current pull down device is used to discharge each NAND string prior to performing sensing. After each NAND string is coupled to a discharge path for a predetermined amount of time, bit lines of the NAND string are coupled to voltage sense components for sensing the programming condition of the selected non-volatile storage elements based on a potential of the bit lines. The selected non-volatile storage elements may have a negative threshold voltage. Further, a word line associated with the selected non-volatile storage elements may be set at ground.
    Type: Grant
    Filed: June 29, 2007
    Date of Patent: December 30, 2008
    Assignee: SanDisk Corporation
    Inventors: Seungpil Lee, Hao Thai Nguyen, Man Lung Mui
  • 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: 20080266963
    Abstract: A source line bias error caused by a voltage drop in a source line of a non-volatile memory device during a read or verify operation is addressed. In one approach, a body bias is applied to a substrate of the non-volatile memory device by coupling the substrate to a source voltage or a voltage which is a function of the source voltage. In another approach, a control gate voltage and/or drain voltage, e.g., bit line voltage, are compensated by referencing them to a voltage which is based on the source voltage instead of to ground. Various combinations of these approaches can be used as well. During other operations, such as programming, erase-verify and sensing of negative threshold voltages, the source line bias error is not present, so there is no need for a bias or compensation. A forward body bias can also be compensated.
    Type: Application
    Filed: April 24, 2007
    Publication date: October 30, 2008
    Inventors: Deepak Chandra Sekar, Nima Mokhlesi, Hao Thai Nguyen, Seungpil Lee, Man Lung Mui
  • Publication number: 20080266964
    Abstract: A source line bias error caused by a voltage drop in a source line of a non-volatile memory device during a read or verify operation is addressed. In one approach, a body bias is applied to a substrate of the non-volatile memory device by coupling the substrate to a source voltage or a voltage which is a function of the source voltage. In another approach, a control gate voltage and/or drain voltage, e.g., bit line voltage, are compensated by referencing them to a voltage which is based on the source voltage instead of to ground. Various combinations of these approaches can be used as well. During other operations, such as programming, erase-verify and sensing of negative threshold voltages, the source line bias error is not present, so there is no need for a bias or compensation. A forward body bias can also be compensated.
    Type: Application
    Filed: April 24, 2007
    Publication date: October 30, 2008
    Inventors: Deepak Chandra Sekar, Nima Mokhlesi, Hao Thai Nguyen, Seungpil Lee, Man Lung Mui
  • 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: 20080247253
    Abstract: A non-volatile storage system in which temperature compensation of a bit line voltage is provided during a sense operation of a non-volatile storage element. A gate voltage of a transistor which couples a bit line associated with the non-volatile storage element to a sense module is temperature-compensated so that it is higher when temperature is higher to compensate for variations with temperature of the bit line voltage. The bit line voltage, in turn, varies due to variations in temperature of a threshold voltage of the non-volatile storage element. The sense module determines a programming condition of the non-volatile storage element, which may be provided in a NAND string, by sensing a voltage. The sense operation may be a read operation, verify operation, or erase-verify operation, for instance. Further, the threshold voltage of the non-volatile storage element may be positive or negative. In another aspect, a source voltage is temperature compensated.
    Type: Application
    Filed: June 29, 2007
    Publication date: October 9, 2008
    Inventors: Hao Thai Nguyen, Seungpil Lee, Man Lung Mui
  • 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: 20080247254
    Abstract: Temperature-compensation is provided during a sense operation of a non-volatile storage element. A gate voltage of a transistor which couples a bit line associated with the non-volatile storage element to a sense module is temperature-compensated so that it is higher when temperature is higher to compensate for variations with temperature of the bit line voltage. The bit line voltage, in turn, varies due to variations in temperature of a threshold voltage of the non-volatile storage element. The sense module determines a programming condition of the non-volatile storage element, which may be provided in a NAND string, by sensing a voltage. The sense operation may be a read operation, verify operation, or erase-verify operation, for instance. Further, the threshold voltage of the non-volatile storage element may be positive or negative. In another aspect, a source voltage is temperature compensated.
    Type: Application
    Filed: June 29, 2007
    Publication date: October 9, 2008
    Inventors: Hao Thai Nguyen, Seungpil Lee, Man Lung Mui
  • 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: 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: 20080247241
    Abstract: A pull down circuit pulls a bit line voltage to a regulated source voltage in a non-volatile storage device during a sense operation such as a verify operation which occurs during programming. The storage device may include NAND strings which have associated bit lines and sense components, and a common source line. When a selected storage element of a NAND string has been programmed to its intended state, the bit line is locked out during subsequent verify operations which occur for other NAND strings which are not yet locked out. The pull down device is coupled to each bit line and to the common source line, whose voltage is regulated at a positive DC level, to prevent coupling of system power bus (VSS) noise from the locked out bit lines to the not yet locked out bit lines.
    Type: Application
    Filed: April 8, 2008
    Publication date: October 9, 2008
    Inventors: Hao Thai Nguyen, Man Lung Mui, Seungpil Lee, Chi-Ming Wang
  • Publication number: 20080239813
    Abstract: Variation in programming efficacy due to variation in time constants along a word line that spans across a memory plane is compensated by adjusting the bit line voltages across the plane to modify the programming rates. In this way, the variation in programming efficacy is substantially reduced during programming of a group of memory cells coupled to the word line. This will allow uniform optimization of programming across the group of memory cells and reduce the number of programming pulses required to program the group of memory cells, thereby improving performance. In one embodiment, during programming, the bit lines in a first half of the memory plane closer to a source of word line voltage is set to a first voltage by a first voltage shifter and the bit lines in a second half of the memory plane further from the source of word line voltage is set to a second voltage by a second voltage shifter.
    Type: Application
    Filed: March 29, 2007
    Publication date: October 2, 2008
    Inventors: Deepak Chandra Sekar, Man Lung Mui, Nima Mokhlesi
  • Publication number: 20080239824
    Abstract: Variation in programming efficacy due to variation in time constants along a word line that spans across a memory plane is compensated by adjusting the bit line voltages across the plane to modify the programming rates. In this way, the variation in programming efficacy is substantially reduced during programming of a group of memory cells coupled to the word line. This will allow uniform optimization of programming across the group of memory cells and reduce the number of programming pulses required to program the group of memory cells, thereby improving performance. In one embodiment, during programming, the bit lines in a first half of the memory plane closer to a source of word line voltage is set to a first voltage and the bit lines in a second half of the memory plane further from the source of word line voltage is set to a second voltage.
    Type: Application
    Filed: March 29, 2007
    Publication date: October 2, 2008
    Inventors: Deepak Chandra Sekar, Man Lung Mui, Nima Mokhlesi
  • Publication number: 20080158973
    Abstract: Shifts in the apparent charge stored by a charge storage region such as a floating gate in a non-volatile memory cell can occur because of electrical field coupling based on charge stored by adjacent cells. To account for the shift, compensations are applied when reading. When reading a selected word line, the adjacent word line is read first and the data stored in a set of data latches for each bit line. One latch for each bit line stores an indication that the data is from the adjacent word line. The selected word line is then read with compensations based on the different states of the cells on the adjacent word line. Each sense module uses the data from the adjacent word line to select the results of sensing with the appropriate compensation for its bit line. The data from the adjacent word line is overwritten with data from the selected word line at the appropriate time and the indication updated to reflect that the latches store data from the selected word line.
    Type: Application
    Filed: December 28, 2006
    Publication date: July 3, 2008
    Inventors: Man Lung Mui, Seungpil Lee
  • Publication number: 20080158949
    Abstract: Shifts in the apparent charge stored by a charge storage region such as a floating gate in a non-volatile memory cell can occur because of electrical field coupling based on charge stored by adjacent cells. To account for the shift, compensations are applied when reading. When reading a selected word line, the adjacent word line is read first and the data stored in a set of data latches for each bit line. One latch for each bit line stores an indication that the data is from the adjacent word line. The selected word line is then read with compensations based on the different states of the cells on the adjacent word line. Each sense module uses the data from the adjacent word line to select the results of sensing with the appropriate compensation for its bit line. The data from the adjacent word line is overwritten with data from the selected word line at the appropriate time and the indication updated to reflect that the latches store data from the selected word line.
    Type: Application
    Filed: December 28, 2006
    Publication date: July 3, 2008
    Inventors: Man Lung Mui, Seungpil Lee