Patents by Inventor Chi-Ming Wang

Chi-Ming Wang 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: 20090296488
    Abstract: Sensing circuits for sensing a conduction current of a memory cell among a group of non-volatile memory cells being sensed in parallel and providing the result thereof to a data bus are presented. A precharge circuit is coupled to a node for charging the node to an initial voltage. An intermediate circuit is also coupled to the node and connectable to the memory cell, whereby current from the precharge circuit can be supplied to the memory cell. The circuit also includes a comparator circuit to perform a determination the conduction current by a rate of discharge at the node; a data latch coupled to the comparator circuit to hold the result of said determination; and a transfer gate coupled to the data latch to supply a result latched therein to the data bus independently of the node. This arrangement improves sensing performance and can help to eliminate noise on the analog sensing path during sensing and reduce switching current.
    Type: Application
    Filed: May 28, 2008
    Publication date: December 3, 2009
    Inventors: Hao Thai Nguyen, Man Lung Mui, Seungpil Lee, Fanglin Zhang, Chi-Ming Wang
  • Patent number: 7606076
    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: Grant
    Filed: April 8, 2008
    Date of Patent: October 20, 2009
    Assignee: SanDisk Corporation
    Inventors: Hao Thai Nguyen, Man Lung Mui, Seungpil Lee, Chi-Ming Wang
  • Patent number: 7518910
    Abstract: Systems and methods in accordance with various embodiments can provide for reduced program disturb in non-volatile semiconductor memory. In one embodiment, select memory cells such as those connected to a last word line of a NAND string are programmed using one or more program verify levels or voltages that are different than a corresponding level used to program other cells or word lines. One exemplary embodiment includes using a lower threshold voltage verify level for select physical states when programming the last word line to be programmed for a string during a program operation. Another embodiment includes applying a lower program voltage to program memory cells of the last word line to select physical states. Additional read levels are established for reading the states programmed using lower verify levels in some exemplary implementations.
    Type: Grant
    Filed: December 21, 2005
    Date of Patent: April 14, 2009
    Assignee: SanDisk Corporation
    Inventors: Jian Chen, Chi-Ming Wang
  • Patent number: 7489542
    Abstract: Systems and methods in accordance with various embodiments can provide for reduced program disturb in non-volatile semiconductor memory. In one embodiment, select memory cells such as those connected to a last word line of a NAND string are programmed using one or more program verify levels or voltages that are different than a corresponding level used to program other cells or word lines. One exemplary embodiment includes using a lower threshold voltage verify level for select physical states when programming the last word line to be programmed for a string during a program operation. Another embodiment includes applying a lower program voltage to program memory cells of the last word line to select physical states. Additional read levels are established for reading the states programmed using lower verify levels in some exemplary implementations.
    Type: Grant
    Filed: June 28, 2007
    Date of Patent: February 10, 2009
    Assignee: SanDisk Corporation
    Inventors: Jian Chen, Chi-Ming Wang
  • Patent number: 7468915
    Abstract: In a non-volatile memory, the displacement current generated in non-selected word lines that results when the voltage levels on an array's bit lines are changed can result in disturbs. Techniques for reducing these currents are presented. In a first aspect, the number of cells being simultaneously programmed on a word line is reduced. In a non-volatile memory where an array of memory cells is composed of a number of units, and the units are combined into planes that share common word lines, the simultaneous programming of units within the same plane is avoided. Multiple units may be programmed in parallel, but these are arranged to be in separate planes. This is done by selecting the number of units to be programmed in parallel and their order such that all the units programmed together are from distinct planes, by comparing the units to be programmed to see if any are from the same plane, or a combination of these.
    Type: Grant
    Filed: October 4, 2006
    Date of Patent: December 23, 2008
    Assignee: SanDisk Corporation
    Inventors: Daniel C. Guterman, George Samachisa, Brian Murphy, Chi-Ming Wang, Khandker N. Quader
  • 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
  • Patent number: 7368979
    Abstract: According to different embodiments of the present invention, various methods, devices and systems are described for managing power in charge pumps in a non-volatile memory system having a high voltage charge pump and associated regulator. A method includes the following operations, receiving an operation command corresponding to an operation, pumping up a charge pump output voltage to a desired output voltage, turning off the regulator and the charge pump when the output voltage is approximately the desired output voltage compensating for charge sharing by turning on the charge pump and setting a pump clock rate to a slow clock rate in order to avoid overshooting the desired output voltage by the charge pump while the operation is being carried out, and compensating for junction leakage by turning on the regulator and the charge pump until the charge pump output voltage is the desired output voltage.
    Type: Grant
    Filed: September 19, 2006
    Date of Patent: May 6, 2008
    Assignee: SanDisk Corporation
    Inventors: Prashanti Govindu, Feng Pan, Man Mui, Gyuwan Kwon, Trung Pham, Chi-Ming Wang
  • Publication number: 20080068067
    Abstract: According to different embodiments of the present invention, various methods, devices and systems are described for managing power in charge pumps in a non-volatile memory system having a high voltage charge pump and associated regulator. A method includes the following operations, receiving an operation command corresponding to an operation, pumping up a charge pump output voltage to a desired output voltage, turning off the regulator and the charge pump when the output voltage is approximately the desired output voltage compensating for charge sharing by turning on the charge pump and setting a pump clock rate to a slow clock rate in order to avoid overshooting the desired output voltage by the charge pump while the operation is being carried out, and compensating for junction leakage by turning on the regulator and the charge pump until the charge pump output voltage is the desired output voltage.
    Type: Application
    Filed: September 19, 2006
    Publication date: March 20, 2008
    Inventors: Prashanti Govindu, Feng Pan, Man Mui, Gyuwan Kwon, Trung Pham, Chi-Ming Wang
  • Patent number: 7339822
    Abstract: A current-limited latch circuit is used within a nonvolatile memory integrated circuit for decoding, programming, erase, and other operations. In one implementation, there are a number of latches connected together in parallel between two power supply lines. A current mirroring scheme limits current supplied to the latch. This reduces a difference of the two supplies, positive voltage, ground, or negative voltages, during data changes. The circuit provides smaller device sizes and fast speeds when data changes in the latch, while also providing lower power consumption. The technique provides greater benefits as the voltage difference between the two power supplies is greater.
    Type: Grant
    Filed: December 6, 2002
    Date of Patent: March 4, 2008
    Assignee: SanDisk Corporation
    Inventors: Chi-Ming Wang, Kuo-Lung Chen, Shouchang Tsao
  • Patent number: 7319630
    Abstract: A current-limited latch circuit is used within a nonvolatile memory integrated circuit for decoding, programming, erase, and other operations. In one implementation, there are a number of latches connected together in parallel between two power supply lines. A current mirroring scheme limits current supplied to the latch. This reduces a difference of the two supplies, positive voltage, ground, or negative voltages, during data changes. The circuit provides smaller device sizes and fast speeds when data changes in the latch, while also providing lower power consumption. The technique provides greater benefits as the voltage difference between the two power supplies is greater.
    Type: Grant
    Filed: December 20, 2004
    Date of Patent: January 15, 2008
    Assignee: SanDisk Corporation
    Inventors: Chi-Ming Wang, Kuo-Lung Chen, Shouchang Tsao
  • Publication number: 20070247916
    Abstract: Systems and methods in accordance with various embodiments can provide for reduced program disturb in non-volatile semiconductor memory. In one embodiment, select memory cells such as those connected to a last word line of a NAND string are programmed using one or more program verify levels or voltages that are different than a corresponding level used to program other cells or word lines. One exemplary embodiment includes using a lower threshold voltage verify level for select physical states when programming the last word line to be programmed for a string during a program operation. Another embodiment includes applying a lower program voltage to program memory cells of the last word line to select physical states. Additional read levels are established for reading the states programmed using lower verify levels in some exemplary implementations.
    Type: Application
    Filed: June 28, 2007
    Publication date: October 25, 2007
    Inventors: Jian Chen, Chi-Ming Wang
  • Patent number: 7259987
    Abstract: Systems and methods in accordance with various embodiments can provide for reduced program disturb in non-volatile semiconductor memory. In one embodiment, select memory cells such as those connected to a last word line of a NAND string are programmed using one or more program verify levels or voltages that are different than a corresponding level used to program other cells or word lines. One exemplary embodiment includes using a lower threshold voltage verify level for select physical states when programming the last word line to be programmed for a string during a program operation. Another embodiment includes applying a lower program voltage to program memory cells of the last word line to select physical states. Additional read levels are established for reading the states programmed using lower verify levels in some exemplary implementations.
    Type: Grant
    Filed: December 21, 2005
    Date of Patent: August 21, 2007
    Assignee: SanDisk Corporation
    Inventors: Jian Chen, Chi-Ming Wang
  • Publication number: 20070146311
    Abstract: A roller apparatus for a computer input device, such as a mouse, that has a sturdier support than prior art supports. A scrolling wheel carriage is supported by a PCB for greater stability. An open hook support for the hinge of a wheel carriage angles outward below a retaining point for the hinge. This combines with the hinge being hollowed out, so that upward forces due to variations in PCB thickness cause the hinge to compress while retained by the hook support. The design also provides long side arms for activating microswitches for lateral scrolling, and stoppers for preventing forward and backward slippage.
    Type: Application
    Filed: December 22, 2005
    Publication date: June 28, 2007
    Applicant: Logitech Europe S.A.
    Inventors: Feng-Hao Lin, Chi-ming Wang, Tzu-Ching Chu, Tsung Hsin Hsieh
  • Publication number: 20070076510
    Abstract: In a non-volatile memory, the displacement current generated in non-selected word lines that results when the voltage levels on an array's bit lines are changed can result in disturbs. Techniques for reducing these currents are presented. In a first aspect, the number of cells being simultaneously programmed on a word line is reduced. In a non-volatile memory where an array of memory cells is composed of a number of units, and the units are combined into planes that share common word lines, the simultaneous programming of units within the same plane is avoided. Multiple units may be programmed in parallel, but these are arranged to be in separate planes. This is done by selecting the number of units to be programmed in parallel and their order such that all the units programmed together are from distinct planes, by comparing the units to be programmed to see if any are from the same plane, or a combination of these.
    Type: Application
    Filed: October 4, 2006
    Publication date: April 5, 2007
    Inventors: John Mangan, Daniel Guterman, George Samachisa, Brian Murphy, Chi-Ming Wang, Khandker Quader
  • Patent number: 7145804
    Abstract: In a non-volatile memory, the displacement current generated in non-selected word lines that results when the voltage levels on an array's bit lines are changed can result in disturbs. Techniques for reducing these currents are presented. In a first aspect, the number of cells being simultaneously programmed on a word line is reduced. In a non-volatile memory where an array of memory cells is composed of a number of units, and the units are combined into planes that share common word lines, the simultaneous programming of units within the same plane is avoided. Multiple units may be programmed in parallel, but these are arranged to be in separate planes. This is done by selecting the number of units to be programmed in parallel and their order such that all the units programmed together are from distinct planes, by comparing the units to be programmed to see if any are from the same plane, or a combination of these.
    Type: Grant
    Filed: September 28, 2005
    Date of Patent: December 5, 2006
    Assignee: SanDisk Corporation
    Inventors: Daniel C. Guterman, George Samachisa, Brian Murphy, Chi-Ming Wang, Khandker N. Quader
  • Publication number: 20060133138
    Abstract: Systems and methods in accordance with various embodiments can provide for reduced program disturb in non-volatile semiconductor memory. In one embodiment, select memory cells such as those connected to a last word line of a NAND string are programmed using one or more program verify levels or voltages that are different than a corresponding level used to program other cells or word lines. One exemplary embodiment includes using a lower threshold voltage verify level for select physical states when programming the last word line to be programmed for a string during a program operation. Another embodiment includes applying a lower program voltage to program memory cells of the last word line to select physical states. Additional read levels are established for reading the states programmed using lower verify levels in some exemplary implementations.
    Type: Application
    Filed: December 21, 2005
    Publication date: June 22, 2006
    Inventors: Jian Chen, Chi-Ming Wang
  • Publication number: 20060098483
    Abstract: Systems and methods in accordance with various embodiments can provide for reduced program disturb in non-volatile semiconductor memory. In one embodiment, select memory cells such as those connected to a last word line of a NAND string are programmed using one or more program verify levels or voltages that are different than a corresponding level used to program other cells or word lines. One exemplary embodiment includes using a lower threshold voltage verify level for select physical states when programming the last word line to be programmed for a string during a program operation. Another embodiment includes applying a lower program voltage to program memory cells of the last word line to select physical states. Additional read levels are established for reading the states programmed using lower verify levels in some exemplary implementations.
    Type: Application
    Filed: December 21, 2005
    Publication date: May 11, 2006
    Inventors: Jian Chen, Chi-Ming Wang
  • Patent number: 7020017
    Abstract: Systems and methods in accordance with various embodiments can provide for reduced program disturb in non-volatile semiconductor memory. In one embodiment, select memory cells such as those connected to a last word line of a NAND string are programmed using one or more program verify levels or voltages that are different than a corresponding level used to program other cells or word lines. One exemplary embodiment includes using a lower threshold voltage verify level for select physical states when programming the last word line to be programmed for a string during a program operation. Another embodiment includes applying a lower program voltage to program memory cells of the last word line to select physical states. Additional read levels are established for reading the states programmed using lower verify levels in some exemplary implementations.
    Type: Grant
    Filed: April 6, 2004
    Date of Patent: March 28, 2006
    Assignee: Sandisk Corporation
    Inventors: Jian Chen, Chi-Ming Wang
  • Publication number: 20060023507
    Abstract: In a non-volatile memory, the displacement current generated in non-selected word lines that results when the voltage levels on an array's bit lines are changed can result in disturbs. Techniques for reducing these currents are presented. In a first aspect, the number of cells being simultaneously programmed on a word line is reduced. In a non-volatile memory where an array of memory cells is composed of a number of units, and the units are combined into planes that share common word lines, the simultaneous programming of units within the same plane is avoided. Multiple units may be programmed in parallel, but these are arranged to be in separate planes. This is done by selecting the number of units to be programmed in parallel and their order such that all the units programmed together are from distinct planes, by comparing the units to be programmed to see if any are from the same plane, or a combination of these.
    Type: Application
    Filed: September 28, 2005
    Publication date: February 2, 2006
    Applicant: SanDisk Corporation
    Inventors: John Mangan, Daniel Guterman, George Samachisa, Brian Murphy, Chi-Ming Wang, Khandker Quader
  • Patent number: D563411
    Type: Grant
    Filed: June 19, 2006
    Date of Patent: March 4, 2008
    Assignee: Logitech Europe S.A.
    Inventors: Feng-Hao Lin, Tzu-Ching Chu, Chi-Ming Wang, Tsung Hsin Hsieh, Yun-Chan Tsai, Chung-Shan Yang, Kuo Hao Bao