Patents by Inventor Shahzad Khalid
Shahzad Khalid 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).
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Publication number: 20070263450Abstract: A non-volatile memory device capable of reading and writing a large number of memory cells with multiple read/write circuits in parallel has an architecture that reduces redundancy in the multiple read/write circuits to a minimum. The multiple read/write circuits are organized into a bank of similar stacks of components. Redundant circuits such as a processor for processing data among stacks each associated with multiple memory cells are factored out. The processor is implemented with an input logic, a latch and an output logic. The input logic can transform the data received from either the sense amplifier or the data latches. The output logic further processes the transformed data to send to either the sense amplifier or the data latches or to a controller. This provides an infrastructure with maximum versatility and a minimum of components for sophisticated processing of the data sensed and the data to be input or output.Type: ApplicationFiled: July 23, 2007Publication date: November 15, 2007Inventors: Raul-Adrian Cernea, Yan Li, Shahzad Khalid, Siu Chan
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Publication number: 20070226434Abstract: Tracking cells are used in a memory system to improve the read process. The tracking cells can provide an indication of the quality of the data and can be used as part of a data recovery operation if there is an error. The tracking cells provide a means to adjust the read parameters to optimum levels in order to reflect the current conditions of the memory system. Additionally, some memory systems that use multi-state memory cells will apply rotation data schemes to minimize wear. The rotation scheme can be encoded in the tracking cells based on the states of multiple tracking cells, which is decoded upon reading.Type: ApplicationFiled: May 22, 2007Publication date: September 27, 2007Inventors: Daniel Guterman, Stephen Gross, Shahzad Khalid, Geoffrey Gongwer
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Publication number: 20070217259Abstract: Tracking cells are used in a memory system to improve the read process. The tracking cells can provide an indication of the quality of the data and can be used as part of a data recovery operation if there is an error. The tracking cells provide a means to adjust the read parameters to optimum levels in order to reflect the current conditions of the memory system. Additionally, some memory systems that use multi-state memory cells will apply rotation data schemes to minimize wear. The rotation scheme can be encoded in the tracking cells based on the states of multiple tracking cells, which is decoded upon reading.Type: ApplicationFiled: May 22, 2007Publication date: September 20, 2007Inventors: Daniel Guterman, Stephen Gross, Shahzad Khalid, Geoffrey Gongwer
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Patent number: 7269069Abstract: When programming a contiguous page of memory storage units, every time a memory storage unit has reached its targeted state and is program-inhibited or locked out from further programming, it creates a perturbation on an adjacent memory storage unit still under programming. The present invention provides as part of a programming circuit and method in which an offset to the perturbation is added to the adjacent memory storage unit still under programming. The offset is added by a controlled coupling between the adjacent bit lines of the program-inhibited memory storage unit and the still under programming memory storage unit. In this way, an error inherent in programming in parallel high-density memory storage units is eliminated or minimized.Type: GrantFiled: June 2, 2006Date of Patent: September 11, 2007Assignee: SanDisk CorporationInventors: Raul-Adrian Cernea, Yan Li, Mehrdad Mofidi, Shahzad Khalid
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Patent number: 7237074Abstract: Tracking cells are used in a memory system to improve the read process. The tracking cells can provide an indication of the quality of the data and can be used as part of a data recovery operation if there is an error. The tracking cells provide a means to adjust the read parameters to optimum levels in order to reflect the current conditions of the memory system. Additionally, some memory systems that use multi-state memory cells will apply rotation data schemes to minimize wear. The rotation scheme can be encoded in the tracking cells based on the states of multiple tracking cells, which is decoded upon reading.Type: GrantFiled: June 13, 2003Date of Patent: June 26, 2007Assignee: Sandisk CorporationInventors: Daniel C. Guterman, Stephen J. Gross, Shahzad Khalid, Geoffrey S. Gongwer
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Publication number: 20070103227Abstract: A voltage buffer for capacitive loads isolates the load from the feedback loop. Using a variation of a follower arrangement, a second transistor outside of the feedback loop introduced. The current to the load is supplied through the second transistor, which is connected to have the same control gate level as the transistor in the feedback loop and provide an output voltage based on the reference input voltage. The output voltage is dependent upon the input voltage, but the load is removed from the feedback loop. By removing the load from the feedback loop, the loop is stabilized with only a very small or no compensating capacitor, allowing the quiescent current of the buffer to be reduced and the settling time to be improved. One preferred use of the present invention is to drive the data storage elements of a non-volatile memory.Type: ApplicationFiled: January 4, 2007Publication date: May 10, 2007Inventor: Shahzad Khalid
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Patent number: 7215574Abstract: When programming a contiguous page of memory storage units, every time a memory storage unit has reached its targeted state and is program-inhibited or locked out from further programming, it creates a perturbation on an adjacent memory storage unit still under programming. The present invention provides as part of a programming circuit and method in which an offset to the perturbation is added to the adjacent memory storage unit still under programming. The offset is added as voltage offset to a bit line of a storage unit under programming. The voltage offset is a predetermined function of whether none or one or both of its neighbors are in a mode that creates perturbation, such as in a program inhibit mode. In this way, an error inherent in programming in parallel high-density memory storage units is eliminated or minimized.Type: GrantFiled: October 13, 2005Date of Patent: May 8, 2007Assignee: Sandisk CorporationInventors: Shahzad Khalid, Yan Li, Raul-Adrian Cernea, Mehrdad Mofidi
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Patent number: 7167041Abstract: A voltage buffer for capacitive loads isolates the load from the feedback loop. Using a variation of a follower arrangement, a second transistor outside of the feedback loop introduced. The current to the load is supplied through the second transistor, which is connected to have the same control gate level as the transistor in the feedback loop and provide an output voltage based on the reference input voltage. The output voltage is dependent upon the input voltage, but the load is removed from the feedback loop. By removing the load from the feedback loop, the loop is stabilized with only a very small or no compensating capacitor, allowing the quiescent current of the buffer to be reduced and the settling time to be improved. One preferred use of the present invention is to drive the data storage elements of a non-volatile memory.Type: GrantFiled: September 12, 2005Date of Patent: January 23, 2007Assignee: SanDisk CorporationInventor: Shahzad Khalid
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Publication number: 20060227614Abstract: When programming a contiguous page of memory storage units, every time a memory storage unit has reached its targeted state and is program-inhibited or locked out from further programming, it creates a perturbation on an adjacent memory storage unit still under programming. The present invention provides as part of a programming circuit and method in which an offset to the perturbation is added to the adjacent memory storage unit still under programming. The offset is added by a controlled coupling between the adjacent bit lines of the program-inhibited memory storage unit and the still under programming memory storage unit. In this way, an error inherent in programming in parallel high-density memory storage units is eliminated or minimized.Type: ApplicationFiled: June 2, 2006Publication date: October 12, 2006Inventors: Raul-Adrian Cernea, Yan Li, Mehrdad Mofidi, Shahzad Khalid
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Publication number: 20060140007Abstract: A non-volatile memory device capable of reading and writing a large number of memory cells with multiple read/write circuits in parallel has an architecture that reduces redundancy in the multiple read/write circuits to a minimum. The multiple read/write circuits are organized into a bank of similar stacks of components. Redundant circuits such as a processor for processing data among stacks each associated with multiple memory cells are factored out. The processor is implemented with an input logic, a latch and an output logic. The input logic can transform the data received from either the sense amplifier or the data latches. The output logic further processes the transformed data to send to either the sense amplifier or the data latches or to a controller. This provides an infrastructure with maximum versatility and a minimum of components for sophisticated processing of the data sensed and the data to be input or output.Type: ApplicationFiled: December 29, 2004Publication date: June 29, 2006Inventors: Raul-Adrian Cernea, Yan Li, Shahzad Khalid, Siu Chan
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Patent number: 7064980Abstract: When programming a contiguous page of memory storage units, every time a memory storage unit has reached its targeted state and is program-inhibited or locked out from further programming, it creates a perturbation on an adjacent memory storage unit still under programming. The present invention provides as part of a programming circuit and method in which an offset to the perturbation is added to the adjacent memory storage unit still under programming. The offset is added by a controlled coupling between the adjacent bit lines of the program-inhibited memory storage unit and the still under programming memory storage unit. In this way, an error inherent in programming in parallel high-density memory storage units is eliminated or minimized.Type: GrantFiled: September 17, 2003Date of Patent: June 20, 2006Assignee: SanDisk CorporationInventors: Raul-Adrian Cernea, Yan Li, Mehrdad Mofidi, Shahzad Khalid
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Patent number: 7002401Abstract: A voltage buffer for capacitive loads isolates the load from the feedback loop. Using a variation of a follower arrangement, a second transistor outside of the feedback loop introduced. The current to the load is supplied through the second transistor, which is connected to have the same control gate level as the transistor in the feedback loop and provide an output voltage based on the reference input voltage. The output voltage is dependent upon the input voltage, but the load is removed from the feedback loop. By removing the load from the feedback loop, the loop is stabilized with only a very small or no compensating capacitor, allowing the quiescent current of the buffer to be reduced and the settling time to be improved. One preferred use of the present invention is to drive the data storage elements of a non-volatile memory.Type: GrantFiled: January 30, 2003Date of Patent: February 21, 2006Assignee: SanDisk CorporationInventor: Shahzad Khalid
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Publication number: 20060034121Abstract: When programming a contiguous page of memory storage units, every time a memory storage unit has reached its targeted state and is program-inhibited or locked out from further programming, it creates a perturbation on an adjacent memory storage unit still under programming. The present invention provides as part of a programming circuit and method in which an offset to the perturbation is added to the adjacent memory storage unit still under programming. The offset is added as voltage offset to a bit line of a storage unit under programming. The voltage offset is a predetermined function of whether none or one or both of its neighbors are in a mode that creates perturbation, such as in a program inhibit mode. In this way, an error inherent in programming in parallel high-density memory storage units is eliminated or minimized.Type: ApplicationFiled: October 13, 2005Publication date: February 16, 2006Inventors: Shahzad Khalid, Yan Li, Raul-Adrian Cernea, Mehrdad Mofidi
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Publication number: 20060007726Abstract: A voltage buffer for capacitive loads isolates the load from the feedback loop. Using a variation of a follower arrangement, a second transistor outside of the feedback loop introduced. The current to the load is supplied through the second transistor, which is connected to have the same control gate level as the transistor in the feedback loop and provide an output voltage based on the reference input voltage. The output voltage is dependent upon the input voltage, but the load is removed from the feedback loop. By removing the load from the feedback loop, the loop is stabilized with only a very small or no compensating capacitor, allowing the quiescent current of the buffer to be reduced and the settling time to be improved. One preferred use of the present invention is to drive the data storage elements of a non-volatile memory.Type: ApplicationFiled: September 12, 2005Publication date: January 12, 2006Inventor: Shahzad Khalid
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Patent number: 6956770Abstract: When programming a contiguous page of memory storage units, every time a memory storage unit has reached its targeted state and is program-inhibited or locked out from further programming, it creates a perturbation on an adjacent memory storage unit still under programming. The present invention provides as part of a programming circuit and method in which an offset to the perturbation is added to the adjacent memory storage unit still under programming. The offset is added as voltage offset to a bit line of a storage unit under programming. The voltage offset is a predetermined function of whether none or one or both of its neighbors are in a mode that creates perturbation, such as in a program inhibit mode. In this way, an error inherent in programming in parallel high-density memory storage units is eliminated or minimized.Type: GrantFiled: September 17, 2003Date of Patent: October 18, 2005Assignee: SanDisk CorporationInventors: Shahzad Khalid, Yan Li, Raul-Adrian Cernea, Mehrdad Mofidi
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Publication number: 20050169051Abstract: The present invention presents several techniques for using writable tracking cells. Multiple tracking cells are provided for each write block of the memory. These cells are re-programmed each time the user cells of the associated write block are written, preferably at the same time, using the same fixed, global reference levels to set the tracking and user cell programmed thresholds. The threshold voltages of the tracking cells are read every time the user cells are read, and these thresholds are used to determine the stored logic levels of the user cells. In one set of embodiments, populations of one or more tracking cells are associated with different logic levels of a multi-state memory. These tracking cell populations may be provided for only a subset of the logic levels. The read points for translating the threshold voltages are derived for all of the logic levels based upon this subset.Type: ApplicationFiled: February 22, 2005Publication date: August 4, 2005Inventors: Shahzad Khalid, Daniel Guterman, Geoffrey Gongwer, Richard Simko, Kevin Conley
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Publication number: 20050057965Abstract: When programming a contiguous page of memory storage units, every time a memory storage unit has reached its targeted state and is program-inhibited or locked out from further programming, it creates a perturbation on an adjacent memory storage unit still under programming. The present invention provides as part of a programming circuit and method in which an offset to the perturbation is added to the adjacent memory storage unit still under programming. The offset is added by a controlled coupling between the adjacent bit lines of the program-inhibited memory storage unit and the still under programming memory storage unit. In this way, an error inherent in programming in parallel high-density memory storage units is eliminated or minimized.Type: ApplicationFiled: September 17, 2003Publication date: March 17, 2005Inventors: Raul-Adrian Cernea, Yan Li, Mehrdad Mofidi, Shahzad Khalid
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Publication number: 20050057967Abstract: When programming a contiguous page of memory storage units, every time a memory storage unit has reached its targeted state and is program-inhibited or locked out from further programming, it creates a perturbation on an adjacent memory storage unit still under programming. The present invention provides as part of a programming circuit and method in which an offset to the perturbation is added to the adjacent memory storage unit still under programming. The offset is added as voltage offset to a bit line of a storage unit under programming. The voltage offset is a predetermined function of whether none or one or both of its neighbors are in a mode that creates perturbation, such as in a program inhibit mode. In this way, an error inherent in programming in parallel high-density memory storage units is eliminated or minimized.Type: ApplicationFiled: September 17, 2003Publication date: March 17, 2005Inventors: Shahzad Khalid, Yan Li, Raul-Adrian Cernea, Mehrdad Mofidi
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Publication number: 20040255090Abstract: Tracking cells are used in a memory system to improve the read process. The tracking cells can provide an indication of the quality of the data and can be used as part of a data recovery operation if there is an error. The tracking cells provide a means to adjust the read parameters to optimum levels in order to reflect the current conditions of the memory system. Additionally, some memory systems that use multi-state memory cells will apply rotation data schemes to minimize wear. The rotation scheme can be encoded in the tracking cells based on the states of multiple tracking cells, which is decoded upon reading.Type: ApplicationFiled: June 13, 2003Publication date: December 16, 2004Inventors: Daniel C. Guterman, Stephen J. Gross, Shahzad Khalid, Geoffrey S. Gongwer
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Publication number: 20040150464Abstract: A voltage buffer for capacitive loads isolates the load from the feedback loop. Using a variation of a follower arrangement, a second transistor outside of the feedback loop introduced. The current to the load is supplied through the second transistor, which is connected to have the same control gate level as the transistor in the feedback loop and provide an output voltage based on the reference input voltage. The output voltage is dependent upon the input voltage, but the load is removed from the feedback loop. By removing the load from the feedback loop, the loop is stabilized with only a very small or no compensating capacitor, allowing the quiescent current of the buffer to be reduced and the settling time to be improved. One preferred use of the present invention is to drive the data storage elements of a non-volatile memory.Type: ApplicationFiled: January 30, 2003Publication date: August 5, 2004Applicant: SanDisk CorporationInventor: Shahzad Khalid