Patents by Inventor Rajan Paudel
Rajan Paudel 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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Patent number: 11573731Abstract: A memory controller includes, in one embodiment, a memory interface and a controller circuit. The memory interface is configured to interface with a memory interface configured to interface with a memory having a plurality of memory blocks. Each memory block has a plurality of strings. The controller circuit is configured to perform a string defect leakage check on one of the memory blocks during a first programming operation of the one memory block, determine whether the one memory block has one or more string to string shorts based on the string defect leakage check, and resolve the string to string shorts in response to determining that the one of the memory blocks has the string to string shorts.Type: GrantFiled: July 26, 2022Date of Patent: February 7, 2023Assignee: Western Digital Technologies, Inc.Inventors: Jayavel Pachamuthu, Rajan Paudel, Deepak Bharadwaj
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Publication number: 20220357874Abstract: A memory controller includes, in one embodiment, a memory interface and a controller circuit. The memory interface is configured to interface with a memory interface configured to interface with a memory having a plurality of memory blocks. Each memory block has a plurality of strings. The controller circuit is configured to perform a string defect leakage check on one of the memory blocks during a first programming operation of the one memory block, determine whether the one memory block has one or more string to string shorts based on the string defect leakage check, and resolve the string to string shorts in response to determining that the one of the memory blocks has the string to string shorts.Type: ApplicationFiled: July 26, 2022Publication date: November 10, 2022Inventors: Jayavel Pachamuthu, Rajan Paudel, Deepak Bharadwaj
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Patent number: 11422736Abstract: A memory controller includes, in one embodiment, a memory interface and a controller circuit. The memory interface is configured to interface with a memory interface configured to interface with a memory having a plurality of memory blocks. Each memory block has a plurality of strings. The controller circuit is configured to perform a string defect leakage check on one of the memory blocks during a first programming operation of the one memory block, determine whether the one memory block has one or more string to string shorts based on the string defect leakage check, and resolve the string to string shorts in response to determining that the one of the memory blocks has the string to string shorts.Type: GrantFiled: June 10, 2020Date of Patent: August 23, 2022Assignee: Western Digital Technologies, Inc.Inventors: Jayavel Pachamuthu, Rajan Paudel, Deepak Bharadwaj
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Publication number: 20210389901Abstract: A memory controller includes, in one embodiment, a memory interface and a controller circuit. The memory interface is configured to interface with a memory interface configured to interface with a memory having a plurality of memory blocks. Each memory block has a plurality of strings. The controller circuit is configured to perform a string defect leakage check on one of the memory blocks during a first programming operation of the one memory block, determine whether the one memory block has one or more string to string shorts based on the string defect leakage check, and resolve the string to string shorts in response to determining that the one of the memory blocks has the string to string shorts.Type: ApplicationFiled: June 10, 2020Publication date: December 16, 2021Inventors: Jayavel Pachamuthu, Rajan Paudel, Deepak Bharadwaj
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Patent number: 10242750Abstract: Techniques are presented for testing the high-speed data path between the IO pads and the read/write buffer of a memory circuit without the use of an external test device. In an on-chip process, a data test pattern is transferred at a high data rate between the read/write register and a source for the test pattern, such as register for this purpose or the read/write buffer of another plane. The test data after the high-speed transfer is then checked against its expected, uncorrupted value, such as by transferring it back at a lower speed for comparison or by transferring the test data a second time, but at a lower rate, and comparing the high transfer rate copy with the lower transfer rate copy at the receiving end of the transfers.Type: GrantFiled: May 31, 2017Date of Patent: March 26, 2019Assignee: SanDisk Technologies LLCInventors: Daniel Linnen, Srikar Peesari, Kirubakaran Periyannan, Shantanu Gupta, Avinash Rajagiri, Dongxiang Liao, Jagdish Sabde, Rajan Paudel
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Publication number: 20180350445Abstract: Techniques are presented for testing the high-speed data path between the IO pads and the read/write buffer of a memory circuit without the use of an external test device. In an on-chip process, a data test pattern is transferred at a high data rate between the read/write register and a source for the test pattern, such as register for this purpose or the read/write buffer of another plane. The test data after the high-speed transfer is then checked against its expected, uncorrupted value, such as by transferring it back at a lower speed for comparison or by transferring the test data a second time, but at a lower rate, and comparing the high transfer rate copy with the lower transfer rate copy at the receiving end of the transfers.Type: ApplicationFiled: May 31, 2017Publication date: December 6, 2018Applicant: SANDISK TECHNOLOGIES LLCInventors: Daniel Linnen, Srikar Peesari, Kirubakaran Periyannan, Shantanu Gupta, Avinash Rajagiri, Dongxiang Liao, Jagdish Sabde, Rajan Paudel
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Patent number: 9548129Abstract: Techniques are provided for operating a memory device which detect word line short circuits, such as short circuits between adjacent word lines. In an example implementation, during a programming operation, the number of program loops used to complete programming or reach another programming milestone for WLn are counted. If the number of program loops exceeds a loop count limit, the memory cells of WLn+1 are evaluated to determine whether a short circuit is present. The evaluation involves a read operation which counts erased state memory cells in the upper tail of the Vth distribution of WLn+1. If the count exceeds a bit count limit, it is concluded that a short circuit exits between WLn and WLn+1, and a corrective action is taken. The loop count limit is adjusted lower as the number of program-erase cycles increases.Type: GrantFiled: October 21, 2015Date of Patent: January 17, 2017Assignee: SanDisk Technologies LLCInventors: Rajan Paudel, Jagdish Sabde, Mrinal Kochar, Sagar Magia
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Patent number: 9496040Abstract: A method is provided for programming a memory cell connected to a selected word line in a memory device. The method includes performing one programming pass of a multi-pass programming operation for the memory cell, wherein a first set of program pulses is applied to the selected word line during the one programming pass, determining a number of the program pulses applied to the selected word line during the one programming pass, determining a difference between the determined number of program pulses applied to the selected word line during the one programming pass and a predetermined number of program pulses, adjusting a parameter of a second set of program pulses for the another programming pass based on the determined difference, and performing the another programming pass for the set of memory cells, wherein the second set of program pulses is applied to the selected word line during the another programming pass.Type: GrantFiled: January 22, 2015Date of Patent: November 15, 2016Assignee: SanDisk Technologies LLCInventors: Rajan Paudel, Jagdish Sabde, Sagar Magia
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Patent number: 9449694Abstract: A stress mode for use in testing non-volatile memory arrays for a number of types of defects is described. More specifically, a multi-word line select option for a given block can be used for a group of selected word lines to be set to the a programming or other high voltage, while the unselected word lines of the block are set to a pass voltage to minimize electric field differences in order to avoid disturb. For example, a group of selected word lines could number 4, 8 or 16. The multi-word line option can be applied to one block per plane, so that if there are two memory planes, for example, two such blocks can be selected simultaneously for the multi-word line option for those blocks.Type: GrantFiled: September 4, 2014Date of Patent: September 20, 2016Assignee: SanDisk Technologies LLCInventors: Rajan Paudel, Jagdish Sabde, Sagar Magia, Khanh Nguyen
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Patent number: 9449698Abstract: Techniques are provided for erasing a memory device. In one aspect, different zones of a block can be separately erased and subject to a verify test. Erase parameters can be optimized for each zone, so that endurance is improved. If one zone is found to be too slow to erase, it can be marked as being bad while other zones remain available for use. In another aspect, the zone-based erase occurs after a block based erased when a criterion is met, such as the block-based erase being too slow or failing to complete within an allowable number of program loops. The zone-based erase can occur after the block-based erase in the same erase operation, or in a subsequent, new erase operation.Type: GrantFiled: October 20, 2015Date of Patent: September 20, 2016Assignee: SanDisk Technologies LLCInventors: Rajan Paudel, Jagdish Sabde, Sagar Magia
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Publication number: 20160260495Abstract: Techniques are provided for operating a memory device which detect word line short circuits, such as short circuits between adjacent word lines. In an example implementation, during a programming operation, the number of program loops used to complete programming or reach another programming milestone for WLn are counted. If the number of program loops exceeds a loop count limit, the memory cells of WLn+1 are evaluated to determine whether a short circuit is present. The evaluation involves a read operation which counts erased state memory cells in the upper tail of the Vth distribution of WLn+1. If the count exceeds a bit count limit, it is concluded that a short circuit exits between WLn and WLn+1, and a corrective action is taken. The loop count limit is adjusted lower as the number of program-erase cycles increases.Type: ApplicationFiled: October 21, 2015Publication date: September 8, 2016Applicant: SanDisk Technologies Inc.Inventors: Rajan Paudel, Jagdish Sabde, Mrinal Kochar, Sagar Magia
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Publication number: 20160217857Abstract: A method is provided for programming a memory cell connected to a selected word line in a memory device. The method includes performing one programming pass of a multi-pass programming operation for the memory cell, wherein a first set of program pulses is applied to the selected word line during the one programming pass, determining a number of the program pulses applied to the selected word line during the one programming pass, determining a difference between the determined number of program pulses applied to the selected word line during the one programming pass and a predetermined number of program pulses, adjusting a parameter of a second set of program pulses for the another programming pass based on the determined difference, and performing the another programming pass for the set of memory cells, wherein the second set of program pulses is applied to the selected word line during the another programming pass.Type: ApplicationFiled: January 22, 2015Publication date: July 28, 2016Applicant: SanDisk Technologies Inc.Inventors: Rajan Paudel, Jagdish Sabde, Sagar Magia
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Publication number: 20160071594Abstract: A stress mode for use in testing non-volatile memory arrays for a number of types of defects is described. More specifically, a multi-word line select option for a given block can be used for a group of selected word lines to be set to the a programming or other high voltage, while the unselected word lines of the block are set to a pass voltage to minimize electric field differences in order to avoid disturb. For example, a group of selected word lines could number 4, 8 or 16. The multi-word line option can be applied to one block per plane, so that if there are two memory planes, for example, two such blocks can be selected simultaneously for the multi-word line option for those blocks.Type: ApplicationFiled: September 4, 2014Publication date: March 10, 2016Inventors: Rajan Paudel, Jagdish Sabde, Sagar Magia, Khanh Nguyen