Patents by Inventor Piyush Sagdeo
Piyush Sagdeo 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: 11704190Abstract: A data storage device includes a memory device having a plurality of blocks and a controller coupled to the memory device. The controller is configured to determine that an uncorrectable error correction code (UECC) failure has occurred to a block of the plurality of blocks, enable a UECC anti-strike mechanism, and erase the block. The UECC anti-strike mechanism comprises converting a read failure associated with the block to an erase failure. The controller is further configured to retire the block upon determining that the erase is unsuccessful.Type: GrantFiled: October 21, 2021Date of Patent: July 18, 2023Assignee: Western Digital Technologies, Inc.Inventors: Ramkumar Subramanian, Mahim Gupta, Piyush Sagdeo
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Publication number: 20230130369Abstract: A data storage device includes a memory device having a plurality of blocks and a controller coupled to the memory device. The controller is configured to determine that an uncorrectable error correction code (UECC) failure has occurred to a block of the plurality of blocks, enable a UECC anti-strike mechanism, and erase the block. The UECC anti-strike mechanism comprises converting a read failure associated with the block to an erase failure. The controller is further configured to retire the block upon determining that the erase is unsuccessful.Type: ApplicationFiled: October 21, 2021Publication date: April 27, 2023Inventors: Ramkumar SUBRAMANIAN, Mahim GUPTA, Piyush SAGDEO
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Patent number: 10936415Abstract: An error correction scheme in flash memory. Methods include extending a lifetime of a memory block, including: receiving an indication that an error occurred during a write operation at a first location in a memory block, the first location associated with a faulty page of the memory block; and performing a modified exclusive OR (XOR) scheme on the memory block by: performing a de-XOR operation that generates recovery data of the faulty page; storing the recovery data in a location different from the faulty page of memory; marking the faulty page for exclusion in future de-XOR operations; and performing a parity calculation that generates an updated parity value that includes all pages of the memory block that have been programmed except for the faulty page.Type: GrantFiled: June 28, 2019Date of Patent: March 2, 2021Assignee: Western Digital Technologies, Inc.Inventors: Chris Yip, Piyush Sagdeo, Gautam Dusija, Vidhu Gupta
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Publication number: 20200409787Abstract: An error correction scheme in flash memory. Methods include extending a lifetime of a memory block, including: receiving an indication that an error occurred during a write operation at a first location in a memory block, the first location associated with a faulty page of the memory block; and performing a modified exclusive OR (XOR) scheme on the memory block by: performing a de-XOR operation that generates recovery data of the faulty page; storing the recovery data in a location different from the faulty page of memory; marking the faulty page for exclusion in future de-XOR operations; and performing a parity calculation that generates an updated parity value that includes all pages of the memory block that have been programmed except for the faulty page.Type: ApplicationFiled: June 28, 2019Publication date: December 31, 2020Applicant: Western Digital Technologies, Inc.Inventors: Chris Yip, Piyush Sagdeo, Gautam Dusija, Vidhu Gupta
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Patent number: 10790031Abstract: A data storage system performs operations including receiving a data read command corresponding to a first memory cell; determining whether the first memory cell is in a first read condition; if the first memory cell is in the first read condition: applying a first voltage level to the first memory cell, the first voltage level being a predetermined voltage level corresponding to a read operation for memory cells in the first read condition; and sensing a first level of current, or lack thereof, through the first memory cell during application of the first voltage level to the first memory cell; and if the first memory cell is not in the first read condition: applying a second voltage level to the first memory cell, the second voltage level being a voltage level corresponding to a read operation for memory cells in a read condition other than the first read condition.Type: GrantFiled: June 5, 2019Date of Patent: September 29, 2020Assignee: Western Digital Technologies, Inc.Inventors: Piyush Sagdeo, Chris Yip, Sourabh Sankule, Pitamber Shukla, Anubhav Khandelwal, Mohan Dunga, Niles Yang
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Patent number: 10691372Abstract: Techniques are provided for maintaining threshold voltages of non-data transistors in a memory device. The memory device has a stack comprising alternating horizontal conductive layers and horizontal dielectric layers. A control circuit is configured to test a threshold voltage criterion of non-data transistors in response to a trigger condition being met with respect to an erase of a data memory cells in a first tier of the stack. The control circuit is configured move valid data out of a data memory cells in a second tier of the stack in response to a determination that the threshold voltage criterion is not met. The control circuit is configured to adjust threshold voltages of the non-data transistors after moving the valid data out of the second set of data memory cells such that the threshold voltage criterion is met.Type: GrantFiled: December 7, 2018Date of Patent: June 23, 2020Assignee: Western Digital Technologies, Inc.Inventors: Srinivasan Seetharaman, Piyush Sagdeo, Sourabh Sankule, Chris Yip
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Publication number: 20200183610Abstract: Techniques are provided for maintaining threshold voltages of non-data transistors in a memory device. The memory device has a stack comprising alternating horizontal conductive layers and horizontal dielectric layers. A control circuit is configured to test a threshold voltage criterion of non-data transistors in response to a trigger condition being met with respect to an erase of a data memory cells in a first tier of the stack. The control circuit is configured move valid data out of a data memory cells in a second tier of the stack in response to a determination that the threshold voltage criterion is not met. The control circuit is configured to adjust threshold voltages of the non-data transistors after moving the valid data out of the second set of data memory cells such that the threshold voltage criterion is met.Type: ApplicationFiled: December 7, 2018Publication date: June 11, 2020Applicant: Western Digital Technologies, Inc.Inventors: Srinivasan Seetharaman, Piyush Sagdeo, Sourabh Sankule, Chris Yip
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Patent number: 10235294Abstract: Apparatuses and techniques are described for performing a pre-read operation in preparation for a read operation in a memory device. The pre-read operation transitions the memory cells from a first read condition to a second read condition so that their threshold voltages will be in a desired, predictable range when the read occurs. The pre-read operation can involve maintaining voltages on a selected word line and unselected word lines at specified levels and for a specified duration which is relatively long compared to a duration of the read operation. The word line voltages, in combination with bit line and source line voltages, provide the channels of a NAND string in a conductive state and gradually transitions the memory cells to the second read condition.Type: GrantFiled: April 23, 2018Date of Patent: March 19, 2019Assignee: SanDisk Technologies LLCInventors: Ching-Huang Lu, Swaroop Kaza, Piyush Sagdeo
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Patent number: 9804922Abstract: Systems and methods for partial bad block reuse may be provided. Data may be copied from a block of a first memory to a block of a second memory. A post write read error may be detected in a first portion the data copied to the block of the second memory without detection of a post write read error in a second portion of the data copied to the block of the second memory. The block of the second memory may be determined to be a partial bad block usable for storage in response to detection of the post write read error in the first portion of the data but not in the second portion of the data.Type: GrantFiled: July 21, 2014Date of Patent: October 31, 2017Assignee: SanDisk Technologies LLCInventors: Mrinal Kochar, Abhijeet Bhalerao, Derek McAuley, Piyush Sagdeo
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Publication number: 20160019111Abstract: Systems and methods for partial bad block reuse may be provided. Data may be copied from a block of a first memory to a block of a second memory. A post write read error may be detected in a first portion the data copied to the block of the second memory without detection of a post write read error in a second portion of the data copied to the block of the second memory. The block of the second memory may be determined to be a partial bad block usable for storage in response to detection of the post write read error in the first portion of the data but not in the second portion of the data.Type: ApplicationFiled: July 21, 2014Publication date: January 21, 2016Inventors: Mrinal Kochar, Abhijeet Bhalerao, Derek McAuley, Piyush Sagdeo
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Patent number: 9235470Abstract: A system and method for adaptive enhanced post write reads (EPWRs) is provided. An error rate of a block of solid state memory may be determined. Foldings may be performed more times between two consecutive enhanced post write reads on the block when the determined error rate of the block is a lower value than when the determined error rate is a higher value. The foldings may be performed by folding data into the block of the solid state memory.Type: GrantFiled: October 3, 2013Date of Patent: January 12, 2016Assignee: SanDisk Technologies, Inc.Inventors: Abhijeet Bhalerao, Mrinal Kochar, Piyush Sagdeo
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Patent number: 9195587Abstract: A dynamic read case designation is determined for each of multiple wordline regions, respectively, of each of a number of single-level cell logic groups within a computer memory. The dynamic read case designation for any given one of the multiple wordline regions specifies a wordline read voltage to be used in reading memory cells of each wordline within the given one of the multiple wordline regions. The number of single-level cell logic groups are folded into a multi-level cell block. The folding includes reading the memory cells of each wordline of each of the multiple wordline regions of each of the number of single-level cell logic groups using a wordline read voltage corresponding to the dynamic read case designation, as determined for the wordline region within which the read memory cells reside.Type: GrantFiled: March 7, 2013Date of Patent: November 24, 2015Assignee: SanDisk Technologies Inc.Inventors: Mrinal Kochar, Piyush Sagdeo, Anubhav Khandelwal
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Publication number: 20150100851Abstract: A system and method for adaptive enhanced post write reads (EPWRs) is provided. An error rate of a block of solid state memory may be determined. Foldings may be performed more times between two consecutive enhanced post write reads on the block when the determined error rate of the block is a lower value than when the determined error rate is a higher value. The foldings may be performed by folding data into the block of the solid state memory.Type: ApplicationFiled: October 3, 2013Publication date: April 9, 2015Inventors: Abhijeet Bhalerao, Mrinal Kochar, Piyush Sagdeo
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Publication number: 20140258590Abstract: A dynamic read case designation is determined for each of multiple wordline regions, respectively, of each of a number of single-level cell logic groups within a computer memory. The dynamic read case designation for any given one of the multiple wordline regions specifies a wordline read voltage to be used in reading memory cells of each wordline within the given one of the multiple wordline regions. The number of single-level cell logic groups are folded into a multi-level cell block. The folding includes reading the memory cells of each wordline of each of the multiple wordline regions of each of the number of single-level cell logic groups using a wordline read voltage corresponding to the dynamic read case designation, as determined for the wordline region within which the read memory cells reside.Type: ApplicationFiled: March 7, 2013Publication date: September 11, 2014Inventors: Mrinal Kochar, Piyush Sagdeo, Anubhav Khandelwal