Patents by Inventor Biswajit Ray
Biswajit Ray 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: 11967229Abstract: A traffic monitoring system has a controller and sensors placed in or on roads such that vehicles pass over or near the sensors, thereby casting shadows on the sensors as they pass. The sensors may be configured to detect the shadows, and a controller may be configured to determine any of a variety of information about the passing vehicles based on the detected shadows. For example, the controller may count the number of vehicles that pass, determine a speed of each passing vehicle, and determine a length of each passing vehicle. The sensors can be relatively inexpensive so that a relatively large number of sensors can be used to monitor a large area at a relatively low cost. In some embodiments, solar cells are used to power the sensors, and if desired, the solar cells may be used as the sensors for detecting the shadows of the vehicles being monitored.Type: GrantFiled: April 20, 2020Date of Patent: April 23, 2024Assignee: Board of Trustees of the University of Alabama, for and on behalf of the University of Alabama in HuntsvilleInventor: Biswajit Ray
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Patent number: 11853719Abstract: An exemplary random number generation system leverages the r includes at least one solar power panel of a solar power system, at least one sensor and a random number generator. The sensor senses one or more output parameters (e.g., voltage or current) from the solar power system and provides the sensed parameter to the random number generator, which uses the sensed parameter to generate a number that is truly random (i.e., is not deterministic). As an example, the random number generator may receive multiple samples of the measured parameter and generate a random number based on a difference of the multiple samples. If desired, the random number generator may include an algorithm to remove biasing in the random number.Type: GrantFiled: May 3, 2019Date of Patent: December 26, 2023Assignee: Board of Trustees of the University of Alabama, for and on behalf of the University of Alabama in HuntsvilleInventor: Biswajit Ray
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Patent number: 11762563Abstract: A system for improving radiation tolerance of memory senses an amount of radiation exposure and, based on the sensed amount of radiation exposure, determines whether to perform one or more techniques for mitigating the effects of the radiation exposure. As an example, the system may perform a data refresh operation by re-writing data that has been corrupted by radiation, or the system may adjust the reference voltage used to read memory cells. In another example, the system may perform a fault repair operation by re-programming cells that have erroneously transitioned from a program state to an erase state. The system may selectively perform different radiation-mitigation techniques in a tiered approach based on the sensed amount of radiation in order to limit the adverse effects of the more invasive techniques.Type: GrantFiled: August 4, 2021Date of Patent: September 19, 2023Assignee: Board of Trustees of the University of Alabama, for and on behalf of the University of Alabama in HuntsvilleInventors: Biswajit Ray, Aleksandar Milenkovic
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Patent number: 11728000Abstract: A system for testing memory includes logic that is configured to perform various normal memory operations (e.g., erase, read and write operations) on a memory device and to determine operational parameters associated with the memory operations. As an example, the amount of time to perform one or more memory operations may be measured, a number of errors resulting from the memory operations may be determined, or a number of memory cells storing noisy bits may be identified. One or more of the operational parameters may then be analyzed to determine whether they are in a range expected for counterfeit or defective memory. If so, the logic determines that the memory under test is counterfeit or defective and provides a notification about such determination.Type: GrantFiled: May 13, 2021Date of Patent: August 15, 2023Assignee: Board of Trustees of the University of Alabama, for and on behalf of the University of Alabama in HuntsvilleInventors: Biswajit Ray, Umeshwarnath Surendranathan, Preeti Kumari, Md Raquibuzzaman
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Patent number: 11728004Abstract: A system for improving radiation tolerance of memory senses an amount of radiation exposure and, based on the sensed amount of radiation exposure, determines whether to perform one or more techniques for mitigating the effects of the radiation exposure. As an example, the system may perform a data refresh operation by re-writing data that has been corrupted by radiation, or the system may adjust the reference voltage used to read memory cells. In another example, the system may perform a fault repair operation by re-programming cells that have erroneously transitioned from a program state to an erase state. The system may selectively perform different radiation-mitigation techniques in a tiered approach based on the sensed amount of radiation in order to limit the adverse effects of the more invasive techniques.Type: GrantFiled: August 4, 2021Date of Patent: August 15, 2023Assignee: Board of Trustees of the University of AlabamaInventors: Biswajit Ray, Aleksandar Milenkovic
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Patent number: 11626169Abstract: A radiation detection system may include a mobile device having a flash memory. The device may monitor various characteristics of the flash memory to determine when damage to the flash memory has occurred from radiation exposure. The device may associate damage to the flash memory with a radiation dose, and determine a level of radiation to which the memory, and thus the device, has been exposed. The device also may determine a length of time and locations where the radiation exposure has occurred. If the device determines that the level of radiation exposure exceeds a threshold associated with a safe level of radiation exposure for a human user, the device may generate an alert to the user.Type: GrantFiled: December 23, 2021Date of Patent: April 11, 2023Assignee: Board of Trustees of the University of Alabama, for and on behalf of The University of Alabama in HuntsvilleInventor: Biswajit Ray
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Patent number: 11620108Abstract: A random number generation system may generate one or more random numbers based on the repeated programming of a memory, such as a flash memory. As an example, a control system may repeatedly store a sequence to a block of flash memory to force a plurality of cells into a random state such that, at any given instant, the values in the cells may be random. The control system may identify which of the cells contain random values and then generate based on the identified values a number that is truly random.Type: GrantFiled: May 17, 2019Date of Patent: April 4, 2023Assignee: Board of Trustees of the University of Alabama for and on behalf of the University of Alabama in HuntsvilleInventors: Biswajit Ray, Aleksander Milenkovic
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Patent number: 11600329Abstract: A system performs analog memory sanitization by forcing voltage levels in memory cells to substantially the same voltage level so that they are indistinguishable regardless of the data that has been previously stored in the cells. In some embodiments, a special programming operation for sanitizing a plurality of memory cells forces the charge in the cells to approximately the same voltage level by increasing the voltage level of all cells regardless of the data currently stored in the cells. As an example, each cell may be programmed to a logical high bit value (e.g., a “0”) by increasing the charge in each cell to a voltage level that is greater than the voltage level for writing the same logical bit value in a normal programming operation. Thus, after the programming operation is performed, the voltage levels of cells storing one logical bit value (e.g., a “0”) prior to the programming operation may be indistinguishable from voltage levels of cells storing a different logical bit value (e.g.Type: GrantFiled: March 19, 2021Date of Patent: March 7, 2023Assignee: Board of Trustees of the University of Alabama, for and on behalf of the University of Alabama in HuntsvilleInventor: Biswajit Ray
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Patent number: 11238943Abstract: A radiation detection system may include a mobile device having a flash memory. The device may monitor various characteristics of the flash memory to determine when damage to the flash memory has occurred from radiation exposure. The device may associate damage to the flash memory with a radiation dose, and determine a level of radiation to which the memory, and thus the device, has been exposed. The device also may determine a length of time and locations where the radiation exposure has occurred. If the device determines that the level of radiation exposure exceeds a threshold associated with a safe level of radiation exposure for a human user, the device may generate an alert to the user.Type: GrantFiled: December 10, 2020Date of Patent: February 1, 2022Assignee: Board of Trustees of the University of Alabama, for and on behalf of the University of Alabama in HuntsvilleInventor: Biswajit Ray
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Patent number: 11177003Abstract: A memory system performs analog sanitization of memory using a partial programming operation to overwrite existing data taking into account the relative voltage levels in the memory cells. By taking into account the relative voltage levels, the timing of a partial programming operation can be controlled to provide matched voltage levels in the memory cells so that conventional computer forensic techniques for data recovery are ineffective.Type: GrantFiled: March 4, 2020Date of Patent: November 16, 2021Assignee: Board of Trustees of the University of Alabama, for and on behalf of the University of Alabama in HuntsvilleInventor: Biswajit Ray
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Patent number: 11164642Abstract: A method for radiation hardening flash memory performs accelerated aging on the flash memory by program-erase (PE) cycling the flash memory. Such accelerated aging induces trap states in the tunnel oxide layer of the flash memory, which results in improved ionizing radiation tolerance. The number of cycles used to harden a given memory cell is optimally determined in order to limit effects of the radiation hardening on the reliability of the cell.Type: GrantFiled: February 11, 2019Date of Patent: November 2, 2021Assignee: Board of Trustees of the University of Alabama, For and on behalf of the University of Alabama in HuntsvilleInventors: Biswajit Ray, Preeti Kumari
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Patent number: 11114179Abstract: A system for testing memory includes logic that is configured to perform various normal memory operations (e.g., erase, read and write operations) on a memory device and to determine operational parameters associated with the memory operations. As an example, the amount of time to perform one or more memory operations may be measured, or a number of errors resulting from the memory operations may be counted or otherwise determined. One or more of the operational parameters may then be analyzed to determine whether they are in a range expected for counterfeit memory. If so, the logic determines that the memory under test is counterfeit (e.g., is recycled or counterfeit) and provides a notification about the authenticity of the memory. The logic may also estimate the age of the memory based on the operational parameters.Type: GrantFiled: December 13, 2018Date of Patent: September 7, 2021Assignee: Board of Trustees of the University of Alabama, for and on behalf of the University of Alabama in HuntsvilleInventors: Biswajit Ray, M. Tauhidur Rahman
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Patent number: 11101009Abstract: A memory system is configured to convert multiple programmable memory or a portion thereof to one-time programmable (OTP) memory. The system is configured to repetitively perform memory operations (such as program and erase procedures) on a portion of memory in order to induce accelerated degradation (aging) of select memory cells, thereby permanently changing the select cells, such that a pattern of the cells with degraded performance indicate a data value that has been permanently encoded into the memory.Type: GrantFiled: March 4, 2020Date of Patent: August 24, 2021Assignee: Board of Trustees of the University of Alabama, for and on behalf of the University of Alabama in HuntsvilleInventor: Biswajit Ray
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Patent number: 10978145Abstract: Apparatuses and techniques are provided for programming memory cells while reducing widening of a threshold voltage distribution due to changes in the temperature between the time of programming and the time of a subsequent read operation. One technique is based on a correlation between program speed and temperature coefficient (Tco). A different verify test is used for different memory cells which have a common assigned data state according to the program loop number and the temperature. Another technique is based on sensing the memory cells to measure their subthreshold slope and classifying the memory cells into groups. The sensing can occur as a separate operation before programming or as part of the programming of user data. The subsequent programming of the memory cells involves adjusting the verify test of each memory cell based on its group and the temperature.Type: GrantFiled: August 14, 2019Date of Patent: April 13, 2021Assignee: SanDisk Technologies LLCInventors: Biswajit Ray, Peter Rabkin, Mohan Dunga, Gerrit Jan Hemink, Changyuan Chen
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Publication number: 20210050054Abstract: Apparatuses and techniques are provided for programming memory cells while reducing widening of a threshold voltage distribution due to changes in the temperature between the time of programming and the time of a subsequent read operation. One technique is based on a correlation between program speed and temperature coefficient (Tco). A different verify test is used for different memory cells which have a common assigned data state according to the program loop number and the temperature. Another technique is based on sensing the memory cells to measure their subthreshold slope and classifying the memory cells into groups. The sensing can occur as a separate operation before programming or as part of the programming of user data. The subsequent programming of the memory cells involves adjusting the verify test of each memory cell based on its group and the temperature.Type: ApplicationFiled: August 14, 2019Publication date: February 18, 2021Applicant: SanDisk Technologies LLCInventors: Biswajit Ray, Peter Rabkin, Mohan Dunga, Gerrit Jan Hemink, Changyuan Chen
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Patent number: 10878922Abstract: A radiation detection system may include a mobile device having a flash memory. The device may monitor various characteristics of the flash memory to determine when damage to the flash memory has occurred from radiation exposure. The device may associate damage to the flash memory with a radiation dose, and determine a level of radiation to which the memory, and thus the device, has been exposed. The device also may determine a length of time and locations where the radiation exposure has occurred. If the device determines that the level of radiation exposure exceeds a threshold associated with a safe level of radiation exposure for a human user, the device may generate an alert to the user.Type: GrantFiled: May 17, 2019Date of Patent: December 29, 2020Assignee: Board of Trustees of the University of Alabama, for and on behalf of the University of Alabama in HuntsvilleInventor: Biswajit Ray
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Patent number: 10818366Abstract: A storage device with a charge trapping (CT) based memory may include improved data retention performance. Data retention problems, such as charge loss in CT memory may increase for a particular programmed state when a neighboring state is at erased state. Modifying the erase state with post write erase conditioning (PWEC) by pushing up deeply erased states can reduce the lateral charge movement and improve high temperature data retention. In particular, the erase state may be reprogrammed such that the erase distribution is tighter with a higher voltage.Type: GrantFiled: January 15, 2020Date of Patent: October 27, 2020Assignee: Western Digital Technologies, Inc.Inventors: Mohan Vamsi Dunga, Changyuan Chen, Biswajit Ray
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Publication number: 20200152281Abstract: A storage device with a charge trapping (CT) based memory may include improved data retention performance. Data retention problems, such as charge loss in CT memory may increase for a particular programmed state when a neighboring state is at erased state. Modifying the erase state with post write erase conditioning (PWEC) by pushing up deeply erased states can reduce the lateral charge movement and improve high temperature data retention. In particular, the erase state may be reprogrammed such that the erase distribution is tighter with a higher voltage.Type: ApplicationFiled: January 15, 2020Publication date: May 14, 2020Inventors: Mohan Vamsi DUNGA, Changyuan CHEN, Biswajit RAY
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Patent number: 10553294Abstract: A storage device with a charge trapping (CT) based memory may include improved data retention performance. Data retention problems, such as charge loss in CT memory may increase for a particular programmed state when a neighboring state is at erased state. Modifying the erase state with post write erase conditioning (PWEC) by pushing up deeply erased states can reduce the lateral charge movement and improve high temperature data retention. In particular, the erase state may be reprogrammed such that the erase distribution is tighter with a higher voltage.Type: GrantFiled: January 25, 2019Date of Patent: February 4, 2020Assignee: Western Digital Technologies, Inc.Inventors: Mohan Vamsi Dunga, Changyuan Chen, Biswajit Ray
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Patent number: 10535411Abstract: Systems and methods for string-based erase verify to create partial good blocks are disclosed. A block in non-volatile flash memory may include multiple strings. In practice, one string may be slower to erase than other strings. In analyzing the strings, the memory device may iteratively analyze the strings to verify as erased. As one example, the iterations are modified by changing which strings are erased in the subsequent iterations (e.g., only the strings that fail the erase verify). As another example, a predetermined number of iterations are performed after a majority of the strings are verified as erased. In this way, the strings verified as erased need not undergo more deep erasing, which may damage the strings. Further, if fewer than all of the strings are verified as erased, the memory device may designate the block as a partially good block.Type: GrantFiled: May 26, 2017Date of Patent: January 14, 2020Assignee: Western Digital Technologies, Inc.Inventors: Mohan Dunga, Anubhav Khandelwal, Changyuan Chen, Biswajit Ray