Patents by Inventor Chitra Subramanian
Chitra Subramanian 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: 20160276012Abstract: A spin-torque magnetoresistive memory includes array read circuits and array write circuits coupled to an array of magnetic bits. The array read circuits sample magnetic bits in the array, apply a write current pulse to the magnetic bits to set them to a first logic state, resample the magnetic bits using an additional offset current, and compare the results of sampling and resampling to determine the bit state for each magnetic bit. For each of the magnetic bits in the page having the second logic state, the array write circuits initiate a write-back, wherein the write-back includes applying a second write current pulse having opposite polarity in comparison with the first write current pulse to set the magnetic bit to the second state. A read or write operation may be received after initiation of the write-back where the write-back can be aborted for a portion of the bits in the case of a write operation.Type: ApplicationFiled: May 27, 2016Publication date: September 22, 2016Inventors: Syed M. Alam, Thomas Andre, Matthew R. Croft, Chitra Subramanian, Halbert Lin
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Patent number: 9401195Abstract: Circuitry and a method provide a plurality of timed control and bias voltages to sense amplifiers and write drivers of a spin-torque magnetoresistive random access memory array for improved power supply noise rejection, increased sensing speed with immunity for bank-to-bank noise coupling, and reduced leakage from off word line select devices in an active column.Type: GrantFiled: December 16, 2015Date of Patent: July 26, 2016Assignee: Everspin Technologies, Inc.Inventors: Thomas Andre, Syed M. Alam, Chitra Subramanian
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Patent number: 9378798Abstract: A spin-torque magnetoresistive memory includes array read circuits and array write circuits coupled to an array of magnetic bits. The array read circuits sample magnetic bits in the array, apply a write current pulse to the magnetic bits to set them to a first logic state, resample the magnetic bits, and comparing the results of sampling and resampling to determine the bit state for each magnetic bit. For each of the magnetic bits in the page having the second logic state, the array write circuits initiate a write-back, wherein the write-back includes applying a second write current pulse having opposite polarity in comparison with the first write current pulse to set the magnetic bit to the second state. A read or write operation may be received after initiation of the write-back where the write-back can be aborted for a portion of the bits in the case of a write operation.Type: GrantFiled: December 16, 2015Date of Patent: June 28, 2016Assignee: Everspin Technologies, Inc.Inventors: Syed M. Alam, Thomas Andre, Matthew R. Croft, Chitra Subramanian, Halbert Lin
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Publication number: 20160099040Abstract: Circuitry and a method provide a plurality of timed control and bias voltages to sense amplifiers and write drivers of a spin-torque magnetoresistive random access memory array for improved power supply noise rejection, increased sensing speed with immunity for bank-to-bank noise coupling, and reduced leakage from off word line select devices in an active column.Type: ApplicationFiled: December 16, 2015Publication date: April 7, 2016Inventors: Thomas Andre, Syed M. Alam, Chitra Subramanian
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Publication number: 20160099039Abstract: A spin-torque magnetoresistive memory includes array read circuits and array write circuits coupled to an array of magnetic bits. The array read circuits sample magnetic bits in the array, apply a write current pulse to the magnetic bits to set them to a first logic state, resample the magnetic bits, and comparing the results of sampling and resampling to determine the bit state for each magnetic bit. For each of the magnetic bits in the page having the second logic state, the array write circuits initiate a write-back, wherein the write-back includes applying a second write current pulse having opposite polarity in comparison with the first write current pulse to set the magnetic bit to the second state. A read or write operation may be received after initiation of the write-back where the write-back can be aborted for a portion of the bits in the case of a write operation.Type: ApplicationFiled: December 16, 2015Publication date: April 7, 2016Inventors: Syed M. Alam, Thomas Andre, Matthew R. Croft, Chitra Subramanian, Halbert Lin
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Publication number: 20160093349Abstract: A memory device is configured to identify a set of bit cells to be changed from a first state to a second state. In some examples, the memory device may apply a first voltage to the set of bit cells to change a least a first portion of the set of bit cells to the second state. In some cases, the memory device may also identify a second portion of the bit cells that remained in the first state following the application of the first voltage. In these cases, the memory device may apply a second voltage having a greater magnitude, duration, or both to the second portion of the set of bit cells in order to set the second portion of bit cells to the second state.Type: ApplicationFiled: September 30, 2014Publication date: March 31, 2016Inventors: Thomas Andre, Dimitri Houssameddine, Syed M. Alam, Jon Slaughter, Chitra Subramanian
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Patent number: 9299411Abstract: A method of reading data from a plurality of bits in a spin-torque magnetoresistive memory array includes performing one or more referenced read operations of the bits, and performing a self-referenced read operation, for example, a destructive self-referenced read operation, of any of the bits not successfully read by the referenced read operation. The referenced read operations can be initiated at the same time or prior to that of the destructive self-referenced read operation.Type: GrantFiled: October 8, 2015Date of Patent: March 29, 2016Assignee: Everspin Technologies, Inc.Inventors: Syed M. Alam, Thomas Andre, Chitra Subramanian
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Publication number: 20160027489Abstract: A method of reading data from a plurality of bits in a spin-torque magnetoresistive memory array includes performing one or more referenced read operations of the bits, and performing a self-referenced read operation, for example, a destructive self-referenced read operation, of any of the bits not successfully read by the referenced read operation. The referenced read operations can be initiated at the same time or prior to that of the destructive self-referenced read operation.Type: ApplicationFiled: October 8, 2015Publication date: January 28, 2016Inventors: Syed M. Alam, Thomas Andre, Chitra Subramanian
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Patent number: 9245611Abstract: A method includes sampling magnetic bits, applying a write current pulse to the magnetic bits to set them to a first logic state, resampling the magnetic bits, and comparing the results of sampling and resampling to determine the bit state for each magnetic bit. A read or write operation may be received after initiation of writing back magnetic bits having the second state, where the write-back can be aborted for a portion of the bits in the case of a write operation. The write-back may be performed such that different portions of the magnetic bits are written back at different times, thereby staggering the write-back current pulses in time. An offset current may also be used during resampling.Type: GrantFiled: May 4, 2015Date of Patent: January 26, 2016Assignee: Everspin Technologies, Inc.Inventors: Syed M. Alam, Thomas Andre, Matthew R. Croft, Chitra Subramanian, Halbert Lin
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Patent number: 9218865Abstract: Circuitry and a method provide a plurality of timed control and bias voltages to sense amplifiers and write drivers of a spin-torque magnetoresistive random access memory array for improved power supply noise rejection, increased sensing speed with immunity for bank-to-bank noise coupling, and reduced leakage from off word line select devices in an active column.Type: GrantFiled: September 23, 2014Date of Patent: December 22, 2015Assignee: Everspin Technologies, IncInventors: Thomas Andre, Syed M. Alam, Chitra Subramanian
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Patent number: 9183911Abstract: A method of reading data from a plurality of bits in a spin-torque magnetoresistive memory array includes performing one or more referenced read operations of the bits, and performing a self-referenced read operation, for example, a destructive self-referenced read operation, of any of the bits not successfully read by the referenced read operation. The referenced read operations can be initiated at the same time or prior to that of the destructive self-referenced read operation.Type: GrantFiled: October 2, 2012Date of Patent: November 10, 2015Assignee: Everspin Technologies, Inc.Inventors: Syed M. Alam, Thomas Andre, Chitra Subramanian
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Patent number: 9121957Abstract: Radiation flux can be adjusted “on the fly” as an object (204) is being scanned in a security examination apparatus. Adjustments are made to the radiation flux based upon radiation incident on a first radiation detector (226) in an upstream portion (233) of an examination region. The object under examination is thus exposed to different radiation flux in coordination with a downstream motion (235) of the object relative to a second radiation detector (228). The radiation flux is adjusted so that a sufficient number of x-rays (that traverse the object) are incident on the second radiation detector. Images of the object can then be generated based upon data from the second radiation detector, where these images are thus of a desired/higher quality.Type: GrantFiled: October 14, 2008Date of Patent: September 1, 2015Assignee: Analogic CorporationInventors: Ram C. Naidu, Chitra Subramanian, Sergey B. Simanovsky, Zhengrong Ying, Dong-Yueh Liang, Douglas Q. Abraham
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Publication number: 20150243337Abstract: A method includes sampling magnetic bits, applying a write current pulse to the magnetic bits to set them to a first logic state, resampling the magnetic bits, and comparing the results of sampling and resampling to determine the bit state for each magnetic bit. A read or write operation may be received after initiation of writing back magnetic bits having the second state, where the write-back can be aborted for a portion of the bits in the case of a write operation. The write-back may be performed such that different portions of the magnetic bits are written back at different times, thereby staggering the write-back current pulses in time. An offset current may also be used during resampling.Type: ApplicationFiled: May 4, 2015Publication date: August 27, 2015Inventors: Syed M. Alam, Thomas Andre, Matthew R. Croft, Chitra Subramanian, Halbert Lin
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Patent number: 9047969Abstract: A method includes destructively reading bits of a spin torque magnetic random access memory and immediately writing back the original or inverted values. A detection of the majority state of the write back bits and a conditional inversion of write back bits are employed to reduce the number of write back pulses. A subsequent write command received within a specified time or before an original write operation is commenced will cause a portion of the write back pulses or the original write operation pulses to abort. Write pulses during subsequent write operations will follow the conditional inversion determined for the write back bits during destructive read.Type: GrantFiled: August 5, 2014Date of Patent: June 2, 2015Assignee: Everspin Technologies, Inc.Inventors: Syed M. Alam, Thomas Andre, Matthew R. Croft, Chitra Subramanian, Halbert Lin
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Patent number: 8958524Abstract: Among other things, one or more techniques and/or systems for correcting projection data representative of an object under examination to account for drift in a radiation system are provided. System drift is measured by performing a drift calibration on the radiation system. During the drift calibration, a temperature of the radiation system is measured and one or more calibration tables, such as an air table and/or offset table, are corrected based upon the measured temperature to derive a theoretical projection (e.g., indicative of measurements that are expected to be acquired from the radiation system during the drift calibration). The theoretical projection is compared to an actual projection acquired during the drift calibration to measure a degree of drift. Based upon the measured degree of drift, one or more correction factors are determined to correct and/or otherwise adjust for system drift in a projection respective of the object.Type: GrantFiled: January 31, 2013Date of Patent: February 17, 2015Assignee: Analogic CorporationInventors: Chitra Subramanian, Ram Naidu
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Publication number: 20150029786Abstract: Circuitry and a method provide a plurality of timed control and bias voltages to sense amplifiers and write drivers of a spin-torque magnetoresistive random access memory array for improved power supply noise rejection, increased sensing speed with immunity for bank-to-bank noise coupling, and reduced leakage from off word line select devices in an active column.Type: ApplicationFiled: September 23, 2014Publication date: January 29, 2015Inventors: Thomas Andre, Syed M. Alam, Chitra Subramanian
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Publication number: 20150006997Abstract: A method includes destructively reading bits of a spin torque magnetic random access memory and immediately writing back the original or inverted values. A detection of the majority state of the write back bits and a conditional inversion of write back bits are employed to reduce the number of write back pulses. A subsequent write command received within a specified time or before an original write operation is commenced will cause a portion of the write back pulses or the original write operation pulses to abort. Write pulses during subsequent write operations will follow the conditional inversion determined for the write back bits during destructive read.Type: ApplicationFiled: August 5, 2014Publication date: January 1, 2015Applicant: EVERSPIN TECHNOLOGIES, INC.Inventors: Syed M. Alam, Thomas Andre, Matthew R. Croft, Chitra Subramanian, Halbert Lin
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Patent number: 8923041Abstract: Circuitry and a method provide a plurality of timed control and bias voltages to sense amplifiers and write drivers of a spin-torque magnetoresistive random access memory array for improved power supply noise rejection, increased sensing speed with immunity for bank-to-bank noise coupling, and reduced leakage from off word line select devices in an active column.Type: GrantFiled: March 15, 2013Date of Patent: December 30, 2014Assignee: Everspin Technologies, Inc.Inventors: Thomas Andre, Syed M. Alam, Chitra Subramanian
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Patent number: 8811071Abstract: A method includes destructively reading bits of a spin torque magnetic random access memory and immediately writing back the original or inverted values. A detection of the majority state of the write back bits and a conditional inversion of write back bits are employed to reduce the number of write back pulses. A subsequent write command received within a specified time or before an original write operation is commenced will cause a portion of the write back pulses or the original write operation pulses to abort. Write pulses during subsequent write operations will follow the conditional inversion determined for the write back bits during destructive read.Type: GrantFiled: January 31, 2012Date of Patent: August 19, 2014Assignee: EverSpin Technologies, Inc.Inventors: Syed M. Alam, Thomas Andre, Matthew R. Croft, Chitra Subramanian, Halbert Lin
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Publication number: 20140211910Abstract: Among other things, one or more techniques and/or systems for correcting projection data representative of an object under examination to account for drift in a radiation system are provided. System drift is measured by performing a drift calibration on the radiation system. During the drift calibration, a temperature of the radiation system is measured and one or more calibration tables, such as an air table and/or offset table, are corrected based upon the measured temperature to derive a theoretical projection (e.g., indicative of measurements that are expected to be acquired from the radiation system during the drift calibration). The theoretical projection is compared to an actual projection acquired during the drift calibration to measure a degree of drift. Based upon the measured degree of drift, one or more correction factors are determined to correct and/or otherwise adjust for system drift in a projection respective of the object.Type: ApplicationFiled: January 31, 2013Publication date: July 31, 2014Applicant: Analogic CorporationInventors: Chitra Subramanian, Ram Naidu