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公开(公告)号：US20210035640A1
公开(公告)日：2021-02-04
申请号：US16526455
申请日：2019-07-30
发明人： CAN LI , CATHERINE GRAVES , JOHN PAUL STRACHAN
IPC分类号： G11C15/04
摘要： A content addressable memory (CAM) structure is provided. The CAM comprises a plurality of CAM cells communicatively coupled to processing circuitry. A plurality of threshold switching (TS) memristors are included, each configured to connect to a one of the plurality of CAM cells, with the first end connected to the CAM cell and the second connected to a match line. A discharge transistor is included and configured to discharge any charge on the match line in response to the CAM receiving a command to perform a search.
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公开(公告)号：US20230137079A1
公开(公告)日：2023-05-04
申请号：US17514847
申请日：2021-10-29
摘要： Embodiments of the disclosure provide a system, method, or computer readable medium for programming a target analog voltage range of an analog content addressable memory (aCAM) row. The method may comprise calculating a threshold current sufficient to switch a sense amplifier (SA) on and discharge a match line (ML) connected to a cell of the aCAM; and based on calculating the threshold current, programming a match threshold value by setting a memristor conductance in association with the target analog voltage range applied to a data line (DL) input. The target analog voltage range may comprise a target analog voltage range vector.
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公开(公告)号：US20240363163A1
公开(公告)日：2024-10-31
申请号：US18308990
申请日：2023-04-28
发明人： RON M. ROTH , LUCA BUONANNO , GIACOMO PEDRETTI , CATHERINE GRAVES
CPC分类号： G11C15/046 , G11C13/0069
摘要： Systems and methods are provided for implementing a low power and area ternary content addressable memory (TCAM). An example of a TCAM comprises a match line, and a plurality of TCAM cells connected along the match line. Each TCAM cell stores a state of a threshold value. The TCAM cells are configured to pull down a signal over the match line in response to inequality between an input search and the threshold value. The plurality of TCAM cells comprises a number of TCAM cells that is less than the threshold value. The input values can be encoded according to a first encoding scheme and the threshold value can be encoded according to one of a second and a third encoding scheme based on an inequality check mapped to the plurality of TCAM cells.
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公开(公告)号：US20240111490A1
公开(公告)日：2024-04-04
申请号：US17953595
申请日：2022-09-27
发明人： CATHERINE GRAVES , GIACOMO PEDRETTI
CPC分类号： G06F7/5443 , G06F17/16 , G11C15/04
摘要： Systems and methods are provided for employing a current input analog content addressable memory (CI-aCAM). The CI-aCAM is particularly structured as aCAM that allows the analog signal that is input into the aCAM cell to be received as current. A larger hardware architecture that combines two core analog compute circuits, namely a dot product engine (DPE) circuit for matrix multiplications and an aCAM circuit for search operations can also be realized using the disclosed CI-aCAM. For instance, a DPE circuit, which output current signals, can be directly connected with the input of a CI-aCAM, which is designed to receive current signals in a manner that eliminates conversion steps and circuits (e.g., analog to digital and current to voltage). By leveraging CI-aCAMs, a combined DPE-aCAM hardware architecture can be a realized as a substantially compact structure.
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5.发明公开公开(公告)号：US20230410903A1
公开(公告)日：2023-12-21
申请号：US17841542
申请日：2022-06-15
CPC分类号： G11C15/046 , H03K19/20
摘要： The disclosure generally provides for a method of solving a K-SAT problem. The method comprises programming one or more clauses of a Boolean expression for a K-SAT problem written in negated disjunctive normal form (DNF) to a ternary-CAM (TCAM) array comprising columns and rows of TCAM cells. The method further includes applying an interpretation comprising one or more binary variables expected to solve the Boolean expression as an input along the columns to the TCAM array, returning a binary value for each clause, randomly selecting one matched match line, determining a selected clause from one or more violated clause, and altering one or more literals within the interpretation using a break count for each variable of the selected clause.
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公开(公告)号：US20210125667A1
公开(公告)日：2021-04-29
申请号：US16667773
申请日：2019-10-29
发明人： AMIT SHARMA , JOHN PAUL STRACHAN , SUHAS KUMAR , CATHERINE GRAVES , MARTIN FOLTIN , CRAIG WARNER
IPC分类号： G11C13/00
摘要： Systems and methods for providing write process optimization for memristors are described. Write process optimization circuitry manipulates the memristor's write operation, allowing the number of cycles in the write process is reduced. Write process optimization circuitry can include write current integration circuitry that measures an integral of a write current over time. The write optimization circuitry can also include shaping circuitry. The shaping circuitry can shape a write pulse, by determining the pulse's termination, width, and slope. The write pulse is shaped depending upon whether the target memristor device exhibits characteristics of “maladroit” cells or “adroit” cells. The pulse shaping circuitry uses the integral and measured write current to terminate the write pulse in a manner that allows the memristor, wherein having maladroit cells and adroit cells, to reach a target state. Thus, utility of memristors is enhanced by realizing an optimized write process with decrease latency and improved efficiency.
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公开(公告)号：US20240029792A1
公开(公告)日：2024-01-25
申请号：US17872882
申请日：2022-07-25
发明人： TOBIAS FREDERIC ZIEGLER , RON M. ROTH , GIACOMO PEDRETTI , LUCA BUONANNO , PEDRO HENRIQUE ROCHA BRUEL , CATHERINE GRAVES
IPC分类号： G11C15/04 , G11C16/12 , G11C16/10 , H03K19/017
CPC分类号： G11C15/04 , G11C16/12 , G11C16/102 , H03K19/01742
摘要： Examples increase precision for aCAMs by converting an input signal (x) received by a circuit into a first analog voltage signal (V(xMSB)) representing the most significant bits of the input signal (x) and a second analog voltage signal (V(xLSB)) representing the least significant bits of the input signal (x). By dividing the input signal (x) bit-wise into the first analog voltage signal (V(xMSB)) and the second analog voltage signal (V(xLSB)), the circuit can utilize aCAM sub-circuits implementing a combination of Boolean operations to search the input signal (x) against 22*M programmable levels, where “M” represents the number of programmable bits for each aCAM sub-circuit. Thus, using similar circuit hardware, example circuits square the number of programmable levels of conventional aCAMs (which generally only have 2M programmable levels). Accordingly, examples provide new aCAMs that can carry out more complex computations than conventional aCAMs of comparable cost, size, and power consumption.
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公开(公告)号：US20230246655A1
公开(公告)日：2023-08-03
申请号：US17580146
申请日：2022-01-20
发明人： JOHN PAUL STRACHAN , CAN LI , CATHERINE GRAVES
CPC分类号： H03M13/1575 , G11C13/004 , G11C13/0069 , G11C27/005 , H03M13/1177 , H03M13/6597
摘要： An analog error correction circuit is disclosed that implements an analog error correction code. The analog circuit includes a crossbar array of memristors or other nonvolatile tunable resistive memory devices. The crossbar array includes a first crossbar array portion programmed with values of a target computation matrix and a second crossbar array portion programmed with values of an encoder matrix for correcting computation errors in the matrix multiplication of an input vector with the computation matrix. The first and second crossbar array portions share the same row lines and are connected to a third crossbar array portion that is programmed with values of a decoder matrix, thereby enabling single-cycle error detection. A computation error is detected based on output of the decoder matrix circuitry and a location of the error is determined via an inverse matrix multiplication operation whereby the decoder matrix output is fed back to the decoder matrix.
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公开(公告)号：US20230197151A1
公开(公告)日：2023-06-22
申请号：US17555260
申请日：2021-12-17
CPC分类号： G11C13/004 , G11C13/0069 , G11C13/0026 , G11C13/0028 , G11C15/04 , G06N7/005
摘要： Systems and methods are provided for employing analog content addressable memory (aCAMs) to achieve low latency complex distribution sampling. For example, an aCAM core circuit can include an aCAM array. Amplitudes of a probability distribution function are mapped to a width of one or more aCAM cells in each row of the aCAM array. The aCAM core circuit can also include a resistive random access memory (RRAM) storing lookup information, such as information used for processing a model. By randomly selecting columns to search of the aCAM array, the mapped probability distribution function is sampled in a manner that has low latency. The aCAM core circuit can accelerate the sampling step in methods relying on sampling from arbitrary probability distributions, such as particle filter techniques. A hardware architecture for an aCAM Particle Filter that utilizes the aCAM core circuit as a central structure is also described.
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公开(公告)号：US20220351794A1
公开(公告)日：2022-11-03
申请号：US17245540
申请日：2021-04-30
发明人： CATHERINE GRAVES , CAN LI , JOHN PAUL STRACHAN
摘要： An analog content addressable memory (aCAM) that enables parallel searching of analog ranges of values and generates analog outputs that quantify matches between input data and stored data is disclosed. The input data can be compared with the stored data, and the input data can be determined to match the stored data based on a value associated with the input data being within a range associated with the stored data. The aCAM can generate an analog output that represents a number of matches and a number of mismatches between the input data and the stored data. Based on the analog output, whether the input data matches the stored data and a degree to which the input data matches the stored data can be determined.
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