Qualcomm Incorporated

Marvell Asia Pte., Ltd.

Michael ThaiThanh Phan

Manish Garg

Chiaming Chai

Jeffrey Herbert Fischer

David Paul Hoff

James Norris Dieffenderfer

Thomas Philip Speier

Jeffrey Todd Bridges

Kevin Neal Magill

Quan Van Nguyen

Rajesh Kumar

Jason Philip Martzloff

Rahul Krishnakumar Nadkarni

Harish Shankar

Clint Wayne Mumford

Manju Rathna Varma

Kshitiz Saxena

Viren Ramesh Patel

Paul Steinmetz

A memory device provides for a multiple-port read operation, and includes an array of bitcells and a control circuit. Each bitcell of the array includes a write wordline port and a first read wordline port. The control circuit provides an output to the write wordline port, and includes as inputs a write select port and a second read wordline port. In a write mode, the control circuit couples the write select port to the output and disables the second read port. In a read mode, the control circuit couples the second read wordline port to the output and disables the write select port, thereby enabling a multiple-port read operation to the array of bitcells.

Memory device implementing multiple port read

A memory system includes a sense amplifier electrically coupled to a first bitline and a second bitline associated with a column of a memory array, a bl transistor electrically coupled to the first bitline, wherein the bl transistor is configured to receive as input a first electrical signal from the first bitline, and a blb transistor electrically coupled to the second bitline, wherein the blb transistor is configured to receive as input a second electrical signal from the second bitline, wherein an output of the bl transistor and an output of the blb transistor are electrically coupled together as a common output, and wherein the sense amplifier is configured to receive as an input the common output of the bl transistor and the blb transistor.

Bitline-driven sense amplifier clocking scheme

Providing efficient handling of memory array failures in processor-based systems is disclosed. In this regard, in one aspect, a memory controller of a processor-based device is configured to detect a defect within a memory element of a plurality of memory elements of a memory array. In response, a disable register of one or more disable registers is set to correspond to the memory element to indicate that the memory element is disabled. The memory controller receives a memory access request to a memory address corresponding to the memory element, and determines, based on one or more disable registers, whether the memory element is disabled. If so, the memory controller disallows the memory access request. Some aspects may provide that the memory controller, in response to detecting the defect, provides a failure indication to an executing process, and subsequently receives, from the executing process, a request to set the disable register.

Providing efficient handling of memory array failures in processor-based systems

Cache memory clock generation circuits for reducing power consumption and read errors in cache memory are provided. In one aspect, a cache memory clock generation circuit employs detector circuit configured to receive a way address and generate a one way hit signal indicating if cache read request results in a single way hit. Clock and enable circuit is configured to generate a cache clock signal in response to a system clock signal and a cache enable signal, and generate a cache read enable signal in response to the cache clock signal and a read enable signal. Gating circuit is configured to generate a read clock signal in response to one way hit signal, cache clock signal, and cache read enable signal. Sense amplifier clock generation circuit is configured to generate sense amplifier clock signal in response to the read clock signal having a defined pulse width.

Cache memory clock generation circuits for reducing power consumption and read errors in cache memory

Systems and method for reducing leakage currents and power consumption in a memory array comprising memory cells, such as 8T SRAM cells. The memory array includes logic for dynamically placing a group of memory cells in the memory array in a reduced power state during sleep mode or inactive states of the group of memory cells, such that leakage parts are effectively eliminated. The memory array further includes logic for dynamically enabling a selected group of the memory cells during read or write access operations on the selected memory cells, wherein corresponding read or write bitlines are precharged before and after the respective rear or write operations.

Method and apparatus of reducing leakage power in multiple port SRAM memory cell

Systems and methods for detecting and improving writeability of a static random access memory (SRAM) cell. A bias voltage value corresponding to an operating condition, such as, a process, a voltage, or a temperature operation condition that indicates a cell write failure condition of an external SRAM array comprising the SRAM cell is generated. This bias voltage value is applied to word lines of SRAM cells in a model SRAM array. A first delay for a trigger signal rippled through the model SRAM array is detected and compared to a reference delay. A write assist indication is generated if the first delay is greater than or equal to the reference delay. Based on the write assist indication, a write assist is provided to the SRAM cell.

SRAM cell writability

Systems and methods for selectively boosting word-line (WL) voltage in a memory cell array. The method relies several embodiments to minimize energy costs associated with WL boost scheme. One embodiment generates a transient voltage boost rather than supply a DC voltage boost. The transient boost generation may be controlled on a cycle basis and can be disabled when the array is not accessed. Another embodiment allows the system to generate the transient voltage boost locally, near a WL driver and only during the cycles when it is needed. Localized boost voltage generation reduces the load capacitance that needs to be boosted to higher voltage. Another embodiment efficiently distributes the transient boost to the WL drivers.

Apparatus for selective word-line boost on a memory cell

Embodiments of the invention are directed to systems and methods for adaptively boosting the supply voltage to an SRAM (Static Random Access Memory) in response to process-voltage-temperature variations when needed. Embodiments include a critical path that simulates a typical memory cell and read-out circuit in the SRAM. Applying a trigger signal to a word-line input port of the critical path, and comparing the output of the critical path to a reference-latch signal, provides an indication of when to boost the supply voltage to the read-out circuits of the SRAM.

Adaptive read wordline voltage boosting apparatus and method for multi-port SRAM

A memory cell includes a storage element, a write circuit coupled to the storage element and a read circuit coupled to the storage element. At least a portion of the storage element and at least a portion of the write circuit are fabricated using a thicker functional gate oxide and at least a portion of the read circuit is fabricated using a thinner functional gate oxide.

Low leakage high performance static random access memory cell using dual-technology transistors

A content addressable memory (CAM) is disclosed. The CAM has first and second CAM cells in which each adjacent CAM cell is rotated 180&#xb0; relative to its neighbor, which provides a compact physical arrangement having overall matched CAM array cell and RAM array cell row heights. Further, an interleaved set scheme can be applied to the CAM cells to provide reduced routing of compare signals and reduced parasitic capacitance.

Content addressable memory

The search key and key fields of a CAM in a cache are encoded with a Hamming distance of at least two to increase the speed of the CAM by ensuring each mismatching match line is discharged by at least two transistors in parallel. Where the cache is physically tagged, the search key is a physical address. The page address portion of the physical address is encoded prior to being stored in a TLB. The page offset bits are encoded in parallel with the TLB access, and concatenated with the encoded TLB entry. If a page address addresses a large memory page size, a plurality of corresponding sub-page addresses may be generated, each addressing a smaller page size. These sub-page addresses may be encoded and stored in a micro TLB. The encoded key and key field are tolerant of single-bit soft errors.

High speed CAM lookup using stored encoded key

Power consumption in a multi-level hierarchical Content Addressable Memory (CAM) circuit is reduced without adversely impacting performance. According to one embodiment of a multi-level hierarchical CAM circuit, the CAM circuit includes a plurality of lower-level match lines, a plurality of higher-level match lines and match line restoration circuitry. The lower-level match lines are configured to be restored to a pre-evaluation state during a pre-evaluation period. The higher-level match lines are configured to capture an evaluation state of respective groups of one or more of the lower-level match lines during an evaluation period and to be restored to a pre-evaluation state during the pre-evaluation period. The match line restoration circuitry is configured to prevent at least one of the lower-level match lines from being restored to the pre-evaluation state responsive to corresponding enable information, e.g., one or more bits indicating whether match line search results are to be utilized.

Method and apparatus for reducing power consumption in a content addressable memory

Content Addressable Memory (CAM) search operations are aborted in response to a search abort signal, thus preserving previous CAM search results. In one embodiment, a CAM search operation is aborted by activating a local CAM match line in response to a search field provided to a CAM and preventing activation of a global CAM match line associated with the local CAM match line in response to a search abort signal. By preventing activation of global CAM match lines, monotonic storage devices included in a holding register that captures CAM search results are prevented from overwriting previously stored CAM search results.

Method and apparatus for aborting content addressable memory search operations

A CAM bank is functionally divided into two or more sub-banks, without replicating CAM driver circuits, by disabling all match line discharge circuits in the bank, and selectively enabling the discharge circuits in entries comprising sub-banks. At least one selectively actuated switching circuit is interposed between the virtual ground node of each discharging comparator in the discharge circuit of a sub-bank and circuit ground. When the switching circuit is in a non-conductive state, the virtual ground node is maintained at a voltage level sufficiently above circuit ground to preclude discharging a connected match line within the CAM access time. When the switching circuit is placed in a conductive state, the virtual ground node is pulled to circuit ground and the connected match line may be discharged by a miscompare. Control signals, which may be decoded from address bits, are distributed to the switching circuits to define the CAM sub-banks.

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Cary, NC, United States of America

Michael ThaiThanh Phan