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Michele M. Franceschini

Michele M. Franceschini, White Plains, NY US

Patent application numberDescriptionPublished
20100214811CODING TECHNIQUES FOR IMPROVING THE SENSE MARGIN IN CONTENT ADDRESSABLE MEMORIES - A content addressable memory using encoded data words and search words, and techniques for operating such device. In one embodiment, the data word is transformed into a code word guaranteeing a mismatch of at least two code word bits of different binary values during the memory search operation when the data word does not match a search word. In another embodiment, the search word is transformed into a search code such that the Hamming distance between the code word and the search code is greater than a given threshold when there is a mismatch of at least one bit between the data word and the search word.08-26-2010
20100214829MEMORY PROGRAMMING - Systems, methods, and devices for iteratively writing contents to memory locations are provided. A statistical model is used to determine a sequence of pulses to write desired contents to a memory location. The contents can be expressed as a resistance value in a range to store one or more bits in a memory cell. For phase change memory, an adaptive reset pulse and one or more annealing pulses are selected based on a desired resistance range. Reading the resistance value of the memory cell can provide feedback to determine adjustments in an overall pulse application strategy. The statistical model and a look up table can be used to select and modify pulses. Adaptively updating the statistical model and look up table may reduce the number of looping iterations to shift the resistance value of the memory cell into the desired resistance range.08-26-2010
20100214830MEMORY READING METHOD FOR RESISTANCE DRIFT MITIGATION - Techniques for reading phase change memory that mitigate resistance drift. One contemplated method includes apply a plurality of electrical input signals to the memory cell. The method includes measuring a plurality of electrical output signals from the memory cell resulting from the plurality of electrical input signals. The method includes calculating an invariant component of the plurality of electrical output signals dependent on the configuration of amorphous material in the memory cell. The method also includes determining a memory state of the memory cell based on the invariant component. In one embodiment of the invention, the method further includes mapping the plurality of electrical output signals to a measurements region of a plurality of measurements regions. The measurements regions correspond to memory states of the memory cell.08-26-2010
20100218071WRITING A SPECIAL SYMBOL TO A MEMORY TO INDICATE THE ABSENCE OF A DATA SIGNAL - A method for writing in a memory system that includes receiving an address corresponding to a memory location in a memory, receiving a desired content to be written, encoding the desired content into a symbol, and writing the symbol to the memory location using an iterative write process of at least one write and one read to the memory location. The iterative write process includes determining if the symbol was successfully written to the memory location and exiting the iterative write process in response to the symbol being successfully written to the memory location. The iterative write process also includes determining if a halt condition has been met and exiting the iterative write process if the halt condition has been met. Once the iterative write process has been exited, the memory location may be identified as a candidate for being written with a special symbol.08-26-2010
20110096594MEMORY READING METHOD FOR RESISTANCE DRIFT MITIGATION - Techniques for reading phase change memory that mitigate resistance drift. One contemplated method includes apply a plurality of electrical input signals to the memory cell. The method includes measuring a plurality of electrical output signals from the memory cell resulting from the plurality of electrical input signals. The method includes calculating an invariant component of the plurality of electrical output signals dependent on the configuration of amorphous material in the memory cell. The method also includes determining a memory state of the memory cell based on the invariant component. In one embodiment of the invention, the method further includes mapping the plurality of electrical output signals to a measurements region of a plurality of measurements regions. The measurements regions correspond to memory states of the memory cell.04-28-2011

Michele M. Franceschini, Yorktown Heights, NY US

Patent application numberDescriptionPublished
20100281340ADAPTIVE ENDURANCE CODING OF NON-VOLATILE MEMORIES - Adaptive endurance coding including a method for storing data that includes receiving write data and a write address. A compression algorithm is applied to the write data to generate compressed data. An endurance code is applied to the compressed data to generate a codeword. The endurance code is selected and applied in response to the amount of space saved by applying the compression to the write data. The codeword is written to the write address.11-04-2010
20110026318ITERATIVE WRITE PAUSING TECHNIQUES TO IMPROVE READ LATENCY OF MEMORY SYSTEMS - Iterative write pausing techniques to improve read latency of memory systems including memory systems with phase change memory (PCM) devices. A PCM device includes a plurality of memory locations and a mechanism for executing an iterative write to one or more of the memory locations in response to receiving a write command that includes data to be written. The executing includes initiating the iterative write, updating a state of the iterative write, pausing the iterative write including saving the state in response to receiving a pause command, and resuming the iterative write in response to receiving a resume command. The resuming is responsive to the saved state and to the data to be written.02-03-2011
20110069521ADJUSTABLE WRITE BINS FOR MULTI-LEVEL ANALOG MEMORIES - An analog memory having adjustable write bins including a system for writing to the memory. The system includes a write apparatus interpreting one or more write control signals, generating a write signal, and applying the write signal at a selected memory location to store a desired content. The selected memory location is subject to data dependent noise and is capable of storing a range of values grouped into ā€œnā€ bins configured such that the average cost to write to at least ā€œn-1ā€ of the bins is within a threshold of a target cost for the selected analog memory location. The system also includes a read apparatus. The system further includes write control circuitry that includes a write signal selector selecting the one or more write control signals responsive to the desired content, current content of the selected memory location, and a bin associated with the desired content.03-24-2011
20110134676RESISTIVE MEMORY DEVICES HAVING A NOT-AND (NAND) STRUCTURE - Resistive memories having a not-and (NAND) structure including a resistive memory cell. The resistive memory cell includes a resistive memory element for storing a resistance value and a memory element access device for controlling access to the resistive memory element. The memory element access device is connected in parallel to the resistive memory element.06-09-2011
20110138104MULTI-WRITE CODING OF NON-VOLATILE MEMORIES - Multi-write coding of non-volatile memories including a method that receives write data, and a write address of a memory page. The memory page is in either an erased state or a previously written state. If the memory page is in the erased state: selecting a first codeword from a code such that the first codeword encodes the write data and is consistent with a target set of distributions of electrical charge levels in the memory page; and writing the first codeword to the memory page. If the memory page is in the previously written state: selecting a coset from a linear code such that the coset encodes the write data and includes one or more words that are consistent with previously written content of the memory page; selecting a subsequent codeword from the one or more words in the coset; and writing the subsequent codeword to the memory page.06-09-2011
20110138105NON-VOLATILE MEMORIES WITH ENHANCED WRITE PERFORMANCE AND ENDURANCE - Enhanced write performance for non-volatile memories including a memory system that includes a receiver for receiving a data rate of a data sequence to be written to a non-volatile flash memory device. The memory system also includes a physical page selector for selecting a physical address of an invalid previously written memory page from a group of physical addresses of invalid previously written memory pages located on the non-volatile memory device, and for determining if the number of free bits in the invalid previously written memory page at the selected physical address is greater than or equal to the data rate. The memory system also includes a transmitter for outputting the selected physical address of the invalid previously written memory page, the outputting in response to the physical page selector determining that the number of free bits is greater than or equal to the data rate.06-09-2011