Abstract:
A method and apparatus for the programming and erasure of a memory cell made out of floating-gate transistors and to the circuit pertaining thereto is described. It can be applied especially to non-volatile electrically erasable and programmable memories, for example EEPROMs and flash EPROMs. A programming voltage or erasure voltage comprising a voltage shift equal in value to a reference voltage is produced, followed by a voltage ramp comprising a rising phase followed possibly by voltage plateau, this voltage ramp being shifted in voltage by the value of the reference voltage and being followed, in turn, by a voltage drop. The value of the voltage shift is fixed at an intermediate value that is lower than the value of a so-called tunnel voltage of the memory cell but greater than the supply voltage.
Abstract:
In a device for programming EPROM-Flash type memory cells of memory words of a memory, a bit line of a memory cell of a given rank of the first word and at least one bit line of a memory cell of the same rank in a word that is horizontally adjacent to this first word are connected together to two common programming connections by means of a bias circuit, and the bias circuit comprises two bias voltage inputs and one bias voltage output. The programming method consists in the successive programming, during different programming cycles, of the different cells of this first word and, during the same programming cycle, a different cell, of the same rank, in at least one word that is different from this first word is programmed.
Abstract:
A random-access memory with an accelerated access time. One or more of the preliminary operations of the sequence of operations carried out for accessing the memory are anticipated by performing the anticipated operation or operations during the end of a sequence of a previous memory access. The anticipated operation is preferably that of the deselection of the bit lines of the memory.
Abstract:
A device for the addressing of redundant elements of an integrated circuit memory is disclosed. This memory comprises an array of row memory elements and column memory elements, respectively addressable by row addresses and column addresses, and at least one group of fuses to store the address of a faulty element of the memory. Each fuse is associated with a row/column address pair. Through the blowing of certain fuses in the group after testing of a memory element, the address either of a column element, if the faulty element is a column element, or of a row element, if the faulty element is a row element, is stored. Only the row addresses are enabled when the stored address is that of a row element, and only the column addresses are enabled when the stored address is that of a column element, in order to address either a row redundant element or a column redundant element.
Abstract:
A method may be for detecting potentially suspicious operation of an electronic device configured to operate in the course of activity sessions. The method may include within the device, a metering, from an initial instant of the number of activity sessions having a duration below a first threshold, and a comparison of this number with a second threshold.
Abstract:
The present invention relates to a method for programming a memory cell having a determined transconductance curve. The programming of the memory cell comprises a series of programming cycles each comprising a step of verifying the state of the memory cell. According to the present invention, the verify step comprises a first read of the memory cell with a first read voltage greater than a reference threshold voltage, and a second read of the memory cell with a second read voltage lower than or equal to the reference threshold voltage. The memory cell is considered not to be in the programmed state if first- and second-read currents flowing through the memory cell are above determined thresholds, and programming voltage pulses are applied to the memory cell while the latter is not in the programmed state. Application in particular to the programming of Flash memory cells.
Abstract:
The present invention relates to a page-erasable FLASH memory including a memory array having a plurality of pages each with floating-gate transistors connected by their gates to word lines, a word line decoder connected to the word lines of the memory, and the application of a positive erase voltage to the source or drain electrodes of all the floating-gate transistors of a sector forming a page to be erased. According to the present invention, the word line decoder includes a unit for applying, when a page is being erased, a negative erase voltage to the gates of the transistors of the page to be erased, while applying a positive inhibit voltage to the gates of the transistors of at least one page that is not to be erased.
Abstract:
A device and method for the reading of cells of an EEPROM is provided. The device includes at least one reference cell and one circuit for comparison between a current flowing into the reference cell and a current flowing in a cell selected in read mode. The reference cell is in a programmed state. The programming of the reference cell is done after the control reading and during the integrated circuit power-on reset phase, activated by the powering on of the integrated circuit.
Abstract:
A circuit for activating page-write operations in a floating-gate memory includes a first and a second time lag circuit. A resetting signal resets a first time lag whenever a word is written in a buffer of the memory. The first time lag circuit provides a state bit indicating that the first time lag has ended or not ended. The second time lag circuit activates a second time lag at the end of the first time lag and the end of the second time lag activates the writing of the page in the memory. The invention also relates to a method of writing in memory that uses a first and a second time lag.
Abstract:
An electrically modifiable multilevel non-volatile memory has autonomous refresh means. The multilevel memory has a real-time clock delivering pulses to periodically activate an operation for refreshing the memory cells of the main matrix. The memory has application to the field of large-capacity memories, for example, several tens of megabits and more.