Sgs-thomson Microelectronics S.a.

Stmicroelectronics S.a.

Alessandro Brigati

Jean Devin

Bruno Leconte

Nicolas Demange

Marc Guedj

Maxence Aulas

Two different types of memory are integrated on the same type of integrated circuit. A microcontroller is associated with each of these memories. In order that the independence of operation of these microcontrollers may be ensured, they are each provided with time delay circuits whose role is to maintain the read or write operation of one microcontroller when another is selected.

Set of two memories on the same monolithic integrated circuit

Method for programming an EPROM-flash type memory

A memory is provided with an addressing circuit comprising an address bus to convey address signals, biasing and selector switch circuits connected to the address bus for the selecting and biasing of lines of the memory and write circuits for the writing of data in cells of the memory. The memory comprises an enabling circuit to enable an operation of writing in memory. This enabling circuit comprises a circuit to memorize a designated address or to write data elements, a comparison circuit to compare a current address available on the address bus with the designated address and a blocking circuit to prevent the writing when the comparison reveals a difference of address.

Circuit for the detection of changes of address

A method for the erasure of a non-volatile and electrically erasable memory in which the amplitude of the pulses that are sent to erase the memory varies as a function of the number of pulses previously sent. A circuit for the generation of erasure pulses of variable amplitude for a non-volatile and electrically erasable memory.

Circuit and method for the erasure of a non-volatile and electrically

An EEPROM is organized in matrix form in word lines and bit lines. Storage cells are placed at the intersections of these lines. The cells include floating gate storage transistors. Groups of cells having separate bit lines but sharing a word line are created. Each group is connected to a group selection transistor. The group selection transistor selectively connects the control gates of the storage transistors to control lines, which provide potentials for enabling programming, erasure or reading of the storage transistors.

EEPROM memory programmable and erasable by Fowler-Nordheim effect

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.

Device and method for the programming of a memory

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.

Page-write indicator for non-volatile memory

An electrically programmable non-volatile memory organized in n-bit words includes a generator circuit to produce a verification voltage to perform a verification of a word in the memory. The generator circuit adjusts the verification voltage as a function of an information element that corresponds to the word to be verified.

Word addressable floating-gate memory comprising a reference voltage

A FLASH memory is compatible with a standard EEPROM memory in terms of a write-by-page instruction with write protection. A circuit successively addresses one of the columns of a storage matrix in order to write a page previously stored in buffers, and the circuit addresses the writing of a protection bit after the writing of the page.

Device for protection after a page-write operation in an electrically

Disclosed is a charge pump type of negative voltage generator circuit, constructed on a P type substrate and supplying a negative voltage at one output by the pumping of negative charges in n series-connected pumping cells, n being an integer, these pumping cells including P type transistors whose wells are connected to a node to be positively biased. This circuit includes a switching circuit for selectively supplying, at the node, a voltage for biasing of the wells that is greater than or equal to the potential present at the output so long as this potential is greater than a positive reference voltage, and provides a voltage of fixed value for biasing of the wells when the potential present at the output is smaller than the reference voltage. Thus, the appearance of latchup phenomena in the transistors of the pumping cells is prevented.

Charge pump type of negative voltage generator circuit and method

A selector switch circuit comprises an input terminal to receive a positive voltage, an input terminal to receive a negative voltage, a command input terminal to receive a first command logic signal and an output terminal to provide an output voltage. The output is connected selectively to one of the input terminals, the first and second input terminals being connected to the output terminal by means of a first transistor and a second transistor and the circuit comprising control means for the production, as a function of the command signal, of the control voltages applied to the control gates of the transistors for the selective connection of the output terminal to one of the input terminals.

Selector switch circuit enabling the selective supply of voltages with

A phase generator circuit cyclically produces a first pair of phase signals and a second pair of phase signals, comprising a first circuit to produce a first phase of each pair of phase signals, these first phase signals being non-overlapping and switching over between a voltage 0 and a voltage VCC, and second and third circuits for the production, from the first phase signals, respectively of the second phase of the first pair and the second phase of the second pair of phase signals, these second phase signals being non-overlapping with the first phase signals and switching over between a negative voltage -V and a voltage VCC. The disclosure finds application in the piloting of charge pump type of negative voltage generator circuit.

Phase generator circuit for charge pump type or negative supply circuit

The present invention concerns an electrically programmable memory and a method for writing within this memory. In order to avoid the degradation of information in a memory cell following a number of write cycles in the other cells of the same row, the present invention includes a sequence to be carried out before each write cycle of a word within a row. A systematic reading of all the words of a row by using three different read reference potentials is performed in order to find a cell that gives non-compatibility results between any two of the three read cycles. The words of the row are stored in a register. If a non-compatible result is found, which indicates a degradation of information in the row, a systematic re-write of all the words of the row is carried out.

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Aix en Provence, France

Alessandro Brigati