Abstract: A circuit verifies and substitutes a defective reference cell of a memory device that includes at least one reference current path including the reference cell and a decoding transistor connected in series. The circuit includes at least one redundant reference current path identical to the at least one reference current path and in parallel therewith. A connection circuit connects in a mutually exclusive way control terminals of the decoding transistor and reference cell of the at least one reference current path to a node or control terminals of the decoding transistor and reference cell of the at least one redundant reference current path to the node. The connecting is based upon a logic signal. A window comparator is coupled to the reference current path for comparing a current therein with a pair of upper and lower thresholds, and outputs the logic signal for the connection circuit based upon the comparison.

Abstract: The invention relates to a voltage regulation system for multiword programming in non volatile memories, for example of the Flash type, with low circuit area occupation, wherein memories comprise at least a memory cell matrix organized in cell rows and columns and with corresponding circuits responsible for addressing, decoding, reading, writing and erasing the memory cell content. The memory cells have drain terminals connected to matrix columns and are biased in the programming step with a predetermined voltage value by means of program load circuits associated to each matrix column. In parallel with each program load circuit, a conduction-to-ground path is enabled by a controlled active element.

Abstract: A method for simultaneously programming a pre-established number of memory cells includes setting an initial number of memory cells to be simultaneously programmed equal to the pre-established number, and subdividing the initial number of memory cells to be programmed into subsets of memory cells. A program operation for simultaneously programming all the memory cells of each subset of memory cells is executed by forcing a current through all the memory cells of each subset of memory cells. The current has a program voltage associated therewith. The program voltage is compared to a threshold voltage during execution of the program operation. The method further includes stopping execution of the program operation if the threshold voltage is surpassed, reducing the initial number of memory cells to be simultaneously programmed, and restarting from the subdividing.

Abstract: A voltage regulator may include an output stage controlled by a control voltage determined as a function of the difference between a reference voltage and a signal representing an output voltage of the regulator generating the output voltage on an output node of the regulator. An auxiliary stage may be connected in parallel to the output stage and cooperate therewith in supplying a load connected to the regulator. A sensing resistance may be connected in series with the output stage, and an voltage drop amplifier may be connected to the sensing resistance to generate a second control voltage of the auxiliary stage.

Abstract: A plurality of non volatile memory cells, for example of the flash type, with low circuit area occupation, are organized in cell matrices with corresponding circuits responsible for addressing, decoding, reading, writing and erasing the memory cell content. Each of the cells has a gate terminal biased in the programming phase with a predetermined voltage value through operation of charge pump voltage regulators. A first and a second regulation stage, which are structurally independent, are responsible for the programming and soft programming phase respectively. The first stage generates a supply voltage for the second stage.

Abstract: The output buffer stage includes a half-bridge output stage having a first pair of complementary drivers connected in series between a supply line and a ground node, the high impedance state or conduction state of which is determined through a pair of control phases. The buffer stage includes a pair of switches controlled by the control phases, connected in series between them and connecting the transistors of the first stage in series. Each driver is connected in series with a switch, that is quickly opened to prevent under-threshold currents from circulating when the respective driver is turned off, and that is rapidly turned off when the respective driver is turned on.

Abstract: Described herein is a reading circuit for a nonvolatile memory device, wherein the currents flowing through an array memory cell to be read, and a reference memory cell with known contents, are converted into an array voltage and, respectively, into a reference voltage, which are compared to determine the contents of the array memory cell. The method envisages reducing the electrical stress to which the reference memory cell is subjected during reading, by generating and holding a sample of the reference voltage, then deselecting the reference memory cell, and then continuing reading using the sample of the reference voltage.

Abstract: A circuit verifies and substitutes a defective reference cell of a memory device that includes at least one reference current path including the reference cell and a decoding transistor connected in series. The circuit includes at least one redundant reference current path identical to the at least one reference current path and in parallel therewith. A connection circuit connects in a mutually exclusive way control terminals of the decoding transistor and reference cell of the at least one reference current path to a node or control terminals of the decoding transistor and reference cell of the at least one redundant reference current path to the node. The connecting is based upon a logic signal. A window comparator is coupled to the reference current path for comparing a current therein with a pair of upper and lower thresholds, and outputs the logic signal for the connection circuit based upon the comparison.

Abstract: A bit-line selection circuit for a memory device includes a decoding line and a dummy line. The decoding line is between a regulated voltage node, and a programming voltage node generating a programming voltage for a cell in the memory device. The decoding line includes at least one input transistor connected to the regulated voltage node, and is controlled by an enable/disable signal. The dummy line is identical to the decoding line, and is controlled by the enable/disable signal. An equalization circuit is connected between the decoding and dummy lines for setting a current in the dummy line equal to a current in the decoding line. A regulating circuit regulates the programming voltage generated at the programming voltage node in the decoding line. The regulating circuit has a first input for receiving a reference voltage, a second input for receiving a sensed voltage on the programming voltage node in the dummy line, and an output for providing the enable/disable signal.

Abstract: The invention relates to a voltage regulation system for multiword programming in non volatile memories, for example of the Flash type, with low circuit area occupation, wherein memories comprise at least a memory cell matrix organized in cell rows and columns and with corresponding circuits responsible for addressing, decoding, reading, writing and erasing the memory cell content. The memory cells have drain terminals connected to matrix columns and are biased in the programming step with a predetermined voltage value by means of program load circuits associated to each matrix column. In parallel with each program load circuit, a conduction-to-ground path is enabled by a controlled active element.

Abstract: A plurality of non volatile memory cells, for example of the flash type, with low circuit area occupation, are organized in cell matrices with corresponding circuits responsible for addressing, decoding, reading, writing and erasing the memory cell content. Each of the cells has a gate terminal biased in the programming phase with a predetermined voltage value through operation of charge pump voltage regulators. A first and a second regulation stage, which are structurally independent, are responsible for the programming and soft programming phase respectively. The first stage generates a supply voltage for the second stage.

Abstract: An output buffer for causing a voltage (Vout) of an integrated circuit output line (OUT,OUT_PAD) to switch from a voltage of a first voltage line (VDD) to a voltage of a second voltage line (GND) and vice versa, comprises a current path switch circuit (111a,111b) activatable for causing a prescribed current (Is) to constantly flow between the first and second voltage lines during a time between two successive switchings of the output line, and for causing the prescribed current to be deviated (Ic1) to the output line during at least an initial phase of an output line switching from the first voltage line voltage to the second voltage line voltage or vice versa. A current delivered by the first and second voltage lines is thus kept substantially constant in the output line switching. In this way, the time derivative of the current flowing between the first and the second voltage lines is kept small and low switching noise is induced.

Abstract: A negative charge pump circuit includes a cascade connection of a plurality of charge pump stages, each stage including at least a charge capacitance and a pass transistor driven by a corresponding phase signal. An input stage may be coupled to an input reference potential. An output stage may include an output terminal for generating a first pumped voltage. In addition, the charge pump circuit may further include a second output stage connected downstream to the input stage and including a second output terminal for generating a second pumped potential. The architecture may also be implemented in positive charge pump circuits.

Abstract: A charge pump for a nonvolatile memory, having a clock generator circuit supplying an output clock signal; a phase generator circuit receiving the output clock signal, and supplying phase signals; and a voltage booster circuit receiving a supply voltage supplied from outside to the nonvolatile memory and the aforesaid phase signals, and supplying a read voltage higher than the supply voltage. The clock generator circuit includes a comparator receiving the read voltage and a reference voltage, and supplying a selection signal indicating the outcome of the comparison between the read and reference voltages; and a multiplexer receiving a first input clock signal having a pre-set frequency, a second input clock signal having a frequency correlated to the transition frequency of the addresses supplied to the nonvolatile memory, and the selection signal, and supplying the aforesaid output clock signal.

Abstract: A negative charge pump circuit includes a cascade connection of a plurality of charge pump stages, each stage including at least a charge capacitance and a pass transistor driven by a corresponding phase signal. An input stage may be coupled to an input reference potential. An output stage may include an output terminal for generating a first pumped voltage. In addition, the charge pump circuit may further include a second output stage connected downstream to the input stage and including a second output terminal for generating a second pumped potential. The architecture may also be implemented in positive charge pump circuits.

Abstract: An output buffer for causing a voltage (Vout) of an integrated circuit output line (OUT,OUT13 PAD) to switch from a voltage of a first voltage line (VDD) to a voltage of a second voltage line (GND) and vice versa, comprises a current path switch circuit (111a,111b) activatable for causing a prescribed current (Is) to constantly flow between the first and second voltage lines during a time between two successive switchings of the output line, and for causing the prescribed current to be deviated (Ic1) to the output line during at least an initial phase of an output line switching from the first voltage line voltage to the second voltage line voltage or vice versa. A current delivered by the first and second voltage lines is thus kept substantially constant in the output line switching. In this way, the time derivative of the current flowing between the first and the second voltage lines is kept small and low switching noise is induced.

Abstract: A circuit for generating a constant pulse signal from an enabling ATD input signal may include a latch structure connected between first and second circuit nodes, with each node being coupled to a corresponding charge and discharge capacitance and being also connected to respective inputs of a logic gate. The circuit may also include a memory element coupled to the circuit nodes for filtering the enabling ATD signal and avoiding a partial discharge of one of the capacitances. An output of the logic gate is provided for generating the pulse signal independent of voltage and/or temperature variations affecting the enabling ATD signal.

Abstract: A charge pump for a nonvolatile memory, having a clock generator circuit supplying an output clock signal; a phase generator circuit receiving the output clock signal, and supplying phase signals; and a voltage booster circuit receiving a supply voltage supplied from outside to the nonvolatile memory and the aforesaid phase signals, and supplying a read voltage higher than the supply voltage. The clock generator circuit includes a comparator receiving the read voltage and a reference voltage, and supplying a selection signal indicating the outcome of the comparison between the read and reference voltages; and a multiplexer receiving a first input clock signal having a pre-set frequency, a second input clock signal having a frequency correlated to the transition frequency of the addresses supplied to the nonvolatile memory, and the selection signal, and supplying the aforesaid output clock signal.

Abstract: A reading circuit for nonvolatile memory cells, including a current-to-voltage converter, having an array load, connected to a memory cell, and a reference load connected to a reference generator. The array load and the reference load include PMOS transistors presenting an array shape factor (W/L)F and, respectively, a reference shape factor (W/L)R. The reading circuit further includes a charge pump that supplies a biasing voltage to a gate terminal of the memory cell. The biasing voltage is proportional to and higher than a supply voltage VDD. The ratio between the array shape factor (W/L)F and the reference shape factor (W/L)R is a non-integer.

Abstract: A method for addressing redundant columns in a nonvolatile memory, which receives, at inputs, selection addresses and comprises a plurality of redundant columns, each including a respective bit line and a plurality of memory cells connected to the bit line. The addressing method comprises the steps of: detecting a transition in the selection addresses; starting charging of all the bit lines upon detection of the transition in the addresses; then detecting whether one of the redundant columns is addressed; should one of the redundant columns be found to be addressed, proceeding with charging of the bit line of the redundant column addressed and interrupting charging of the bit lines of the redundant columns not addressed; and should none of the redundant columns be found to be addressed, interrupting charging of all the bit lines.