Abstract: A method and system for protecting a memory having a plurality of blocks from modification is disclosed. The method and system include providing a plurality of one time programmable (OTP) cells and OTP cell logic coupled with the OTP cells. An OTP cell of the plurality of OTP cells corresponds to a portion of a block of the plurality of blocks. The OTP cell allows modification of the portion of the block when the OTP cell is in a first state and permanently prevents modification of the portion of the block when the OTP cell is in a second state. The OTP cell logic uses the plurality of OTP cells to select the portion of the block as corresponding to the OTP cell. This portion of the block is write protected when the OTP cell is placed in the second state.

Abstract: A system and method for reducing soft-writing in a multilevel flash memory during read or verify includes a memory cell. A first and second reference cells are coupled to the memory cell and are configured to receive a first and a second voltage. A current comparison circuit is coupled to the first and second reference cells and to the memory cell and is configured to compare current flow through the memory cell with current flow through the first and second reference cells, and to determine whether the memory cell holds a first range of values while the first reference cell receives the first voltage, and if the memory cell does not hold the first range of values, to determine whether the memory cell holds a second range of values while the second reference cell receives the second voltage, thereby reducing soft-writing during the read operation.

Abstract: A method and system for protecting a memory having a plurality of blocks from modification is disclosed. The method and system include providing a plurality of one time programmable (OTP) cells and OTP cell logic coupled with the OTP cells. An OTP cell of the plurality of OTP cells corresponds to a portion of a block of the plurality of blocks. The OTP cell allows modification of the portion of the block when the OTP cell is in a first state and permanently prevents modification of the portion of the block when the OTP cell is in a second state. The OTP cell logic uses the plurality of OTP cells to select the portion of the block as corresponding to the OTP cell. This portion of the block is write protected when the OTP cell is placed in the second state.

Abstract: A method for discharge in a flash memory device includes: initiating a discharge of a memory cell after an erase operation; coupling a first discharge circuit to a first plate of a gate-bulk capacitor, and a second discharge circuit to a second plate of the gate-bulk capacitor, where the first plate represents the common gate node of the memory cell and the second plate represents the bulk-source node of the memory cell; and coupling the common gate node and the bulk-source node to ground to provide for a complete discharge. The current injected into the first plate approximately equals the current extracted from the second plate. In this manner, dangerous oscillations of the gate and bulk-source voltages as they go to ground are eliminated without complicated designs or voltage limitators, and without sacrificing the fast discharge after the erase operation. The reliability of the discharge operation is thus significantly improved.

Abstract: A fast power-on band-gap reference circuit includes a band-gap logic and a band-gap dummy logic. During power-on, both the band-gap logic and the band-gap dummy logic are activated and charges the capacitance of a band-gap line. When an output of the band-gap logic reaches a predetermined value, the band-gap dummy logic is deactivated. Thus, the band-gap dummy logic, with a high drive capability, charges the band-gap capacitance at the same time the band-gap logic starts to generate the compensate temperature voltage. In this manner, the band-gap reference circuit reaches its stable, functional state faster than conventional circuits, in the range of a few microseconds.

Abstract: An n-channel MOS transistor negative-voltage charge pump is disclosed in which the bulks of the n-channel MOS transistors are biased in such a manner as to prevent turning on the parasitic bipolar transistor inherent in the CMOS environment of the charge pump structure.

Abstract: A circuit comprises an amplifier having first output node comprising a first n-channel MOS transistor and a second output node comprising a second n-channel MOS transistor. A first p-channel MOS transistor is coupled to a supply potential, and the second output node. A first PNP bipolar transistor is coupled to the first p-channel MOS transistor through a first resistor and to the second n-channel MOS transistor and to ground. A second PNP bipolar transistor is coupled to the first p-channel MOS transistor through a second resistor in series with a third resistor and to ground. The first n-channel MOS transistor is coupled to a common node between the second and third resistors. A third n-channel MOS transistor is coupled to the first p-channel MOS transistor, to ground through a fourth resistor, and to either a reference potential or to the common node between the second and third resistors.

Abstract: An n-channel MOS transistor negative-voltage charge pump is disclosed in which the bulks of the n-channel MOS transistors are biased in such a manner as to prevent turning on the parasitic bipolar transistor inherent in the CMOS environment of the charge pump structure.

Abstract: A circuit comprises an amplifier having first output node comprising a first n-channel MOS transistor and a second output node comprising a second n-channel MOS transistor. A first p-channel MOS transistor is coupled to a supply potential, and the second output node. A first PNP bipolar transistor is coupled to the first p-channel MOS transistor through a first resistor and to the second n-channel MOS transistor and to ground. A second PNP bipolar transistor is coupled to the first p-channel MOS transistor through a second resistor in series with a third resistor and to ground. The first n-channel MOS transistor is coupled to a common node between the second and third resistors. A third n-channel MOS transistor is coupled to the first p-channel MOS transistor, to ground through a fourth resistor, and to either a reference potential or to the common node between the second and third resistors.

Abstract: A transistor includes a substrate region (14) of a first type (P) of conductivity in a semiconductor material layer of the same type (P) of conductivity, at least a first contact region (13) of the first type (P+) of conductivity inside the substrate region (14) and adjacent to a first terminal (C) of the transistor, a well (11) of second type (N) of conductivity placed inside the substrate region (14), wherein the well (11) of second type (N) of conductivity includes at least a second contact region (12) of a second type of conductivity (N+) adjacent to a region of a second terminal (B) of the transistor, and a plurality of third contact regions (10) of the first type of conductivity (P+) adjacent to a plurality of regions of a third terminal (E1, . . . , E3) of the transistor interposed each one (10) and other (12) by proper insulating shapes (20).

Abstract: The voltage applied to the gate terminals of the charging transistors and charge-transfer transistors of two parallel pumping branches forming a charge pump is a boosted voltage generated internally and supplied in a crosswise manner. In particular, for driving the charge pump, first and second driving signals are generated respectively for the first and for the second pumping branch via a first and respectively a second driving circuit; the first and second driving signals are also supplied respectively to a first and to a second auxiliary charge pump to obtain respectively first and second voltage-boosted signals; and the first and second boosted voltages are respectively supplied to the second and to the first driving circuit.

Abstract: A charge pump having a phase-generator circuit generating phase signals and an oscillator circuit supplying a clock signal, a current-limitation circuit to limit the current flowing in the oscillator circuit, and a control circuit supplying on an output a control signal supplied to the current-limitation circuit. The control circuit has a first current mirror connected to a ground line, a second current mirror connected to a supply line, a cascode structure arranged between the first and the second current mirrors and connected to the output of the control circuit to compensate the effects on the control signal caused by sharp relative variations between the potential of the supply line and the potential of the ground line, and a compensation circuit to compensate the effects on the control signal caused by sharp relative variations between the potential of the supply line and the potential of the ground line and by slow variations in temperature.

Abstract: A circuit structure for reading data contained in an electrically programmable/erasable integrated non-volatile memory device includes a matrix of memory cells and at least one reference cell for comparison with a memory cell during a reading phase. The reference cell is incorporated in a reference cells sub-matrix which is structurally independent of the matrix of memory cells. Also provided is a conduction path between the matrix and the sub-matrix, which path includes bit lines of the sub-matrix of reference cells extended continuously into the matrix of memory cells.

Abstract: A circuit and method for programming a multilevel nonvolatile memory are disclosed. The circuit uses one or more address pins as one or more synchronization signals during a programming operation. The circuit includes a counter, controlled by the one or more address pins, for selecting a programming voltage to apply to an addressed memory cell. The circuit further includes compare circuitry for comparing the data value stored in the addressed memory cell with a desired data value. The counter is selectively incremented to apply a higher voltage for further programming of the addressed memory cell, based up the comparison.

Abstract: The voltage applied to the gate terminals of the charging transistors and charge-transfer transistors of two parallel pumping branches forming a charge pump is a boosted voltage generated internally and supplied in a crosswise manner. In particular, for driving the charge pump, first and second driving signals are generated respectively for the first and for the second pumping branch via a first and respectively a second driving circuit; the first and second driving signals are also supplied respectively to a first and to a second auxiliary charge pump to obtain respectively first and second voltage-boosted signals; and the first and second boosted voltages are respectively supplied to the second and to the first driving circuit.

Abstract: A circuit structure for programming data in reference cells of an electrically programmable/erasable integrated non-volatile memory device includes a matrix of multi-level memory cells and a corresponding reference cell provided for comparison with a respective memory cell during the read phase. The reference cell is incorporated, along with other cells of the same type, in a reference cell sub-matrix which is structurally independent of the memory cell matrix and directly accessed from outside in the DMA mode. The bit lines of the sub-matrix branch off to a series of switches which are individually operated by respective control signals REF(i) issued from a logic circuit with the purpose of selectively connecting the bit lines to a single external I/O terminal through a single addressing line of the access DMA mode.

Abstract: The integrated device comprises a PMOS transistor and a voltage selector having an output connected to the bulk terminal of the PMOS transistor. The voltage selector comprises an input stage supplying a supply voltage or a programming voltage according to whether the device is in a reading step or in a programming step; a comparator connected to the output of the input stage, receiving a boosted voltage, and generating a first control signal, the state whereof depends upon the comparison of the voltages at the inputs of the comparator; a logic circuit connected to the output of the comparator and generating a second control signal, the state whereof depends upon the state of the first control signal and of a third-level signal; and a switching circuit controlled by the first control signal, by the second control signal, and by the third-level signal and supplying each time the highest among the supply voltage, the boosted voltage, and the programming voltage.

Abstract: A transistor includes a substrate region (14) of a first type (P) of conductivity in a semiconductor material layer of the same type (P) of conductivity, at least a first contact region (13) of the first type (P+) of conductivity inside the substrate region (14) and adjacent to a first terminal (C) of the transistor, a well (11) of second type (N) of conductivity placed inside the substrate region (14), wherein the well (11) of second type (N) of conductivity includes at least a second contact region (12) of a second type of conductivity (N+) adjacent to a region of a second terminal (B) of the transistor, and a plurality of third contact regions (10) of the first type of conductivity (P+) adjacent to a plurality of regions of a third terminal (E1, . . . , E3) of the transistor interposed each one (10) and other (12) by proper insulating shapes (20).

Abstract: A voltage boosting device for speeding power-up of multilevel nonvolatile memories, including a voltage regulator and a charge pump and having an output terminal; the voltage regulator having a regulation terminal connected to the output terminal, and an output supplying a control voltage; the read charge pump having an output connected to the output terminal and supplying a read voltage. The device further includes an enable circuit connected to the output and having a pump enable output connected to a charge pump enable terminal and supplying a pump enable signal. The pump enable signal is set at a first logic level so as to activate the charge pump when the read voltage is lower than a nominal value. In addition, the device generates a power-up sync signal which activates a read operation when the read voltage reaches its nominal value and a chip enable signal is set at an active value.

Abstract: A circuit and method for programming a multilevel nonvolatile memory are disclosed. The circuit uses one or more address pins as one or more synchronization signals during a programming operation. The circuit includes a counter, controlled by the one or more address pins, for selecting a programming voltage to apply to an addressed memory cell. The circuit further includes compare circuitry for comparing the data value stored in the addressed memory cell with a desired data value. The counter is selectively incremented to apply a higher voltage for further programming of the addressed memory cell, based up the comparison.