Stmicroelectronics S.r.l.

Sgs-Thomson Microelectronics S.r.l.

Other

Marcello Carrera

Mauro Luigi Sali

Corrado Villa

Jacopo Mulatti

Rino Micheloni

Giovanni Campardo

Atsushi Ohba

Stefano Zanardi

Maurizio Branchetti

Luigi Pascucci

Marco Dallabora

Andrea Ghilardelli

Marco Defendi

Matteo Zammattio

The switch circuit receives a first supply voltage and a second supply voltage different from each other; a control input receiving a control signal that may be switched between the first supply voltage and ground; a driving inverter stage supplied by the second supply voltage and defining the output of the circuit; a feedback inverter stage supplied by the second supply voltage and including a top transistor and a bottom transistor defining an intermediate node and having respective control terminals. The control terminal of the top transistor is connected to the output node, the control terminal of the bottom transistor is connected to the control input, and the intermediate node is connected to the input of the driving inverter stage. An activation element helps switching of the intermediate node from the second supply voltage to ground; current limiting transistors are arranged in the inverter stages to limit the current flowing during switching and to reduce the consumption of the circuit.

CMOS switch circuit for transferring high voltages, in particular for line decoding in nonvolatile memories, with reduced consumption during switching

The row decoder includes, for each word line of the memory, a respective biasing circuit receiving at the input a row selection signal switching, in preset operating conditions, between a supply voltage and a ground voltage and supplying at the output a biasing signal for the respective word line switching between a first operating voltage, in turn switching at least between the supply voltage and a programming voltage higher than the supply voltage, and a second operating voltage, in turn switching at least between the ground voltage and an erase voltage lower than the ground voltage. Each biasing circuit includes a level translator circuit receiving at the input the row selection signal and supplying as output a control signal switching between the first and the second operating voltages and an output driver circuit receiving as input the control signal and supplying at the output the biasing signal.

Row decoder for a nonvolatile memory with capability of selectively biasing word lines to positive or negative voltages

A voltage regulator for memory circuits has a differential stage having a non-inverting input terminal receiving a control voltage independent of the temperature; an inverting input terminal connected to a ground voltage reference; a feed terminal connected to a booster circuit adapted for producing a boosted voltage; and an output terminal connected to an output terminal of the voltage regulator, for producing an output voltage reference starting from the comparison of input voltages. The voltage regulator further comprises a connecting transistor inserted between the feed terminal and the output terminal of the differential stage, the connecting transistor being source follower having a control terminal connected to the output terminal of the differential stage, as well as a source terminal connected to the output terminal of the voltage regulator, in such a way as to self-limit the transition of the voltage on the output terminal.

Voltage regulator for single feed voltage memory circuits, and flash type memory in particular

A temperature-related voltage generating circuit has an input terminal receiving a control voltage independent of temperature, and an output terminal delivering a temperature-related control voltage. The input and output terminals are connected together through at least an amplifier stage adapted to set an output reference voltage from a comparison of input voltages. The voltage generating circuit also includes a generator element generating a varying voltage with temperature and connected between a ground voltage reference and a non-inverting input terminal of the amplifier stage. The amplifier stage has an output terminal adapted to deliver a multiple of the varying voltage with temperature to an inverting input terminal of a comparator stage. The comparator stage has its output connected to the temperature-related voltage generating circuit and a non-inverting input terminal receiving the control voltage independent of temperature to evaluate the difference between the control voltage independent of temperature and said voltage being a multiple of the varying voltage with temperature and to output a temperature-related control voltage having at room temperature a mean value which is independent of its thermal differential and increases with temperature. The voltage generating circuit can be incorporated into a regulator for a drain voltage of a single-supply memory cell.

Memory cell voltage regulator with temperature correlated voltage generator circuit

Voltage regulator for single feed voltage memory circuits, and flash

A Flash EEPROM having at least one memory sector. The memory sector includes a plurality of rows and columns of memory cells; at least one negative voltage generator for generating a negative voltage commonly charging the plurality of rows to a negative potential during an erase pulse for erasing the memory cells of the at least one memory sector and control logic activating the negative voltage generator at the beginning of the erase pulse and deactivating the negative voltage generator at the end of the erase pulse. The Flash EEPROM having for controlling a discharge time of the rows of the at least one memory sector at the end of the erase pulse.

Flash EEPROM with controlled discharge time of the word lines and source

A negative word line voltage regulation circuit integratable in an electrically erasable semiconductor memory device. The circuit regulates a negative word line voltage to be supplied to word lines of the memory device during an electrical erasure of the memory device. The circuit includes an operational amplifier with a first input coupled to a reference voltage, a second input coupled to the negative word line voltage, and an output controlling a voltage regulation branch connected between an external power supply and the negative word line voltage, to provide a regulation current for regulating the negative word line voltage. The output of the operational amplifier also controls a voltage sensing branch, connected between the external power supply and the negative word line voltage, to provide a sensing signal coupled to the second input of the operational amplifier.

Negative word line voltage regulation circuit for electrically erasable

A method for setting the threshold voltage of a reference memory cell of a memory device is described, the reference memory cell being used as a reference current generator for generating a reference current which is compared by a sensing circuit of the memory device with currents sunk by memory cells to be sensed, belonging to a memory matrix of the memory device. The method comprises a first step in which the reference memory cell is submitted to a change in its threshold voltage, and a second step in which the threshold voltage of the reference memory cell is verified. The second step provides for performing a sensing of the reference memory cell using a memory cell with known threshold voltage belonging to the memory matrix as a reference current generator for generating a current which is compared by the sensing circuit with the current sunk by the reference memory cell.

Method for setting the threshold voltage of a reference memory cell

Redundancy circuitry layout for a semiconductor memory device comprises an array of programmable non-volatile memory elements for storing the addresses of detective bit lines and word lines which must be functionally replaced respectively by redundancy bit lines and word lines. The redundancy circuitry layout is divided into identical layout strips which are perpendicular to the array of memory elements and which each comprise first and a second strip sides located at opposite sides of the array of memory elements, the first strip side containing at least one programmable non-volatile memory register of a first plurality for the selection or redundancy bit lines and being crossed by a column address signal bus running parallel to the array or memory elements, the second strip side containing one programmable non-volatile memory register of a second plurality for the selection or redundancy word lines and being crossed by a row address signal bus running parallel to the array of memory elements.

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Trescore Balneario, Italy

Marcello Carrera