Sgs-thomson Microelectronics S.r.l.

Silvia Padoan

Marco Olivo

Luigi Pascucci

Carla Maris Golla

Marco MacCarrone

Carla Maria Golla

Marco Maccarrone

A circuit for generating a stable reference voltage (Vref) as temperature and process parameters vary, including at least one field-effect transistor (M ) and an associated resistive bias element (R) connected in series between a supply voltage (Vcc) and ground (GND), further includes a second field-effect transistor (M ) connected to the first transistor such that the reference voltage (Vref) can be picked up as the difference between the respective threshold voltages of the two transistors. This provides a reference voltage which is uniquely stable against variations in temperature and process parameters.

Stable reference voltage generator circuit

A voltage booster comprising a charge pump for generating a boost voltage over a boost line. The booster comprises a comparator which is supplied by a voltage divider with a voltage proportional to the boost voltage, and by a reference source with a low reference voltage, and which, depending on the outcome of the comparison, enables or disables the charge pump. A voltage limiter is connected between the boost line and ground; and a acceleration circuit accelerates the voltage increase on the acceleration line following low-power operation in which the paths toward ground are interrupted for reducing consumption.

Voltage booster with an acceleration circuit

A circuit for detecting a reduction below a threshold value in a supply voltage provided to storage devices integrated into a semiconductor. A comparator is coupled between a voltage supply line and a signal ground and has a first or reference input and a second or test-signal input. A generator of a stable voltage reference has an output coupled to the first input and a divider of the supply voltage coupled to the second input of the comparator. A circuit means is arranged to feed the voltage supply line with the higher of the supply voltage and a programming voltage also provided to the storage devices.

Device for detecting a reduction in a supply voltage

A circuit for selectively programming a single bit in non-volatile memory is disclosed. The circuit consists of at least one comparator, at least one transistor, and at least one logic gate for each elementary memory in the memory word. In operation, the circuit allows for individual correction of mis-programmed cells within the memory by comparing the actual contents of the memory with the desired contents. If the actual contents does not match the desired contents, that individual cell is re-programmed.

Circuit for identifying a memory cell having erroneous data stored

A charge pump circuit including a number of pull-up stages connected in parallel with one another between a reference potential line and an output line. Each stage includes a capacitor having a first terminal connected to a charging and discharging node, and a second terminal connected to a pull-up node for switching between a first charging operating phase and a second charge transferring operating phase. The charging and discharging node is connected to the supply line via a charging transistor having a control terminal connected to a high-voltage bias node formed by the adjacent stage in the opposite operating phase, for charging the capacitor substantially up to the supply voltage.

Charge pump circuit

In an integrated circuit for programming a memory cell in a non-volatile memory register which is associated with a memory matrix wherein the non-volatile memory register is used to store a redundancy address, the memory cell has at least one programmable non-volatile memory element having a control electrode and a data electrode and is suitable to store one bit of information. A load circuit associated to the memory element reads the information stored therein. The integrated circuit has switching means connected in series between the data electrode and a respective address signal line of an address signal bus which also supplies a decoding circuitry of the memory matrix. The switching means are controlled by a signal which determines the switching means to electrically connect the data electrode of the memory element to the address signal line when the memory cell of the non-volatile memory register is to be programmed, and to electrically disconnect the data electrode of the memory element from the address signal line when the information stored in the memory element is to be read by the load circuit.

Integrated circuit for the programming of a memory cell in a

A device including a load connected by a selection circuit to a number of bit lines, and a load connected to a reference cell, for detecting the current in the selected bit line and in the reference cell. The load connected to the bit lines comprises a transistor, and the reference load comprises two current paths, each formed by one transistor. One of the two transistors is diode-connected, and the other is switchable by a switching network connected to the gate terminal of the respective transistor, for turning it off when only one reference current path is to be enabled, and for diode-connecting it when both the reference current paths are to be enabled.

Reading circuit for an integrated semiconductor memory device

A regulating circuit for discharging non-volatile memory cells in an electrically programmable memory device, of the type which comprises at least one switch connected between a programming voltage reference and a line shared by the source terminals of the transistors forming said memory cells, and at least one discharge connection between said common line to the source terminals and a ground voltage reference, further comprises a second connection to ground of the line in which a current generator is connected and a normally open switch. Also provided is a logic circuit connected to the line to compare the voltage value present on the latter with a predetermined value, and to output a control signal for causing the switch to make. This solution allows a slow discharging phase of the line to be effected at the end of the erasing phase.

Regulation circuit and method for the erasing phase of non-volatile

A circuit device for measuring the threshold voltage distribution among electrically programmable, non-volatile memory cells, which device comprises a differential amplifier having a first input connected to a first circuit leg including at least one memory cell and a second input connected to a second or reference circuit leg, and circuit means effective to cause an unbalance in the values of the currents flowing in the reference leg. The device is connected between a first supply voltage reference and a second voltage reference, and said circuit means comprise a generator of a varying current as a function of the supply voltage which is associated with the reference leg.

Threshold voltage measuring device for memory cells

A method for generating a reset signal in an electrically programmable non-volatile storage device of a type which comprises a matrix of memory cells and a control logic portion being supplied a supply voltage and a programming voltage, and a threshold detection circuit adapted to detect a decrease in the supply voltage, provides for the signal applied to the control logic to be obtained as a change-over function between the output signal from the threshold detector and a reset signal generated during the power-on transient of the device.

Circuit device and corresponding method for resetting non-volatile and

The PLA, which implements a state machine of a nonvolatile memory, presents a dynamic NAND-NOT-NOR configuration, and the timing signals for correct reading of the PLA are generated by a clock generator which generates a monostable succession of read enabling signals on receiving a predetermined switching edge of an external clock signal. The clock generator enables evaluation of the AND and OR planes of the PLA and subsequently storage of the results through sections duplicating the propagation delays of the signals in the corresponding parts of the PLA. Reading is terminated as soon as completion of the storage step is indicated, so that reading of the PLA lasts only as long as strictly necessary, thus preventing erroneous switching while at the same time ensuring correct reading of the PLA.

Programmable logic array structure for semiconductor nonvolatile

An integrated programming circuitry for an electrically programmable semiconductor memory device comprises a plurality of programming load circuits, each one associated with a respective memory matrix portion or group of columns, and a plurality of programming load control circuits, each one controlling the activation of one respective programming load circuit according to the logic state of a respective data line carrying a datum to be programmed; the memory device comprises a group of redundancy bit lines and an associated redundancy programming load circuit; each programming load control circuit comprises decoding means supplied with signals which, when a defective column address is supplied to the memory device during programming, are generated from a matrix portion identifying code stored in a non-volatile register wherein the defective column address is stored, and switch means responsive to a decoded signal at the output of said decoding means to enable the activation of the redundancy programming load circuit according to the logic state of the data signal line and to cause the inhibition of the activation of the respective programming load circuit.

Integrated programming circuitry for an electrically programmable

A circuit comprises a section generating a pulse signal for asynchronously enabling the read phases; a section generating precharge and detecting signals of adjustable duration, for controlling data reading from the memory and data supply to the output buffers; a section generating a noise suppressing signal for freezing the data in the output buffers during loading into the output circuits, and the duration of which is exactly equal to the propagation time of the data to the output circuits of the memory, as determined by propagating a data simulating signal in an output simulation circuit; a section generating a loading signal, the duration of which may be equal to that of the noise suppressing signal or extended by an extension circuit in the event the array presents slower elements which may thus be read; and a section generating a circuit reset signal.

Method and circuit for timing the reading of nonvolatile memories

A voltage regulator for programming non-volatile memory cells, which comprises an amplifier stage being powered between a first and a second voltage reference and having a first input terminal connected to a resistive divider of the first reference voltage and an output terminal fed back to said input through a current mirror, and a source-follower transistor controlled by the output and connected to the cells through a programming line. Also provided is a MOS transistor which connects to ground the programming line and a corresponding resistive path connected between the current mirror and the second voltage reference.

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Rimini, Italy

Silvia Padoan