Abstract: A current reference circuit for low supply voltages is provided. The current reference circuit includes a series including a resistor and a diode, a current source having one terminal coupled to a supply voltage and another terminal coupled to the series, an operational amplifier having its negative electrode connected to a band gap reference voltage, and a transistor. The diode has its cathode electrode coupled to ground and its anode electrode coupled to the resistor. The transistor has its gate electrode coupled to the output of the operational amplifier, its source electrode coupled to ground, and its drain electrode coupled to both the positive electrode of the operational amplifier and the current source. Also provided are an integrated circuit that includes at least one current reference circuit for low supply voltages and a signal processing system that includes at least one current reference circuit for low supply voltages.

Abstract: A reading circuit is provided for reading a memory cell. The reading circuit includes a reference current source, a memory cell biased between its first and second terminals at a predetermined voltage, comparison means for comparing a current flowing in the memory cell with the reference current, and a control gate voltage source coupled to a third terminal of the memory cell. The control gate voltage source includes a virgin memory cell that is biased between two terminals with a voltage of equal value to the biasing voltage of the memory cell. The control gate voltage source produces a control gate voltage at another terminal of the virgin memory cell. In one preferred embodiment, the memory cell and the virgin memory cell are EEPROM cells.

Abstract: A current reference circuit for low supply voltages is provided. The current reference circuit includes a series including a resistor and a diode, a current source having one terminal coupled to a supply voltage and another terminal coupled to the series, an operational amplifier having its negative electrode connected to a band gap reference voltage, and a transistor. The diode has its cathode electrode coupled to ground and its anode electrode coupled to the resistor. The transistor has its gate electrode coupled to the output of the operational amplifier, its source electrode coupled to ground, and its drain electrode coupled to both the positive electrode of the operational amplifier and the current source. Also provided are an integrated circuit that includes at least one current reference circuit for low supply voltages and a signal processing system that includes at least one current reference circuit for low supply voltages.

Abstract: Sensing circuitry for reading and verifying the contents of electrically programmable and erasable non-volatile memory cells, comprises a sense amplifier having a first sensing circuit portion connected to a cell to be read and provided with an output terminal for connection to a first input terminal of a comparator, and having a second reference circuit portion connected to a reference current generator and provided with an output terminal for connection to a second input terminal of said comparator, characterized in that said first and said second circuit portions comprise a series of first and second transistors, respectively, being connected between a first voltage reference and a second voltage reference and having respective points of interconnection connected to said output terminals of said first and second circuit portions.

Abstract: A reading circuit for a memory includes a current detector for each bit line of the memory, a reference voltage generator, and a comparator that compares the reference voltage with the voltage of a reading terminal of the current detector. Each current detector includes a first transistor whose gate is selectively connected to the reading terminal, and whose drain-source path is in series with a respective bit line. An input of a first inverter stage is connected to the source of the first transistor, and an output thereof is connected to the gate of the first transistor. The circuit has a very short reading time based upon each of the current detectors including a first resistor between the source of the first transistor and the bit line, along with second and third transistors having their drain-source paths connected in series with the respective bit line, and along with second and third inverters connected to the respective bit line.

Abstract: A variable charge pump contains several individual simple charge pumps, each with a pumping capacitor and a switching mechanism. Additionally, a switching network is coupled to the individual charge pumps so that the different lines in the charge pump can be connected together in a serial mode or parallel mode (or mixed serial and parallel modes) to match the needs of the output load. The switching network is easily changed to provide the necessary driving capability as the needs of the output load changes.

Abstract: Bandgap type reference voltage source using an operational transimpedance amplifier. The bandgap stage is formed by a first and a second bandgap branch parallel-connected; the first bandgap branch comprises a first diode and a transistor, series-connected and forming a first output node; the second bandgap branch comprises a second diode and a second transistor series-connected and forming a second output node. The operational amplifier has inputs connected to the output nodes of the bandgap stage. An amplifier current detecting stage is connected to the outputs of the operational amplifier and supplies a current related to the current drawn by the operational amplifier. A diode current detecting stage is connected to the output of the amplifier current detecting stage and to an output of the operational amplifier and supplies a current related to the current flowing in the first diode. An output stage transforms this current into a stabilized voltage.

Abstract: A reading circuit is provided for reading a memory cell. The reading circuit includes a reference current source, a memory cell biased between its first and second terminals at a predetermined voltage, comparison means for comparing a current flowing in the memory cell with the reference current, and a control gate voltage source coupled to a third terminal of the memory cell. The control gate voltage source includes a virgin memory cell that is biased between two terminals with a voltage of equal value to the biasing voltage of the memory cell. The control gate voltage source produces a control gate voltage at another terminal of the virgin memory cell. In one preferred embodiment, the memory cell and the virgin memory cell are EEPROM cells.

Abstract: A sense amplifier for a memory includes a comparator and a bit line polarization circuit. The comparator receives a first signal representative of a current flowing through a memory cell and a second signal representative of a reference current. Additionally, the comparator includes a stage in a common source configuration and an active load for the stage, and the bit line polarization circuit provides a polarization voltage level that is independent of the supply voltage level. In a preferred embodiment, the sense amplifier also includes an output stage that improves switching time at high supply voltages. Additionally, there is provided a method for sensing logic levels in a memory device. According to the method, a bit line is polarized at a polarization voltage level, and a first signal representative of a current flowing through a memory cell is compared with a second signal representative of a reference current. The polarization voltage level is independent of the supply voltage level.

Abstract: A memory read amplifier circuit includes at least one memory cell to be read and a bit line connected thereto, a first pre-charge amplifier circuit connected to the bit line. A first cascode circuit is connected between a supply voltage and the memory cell for providing a first current to the memory cell. The memory read amplifier circuit also includes at least one reference memory cell and a reference bit line connected thereto, and a second pre-charge amplifier circuit connected to the reference bit line. A second cascode circuit is connected between the supply voltage and the reference memory cell for providing a second current to the reference memory cell. A differential comparator circuit having a first input is connected to the control terminal of the first cascode circuit for receiving a first voltage based upon the first current, and a second input connected to the control terminal of the second cascode circuit for receiving a second voltage based upon the second current.

Abstract: A bias circuit for read amplifier circuits for memories includes at least one first circuit branch formed by a first pair of MOS transistors connected between a supply voltage and ground. The first pair of MOS transistors includes a P-channel diode connected transistor and an N-channel transistor connected in series, with an enable transistor interposed therebetween. The first circuit branch drives a capacitive load for coupling to the supply voltage. The bias circuit further includes reference current amplifier circuit branches for amplifying a reference current which flows in the first circuit branch for charging the capacitive load. A circuit portion, which controls the charging current of the capacitive load, includes a feedback loop between the reference current amplifier circuit branches and the capacitive load.