Abstract: A device for detecting load impedance having an analog circuit portion for detecting the impedance value of a load, and a digital circuit portion adapted to provide load impedance type information. The analog circuit portion having two power MOS transistors connected in series to each other and between a supply voltage and the ground, and a pair of mirror MOS transistors common-connected with their respective gate terminals to the gate terminals of the power MOS transistors. The digital circuit portion includes a first comparitor to determine whether the output current of an audio amplifier is higher or lower than a threshold value and a second comparator to determine whether the output voltage of the amplifier is higher than a threshold voltage, a memory to store output signals of the first and second comparitors, and a logic circuit arranged in cascade with the memory to output a load-type indication signal.

Abstract: A device for detecting load impedance having an analog circuit portion for detecting the impedance value of a load, and a digital circuit portion adapted to provide load impedance type information. The analog circuit portion having two power MOS transistors connected in series to each other and between a supply voltage and the ground, and a pair of mirror MOS transistors common-connected with their respective gate terminals to the gate terminals of the power MOS transistors. The digital circuit portion includes a first comparitor to determine whether the output current of an audio amplifier is higher or lower than a threshold value and a second comparitor to determine whether the output voltage of the amplifier is higher than a threshold voltage, a memory to store output signals of the first and second comparitors, and a logic circuit arranged in cascade with the memory to output a load-type indication signal.

Abstract: A device for detecting load impedance having an analog circuit portion for detecting the impedance value of a load, and a digital circuit portion adapted to provide load impedance type information. The analog circuit portion having two power MOS transistors connected in series to each other and between a supply voltage and the ground, and a pair of mirror MOS transistors common-connected with their respective gate terminals to the gate terminals of the power MOS transistors. The digital circuit portion includes a first comparitor to determine whether the output current of an audio amplifier is higher or lower than a threshold value and a second comparitor to determine whether the output voltage of the amplifier is higher than a threshold voltage, a memory to store output signals of the first and second comparitors, and a logic circuit arranged in cascade with the memory to output a load-type indication signal.

Abstract: A power stage for an operational amplifier includes an output stage, a current source stage, and a gain stage. The output stage is formed by first and second NPN output transistors arranged in a Totem-Pole configuration, each having respective resistors connected between their respective base and emitter terminals. The output transistors are biased in class AB by a quiescent current supplied by the current source stage and are controlled dynamically by the gain stage. The gain stage includes an NPN gain transistor having a collector terminal connected to the base terminal of the first output transistor and an emitter terminal connected to the base terminal of the second output transistor.

Abstract: A power supply regulator comprising a regulated-voltage source; a buffer connected to the voltage source; and a diode connected to the output of the buffer. A bootstrap capacitor is located between the diode and the output of a power stage; and the output of the power stage is switched between a low and a high value by a digital signal also supplied to the input of the buffer which therefore generates a switched regulated output voltage varying between a first value equal to the regulated voltage and a second lower value. The switched regulated voltage switches from the first to the second value before the output of the power stage switches to high, thus immediately disabling the diode and preventing current spikes due to minority carriers in the diode from being transmitted to the regulated-voltage source.

Abstract: A manufacturing method for fabricating integrated electronic circuits on a semiconductor support provides a plurality of integrated circuits and provides a plurality of scribing lines. The scribing lines are located such that the electronic circuits are regularly spaced apart by the scribing lines. A network of electrical connection lines is provided in at least one of the scribing lines. Metallization strips are provided in the scribing lines as electrical connection lines, and the electrical connection lines are connected to the integrated circuit. At least one current limitation element is provided between the electrical connection line and the integrated circuit. In this manner it is possible to simultaneously perform electrical testing of all the circuits present on the same wafer.

Abstract: A connection system of the multiplex type between at least one master processing unit and slave units, in particular associated with electrical devices in a vehicle for activating or controlling at least one electrically functioning component in the corresponding device, the slave units being connected in groups to the master unit by means of corresponding communication channels common to the units of each group, and in which the master unit includes logical means for controlling the exchange of communications between the various channels; in particular these logical means include a microprocessor and control corresponding first blocks enabling transmission on such communication channels and corresponding second blocks enabling communication between the abovementioned channels.

Abstract: For detecting the position of a magnetic element having a field component zeroing in at least one point in space, typically in a plane, a plurality of elementary Hall-effect sensors are integrated side by side and aligned in a direction perpendicular to the zeroing field component and to the current flowing through the elementary sensors. The elementary sensor generating a zero output voltage therefore indicates the zero position of the field component and consequently the position of the magnetic element with respect to the position sensor, so that The outputs of the elementary sensors provide a quantized numeric code indicating the position of the magnetic element.

Abstract: A communication system of the multiplex type between a master processing unit incorporating a microprocessor and slave units associated in particular with electrical devices in a vehicle for activating or controlling at least one electrically functioning component of the corresponding device the slave units being connected in groups to the master unit by means of corresponding communication channels, and in which these slave units include logic means for the exchange of communication messages with the master unit and are capable of independently initiating transmission towards the master unit; such messages in particular include a first field for identification of the slave unit which is sending or is to receive the communication, a second data field, and a preliminary field used to activate such units from a resting state of minimum power consumption.

Abstract: The additional voltage drop across a guard diode against supply polarity inversion in an integrated bridge circuit for driving an external load and employing two high-side NPN power switches driven by two PNP transistors, all monolithically integrated using a junction-type isolation technique, is substantially eliminated by connecting the emitters of the two PNP drive transistors directly to the positive rail, i.e. to the anode of the guard diode. Integrated PNP transistors are per se intrinsically protected against polarity inversion and when so connected permit to reduce the overall voltage drop across the driving bridge circuit. Using a Zener diode as the guard diode and a second Zener diode connected in opposition to the first Zener between the cathode thereof and the negative supply rail an additional spike protection of the circuit's components is implemented.

Abstract: A circuit for holding a MOS power transistor in a conduction state on the occurrence of an outage in the voltage supply, being of a type which comprises a first MOS transistor having its source connected to a line of the voltage supply and its drain connected to the gate of the power transistor, further comprises a diode connected between the drain of the first transistor and the gate of the power transistor, and a second transistor of the MOS type having its gate connected to the gate of the first transistor drain connected to the gate of the power transistor. The circuit prevents the gate capacitance of the power transistor from becoming discharged on a failure of the voltage supply, thus holding that transistor in a conducting state.

Abstract: An improved logic interface circuit having both a low current drain under rest conditions and a great stability in respect of temperature variations, is based on an original and effective implementation of the so-called bandgap-type voltage reference circuit, according to which the intrinsic gain of the bandgap system is not utilized, as normally happens in such voltage reference circuits for providing a negative feedback capable of compensating the temperature coefficient of the V.sub.be, but for obtaining, under open loop conditions, a transition of the output of the circuit when the input of the circuit crosses a certain threshold voltage.

Abstract: In case of short circuit the overcurrent which passes through a detecting resistance in series with the excitation winding of the alternator operates a threshold current generator, which reduces the voltage of the central node of a voltage divider. A trigger interposed between said central node and an actuator circuit (for example a Darlington circuit) placed in series with the excitation winding of the alternator and with the above mentioned resistance turns off said actuator circuit, thus interrupting the current passage through the excitation winding. A filtering condenser associated to the voltage divider restores with delay the initial condition. The cycle is periodically repeated until the short circuit condition remains.

Abstract: An electric power generator which includes a component, for example, a Zener diode, connected in series with the usual return diode which is connected in parallel to the excitation winding of the alternator. The Zener diode makes it possible to set the discharging voltage due to the energy stored in the magnetic field associated with the inductance of the excitation winding at a relatively high level during high-voltage transients caused by the accidental disconnection of the wire connecting the alternator to a load or a terminal of the motor vehicle battery while it is in the charging stage. The result is a more rapid dissipation of the energy stored in the excitation circuit, and therefore results in an output transient having a reduced energy content. Thus, it is possible to construct a voltage regulator and such other devices as may be powered by the alternator in the form of low-voltage integrated circuits.

Abstract: The additional voltage drop across a guard diode against supply polarity inversion in an integrated bridge circuit for driving an external load and employing two high-side NPN power switches driven by two PNP transistors, all monolithically integrated using a junction-type isolation technique, is substantially eliminated by connecting the emitters of the two PNP drive transistors directly to the positive rail, i.e. to the anode of the guard diode. Integrated PNP transistors are per se intrinsically protected against polarity inversion and when so connected permit to reduce the overall voltage drop across the driving bridge circuit. Using a Zener diode as the guard diode and a second Zener diode connected in opposition to the first Zener between the cathode thereof and the negative supply rail an additional spike protection of the circuit's components is implemented.