Abstract: An antisaturation circuit for an integrated PNP transistor, having a generic current generator in the base branch of the bias circuit capable of limiting the maximum base current, comprises two NPN transistors, a diode and a voltage divider formed by two resistors, and permits to limit the base current of the PNP transistor below the maximum value, set by the current generator, every time the voltage across the base-collector junction of the PNP transistor exceeds a certain preset value thus preventing saturation or limiting it.

Abstract: This dynamic protection device is particularly intended for integrated circuits having input MOS stages and logic or analog inputs fed by voltages and/or currents whose value can increase above those bearable with traditional protection systems. The device is composed of a first section for protection against voltages above a first set threshold value and a second protection section against voltages below a set threshold value. The device is made in MOS technology and is disposed between the input of the circuit to be protected and the power supply.

Abstract: Four switches are controlled two by two by clock signal generators without overlapping in such a manner as to connect alternatively a sampling capacitor to an input signal source and in parallel to an integration capacitor between an input of a unitary-gain amplifier and ground.

Abstract: The voltage regulating device, compensating the error due to the heat dissipated by the power element that drives the load, specifically an excitation winding of a motor car battery charging alternator, comprises a control stage including a temperature sensing element and a power stage driven by the control stage for generating an output voltage dependent on the ambient temperature. The power stage includes a sensor for detecting the power dissipated therein and generating a dissipated power signal fed to a compensation section in the control stage which also receives the temperature signal detected by the temperature sensing element for generating an actual ambient temperature signal unaffected by the error due to internal heat dissipation.

Abstract: A short circuit protection device for a unitary voltage gain signal transducer circuit (G.sub.v) and for a load impedance (R.sub.L) coupled to the transducer circuit includes a first (A.sub.1) and a second (A.sub.2) threshold comparator circuit and an actuator circuit (ACT). The input terminals of the first comparator (A.sub.1) are coupled to the transducer circuit input and output terminals and the output terminal of the first comparator is coupled to an activation terminal of the actuator circuit. The input terminals of the second comparator (A.sub.2) are coupled to the ends of the load impedance and the output terminal is coupled to an inhibit terminal of the actuator circuit. A first output terminal of the actuator circuit is coupled to an inhibit terminal of the transducer circuit, while a second output terminal of the transducer circuit is used to deliver a small current I.sub.1 to the load impedance.

Abstract: This integrated semiconductor device aims at drastic reduction of the direct secondary breakdown phenomena and has a plurality of side-by-side elementary transistors forming an interdigited structure. To reduce the thermal interaction between the elementary transistors, the latter are spaced apart from one another by a distance approximately equal to the width of one elementary transistor and are driven by current sources. Spacing apart reduces electrothermal interaction. Further, in order to minimize the device area requirements, the space between any two adjacent elementary transistors is made to accommodate drive transistors operating as current sources, or the elementary transistors of the complementary stage where the device forms a class B output stage, the two output transistors whereof are alternatively switched on.

Abstract: A telephone circuit for ring trip detection that can be monolithically integrated, includes a current transducer coupled to a user's telephone line, and an integrator circuit. The output current of the current transducer is proportional to the line current until equal and opposite threshold values are reached. When the line current threshold values are exceeded, the transducer output current is constant. The transducer output current is integrated by the integrator circuit over at least one complete cycle. When a telephone headset is removed, a direct current is applied to the ringing signal current resulting in asymmetry in the half-cycles of the transducer output current. The asymmetry provides a non-zero integrated current for a complete cycle. When the integrated value of the asymmetrical current is greater than a selected value, a signal is applied to the ringing circuit, halting the ringing signal.

Abstract: In an audio switching power amplifier, muting apparatus provided for eliminating noise signals associated with turn-on and turn-off operations of the apparatus is disclosed. The muting apparatus disables the output power amplifiers and controls signal levels at various positions in the power amplifier to reduce transient conditions. Control apparatus applies the muting signals to the power amplifier during a predetermined period during start-up of the amplifier and applies the muting conditions immediately upon the turning off of power to the power amplifier.

Abstract: A power transistor comprising a plurality of elementary transistors coupled in parallel and an identical number of current generators, each of which has a terminal coupled individually to the base of an elementary transistor is described. High power levels may be achieved with a transistor of this type without forward secondary breakdown taking place.

Abstract: This high accuracy, RC oscillator, particularly for monitors, has different switch-over thresholds independent from such variable parameters as the saturating voltage of transistors, and has a high operating frequency. The oscillator comprises a capacitor having an output terminal, a capacitor power current source, and a control section. The control section is composed of a plurality of differential stages sharing a common input and each having an input connected to a different switch-over threshold. The control section further comprises a switch-over drive stage connected to the oscillator output terminal and to an input terminal thereof for controlling activation and deactivation of the different differential stages (and hence, of the respective associated thresholds) according to the signal present at the output and input terminals of the oscillator.

Abstract: The invention relates to a method for the manufacture of high voltage semiconductor devices with at least one planar junction with a variable charge concentration.The method consists in doping with impurities of a same type, in a region of monocrystalline semiconductor material, a first zone, and then a second zone which comprises the first, and so on, and in carrying out a subsequent heat treatment so as to provide a planar junction with a stepped profile and a concentration of impurities which decreases from the center to the periphery in a predetemined range. In this way the intensity of the surface electric field, when the junction is reverse biased, is reduced as a result of which it is possible to provide planar junctions having very high breakdown voltages of some thousands of volts.

Abstract: In a buffer with an operational amplifier having two inputs and two outputs and two feedback capacitances are inserted two other capacitances which in the measurement stage are switched in parallel to the feedback ones with opposite sign in such a manner as to cancel out the effects on the output voltage signal.