摘要:
A voltage stabilizer with a very low voltage drop includes a series voltage regulator circuit having a first PNP transistor connected to an input terminal of the stabilizer via a second PNP transistor and being connected to ground via a capacitor. The stabilizer has biasing and switching circuits disposed between the input terminal thereof, a base terminal of the second transistor and ground.
摘要:
A voltage stabilizer with a minimal voltage drop designed to withstand high voltage transients includes a "series" type voltage regulator circuit with an NPN power transistor. The collector terminal of this transistor is connected to ground via a capacitor and to the cathode of a diode whose anode forms an input terminal of the stabilizer. The base terminal of the power transistor is connected to the collector terminals of first and second PNP transistors which have their emitter terminals respectively connected to the cathode and anode of the diode and their base terminals connected to a circuit biasing circuit.
摘要:
A voltage regulator comprising a first power switch connected between the input terminal and output terminal; a storage condenser connected to the input terminal via a one-way switch; a second power switch connected between the condenser and the input terminal; and a regulating element connected to the output terminal and driving the power switches in such a manner as to maintain the output voltage constant. For better distributing electric and thermal stress and improving the reliability and working life of the regulator by reducing the interference caused by switching of the two power switches, a drive device is provided between the regulating element and the switches for detecting the input voltage and the voltage of the condenser, and keeping both switches on as long as the input voltage is above two given thresholds, turning off the second switch when the input voltage is higher than the condenser voltage and below the first threshold, and turning off the first switch when the input voltage is lower than the condenser voltage and below the second threshold.
摘要:
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.
摘要:
In a pressure sensor with double measuring scale: a monolithic body of semiconductor material has a first main surface, a bulk region and a sensitive portion upon which pressure acts; a cavity is formed in the monolithic body and is separated from the first main surface by a membrane, which is flexible and deformable as a function of the pressure, and is arranged inside the sensitive portion and is surrounded by the bulk region; a low-pressure detecting element of the piezoresistive type, sensitive to first values of pressure, is integrated in the membrane and has a variable resistance as a function of the deformation of the membrane; in addition, a high-pressure detecting element, also of a piezoresistive type, is formed in the bulk region inside the sensitive portion and has a variable resistance as a function of the pressure. The high-pressure detecting element is sensitive to second values of pressure.
摘要:
Saturation of a bipolar power transistor is controlled by sensing the current which is eventually injected into the substrate of the integrated circuit by the saturating transistor and using this signal for exerting a limiting action on the current which is driven to the base of the power transistor by a dedicated driving circuit. Unlike the prior art antisaturation systems, it is no longer necessary to precisely monitor the operating voltages across the terminals of the bipolar power transistor. A suitable sensing resistance may be integrated conveniently at a distance from the often complex integrated structure of the bipolar transistor. The system of the invention offers numerous advantages and ensures intervention of the antisaturation circuit only when the power transistor has positively reached a state of saturation, but well before any unwanted consequence.
摘要:
A flip-flop circuit able to commute in correspondence with any logic transition of the input signal using a flip-flop and a logic gate of the EXNOR type receiving at its input a signal and the inverted output of the flip-flop. To the output of the EXNOR gate is connected a set-reset flip-flop which allows a reset to be effected after each commutation of the circuit in order to prepare it for the next transition.
摘要:
The device for protection comprises a zener diode voltage limiter having a breakdown voltage pre-set at a value (say, 30 volts) lower than the maximum value sustainable by the protected circuit in the closed condition and a quenching circuit having a pre-set lag controlled by each overvoltage impulse and suitable for disactivating said voltage limiter and to control the opening of said protected circuit with a time lag pre-set with respect to the start of each overvoltage impulse. In succession to said voltage limiter there is introduced in addition a zener diode with a higher breakdown voltage, say, equal to 110 volts, which allows the limitation to such a value of any overvoltages having a very low energy content superimposed over overvoltages having limited amplitude and long duration.
摘要:
A circuit for recirculating an inductive load's (L) discharge current through the driving power switching transistor (Tpw) utilizes a control transistor (Tc) of opposite polarity to that of the power transistor and capable of withstanding a minimum fraction (1/.beta.) of the discharge current. The circuit has the advantage of allowing recirculation of current with a fixed overvoltage independent of the value of the supply voltage, without requiring additional power devices. The circuit may also be provided with means (D1, D2 and DZ1) to turn-on the control transistor in the presence of concomitant supply overvoltages to protect the power device from dumping effects.
摘要:
An embodiment of an electronic device includes first and second semiconductor bodies. The first semiconductor body houses a first conductive strip having a first end portion and a second end portion, and houses a first conduction terminal electrically coupled to the first end portion and facing a surface of the first semiconductor body. The second semiconductor body houses a second conductive strip having a third end portion and a fourth end portion, and houses a second conduction terminal electrically coupled to the third end portion and facing a surface of the second semiconductor body. The first and second semiconductor bodies are arranged relative to one another so that the respective surfaces face one another, and the first conduction terminal and the second conduction terminal are coupled to one another by means of a conductive element so as to form a loop of an inductor.