Sgs-thomson Microelectronics S.r.l.

Valeo Equipements Electriques Moteur

Sgs-thomson Microelectronics Limited

Alessio Pennisi

Fabio Marchio

Didier Canitrot

Jean M Pierret

Jean-Marie Pierret

Francois Brandy

A voltage reference circuit with programmable thermal coefficient, comprising first and second bipolar transistors having their base terminals connected together and collector terminals connected to two legs of a current mirror circuit. The emitter terminal of the first transistor is connected to ground through two resistors in series with each other, and the emitter terminal of the second transistor is connected to a node between the two resistors. The emitter of at least one of the two transistors has discrete portions adapted to be connected electrically together in a predetermined fashion.

Voltage reference circuit with programmable thermal coefficient

A bandgap type, thermal protection circuit for an integrated circuit does not require the use of a comparator and a voltage divider of the bandgap voltage. By contrast, the simplified thermal protection circuit of the invention utilizes a first transistor for mirroring the current flowing through the bandgap circuit through a second transistor that is functionally connected between the output node and ground. The control terminal of the second transistor is connected to a temperature dependent voltage derived from the bandgap circuit. The crossing point between the characteristic of such a temperature dependent voltage and of the VBE characteristic of the second transistor versus temperature determine the required transition on the output node.

Thermal protection circuit

The functioning of a simple voltage regulator loop of an integrated power stage employing a plurality of bond-wires is ensured by realizing a conductive path connecting said pads to each other having a resistance lower by at least two orders of magnitude than the resistance of a voltage sensing divider of the regulation loop. Eventual ruptures of any of the bond-wires remain detectable through a final testing of the integrated circuit.

Safeguard for integrated power stages employing multiple bond-wires to a

A time delay filter includes at least one field-effect transistor of the MOS type and at least one bipolar transistor having their respective base and gate terminals connected together. The bipolar transistor is coupled to an input terminal through a drive transistor, and the field-effect transistor is coupled to an output terminal. The charge time for the gate capacitance of the field-effect transistor, using the low base current of the bipolar transistor, enables high-frequency noise to be filtered out of input digital signals.

Time delayed filter monolithically integratable

A detection circuit for detecting the voltage between phases of a polyphase alternator for the purpose of controlling the putting into operation of a regulator for regulating the charging of a motor vehicle battery by said alternator, the circuit comprising differential discrimination means for the amplitude of the voltage between a pair of phase signals delivered by the alternator. The differential discrimination means comprise a pair of transistors each constituting means for comparing the inter-phase voltage with a threshold voltage defined by its emitter-base junction voltage, said threshold voltages being of small magnitude and of opposite polarity with respect to each other.

Circuit for detecting the inter-phase voltage of an alternator for

A regulator device for charging a battery from an alternator that delivers a rectified voltage including a ripple component. The device is of the type including a regulator circuit acting on the mean value of the rectified alternator voltage and includes a circuit for obtaining the main value, a threshold comparator, a time delay circuit, and a power stage for controlling the current flowing through the excitation winding of the alternator. According to the invention, the device includes a negative feedback circuit between a point downstream from the time delay circuit, and the input to the circuit for obtaining the mean value. The device also shifts the mean value downwards during periods when the excitation current is decreasing. The device is particularly applicable to increasing the frequency of regulation under a heavy load.

Voltage regulator device for charging a battery by an alternator

The invention relates to a regulator device for charging a battery by an alternator that delivers a rectified voltage including a ripple component. The device is of the type comprising a regulator circuit acting on the mean value of the rectified alternator voltage and a regulator circuit acting on the voltages of the positive peaks of the ripple component. The regulator circuits are powered by a stabilized voltage derived from the rectified alternator voltage and the device further comprises a power stage for controlling the excitation current of the alternator. According to the invention, the device further includes a regulator circuit acting on the values of the negative peaks of the ripple component. This regulator circuit is also powered by the stabilized voltage, and capable of causing the excitation current to be reduced whenever the voltage of the negative peaks falls below a given threshold.

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Milan, Italy

Alessio Pennisi