Sgs-thomson Microelectronics S.r.l.

Other

Sgs-thomson Microelectronics S.p.a.

Stmicroelectronics S.r.l.

Sgs Microelettronica Spa

Mauro Merlo

Franco Cocetta

Silvano Coccetti

Silvano Gornati

David F Swanson

Bruno Murari

Maurizio Zuffada

Sergio Lecce

Pietro Erratico

Fabio Marchio

Roberto Viscardi

Loic Lietar

Massimo Grasso

Alessandro Zafarana

Luigi Gervasi

A system and method regulates an alternator charging system and includes a memory for storing and regulating voltages used at specific temperatures for the specific alternator charging system requirements of an alternator. A circuit generates a digital signal indicative of both temperature of a battery supplied by the alternator charging system and the charging system voltage. A digital comparator receives the digital signal and compares the digital signal with the regulating voltage stored within the memory for the specific temperature that is indicative of the temperature of the battery supplied by the alternator charging system to generate a regulator control signal.

Programmable system and method for regulating an alternator

A system and method regulates an alternator and includes a circuit for digitally generating a sawtooth waveform. An error amplifier circuit generates a divided down and error amplified alternator system voltage. A comparator circuit receives and compares to each other the digitally generated sawtooth waveform and the error amplified alternator system voltage and has an output to produce an alternator field input signal used for driving the field of an alternator.

System and method for regulating an alternator

Relatively low currents are monitored through an integrated DMOS power transistor in a low-side driver configuration. A feedback circuit is responsive to the voltage applied to a gate of the DMOS power transistor to limit the minimum value to which the drain-source voltage may drop to keep it sufficiently high, and to allow a reliable monitoring of the current through the power transistor, even at relatively low levels. This is performed by increasing the conduction resistance of the power transistor at low current levels.

Monitoring of low currents through a low-side driver DMOS by modulating its internal resistance

A voltage regulator of the type comprising a linear filter, a comparator, and a stretcher filter which are connected in cascade with one another between an input terminal and an output terminal of the regulator. The input terminal receives an error signal as converted by the comparator into a square-wave error signal, and the output terminal deliveres a square-wave output control signal which has a stretched duty cycle over the square-wave error signal by a time delay introduced from the stretcher filter. The regulator further comprises a non-linear filtering section for the error signal which is connected between the input terminal of the regulator and the linear filter and has linear gain with the error signal below a first value, gain approximately of unity with the error signal between the first value and a second value, and zero gain with the error signal above the second value.

Non-linear voltage regulator, particularly for an automotive alternator

A reference voltage generator having a dual slope temperature characteristic, for use in an automotive alternator voltage regulator, comprises a bandgap circuit (R1,R2,R3,R4) which generates a voltage (A) having a thermal drift coefficient of zero and a voltage (B) having a non-zero thermal drift coefficient. These voltages are applied to a voltage divider (R5,R6) and a voltage-follower type of circuit (OPA1). A unidirectional conduction amplifier circuit (OPA2) has an input terminal connected to an intermediate point (C) on the voltage divider. A second voltage divider (R7,R8) is connected between the output terminals of the voltage-follower circuit (D) and the amplifier circuit (E) . An intermediate node (F) of the second voltage divider is coupled to an output terminal (VREF) of the generator.

Reference voltage generator, having a double slope temperature

A device for controlling the linearity of a horizontal deflection stage comprising a deflection yoke supplied with a yoke current controlled by a switch and series-connected to a capacitor for varying the yoke voltage according to the phase of the yoke current; the device comprising a circuit for detecting and generating a real signal proportional to the yoke current, a ramp generator for generating an ideal ramp signal having rising portions defining a given S-shaped wave:form, and an error amplifier for receiving the real and ideal ramp signals and generating an error signal for driving a power transistor having its emitter and collector terminals connected parallel to the capacitor for modifying the voltage in the capacitor so that the yoke current assumes the required waveform.

Horizontal deflection stage linearity control device

A broad operational range, automatic device for the change of frequency in the horizontal deflection of multi-synchronization monitors comprises an integrated circuit incorporating,

Broad operational range, automatic device for the change of frequency in

The circuit, particularly suitable for high-definition monitors, wherein a power amplifier is fed by a supply voltage source to generate a deflection current in a yoke, furthermore comprises switching means which are activatable to connect another source of a supply voltage higher than the source to the amplifier, and flyback detector means to activate said switching means at the beginning of the flyback.

Vertical deflection circuit for kinescope yokes, with flyback voltage

A high capacity current mirror circuit comprises an operational amplifier electrically connected with its input, on the one side, to both a reference current source and a power supply pole through a first resistor, and on the other side, to said power supply pole through a second, feedback resistor, said amplifier being connected with its output to the base of a transistor, thereby supplying a current which is a mirror image of the reference current. According to the invention, that transistor is of the npn type, and in one embodiment, the transistor is connected in a Darlington configuration at the output of the operational amplifier which is of the transconductance type.

High capacity current mirror circuit

This generator of periodic signals with exponential edges, which may be integrated at low cost, comprises a current source circuit connected to a capacitor and to a resistive element to supply them with currents having mutually correlated amplitudes, an amplifier interposed between the capacitor and the resistive element and adapted to maintain the voltage drop on the resistive element proportional to the voltage drop on the capacitor, and a switch device, connected in parallel to the capacitor and periodically switched off to allow the discharge of the capacitor.

Generator of periodial signals, in particular for switch-mode power

An amplifier stage with variable gain dependent on the anode voltage is interposed between a ramp generator having constant amplitude ramp output voltage and the vertical deflection stage in such a manner as to vary the input voltage of said vertical deflection stage in accordance with anode voltage variations. In such a manner the vertical deflection current varies correspondingly.

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Pavia, Italy

Mauro Merlo