Sgs-thomson Microelectronics S.r.l.

Mirco Contucci

Giampietro Maggioni

Valerio Giorgetta

Paolo Mastella

A circuit comprises a measurement resistor in series with a heater, a detector circuit for providing a signal indicative of the current flowing in the resistor, switching devices for controlling the connection of the heater to a voltage source and the connection of the measurement resistor in the supply circuit comprising the source and the heater, and a control unit arranged to drive the switching devices in a manner such that each time the heater is activated, the measurement resistor is kept disconnected from the supply circuit of the heater for a predetermined period of time and the measurement resistor is then connected in the supply circuit of the heater.

Heater control circuit

A circuit for regulating the charging voltage to a battery and connected to the field inductor (IND) of an alternator (ALT) which supplies that voltage. It is connected by a control cable to the battery and comprises an electric path, extending between a terminal for connection to the alternator and ground, which is only activated when the battery voltage drops below a predetermined threshold value. This electric path comprises a switch (TSW) driven from a control circuit (COMP1,T4) which sense the battery voltage, and when activated, the voltage drop across the path is substantially equal to that of the regulated voltage. The control circuit also senses breakage in the battery sensing cable, and ceases driving the alternator when this occurs.

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Sant'Arcangelo, Italy

Mirco Contucci