| 摘要 |
A circuit device is described for controlling the piloting voltage applied to the solenoid of an electromagnet associated with an electric starter motor of an internal combustion engine of a motor vehicle. This control device comprises: a voltage generator operable selectively to provide a first predetermined reference voltage corresponding to a desired speed of displacement of the movable core coupled to the solenoid, and a second reference voltage of lower value than the first; a sensor operable to provide a signal indicative of the current flowing in the solenoid; an amplifier having a variable gain with its input connected to this sensor; and a summing device with first and second inputs connected to the generator and the output of the amplifier respectively, and having an output connected to the solenoid. A control and calibration circuit controls the generator when the control device is activated, initially to generate a low reference voltage and then to provide the amplifier with a signal such that its gain increases until the voltage applied to the solenoid reaches a predetermined maximum value, and the signal at the output of the amplifier corresponds to the voltage drop across the resistance of the solenoid; it finally maintains the gain of the amplifier at this value and controls the generator to generate the first reference voltage.
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