Bendix Electronics S.a.

Michel Suquet

The circuit according to the invention comprises a hysteresis comparator 9 connected to a transistor 2 controlling the current flowing in an inductive load 1. The voltage taken across the terminals of a measurement resistor 3 is compared with a reference voltage established by a source 6. According to the invention, a feedback loop 10 establishes a proportional action of the transistor 2 on the current in the load 1 when the voltage at S exceeds a predetermined threshold. In this way an oscillation is obtained between two values on either side of a nominal value, these two values being associated with the thresholds of the hysteresis comparator. Application to the production of an integrated circuit for the control of the ignition coil of an internal combustion engine.

Circuit for regulating current in an inductive load

The circuit comprises a comparator 1 fed by a quasi-sinusoidal signal delivered by a source 2 for converting the positive alternations of the signal into pulses acceptable by digital computing means. According to the invention, the circuit comprises a current source 7 selectively connectible to the circuit in order to vary its sensitivity and to thus enable an evaluation of the amplitude of the signal delivered by the source 2. Application to the diagnosis of the operating state of a variable reluctance sensor delivering a quasi-sinusoidal signal representing the speed of rotation of a shaft fitted in a motor vehicle.

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Cugnaux, France

Michel Suquet