CIRCUIT FOR EXCITATION OF A MOTOR VEHICLE ALTERNATOR, VOLTAGE REGULATOR AND ALTERNATOR INCORPORATING IT

摘要

The excitation circuit according to the invention controls an excitation current (lexc) in an excitation winding (2) of an alternator by means of a regulation loop of an on-board voltage (Vbat +, 3 ) of the vehicle, and comprises a first MOS power transistor (9) connected between a first positive power supply terminal Vbat + (6) and a first excitation terminal (7) and controlled by the regulation loop by means of a first driving circuit (10), and a second MOS power transistor (11) connected between the first excitation terminal and a second excitation terminal (8) connected to a ground terminal (5) and acting as a diode freewheel by being controlled by means of a second control circuit (12). According to the invention, the circuit further comprises a servocontrol loop (15) of a drain-source voltage (Vds) of the second transistor.