Excitation circuit of a motor vehicle alternator, voltage regulator, and alternator which incorporates 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 an on-board network voltage control loop (Vbat+, 3) of the vehicle, and comprises a first MOS power transistor (9) which is connected between a first positive supply terminal Vbat+ (6), and a first excitation terminal (7), and is controlled by the control loop by means of a first control circuit (10), a second MOS power transistor (11), which is connected between the first excitation terminal and a second excitation terminal (8) which is connected to a ground terminal (5) and acts as a free wheel diode, whilst being controlled by means of a second control circuit (12). According to the invention, the circuit additionally comprises a control loop (15) of a drain-source voltage (Vds) of the second transistor.