Starter circuit for a motor vehicle comprising a device for stepping up the battery voltage and starter so equipped

The combination has a starter comprising a direct current electric motor (DCM) and an electromagnetic contactor (EC), and a stepping up device preventing a drop of battery voltage (Vbat) consecutive to current peak produced by start-up in a power circuit of the starter. An inductive filtering device (LPF) i.e. armored transformer, is mounted in series with the motor. The filtering device has a secondary winding circuit (W2) in short-circuit and a reverse pre-polarization unit formed of a coil and a permanent magnet for reverse pre-polarization of magnetic circuit formed in a magnetic carcass.