A power MOS voltage regulator for recharging batteries of motor vehicles; a voltage generator is selectively connected to a battery, respectively to an earth by a controlled rectifier bridge. The rectifier bridge includes a Schottky diode connected between each phase winding of the generator and the positive terminal of the battery, and a power MOS transistor branched between the phase winding and the earth; a control electrode of the power MOS transistor is driven by a control circuit for controlling the charging state of the battery, to enable the changeover of the power MOS transistor between a conductive state and a non conductive state, and vice versa, when the voltage of the phase winding is zero.