Power supply and drive device for a permanent magnet motor including a full-wave voltage rectifier stage, which can be supplied with an alternating current voltage to provide a rectified voltage, a power factor corrector stage, a smoothing capacitor to provide a direct current voltage and a motor drive stage, which is supplied with the direct current voltage and provides a signal indicating the power required by the motor. The smoothing capacitor is not of the electrolytic type and the power factor corrector stage has feedback control means to generate a reference current as a function of the direct current voltage and of the signal indicating the power required and to control an input current of the power factor corrector stage as a function of the reference current.