Electric charge control device having a switching regulator and a series regulator

A load driving device includes an electric charge control unit 3, which charges a secondary battery 7 with a direct-current voltage from a DC/DC converter 2 that converts a high voltage from a high-voltage battery 1 into a low voltage. The electric charge control unit 3 includes a switching regulator 11, a series regulator 12 a voltage-current detector 13 for detecting the output voltage of the switching and series regulators, and a control means 14 which controls the operation of the switching regulator and series regulator depending on the voltage detected. The device is particularly for use in a vehicle where the load 6 may be an E.C.U.