Mitsubishi Electric Corporation

Takayuki Ubukata

Nobuhiro Kihara

Naoki Itoi

A vehicle power-supply unit has chargeable and rechargeable first power supply and second power supply connected to a voltage transducer at input and output terminals, respectively, and a switch element connected between the output terminal of the voltage transducer and the second power supply. By controlling a rector current flown through a reactor connected to at least two switching elements at one end when the voltage transducer is started, a capacitor connected between the other end of the reactor and the ground is charged, and the switch element is brought in a connection state according to a charging voltage of the capacitor and a voltage value of the second power supply. Consequently, a vehicle power-supply unit can protect the elements by preventing a rush current during a backflow and reverse connection and at start-up.

Vehicle power-supply unit

A vehicular power supply device mounted on a vehicle equipped with an idle stop function is provided that enhances engine startability and suppresses a voltage drop at a battery driving the starter, so as to reduce energy consumption by the engine or other drive sources. The device includes a voltage converter for converting a DC voltage Voutput from a generator into a DC voltage control value Vand for outputting the value, and when the idle-stop determination unit determines that the engine is in the idle stop state, the voltage converter outputs, depending on a current and voltage supplied to an electrical load including a starter, a second DC voltage control value Vhigher than a first DC voltage control value Vthat is a target output voltage for the battery.

Growing community of inventors

Chiyoda-ku, Japan

Takayuki Ubukata