| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a vehicle power supply device which can operate a DC/DC converter with high efficiency even if the current changes. <P>SOLUTION: The vehicle power supply device comprises the DC/DC converter 15 connected between a high voltage power storage unit 11 and a low voltage power storage unit 19, an output current detection unit 23, a load current detection unit 25, a low voltage power storage unit voltage detection circuit 27, and a control unit 29 being connected with them. The control unit 29 drives the DC/DC converter 15 so that power storage unit voltage Vb is maintained at a default power storage unit voltage Vbk when output current Io is equal to or higher than a default output current Iok, and repeats an operation to stop the DC/DC converter 15 until the amount of charges discharged Qd of the low voltage power storage unit 19 reaches a default amount of charges discharged Qdk while the output current Io is equal to or lower than the default output current Iok, and the operation to drive the DC/DC converter 15 so that the default output current Iok flows to an output terminal 17 over a drive period tc when the amount of charges discharged Qd reaches the default amount of charges discharged Qdk. <P>COPYRIGHT: (C)2012,JPO&INPIT |
