Patent ID: 7453232

Claim:
A power supply apparatus for a vehicle, the power supply apparatus comprising: a driving battery including a plurality of battery modules that are connected to each other in series, said driving battery to be connected to a chassis of the vehicle via a leakage detection resistance; and a voltage detection circuit operable to detect a voltage of said driving battery, said voltage detection circuit comprising: a multiplexer having a plurality of channels, with a number of said plurality of channels being not less than a number of said plurality of battery modules of said driving battery, said multiplexer being operable to switch one of said plurality of battery modules of said driving battery of which a voltage is to be detected; and a voltage detection portion operable to detect a voltage of one of said plurality of battery modules of said driving battery switched to by said multiplexer; wherein said voltage detection circuit is operable to detect a chassis voltage induced across said leakage detection resistance by switching to one of said plurality of channels of said multiplexer of said voltage detection circuit which is not in use for switching said plurality of battery modules of said driving battery, thereby detecting a leakage resistance based on said chassis voltage.