Vehicle power supply apparatus

A vehicle power supply apparatus, comprising:

• a first device battery and a second device battery configured to supply electric power to an electric device of a vehicle;
• a power supply line including a first end and a second end between which a first switch and a first diode are interposed, the first diode being directed to make a current flow from the first switch, the power supply line including a first segment, a second segment, and a third segment, the first segment being coupled between the first end and the first diode, the second segment being coupled between the first diode and the first switch, and the third segment being coupled between the first switch and the second end;
• and
• a current path routed from the third segment to the first segment through a second diode, to bypass the second segment, the second diode being directed to make a current flow toward the first segment,
• the electric device being coupled to the first segment,
• the second device battery being coupled to the second segment, and
• the first device battery being coupled to the third segment through a second switch.