| abstract |
A power supply system using a high voltage circuit as a backup power supply for a low voltage circuit, which can quickly finish the precharging of a capacitor provided in the high voltage circuit. A power supply system 1 of a vehicle V includes a high voltage circuit 2 including a high voltage battery 21 connected to a main circuit 29, a system ECU 8 for controlling the main circuit 29, a low voltage battery 31, and the system ECU 8. A first system control power line 32 to be connected, a second system control power line 53 connecting the high voltage circuit 2 and the first system control power line 32, a step-down device 55 to step down the power from the high voltage circuit 2, When precharging the smoothing capacitors C1 and C2 provided in the main circuit 29 by supplying power of the second switch 59 provided on the system control power line 53 and the high voltage battery 21, the second switch 59 is used. And a backup power source ECU 57 for turning off the power. [Selected figure] Figure 1 |