POWER SUPPLY SYSTEM

A power supply system includes a DC-DC converter, a relay, and a control unit configured to i) start up the DC-DC converter based on a state transition of an ignition signal from OFF to ON, ii) causethe DC-DC converter to output a first low voltage when a high-voltage battery is connected to the DC-DC converter by the relay, iii) cause the DC-DC converter to output a voltage specified by an output voltage command in a case where the output voltage command is provided from a high-order ECU after output of the first low voltage is started, and iv) cause the DC-DC converter to output a fixed voltage higher than the first low voltage in a case where the output voltage command is not provided from the high-order ECU by a time at which a first time elapses after the output of the first low voltage is started. 电源系统，其包括DC-DC转换器、继电器和控制单元，该控制单元配置为：i)基于点火信号从OFF到ON的状态转变而启动DC-DC转换器，ii)当高压电池通过继电器连接至DC-DC转换器时，使得DC-DC转换器输出第一低压，iii)在第一低压的输出开始之后，在从高阶ECU提供输出电压命令的情况下，使得DC-DC转换器输出由输出电压命令所指定的电压，iv)在第一低压的输出开始之后，在第一时间过去之前没有从高阶ECU提供输