CONTROLLER FOR A POWER SUPPLY SYSTEM IN A VEHICLE

A power supply system includes a first circuit (100), a second circuit (200) and a voltage controller (10). The first circuit (100) includes a first power supply line (102) connected to each of a first load (120, 121, 122, 123, 124, 125, 126, 127), a power supply source (103), and a first battery (101). The second circuit (200) includes a second power supply line (202) connected to a second load (211, 212, 213, 214, 215, 216, 217, 218, 219) and a second battery (201) connected to the second power supply line (202). The voltage controller (10) includes a DC-DC converter (17) connected between the first power supply line (102) and the second power supply line (202). The second load (211, 212, 213, 214, 215, 216, 217, 218, 219) is able to perform a function that substitutes for at least part of a function that the first load (120, 121, 122, 123, 124, 125, 126, 127) performs. The voltage controller (10) includes a converter control unit (13) configured to control the DC-DC converter (17)such that an output voltage higher than or equal to a voltage of the second battery (201) is output to the second power supply line (202).