Backup power supply control system, backup power supply system, and moving vehicle

A backup power supply control system comprising:

• a first semiconductor switch configured to switch a main power supply line to either an electrically conductive state or an electrically non-conductive state, the main power supply line connecting a main power supply to a load;
• an auxiliary power supply switch configured to switch an auxiliary power supply line to either the electrically conductive state or the electrically non-conductive state, the auxiliary power supply line connecting an auxiliary power supply to the load;
• a failure detection unit configured to determine whether the main power supply is in a failure state or a non-failure state;
• a first driving unit configured to control, in the non-failure state, the first semiconductor switch ON and control, in the failure state, the first semiconductor switch OFF;
• and
• a second driving unit configured to control, in the non-failure state, the auxiliary power supply switch OFF and control, in the failure state, the auxiliary power supply switch ON,
• the first semiconductor switch being an MISFET,
• the first driving unit including:
• a voltage divider circuit configured to divide a voltage on the main power supply line and apply the voltage thus divided to between a gate and source of the first semiconductor switch;
• and a second semiconductor switch connected between the gate and source of the first semiconductor switch,
• the first driving unit being configured to, when the failure detection unit detects the non-failure state, control the second semiconductor switch OFF and thereby control the first semiconductor switch ON,
• the first driving unit being configured to ensure, in the failure state, at least a gate-plateau voltage of the first semiconductor switch as a drive voltage for the second semiconductor switch,
• the first driving unit being configured to, when the failure detection unit detects the failure state, control the second semiconductor switch ON and thereby control the first semiconductor switch OFF.