Relay control apparatus

A relay control apparatus for receiving a supply of power and controlling a latching relay including a closing side coil and an opening side coil, the relay control apparatus comprising:

• a power supply control unit including a power supply resistor and a power supply switch connected in parallel between a first electrode and a connection point between a first end of the closing side coil and a first end of the opening side coil;
• a relay close control unit including a relay close switch connected between a second electrode and a second end of the closing side coil;
• a relay open control unit including a relay open switch connected between the second electrode and a second end of the opening side coil;
• a voltage detection unit including a voltage detection resistor and a voltage detection switch connected in series between the connection point and the second electrode, the voltage detection unit being configured to output a voltage signal based on a voltage of the connection point;
• and
• a control unit configured to output a power supply signal for controlling ON/OFF of the power supply switch, a relay close signal for controlling ON/OFF of the relay close switch, a relay open signal for controlling ON/OFF of the relay open switch, and a detection signal for controlling ON/OFF of the voltage detection switch, the control unit being configured to detect malfunction based on the power supply signal, the relay close signal, the relay open signal, the detection signal, and the voltage signal,
• wherein the control unit has a diagnosis mode, and the control unit is configured to change the power supply signal to an OFF state in a case where, in the diagnosis mode, the relay close signal is changed to an ON state or the relay open signal is changed to an ON state.