Power supply unit and its control device

A control device comprising a power supply unit and a control unit externally connected to the power supply unit,

• the power supply unit including:
• a sub power supply;
• a sub power supply line that connects the sub power supply to a load;
• a first semiconductor switch serially connected to the sub power supply line by connecting a source thereof to the sub power supply;
• a second semiconductor switch serially connected to the sub power supply line by connecting a drain thereof to a drain of the first semiconductor switch;
• and
• a sub control unit that controls on/off of the first semiconductor switch and the second semiconductor switch, and monitors a drain voltage between the first semiconductor switch and the second semiconductor switch and a source voltage of the second semiconductor switch, to thereby perform fault diagnosis, and
• the control unit including:
• a sub power supply line connected to the sub power supply line of the power supply unit to connect the sub power supply to the load;
• a third semiconductor switch serially connected to the sub power supply line by connecting a source thereof to the sub power supply;
• a fourth semiconductor switch serially connected to the sub power supply line by connecting a drain thereof to a drain of the third semiconductor switch;
• a main power supply line that connects a main power supply separate from the sub power supply to the load and is provided in parallel with the sub power supply line;
• a relay provided in the main power supply line;
• and
• a main control unit that controls on/off of the relay, the third semiconductor switch, and the fourth semiconductor switch, and monitors a drain voltage between the third semiconductor switch and the fourth semiconductor switch and a source voltage of the third semiconductor switch, to thereby perform fault diagnosis.

A control device comprising a power supply unit and a control unit externally connected to the power supply unit,

• the power supply unit including:
• a sub power supply;
• a sub power supply line for connecting the sub power supply to a load;
• a first semiconductor switch serially connected to the sub power supply line, that is switched on to cause a current to flow between a source and a drain;
• a second semiconductor switch serially connected to the power supply line on a load side of the first semiconductor switch, that is switched on to cause a current to flow between a source and a drain, and is switched off to cause a discharge current to flow from the sub power supply by a parasitic diode;
• and
• a sub control unit that controls on/off of the first semiconductor switch and the second semiconductor switch, and monitors a voltage between the first semiconductor switch and the second semiconductor switch, and a voltage on a load side of the second semiconductor switch, to diagnosis a fault of the first semiconductor switch and the second semiconductor switch, and a fault of a power supply drain on a load side of the second semiconductor switch, and
• the control unit including:
• a sub power supply line connected to the power supply line of the power supply unit and connected to the load;
• a third semiconductor switch serially connected to the sub power supply line, that is switched on to cause a current to flow between a source and a drain, and is switched off to cause a current to flow towards the control unit side via a parasitic diode;
• a fourth semiconductor switch serially connected to the sub power supply line on a load side of the third semiconductor switch, that is switched on to cause a current to flow between a source and a drain, and is switched off to cause a discharge current to flow from the power supply unit side via a parasitic diode;
• a main power supply line serving as a power supply line that connects a main power supply provided separate from a sub power supply of the power supply unit, to the load, and which is provided in parallel with the sub power supply line;
• a relay provided in the main power supply line;
• and
• a main control unit that controls on/off of the relay, the third semiconductor switch, and the fourth semiconductor switch, and monitors a voltage between the third semiconductor switch and the fourth semiconductor switch and a voltage on the power supply unit side of the third semiconductor switch, to diagnose a fault in the third semiconductor switch and the fourth semiconductor switch, and a fault in a sub power supply line on a power supply unit side of the third semiconductor switch,
• the sub control device and the main control device controlling the first semiconductor switch, the second semiconductor switch, the third semiconductor switch, the fourth semiconductor switch, and the relay, to thereby connect either one of the sub power supply and the main power supply to the load.