Power source, supervisory apparatus and control system
A power source supervisory apparatus is provided with a connection path that connects between a first path and a second path, an inter-path switch SW provided on the connection path, a current limiting element disposed to be in series to the inter-path switch SW on the connection path enabling a conduction from a first path side to a second path side under a current limiting state and obstructing conduction from the second path side to the first path side, a supervisory unit that supervises occurrence of a voltage drop on the first path in a state where the inter-switch is closed, and a switch operation unit that opens the inter-path switch SW when the supervisory unit determines that a voltage drop occurs on the first path.
1 . A power source supervisory apparatus adapted for a control system provided with an electronic control unit (“ECU”) comprising a first control apparatus and a second control apparatus that each comprise a processor and associated memory and are capable of controlling an electrical load, power being supplied to the first control apparatus from a first power source via a first path and power being supplied to the second control apparatus from a second power source via a second path, the power source supervisory apparatus comprising:
a connection path that connects between the first path and the second path;
an inter-path switch provided on the connection path;
a current limiting element in series with the inter-path switch on the connection path and enabling conduction from a first path side to a second path side under a current limiting state and obstructing conduction from the second path side to the first path side; and
a hardware circuit or microcomputer composed of a processor and memory and configured to
supervise occurrence of a voltage drop on the first path in a state where the inter-switch is closed; and
open the inter-path switch when the supervisory unit determines that a voltage drop occurs on the first path.
2 . The power source supervisory apparatus according to claim 1 , wherein
a diode is provided as the current limiting element such that a forward direction thereof is a direction towards the second path side from the first path side.
3 . The power source supervisory apparatus according to claim 1 , wherein
a pair of semiconductor switches are provided in series on the connection path in which directions of parasitic diodes are mutually opposite; and
one semiconductor switch in the pair of semiconductor switches serves as the inter-path switch and the parasitic diode of the other semiconductor switch serves as the current limiting element.
4 . A control system comprising:
an electronic control unit (“ECU”) comprising a first control apparatus and a second control apparatus that each comprise a processor and associated memory and are capable of controlling an electrical load;
a first path though which power is supplied to the first control apparatus from a first power source;
a second path though which power is supplied to the second control apparatus from a second power source;
a power source supervisory apparatus comprising:
a connection path that connects between the first path and the second path;
an inter-path switch provided on the connection path;
a current limiting element disposed in series with the inter-path switch on the connection path and enabling conduction from a first path side to a second path side under a current limiting state and obstructing conduction from the second path side to the first path side; and
a hardware circuit or microcomputer composed of a processor and memory and configured to
supervise occurrence of a voltage drop on the first path in a state where the inter-switch is closed; and
open the inter-path switch when it is determined that a voltage drop occurs on the first path, wherein
the processor of the first control apparatus performs a first control process that calculates a first control command value and the electrical load is controlled using the first control command value calculated by the first control process;
the processor of the second control apparatus performs, in parallel to the first control process, the second control process that calculates a second control command value; and
the electrical load is controlled using the second control command value calculated by the second control apparatus when a fault occurs in the first control apparatus.
5 . The control system according to claim 4 , wherein
at least either a calculation process or a calculation period differs between the first control process performed by the processor of the first control apparatus and the second control process performed by the processor of the second control apparatus; and
a processing load of the second control process is smaller than a processing load of the first control process.
6 . The control system according to claim 4 , wherein
a plurality of first path side loads connected to the first path as the electrical load are provided;
the first path includes branch paths, each connected to one of the first path side loads, and a fuse is provided on each branch path; and
the processor of the second control apparatus determines whether a voltage-recovery occurs from a voltage drop in the first path and, when it is determined that the voltage-recovery occurs, causes a closed state of the inter-path switch to resume.