Abstract: A microcomputer of an ECU which is a master determines whether to turn on or off the power supply of a slave ECU, and outputs a power supply control signal indicating power-on/off via serial communication on the basis of the result of determination. A signal superposition circuit accepts the output power supply control signal and transmits the accepted power supply control signal to a CAN bus to which a CAN transceiver is connected. In the slave ECU, a signal separation circuit individually receives a CAN communication signal and a serial communication signal transmitted to the CAN bus, while an input/output control circuit to which the serial communication signal is input as the power supply control signal outputs a signal to the power supply circuit to control power-on/off of the microcomputer.

Abstract: A microcomputer of an ECU which is a master determines whether to turn on or off the power supply of a slave ECU, and outputs a power supply control signal indicating power-on/off via serial communication on the basis of the result of determination. A signal superposition circuit accepts the output power supply control signal and transmits the accepted power supply control signal to a CAN bus to which a CAN transceiver is connected. In the slave ECU, a signal separation circuit individually receives a CAN communication signal and a serial communication signal transmitted to the CAN bus, while an input/output control circuit to which the serial communication signal is input as the power supply control signal outputs a signal to the power supply circuit to control power-on/off of the microcomputer.

Abstract: It is an object of the invention to provide a vehicle-mounted load drive control system that allows synchronous drive of electrical loads located at dispersed sites while achieving great efficiency in mounting in a limited space. Bus connections between an electronic control unit (13A) connected to a load drive switch (12A) and electronic control units (13B to 13D) are established via a multiplex communication line (14) to which CAN is applicable. The electronic control unit (13A) stores a drive command signal from the load drive switch (12A) in a storage (13Aa), and generates and transmits a data frame to the electronic control units (13B to 13D). The electronic control units (13B to 13D) drive electrical loads (15) upon receipt of a transmission signal, and the electronic control unit (13A) drives electrical loads (15) at the completion of transmission of the transmission signal. At the detection of a communication error, the prescribed contents of fail-safe processing is carried out.