Toyota Jidosha Kabushiki Kaisha

Denso Corporation

Masayuki Tsuda

Akito Itou

Naoki Maeda

Atsuko Yokoyama

A controller includes a microcomputer that operates in a normal mode or in a low power mode and communicates with an external device, a monitor circuit that monitors an operation state of the microcomputer based on a monitor signal output from the microcomputer, and a start circuit that controls a drive of the monitor circuit. Communication signals exchanged between the microcomputer and the external device include a dominant state and a recessive state, and the start circuit monitors the communication signals. When the communication signals in the low power mode of the microcomputer include the dominant state, the start circuit puts the monitor circuit in a monitoring state. When no monitor signal is input from the microcomputer to the monitor circuit that is operating in the monitoring state, the monitor circuit determines that an abnormality has occurred in the microcomputer.

Controller for reducing power

An electronic control unit includes a microcomputer and a power circuit that supplies an electric power to the microcomputer. The microcomputer and the power circuit respectively operate in a normal operation mode and in a low power operation mode that consumes less power than the normal operation mode. The electronic control unit further includes a mode switcher for switching the operation modes of the microcomputer and the power circuit according to an input signal from an external device. When a mode switch signal for switching the operation mode of both devices to the normal operation mode, the mode switcher first switches the power circuit to the normal operation mode and subsequently switches the microcomputer to the normal operation mode, which prevents a reset operation of the microcomputer without using a large capacity capacitor.

Electronic control unit

An electronic control unit includes a microcomputer, a monitoring unit, a clock-generating oscillator circuit, a first power circuit supplying power to the microcomputer, and a second power circuit supplying power to the monitor microcomputer. The first power circuit includes a first switching power source including a first transistor and a first series power source including a second transistor. The second power circuit includes a second switching power source including a third transistor and a second series power source including a fourth transistor. Further, the ECU includes a power control circuit controlling each of the transistors and an oscillation stop detection circuit. When a stop of oscillation is detected, the power control circuit switches ON the second transistor, and switches OFF the fourth transistor, thereby diminishing a no-monitoring period of the microcontroller during a stop of the clock output.

Growing community of inventors

Nagakute, Japan

Masayuki Tsuda