Mitsubishi Electric Corporation

Mitsubishi Denki Kabushiki Kaisha

Masao Motonobu

Shuichi Matsumoto

Osamu Nishizawa

Shuuiti Matsumoto

Tetsushi Watanabe

Hiroaki Tanihara

Masahiko Sayama

In order to avoid the continuation of the abnormality control state by detecting the disconnection abnormality of the ground wiring line of a power supply control device provided between a DC power supply and a plurality of inductive loads, the power supply control device to which electric power is supplied through a power supply terminal includes a microprocessor that performs switching control of power switching elements, a constant voltage power supply, and commutation diodes connected in parallel to inductive loads, a power capacitor connected between the power supply terminal and a ground terminal is charged by the commutation current of the intermittently driven inductive loads when the ground terminal is disconnected and accordingly the voltage of the power capacitor rises, and the disconnection abnormality of the ground wiring line is detected when the voltage exceeds a predetermined threshold value and the power switching elements are simultaneously cut off.

Power supply control device for inductive loads

Initial calibration is performed only under normal-temperature environment, and accurate current control is performed under practical use temperature environment. A temperature sensoris arranged close to a current detection resistorhaving predetermined temperature characteristics. Resistance values are estimated in a calibration environment and a practical use environment, an actually measured load current in the calibration environment corresponding to a target load current is stored as control characteristic data, a corrected target current corresponding to the target load current is calculated, and a converted target current based on a change ratio of current detection resistance is controlled as a target current for current control. A resistance change amount by heat generation of the current detection resistorwhich cannot be entirely detected by the temperature sensoris corrected in control characteristic data, such that linearity of control characteristics is improved.

Current control device for electric load

An electrical load is supplied with power from a driving power source, and a microprocessor (CPU) controls the opening/closing current supply rate (duty factor) of an opening/closing element in accordance with target current and driving power source voltage so that open loop control is carried out to achieve predetermined target current. The voltage between both the ends of a current detecting resistor connected to the ground side of the opening/closing element is input as a monitoring voltage from a current detecting amplifying circuit portion through a multichannel AD converter to CPU. When the error between the comparison target voltage corresponding to the target current and the monitoring voltage is above a first permissible error, CPU judges that there is an abnormality sign, and if the error is above a larger second permissible error, CPU judges that there is appearing abnormality. Accordingly, an abnormality sign of a semi-wire-breaking/semi-short-circuit state of the electrical load can be sensed, and abnormality notification can be carried out.

Non-feedback type load current controller

A power supply control device for on-vehicle electric loads is proposed, the control device being capable of detecting breakages at a plurality of electrical loads, a positive side wiring thereof, a negative side wiring thereof, and a commutation circuit. Energization of electrical loads from driving power supply is controlled using switching elements. Anode terminals of commutation diodes connected in parallel with the electrical loads are connected to a load ground by an external common negative line or external individual negative lines. A breakage abnormality at the external common negative line or external individual negative lines is detected by negative line breakage abnormality detection circuit. Load currents at the electrical loads are detected by current detection resistors and current detecting differential amplifier circuits, and it is determined that there is an individual abnormality when a detected current is greatly different from a target current.

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Tokyo, Japan

Masao Motonobu