Anden Co., Ltd.

Denso Corporation

Other

Toyota Jidosha Kabushiki Kaisha

Nippondenso Co., Ltd.

Fukuo Ishikawa

Akira Sugiura

Hiroyuki Ban

Nobutomo Takagi

Kazunori Ozawa

Takeyoshi Hisada

Shinji Oshita

Shigekazu Sugimoto

Kenichi Takayoshi

Hideki Kabune

Junji Hayakawa

Takeshi Ishikawa

Hiroshi Hattori

Yoshichika Abe

Ippei Kawamoto

Katsumi Nakamura

Hirofumi Mokuya

Hideyuki Ohtani

Takeshi Hattori

Toshio Ishida

Yoshimitsu Ukai

Masahisa Makino

Naoya Tuchiya

Shuuichi Konishi

Hideyuki Ikemoto

A load drive apparatus includes: a first drive element that drives a first load; a second drive element that drives a second load; a control circuit that controls the first drive element and the second drive element; a power supply circuit that supplies electric power; and a failsafe circuit that includes an abnormality detection portion detecting whether an abnormality occurs in at least one of the control circuit and the power supply circuit, the failsafe circuit controlling the first drive element and the second drive element to drive the first load and the second load when the abnormality detection portion has detected that an abnormality occurs in at least one of the control circuit and the power supply circuit and also when the load drive apparatus receives at least one of a command directing a drive of the first load and a command directing a drive of the second load.

Load drive apparatus

An overcurrent protection circuit includes a load drive portion that drives a load based on a power supply voltage; a wire that connects the load and the load drive portion; a current detection portion that detects a load current showing a value of a current flowing through the load; a voltage detection portion; and a controller that controls the load drive portion to control a drive of the load, the controller determining an addition-and-subtraction value, controlling the load drive portion to cut off the load current, and stopping driving the load to protect a protection target from an overcurrent. The controller subtracts the integration value based on an elapsed time after cutoff of the load current. The controller controls the load drive portion to again start to drive the load, and also calculates a post-correction integration value lower than a pre-correction integration value by correcting the pre-correction integration value.

Overcurrent protection circuit

An overcurrent protection circuit includes a load drive section driving a load, a wire coupled with the load and the load drive section, a current detection section detecting a load current value of an electric current that flows to the load, an addition and subtraction section determining an addition and subtraction value based on the load current value and transmitting an integration result of addition and subtraction, a comparison circuit comparing the integration result with a threshold value, and a control circuit controlling the load drive section based on the comparison result. The addition and subtraction section includes an addition value determination circuit that determines an addition value in the addition and subtraction value based on the load current value and a function expression or information indicating a relationship between the load current value and the addition value.

An electric current detection circuit for detecting an electric current flowing to a load includes a voltage generation circuit, a plurality of comparators, and a reference voltage shift circuit. The voltage generation circuit includes a plurality of resistors coupled in series and generates different voltages by dividing a reference voltage with the resistors. The comparators determine a current level of the electric current flowing to the load using the voltages generated by the voltage generation circuit as threshold values. The reference voltage shift circuit shifts the reference voltage. The electric current flowing to the load is detected based on the current level determined by the plurality of comparators before shifting the reference voltage and the current level determined by the plurality of comparators after shifting the reference voltage.

Electric current detection circuit

An overcurrent protection circuit includes a load driver for driving a load, a controller for turning ON and OFF the load driver, a current sensor for measuring a load current flowing through the load, and an add/subtract circuit for performing both an addition operation and a subtraction operation on a previous calculation result or for performing only the subtraction operation on the previous calculation result so as to produce a present calculation result. The addition operation uses an added value depending on the presently measured current. The subtraction operation uses a subtracted value depending on the presently measured current. The controller turns OFF the load driver, when the present calculation result of the add/subtract circuit exceeds a predetermined determination value.

A load driving semiconductor apparatus includes: a driving transistor, which operates based on an input voltage from an external circuit; a power semiconductor device controlling power supply to a load in such a manner that the power semiconductor device supplies electric power to the load when the transistor operates, and the power semiconductor device stops supplying electric power to the load when the transistor stops operating; and a mounting board, on which the driving transistor and the power semiconductor device are mounted. The mounting board includes a heat radiation pattern for emitting heat generated in the power semiconductor device. The heat radiation pattern includes a heat receiving pattern, on which the driving transistor is mounted.

Load driving semiconductor apparatus

In a temperature protection device for power devices of the present invention, detected temperatures of power devices are compared with respective threshold values by determination units. If either one of the determination units determines that there is abnormal heat build-up of the respective power devices, the output of that determination units is maintained by a latch circuit, and the current carried by the power device subject to abnormal heat build-up is interrupted. In addition, due to the output of the determination units making the determination, the threshold value of the other determination units is changed to a temperature threshold value that is higher than that set previously, so that it is not determined that the normally operating power device is subject to abnormal heat build-up. This changing of the threshold value is only executed for a fixed time period based upon a timer circuit.

Temperature protection device for power devices

An electrical resource device of the present invention includes a current restriction portion for restricting current flowing in a semiconductor element based on a predetermined overcurrent restriction threshold by controlling the semiconductor element when the current detected by a current detecting portion exceeds the predetermined overcurrent restriction threshold. The predetermined overcurrent restriction threshold is defined based on a relationship between time and a change of a destruction current amount by which wiring may be destroyed, and is determined to be under the destruction current. Therefore, it is possible to prevent the wiring from being destroyed.

Electrical resource device and load driving device

A charge pump circuit receives a battery voltage of a power line, and outputs a raising voltage proportional to the battery voltage. A low voltage detecting circuit detects a low voltage state in which a detecting voltage obtained by dividing the raising voltage. Thus, it is possible to indirectly detect a low voltage state in which the battery voltage is lower than a predetermined threshold value. When the low voltage state is detected, a drive circuit turns off a MOSFET. At this time, the battery voltage is temporarily varied, but the charge pump circuit has a filter action and a delay action, whereby temporary variation does not easily appear in the raising voltage (detecting voltage), and an error in operation of the MOSFET can be prevented.

Load drive circuit having low voltage detector

Circuit elements of surface-mounting type such as MOSFETs etc. are mounted on a circuit board by soldering. The circuit board is retained slantingly by a base so that any one of the MOSFET falls out by its self-weight when the solder melts due to an abnormal heat generation of the MOSFET. The falling of the MOSFET is stopped by a stopper member, and then the MOSFET becomes in an electrically open state and retained at the stopped position in consequence of the subsequent cooling of the solder. Accordingly, even if one or more of the MOSFETs cause the abnormal heat generation, the continuous heat generation of the MOSFET is stopped and also the other circuit elements are prevented from being short-circuited.

Electric circuit apparatus

A pad for input/output signals is formed on a first conductive type insulated island region interposing an insulating film therebetween. The insulated island region is electrically insulated and isolated from other semiconductor regions in a semiconductor substrate. A fixed potential is provided to the insulated island region through an n.sup.+ -type layer and an electrode. As a result, it is possible to prevent noise superimposed on the input/output signals from interfering in the operation of the other semiconductor regions, and to prevent noise produced in the other semiconductor regions from being superimposed on the input/output signals.

Semiconductor device

An over-voltage protection apparatus includes a power feed line. A load has a given low impedance. A current supplying device operates for supplying a current to the load via the power feed line. A load drive device operates for controlling the supply of the current to the load by the current supplying device. An over-voltage detecting device operates for detecting an over-voltage at the power feed line. A discharge command device operates for, when the over-voltage at the power feed line is detected by the over-voltage detecting device, controlling the load drive device to enable a discharge current to flow from the power feed line into the load and thereby to remove the over-voltage from the power feed line through discharge. A current detecting device operates for detecting the discharge current. A discharge continuing device operates for continuing the discharge and the flow of the discharge current from the power feed line in cases where the discharge current detected by the current detecting device exceeds a predetermined reference level.

Over-voltage protection apparatus and vehicular direction indicating

A driving circuit for the electromagnetic relay provides a coil of the electromagnetic relay with stepped voltage having a first voltage which is slightly larger than a minimum operating voltage which caused the coil to generate magnetic field capable of closing contacts of the electromagnetic relay and a second voltage higher than the first voltage, in response to a triggering signal to trigger the electromagnetic relay. According to this structure, because the first voltage lower than the second voltage is applied to the coil firstly, the contacts are closed by attracting force of the coil risen gently. As a result, the bouncing of the moving contact can be prevented. In addition, the response time required for the closing of the contacts can be prevented to become long.

Driving circuit for electromagnetic relay

In a load actuation circuit of an emitter-follower circuit arrangement, a surge detection circuit detects a power surge voltage superposed on a power voltage of a power line. A feed circuit supplies current to a control electrode of an output transistor (i.e. emitter-follower transistor) from the power line to turn on the output transistor forcibly when any power surge voltage is detected by the surge detection circuit. Thus, the power surge voltage is absorbed by the output transistor.

Load actuation circuit with a surge protecting function

A load drive apparatus is used in a vehicle direction indicating apparatus operable free from overcurrents and overvoltage. The load drive apparatus includes: a charging/recharging capacitor; a charging/recharging circuit for charging/recharging the capacitor at a preselected time constant in such a manner that a voltage across the capacitor is varied between a preset upper limit voltage and a preset lower limit voltage; a drive circuit for turning ON a power transistor series-connected to a current path employed to supply a current from a DC power source to a load, thereby driving the load when the charging/discharging circuit causes the capacitor to be charged, or the voltage across the capacitor is higher than, or equal to a predetermined voltage defined between the upper limit voltage and the lower limit voltage; overcurrent judging means for judging whether or not a voltage across terminals of the power transistor connected to the above-described current path exceed an overcurrent judging voltage.

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Kariya, Japan

Fukuo Ishikawa