Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A relay drive circuit includes a power supply circuit for producing a constant voltage, an initial energization circuit for performing an initial energization such that a power supply provides an initial energizing voltage to a relay, a low-holding energization circuit for performing a low-holding energization such that the constant voltage provides a constant current to the relay after the initial energizattion. Due to the low-holding energization, the relay contact can be firmly held even when relay coil resistance changes. The constant voltage for performing the low-holding energization is lower than the power supply voltage so that power consumption and heat generation can be reduced.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: In a load drive circuit, a charge pump circuit inputs 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 is lower than a reference 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.