Abstract: A driving circuit for a brushless motor includes a current sensor for detecting alternating phase-current flowing in one of the phase coils, a switching driver for supplying each phase-coil with prescribed alternating phase-current, a reference value setting circuit which provides a reference value which changes in synchronism with the prescribed phase-current to be larger than the same and an abnormality determining circuit which determines abnormality if the current detected by the current sensor is larger than the reference value.

Abstract: A driving circuit for a brushless motor includes a current sensor for detecting alternating phase-current flowing in one of the phase coils, a switching driver for supplying each phase-coil with prescribed alternating phase-current, a reference value setting circuit which provides a reference value which changes in synchronism with the prescribed phase-current to be larger than the same and an abnormality determining circuit which determines abnormality if the current detected by the current sensor is larger than the reference value.

Abstract: A control system for an electric power steering apparatus detects calculation anomalies in a CPU regardless of the magnitude of a modified control quantity. The CPU has a basic control quantity calculating means for calculating a basic control quantity to drive a motor based on an output from a torque sensor, and a modified control quantity calculating means for calculating a modified control quantity corresponding to the steering conditions (for example, steering speed) of the steering wheel. The CPU-calculation monitoring unit has a first anomaly deciding means for deciding whether the calculation result of the basic control quantity calculating means is normal or anomalous in light of the output from the torque sensor, and a second anomaly deciding means for deciding whether the calculation result of the modified control quantity calculating means is normal or anomalous in light of the steering conditions. The motor is deactivated if anomalies are detected.

Abstract: A monitoring system monitors a microcomputer in which an angle calculator calculates the electrical angle of a motor using output signals from a rotation angle sensor. In the microcomputer, a control signal generator generates a coded control signal that indicates the range to which the calculated electrical angle belongs. In the monitoring system, the electrical angle detected by the rotation angle sensor is multiplied by an excitation signal provided for the rotation angle sensor, and an angle detector detects the resultant signals. Based on the detected signals, a supervisory signal generator outputs a coded supervisory signal that indicates the range to which the electrical angle detected by the rotation angle sensor belongs. Then a fault detector determines that a failure occurs in the microcomputer, if a comparator determines that the coded control signal disagrees with the coded supervisory signal.

Abstract: A control system for an electric power steering apparatus detects calculation anomalies in a CPU regardless of the magnitude of a modified control quantity. The CPU has a basic control quantity calculating means for calculating a basic control quantity to drive a motor based on an output from a torque sensor, and a modified control quantity calculating means for calculating a modified control quantity corresponding to the steering conditions (for example, steering speed) of the steering wheel. The CPU-calculation monitoring unit has a first anomaly deciding means for deciding whether the calculation result of the basic control quantity calculating means is normal or anomalous in light of the output from the torque sensor, and a second anomaly deciding means for deciding whether the calculation result of the modified control quantity calculating means is normal or anomalous in light of the steering conditions. The motor is deactivated if anomalies are detected.

Abstract: An abnormality detection circuit for detecting abnormality of a CPU includes a command value check circuit for checking whether a current command value calculated by the CPU is normal or abnormal with respect to a torque signal, and a drive signal check circuit for checking whether a motor drive signal outputted based on the current command value is normal or abnormal. When the command value abnormality of the CPU is detected by the abnormality detection circuit, a counter circuit is started to count a time of an abnormality state of the CPU. If the counted time reaches a predetermined time, a control stop command is outputted from a system stop circuit to the CPU, thereby stopping the system control of the CPU.

Abstract: A monitoring system monitors a microcomputer in which an angle calculator calculates the electrical angle of a motor using output signals from a rotation angle sensor. In the microcomputer, a control signal generator generates a coded control signal that indicates the range to which the calculated electrical angle belongs. In the monitoring system, the electrical angle detected by the rotation angle sensor is multiplied by an excitation signal provided for the rotation angle sensor, and an angle detector detects the resultant signals. Based on the detected signals, a supervisory signal generator outputs a coded supervisory signal that indicates the range to which the electrical angle detected by the rotation angle sensor belongs. Then a fault detector determines that a failure occurs in the microcomputer, if a comparator determines that the coded control signal disagrees with the coded supervisory signal.

Abstract: An abnormality detection circuit for detecting abnormality of a CPU includes a command value check circuit for checking whether a current command value calculated by the CPU is normal or abnormal with respect to a torque signal, and a drive signal check circuit for checking whether a motor drive signal outputted based on the current command value is normal or abnormal. When the command value abnormality of the CPU is detected by the abnormality detection circuit, a counter circuit is started to count a time of an abnormality state of the CPU. If the counted time reaches a predetermined time, a control stop command is outputted from a system stop circuit to the CPU, thereby stopping the system control of the CPU.

Abstract: A CPU operates as an abnormality detection circuit for detecting an ON-state failure of FETs forming a motor drive circuit and a failure of terminals of the motor. The abnormality detection circuit inputs a motor supply voltage, a motor left-terminal voltage and a motor right-terminal voltage from a power supply voltage detection circuit, a motor left-terminal voltage detection circuit and amotor right-terminal voltage detection circuit, respectively.